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? 2007 microchip technology inc. preliminary ds39775b pic18f87j50 family data sheet 64/80-pin high-performance, 1-mbit flash us b microcontrollers with nanowatt technology
ds39775b-page ii preliminary ? 2007 microchip technology inc. information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. it is your responsibility to ensure that your application meets with your specifications. microchip makes no representations or warranties of any kind whether express or implied, written or oral, statutory or otherwise, related to the information, including but not limited to its condition, quality, performance, merchantability or fitness for purpose . microchip disclaims all liability arising from this information and its use. use of microchip devices in life support and/or safety applications is entirely at the buyer?s risk, and the buyer agrees to defend, indemnify and hold harmless microchip from any and all damages, claims, suits, or expenses resulting from such use. no licenses are conveyed, implicitly or otherwise, under any microchip intellectual property rights. trademarks the microchip name and logo, the microchip logo, accuron, dspic, k ee l oq , k ee l oq logo, micro id , mplab, pic, picmicro, picstart, pro mate, rfpic and smartshunt are registered trademarks of micr ochip technology incorporated in the u.s.a. and other countries. amplab, filterlab, linear active thermistor, migratable memory, mxdev, mxlab, seeval, smartsensor and the embedded control solutions company are registered trademarks of microchip tec hnology incorporated in the u.s.a. analog-for-the-digital age, appl ication maestro, codeguard, dspicdem, dspicdem.net, dspicworks, ecan, economonitor, fansense, flexrom, fuzzylab, in-circuit serial programming, icsp, icepic, mindi, miwi, mpasm, mplab certified logo, mplib, mplink, pickit, picdem, picdem.net, piclab, pictail, powercal, powerinfo, powermate, powertool, real ice, rflab, select mode, smart serial, smarttel, total endurance, uni/o, wiperlock and zena are tr ademarks of microchip technology incorporated in the u.s.a. and other countries. sqtp is a service mark of microchip technology incorporated in the u.s.a. all other trademarks mentioned herein are property of their respective companies. ? 2007, microchip technology incorporated, printed in the u.s.a., all rights reserved. printed on recycled paper. note the following details of the code protection feature on microchip devices: ? microchip products meet the specification cont ained in their particular microchip data sheet. ? microchip believes that its family of products is one of the mo st secure families of its kind on the market today, when used i n the intended manner and under normal conditions. ? there are dishonest and possibly illegal methods used to breach the code protection feature. all of these methods, to our knowledge, require using the microchip produc ts in a manner outside the operating specifications contained in microchip?s data sheets. most likely, the person doing so is engaged in theft of intellectual property. ? microchip is willing to work with the customer who is concerned about the integrity of their code. ? neither microchip nor any other semiconductor manufacturer c an guarantee the security of their code. code protection does not mean that we are guaranteeing the product as ?unbreakable.? code protection is constantly evolving. we at microchip are co mmitted to continuously improvi ng the code protection features of our products. attempts to break microchip?s c ode protection feature may be a violation of the digital millennium copyright act. if such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that act. microchip received iso/ts-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona; gresham, oregon and design centers in california and india. the company?s quality system processes and procedures are for its pic ? mcus and dspic ? dscs, k ee l oq ? code hopping devices, serial eeproms, microperipherals, nonvolatile memory and analog products. in addition, microchip?s quality system for the design and manufacture of development systems is iso 9001:2000 certified.
? 2007 microchip technology inc. preliminary ds39775b-page 1 pic18f87j50 family universal serial bus features: ? usb v2.0 compliant sie ? low speed (1.5 mb/s) and full speed (12 mb/s) ? supports control, interrupt, isochronous and bulk transfers ? supports up to 32 endpoints (16 bidirectional) ? 3.9-kbyte dual access ram for usb ? on-chip usb transceiver flexible oscillator structure: ? high-precision pll for usb ? two external clock modes, up to 48 mhz ? internal 31 khz oscillator, tunable internal oscillator, 31 khz to 8 mhz ? secondary oscillator using timer1 @ 32 khz ? fail-safe clock monitor: - allows for safe shutdown if any clock stops peripheral highlights: ? high-current sink/source 25 ma/25ma (portb and portc) ? four programmable external interrupts ? four input change interrupts ? two capture/compare/pwm (ccp) modules ? three enhanced capture/compare/pwm (eccp) modules: - one, two or four pwm outputs - selectable polarity - programmable dead time - auto-shutdown and auto-restart ? two master synchronous serial port (mssp) modules supporting 3-wire spi (all 4 modes) and i 2 c? master and slave modes ? 8-bit parallel master port/enhanced parallel slave port with 16 address lines ? dual analog comparators with input multiplexing peripheral highlights (continued): ? 10-bit, up to 12-channel analog-to-digital (a/d) converter module: - auto-acquisition capability - conversion available during sleep ? two enhanced usart modules: - supports rs-485, rs-232 and lin 1.2 - auto-wake-up on start bit - auto-baud detect external memory bus (80-pin devices only): ? address capability of up to 2 mbytes ? 8-bit or 16-bit interface ? 12-bit, 16-bit and 20-bit addressing modes special microcontroller features: ? 5.5v tolerant inputs (digital-only pins) ? low-power, high-speed cmos flash technology ? c compiler optimized architecture for re-entrant code ? power management features: - run: cpu on, peripherals on - idle: cpu off, peripherals on - sleep: cpu off, peripherals off ? priority levels for interrupts ? self-programmable under software control ? 8 x 8 single-cycle hardware multiplier ? extended watchdog timer (wdt): - programmable period from 4 ms to 131s ? single-supply in-circuit serial programming? (icsp?) via two pins ? in-circuit debug (icd) with 3 breakpoints via two pins ? operating voltage range of 2.0v to 3.6v ? on-chip 2.5v regulator ? flash program memory of 10000 erase/write cycles and 20-year data retention 64/80-pin high-performan ce, 1-mbit flash usb microcontrollers with nanowatt technology
pic18f87j50 family ds39775b-page 2 preliminary ? 2007 microchip technology inc. pin diagrams device flash program memory (bytes) sram data memory (bytes) i/o 10-bit a/d (ch) ccp/ eccp (pwm) mssp eusart comparators timers 8/16-bit external bus pmp/psp spi master i 2 c? pic18f65j50 32k 3904* 49 8 2/3 2 y y 2 2 2/3 n y pic18f66j50 64k 3904* 49 8 2/3 2 y y 2 2 2/3 n y pic18f66j55 96k 3904* 49 8 2/3 2 y y 2 2 2/3 n y pic18f67j50 128k 3904* 49 8 2/3 2 y y 2 2 2/3 n y pic18f85j50 32k 3904* 65 12 2/3 2 y y 2 2 2/3 y y PIC18F86J50 64k 3904* 65 12 2/3 2 y y 2 2 2/3 y y pic18f86j55 96k 3904* 65 12 2/3 2 y y 2 2 2/3 y y pic18f87j50 128k 3904* 65 12 2/3 2 y y 2 2 2/3 y y * includes the dual access ram used by the usb module which is shared with data memory. 64-pin tqfp pic18f6xj5x 1 2 3 4 5 6 7 8 9 10 11 12 13 14 38 37 36 35 34 33 50 49 17 18 19 20 21 22 23 24 25 26 re2/pmbe/p2b re3/pma13/p3c/refo re4/pma12/p3b re5/pma11/p1c re6/pma10/p1b re7/pma9/eccp2 (1) /p2a (1) rd0/pmd0 v dd v ss rd1/pmd1 rd2/pmd2 rd3/pmd3 rd4/pmd4/sdo2 rd5/pmd5/sdi2/sda2 rd6/pmd6/sck2/scl2 rd7/pmd7/ss2 re1/pmwr/p2c re0/pmrd/p2d rg0/pma8/eccp3/p3a rg1/pma7/tx2/ck2 rg2/pma6/rx2/dt2 rg3/pmcs1/ccp4/p3d mclr rg4/pmcs2/ccp5/p1d v ss v ddcore /v cap rf7/ss1 /c1out rf6/an11/c1ina rf5/an10/c1inb/cv ref rf4/d+ rf3/d- rf2/pma5/an7/c2inb rb0/flt0/int0 rb1/int1/pma4 rb2/int2/pma3 rb3/int3/pma2 rb4/kbi0/pma1 rb5/kbi1/pma0 rb6/kbi2/pgc v ss osc2/clko/ra6 osc1/clki/ra7 v dd rb7/kbi3/pgd rc4/sdi1/sda1 rc3/sck1/scl1 rc2/eccp1/p1a envreg v usb av dd av ss ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 v ss v dd ra4/t0cki ra5/an4/c2ina rc1/t1osi/eccp2 (1) /p2a (1) rc0/t1oso/t13cki rc7/rx1/dt1 rc6/tx1/ck1 rc5/sdo1/c2out 15 16 31 40 39 27 28 29 30 32 48 47 46 45 44 43 42 41 54 53 52 51 58 57 56 55 60 59 64 63 62 61 note 1: the eccp2/p2a pin placement depends on the setting of the ccp2mx configuration bit.
? 2007 microchip technology inc. preliminary ds39775b-page 3 pic18f87j50 family pin diagrams (continued) 80-pin tqfp pic18f8xj5x 3 4 5 6 7 8 9 10 11 12 13 14 15 16 48 47 46 45 44 43 42 41 40 39 64 63 62 61 21 22 23 24 25 26 27 28 29 30 31 32 re2/ad10/pmbe (3) /p2b re3/ad11/pma13/p3c (2) /refo re4/ad12/pma12/p3b (2) re5/ad13/pma11/p1c (2) re6/ad14/pma10/p1b (2) re7/ad15/pma9/eccp2 (1) /p2a (1) rd0/ad0/pmd0 v dd v ss rd1/ad1/pmd1 (3) rd2/ad2/pmd2 (3) rd3/ad3/pmd3 (3) rd4/ad4/pmd4 (3) /sdo2 rd5/ad5/pmd5 (3) /sdi2/sda2 rd6/ad6/pmd6 (3) /sck2/scl2 rd7/ad7/pmd7 (3) /ss2 re1/ad9/pmwr (3) /p2c re0/ad8/pmrd (3) /p2d rg0/pma8/eccp3/p3a rg1/pma7/tx2/ck2 rg2/pma6/rx2/dt2 rg3/pmcs1/ccp4/p3d mclr rg4/pmcs2/ccp5/p1d v ss v ddcore /v cap rf7/pmd0 (4) /ss1 /c1out rb0/flt0/int0 rb1/int1/pma4 rb2/int2/pma3 rb3/int3/eccp2 (1) / rb4/kbi0/pma1 rb5/kbi1/pma0 rb6/kbi2/pgc v ss osc2/clko/ra6 osc1/clki/ra7 v dd rb7/kbi3/pgd rc4/sdi1/sda1 rc3/sck1/scl1 rc2/eccp1/p1a envreg v usb av dd av ss ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 v ss v dd ra4/pmd5 (4) /t0cki ra5/pmd4 (4) /an4/c2ina rc1/t1osi/eccp2 (1) /p2a (1) rc0/t1oso/t13cki rc7/rx1/dt1 rc6/tx1/ck1 rc5/sdo1/c2out rj0/ale rj1/oe rh1/a17 rh0/a16 1 2 rh2/a18/pmd7 (4) rh3/a19/pmd6 (4) 17 18 rh7/pmwr (4) /an15/p1b (2) rh6/pmrd (4) /an14/ rh5/pmbe (4) /an13/p3b (2) /c2ind rh4/pmd3 (4) /an12/p3c (2) /c2inc rj5/ce rj4/ba0 37 rj7/ub rj6/lb 50 49 rj2/wrl rj3/wrh 19 20 33 34 35 36 38 58 57 56 55 54 53 52 51 60 59 68 67 66 65 72 71 70 69 74 73 78 77 76 75 79 80 note 1: the eccp2/p2a pin placement depends on the setting of the ccp2mx configuration bit and the program memory mode. 2: p1b, p1c, p3b and p3c pin placement depends on the setting of the eccpmx configuration bit. 3: pmp pin placement when pmpmx = 1 . 4: pmp pin placement when pmpmx = 0 . rf5/pmd2 (4) /an10/ rf4/d+ rf3/d- rf2/pma5/an7/c2inb rf6/pmd1 (4) /an11/c1ina c1inb/cv ref p1c (2) /c1inc p2a (1) /pma2
pic18f87j50 family ds39775b-page 4 preliminary ? 2007 microchip technology inc. table of contents 1.0 device overview ............................................................................................................. ............................................................. 7 2.0 oscillator configurations .................................... ............................................................... ......................................................... 33 3.0 power-managed modes ......................................................................................................... .................................................... 45 4.0 reset ....................................................................................................................... ................................................................... 53 5.0 memory organization ......................................................................................................... ........................................................ 67 6.0 flash program memory........................................................................................................ ...................................................... 95 7.0 external memory bus ......................................................................................................... ...................................................... 105 8.0 8 x 8 hardware multiplier................................................................................................... ....................................................... 117 9.0 interrupts .................................................................................................................. ................................................................ 119 10.0 i/o ports .................................................................................................................. ................................................................. 135 11.0 parallel master port ....................................................................................................... ........................................................... 165 12.0 timer0 module .............................................................................................................. ........................................................... 189 13.0 timer1 module .............................................................................................................. ........................................................... 193 14.0 timer2 module .............................................................................................................. ........................................................... 199 15.0 timer3 module .............................................................................................................. ........................................................... 201 16.0 timer4 module .............................................................................................................. ........................................................... 205 17.0 capture/compare/pwm (ccp) modules .......................................................................................... ....................................... 207 18.0 enhanced capture/compare/pwm (eccp) module................................................................................. ............................... 215 19.0 master synchronous serial port (mssp) module ............................................................................... ..................................... 231 20.0 enhanced universal synchronous asynchronous receiver transmitter (eusart) .................................................. ............. 277 21.0 10-bit analog-to-digital converter (a/d) module ............................................................................ .......................................... 299 22.0 universal serial bus (usb) ................................................................................................. ..................................................... 309 23.0 comparator module.......................................................................................................... ........................................................ 335 24.0 comparator voltage reference module ........................................................................................ ........................................... 343 25.0 special features of the cpu ................................................................................................ .................................................... 347 26.0 instruction set summary .................................................................................................... ...................................................... 363 27.0 development support........................................................................................................ ....................................................... 413 28.0 electrical characteristics ................................................................................................. ......................................................... 417 29.0 packaging information...................................................................................................... ........................................................ 457 appendix a: revision history................................................................................................... .......................................................... 461 appendix b: device differences................................................................................................. ........................................................ 461 index .......................................................................................................................... ........................................................................ 463 the microchip web site ......................................................................................................... ............................................................ 475 customer change notification service ........................................................................................... ................................................... 475 customer support ............................................................................................................... ............................................................... 475 reader response ................................................................................................................ .............................................................. 476 product identification system.................................................................................................. ........................................................... 477
? 2007 microchip technology inc. preliminary ds39775b-page 5 pic18f87j50 family to our valued customers it is our intention to provide our valued customers with the best documentation possible to ensure successful use of your micro chip products. to this end, we will continue to improve our publications to better suit your needs. our publications will be refined and enhanced as new volumes and updates are introduced. if you have any questions or comments regar ding this publication, please contact the marketing communications department via e-mail at docerrors@microchip.com or fax the reader response form in the back of this data sheet to (480) 792-4150. we welcome your feedback. most current data sheet to obtain the most up-to-date version of this data s heet, please register at our worldwide web site at: http://www.microchip.com you can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page . the last character of the literature number is the vers ion number, (e.g., ds30000a is version a of document ds30000). errata an errata sheet, describing minor operational differences fr om the data sheet and recommended workarounds, may exist for curren t devices. as device/documentation issues become known to us, we will publish an errata sheet. the errata will specify the revisi on of silicon and revision of document to which it applies. to determine if an errata sheet exists for a particular device, please check with one of the following: ? microchip?s worldwide web site; http://www.microchip.com ? your local microchip sales office (see last page) when contacting a sales office, please specify which device, re vision of silicon and data sheet (include literature number) you are using. customer notification system register on our web site at www.microchip.com to receive the most current information on all of our products.
pic18f87j50 family ds39775b-page 6 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 7 pic18f87j50 family 1.0 device overview this document contains device-specific information for the following devices: this family introduces a new line of low-voltage usb microcontrollers with the main traditional advantage of all pic18 microcontrollers ? namely, high computa- tional performance and a rich feature set ? at an extremely competitive price point. these features make the pic18f87j50 family a logical choice for many high-performance applications, where cost is a primary consideration. 1.1 core features 1.1.1 nanowatt technology all of the devices in the pi c18f87j50 family incorporate a range of features that c an significantly reduce power consumption during operation. key items include: ? alternate run modes: by clocking the controller from the timer1 source or the internal rc oscilla- tor, power consumption during code execution can be reduced by as much as 90%. ? multiple idle modes: the controller can also run with its cpu core disabled but the peripherals still active. in these states, power consumption can be reduced even further, to as little as 4% of normal operation requirements. ? on-the-fly mode switching: the power-managed modes are invoked by user code during operation, allowing the user to incorporate power-saving ideas into their application?s software design. 1.1.2 universal serial bus (usb) devices in the pic18f87j50 family incorporate a fully-featured universal serial bus communications module with a built-in transceiver that is compliant with the usb specification revision 2.0. the module supports both low-speed and full-speed communication for all supported data transfer types. 1.1.3 oscillator options and features all of the devices in the pic18f87j50 family offer five different oscillator options, allowing users a range of choices in developing application hardware. these include: ? two crystal modes, using crystals or ceramic resonators. ? two external clock modes, offering the option of a divide-by-4 clock output. ? an internal oscillator block which provides an 8 mhz clock and an intrc source (approxi- mately 31 khz, stable over temperature and v dd ), as well as a range of 6 user-selectable clock frequencies, between 125 khz to 4 mhz, for a total of 8 clock frequencies. this option frees an oscillator pin for use as an additional general purpose i/o. ? a phase lock loop (pll) frequency multiplier, available to the high-speed crystal, external oscillator and internal oscillator, providing a clock speed up to 48 mhz. ? dual clock operation, allowing the usb module to run from a high-frequency oscillator while the rest of the microcontroller is clocked at a different frequency. the internal oscillator block provides a stable reference source that gives the family additional features for robust operation: ? fail-safe clock monitor: this option constantly monitors the main clock source against a reference signal provided by the internal oscillator. if a clock failure occurs, the controller is switched to the internal oscillator, allowing for continued low-speed operation or a safe application shutdown. ? two-speed start-up: this option allows the internal oscillator to serve as the clock source from power-on reset, or wake-up from sleep mode, until the primary clock source is available. 1.1.4 expanded memory the pic18f87j50 family provides ample room for application code, from 32 kbytes to 128 kbytes of code space. the flash cells for program memory are rated to last in excess of 10000 erase/write cycles. data retention without refresh is conservatively estimated to be greater than 20 years. the flash program memory is readable and writable during normal operation. the pic18f87j50 family also provides plenty of room for dynamic application data with up to 3904 bytes of data ram. ? pic18f65j50 ? pic18f85j50 ? pic18f66j50 ? PIC18F86J50 ? pic18f66j55 ? pic18f86j55 ? pic18f67j50 ? pic18f87j50
pic18f87j50 family ds39775b-page 8 preliminary ? 2007 microchip technology inc. 1.1.5 external memory bus in the event that 128 kbytes of memory are inadequate for an application, the 80-pin members of the pic18f87j50 family also implement an external mem- ory bus (emb). this allows the controller?s internal program counter to address a memory space of up to 2 mbytes, permitting a level of data access that few 8-bit devices can claim. this allows additional memory options, including: ? using combinations of on-chip and external memory up to the 2-mbyte limit ? using external flash memory for reprogrammable application code or large data tables ? using external ram devices for storing large amounts of variable data 1.1.6 extended instruction set the pic18f87j50 family implements the optional extension to the pic18 instruction set, adding 8 new instructions and an indexed addressing mode. enabled as a device configuration option, the extension has been specifically designed to optimize re-entrant application code originally developed in high-level languages, such as ?c?. 1.1.7 easy migration regardless of the memory size, all devices share the same rich set of peripherals, allowing for a smooth migration path as applications grow and evolve. the consistent pinout scheme used throughout the entire family also aids in migrating to the next larger device. this is true when moving between the 64-pin members, between the 80-pin members, or even jumping from 64-pin to 80-pin devices. the pic18f87j50 family is also pin compatible with other pic18 families, such as the pic18f87j10, pic18f87j11, pic18f8720 and pic18f8722. this allows a new dimension to the evolution of applications, allowing developers to select different price points within microchip?s pic18 portfolio, while maintaining the same feature set. 1.2 other special features ? communications: the pic18f87j50 family incorporates a range of serial and parallel com- munication peripherals, including a fully featured universal serial bus communications module that is compliant with the usb specification revision 2.0. this device also includes 2 indepen- dent enhanced usarts and 2 master ssp modules, capable of both spi and i2c? (master and slave) modes of operation. the device also has a parallel port and can be configured to serve as either a parallel master port or as a parallel slave port. ? ccp modules: all devices in the family incorporate two capture/compare/pwm (ccp) modules and three enhanced ccp modules to maximize flexibility in control applications. up to four different time bases may be used to perform several different operations at once. each of the three eccps offers up to four pwm outputs, allowing for a total of 12 pwms. the eccps also offer many beneficial features, including polarity selection, programmable dead time, auto-shutdown and restart and half-bridge and full-bridge output modes. ? 10-bit a/d converter: this module incorporates programmable acquisition time, allowing for a channel to be selected and a conversion to be initiated without waiting for a sampling period, and thus, reducing code overhead. ? extended watchdog timer (wdt): this enhanced version incorporates a 16-bit prescaler, allowing an extended time-out range that is stable across operating voltage and temperature. see section 28.0 ?electrical characteristics? for time-out periods. 1.3 details on individual family members devices in the pic18f87j50 family are available in 64-pin and 80-pin packages. block diagrams for the two groups are shown in figure 1-1 and figure 1-2. the devices are differentiated from each other in two ways: 1. flash program memory (six sizes, ranging from 32 kbytes for pic18fx5j50 devices to 128 kbytes for pic18fx7j50). 2. i/o ports (7 bidirectional ports on 64-pin devices, 9 bidirectional ports on 80-pin devices). all other features for devices in this family are identical. these are summarized in table 1-1 and table 1-2. the pinouts for all devices are listed in table 1-3 and table 1-4.
? 2007 microchip technology inc. preliminary ds39775b-page 9 pic18f87j50 family table 1-1: device features for the pic18f6xj5x (64-pin devices) table 1-2: device features for the pic18f8xj5x (80-pin devices) features pic18f65j50 pic18f66j50 pic18f66j55 pic18f67j50 operating frequency dc ? 48 mhz dc ? 48 mhz dc ? 48 mhz dc ? 48 mhz program memory (bytes) 32k 64k 96k 128k program memory (instructions) 16384 32768 49152 65536 data memory (bytes) 3904 3904 3904 3904 interrupt sources 30 i/o ports ports a, b, c, d, e, f, g timers 5 capture/compare/pwm modules 2 enhanced capture/ compare/pwm modules 3 serial communications mssp (2), enhanced usart (2), usb parallel communications (pmp) yes 10-bit analog-to-digital module 8 input channels resets (and delays) por, bor, reset instruction, stack full, stack underflow, m clr , wdt (pwrt, ost) instruction set 75 instructions, 83 with extended instruction set enabled packages 64-pin tqfp features pic18f85j50 PIC18F86J50 pic18f86j55 pic18f87j50 operating frequency dc ? 48 mhz dc ? 48 mhz dc ? 48 mhz dc ? 48 mhz program memory (bytes) 32k 64k 96k 128k program memory (instructions) 16384 32768 49152 65536 data memory (bytes) 3904 3904 3904 3904 interrupt sources 30 i/o ports ports a, b, c, d, e, f, g, h, j timers 5 capture/compare/pwm modules 2 enhanced capture/ compare/pwm modules 3 serial communications mssp (2), enhanced usart (2), usb parallel communications (pmp) yes 10-bit analog-to-digital module 12 input channels resets (and delays) por, bor, reset instruction, stack full, stack underflow, mclr , wdt (pwrt, ost) instruction set 75 instructions, 83 with extended instruction set enabled packages 80-pin tqfp
pic18f87j50 family ds39775b-page 10 preliminary ? 2007 microchip technology inc. figure 1-1: pic18f6xj5x (6 4-pin) block diagram instruction decode and control porta data latch data memory (3.9 kbytes) address latch data address<12> 12 access bsr fsr0 fsr1 fsr2 inc/dec logic address 4 12 4 pch pcl pclath 8 31 level stack program counter prodl prodh 8 x 8 multiply 8 bitop 8 8 alu<8> address latch program memory (32-128 kbytes) data latch 20 8 8 table pointer<21> inc/dec logic 21 8 data bus<8> table latch 8 ir 12 3 pclatu pcu note 1: see table 1-3 for i/o port pin descriptions. 2: bor functionality is provided when the on-board voltage regulator is enabled. eusart1 comparators mssp1 timer2 timer1 timer3 timer0 eccp1 adc 10-bit w instruction bus <16> stkptr bank 8 state machine control signals decode 8 8 eusart2 eccp2 rom latch eccp3 mssp2 ccp4 ccp5 portc portd porte portf portg ra0:ra5 (1) rc0:rc7 (1) rd0:rd7 (1) re0:re7 (1) rf2:rf7 (1) rg0:rg4 (1) portb rb0:rb7 (1) timer4 osc1/clki osc2/clko v dd , 8 mhz intosc v ss mclr power-up timer oscillator start-up timer power-on reset watchdog timer brown-out reset (2) precision reference band gap intrc oscillator regulator voltage v ddcore /v cap envreg usb pmp timing generation usb module v usb
? 2007 microchip technology inc. preliminary ds39775b-page 11 pic18f87j50 family figure 1-2: pic18f8xj5x (80-pin) block diagram prodl prodh 8 x 8 multiply 8 bitop 8 8 alu<8> 8 8 3 w 8 8 8 instruction decode & control data latch address latch data address<12> 12 access bsr fsr0 fsr1 fsr2 inc/dec logic address 4 12 4 pch pcl pclath 8 31 level stack program counter address latch program memory (32-128 kbytes) data latch 20 table pointer<21> inc/dec logic 21 8 data bus<8> ta b l e la t c h 8 ir 12 rom latch pclatu pcu instruction bus <16> stkptr bank state machine control signals decode system bus interface ad15:ad0, a19:a16 (multiplexed with portd, porte and porth) porta portc portd porte portf portg ra0:ra5 (1) rc0:rc7 (1) rd0:rd7 (1) re0:re7 (1) rf2:rf7 (1) rg0:rg4 (1) portb rb0:rb7 (1) porth rh0:rh7 (1) portj rj0:rj7 (1) eusart1 comparators mssp1 timer2 timer1 timer3 timer0 eccp1 adc 10-bit eusart2 eccp2 eccp3 mssp2 ccp4 ccp5 timer4 note 1: see table 1-4 for i/o port pin descriptions. 2: bor functionality is provided when the on-board voltage regulator is enabled. data memory (3.9 kbytes) usb pmp osc1/clki osc2/clko v dd , 8 mhz intosc v ss mclr power-up timer oscillator start-up timer power-on reset watchdog timer brown-out reset (2) precision reference band gap intrc oscillator regulator voltage v ddcore /v cap envreg timing generation usb module v usb
pic18f87j50 family ds39775b-page 12 preliminary ? 2007 microchip technology inc. table 1-3: pic18f6xj5x pi nout i/o descriptions pin name pin number pin type buffer type description 64-tqfp mclr 7 i st master clear (reset) input. this pin is an active-low reset to the device. osc1/clki/ra7 osc1 clki ra7 (3) 39 i i i/o st cmos ttl oscillator crystal or external clock input. oscillator crystal input or external clock source input. st buffer when configured in rc mode; cmos otherwise. main oscillator input connection. external clock source input. always associated with pin function osc1. (see related osc1/clki, osc2/clko pins.) main clock input connection. general purpose i/o pin. osc2/clko/ra6 osc2 clko ra6 (3) 40 o o i/o ? ? ttl oscillator crystal or clock output. oscillator crystal output. connects to crystal or resonator in crystal oscillator mode. main oscillator feedback output connection. in rc mode, osc2 pin outputs clko which has 1/4 the frequency of osc1 and denotes the instruction cycle rate. system cycle clock output (f osc /4). general purpose i/o pin. legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 13 pic18f87j50 family porta is a bidirectional i/o port. ra0/an0 ra0 an0 24 i/o i ttl analog digital i/o. analog input 0. ra1/an1 ra1 an1 23 i/o i ttl analog digital i/o. analog input 1. ra2/an2/v ref - ra2 an2 v ref - 22 i/o i i ttl analog analog digital i/o. analog input 2. a/d reference voltage (low) input. ra3/an3/v ref + ra3 an3 v ref + 21 i/o i i ttl analog analog digital i/o. analog input 3. a/d reference voltage (high) input. ra4/t0cki ra4 t0cki 28 i/o i st st digital i/o. timer0 external clock input. ra5/an4/c2ina ra5 an4 c2ina 27 i/o i ? ttl analog analog digital i/o. analog input 4. comparator 2 input a ra6 ra7 ? ? ? ? ? ? see the osc2/clko/ra6 pin. see the osc1/clki/ra7 pin. table 1-3: pic18f6xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 14 preliminary ? 2007 microchip technology inc. portb is a bidirectional i/o port. portb can be software programmed for internal weak pull-ups on all inputs. rb0/flt0/int0 rb0 flt0 int0 48 i/o i i ttl st st digital i/o. eccp1/2/3 fault input. external interrupt 0. rb1/int1/pma4 rb1 int1 pma4 47 i/o i o ttl st ? digital i/o. external interrupt 1. parallel master port address. rb2/int2/pma3 rb2 int2 pma3 46 i/o i o ttl st ? digital i/o. external interrupt 2. parallel master port address. rb3/int3/pma2 rb3 int3 pma2 45 i/o i o ttl st ? digital i/o. external interrupt 3. parallel master port address. rb4/kbi0/pma1 rb4 kbi0 pma1 44 i/o i i/o ttl ttl ? digital i/o. interrupt-on-change pin. parallel master port address. rb5/kbi1/pma0 rb5 kbi1 pma0 43 i/o i i/o ttl ttl ? digital i/o. interrupt-on-change pin. parallel master port address. rb6/kbi2/pgc rb6 kbi2 pgc 42 i/o i i/o ttl ttl st digital i/o. interrupt-on-change pin. in-circuit debugger and icsp? programming clock pin. rb7/kbi3/pgd rb7 kbi3 pgd 37 i/o i i/o ttl ttl st digital i/o. interrupt-on-change pin. in-circuit debugger and icsp programming data pin. table 1-3: pic18f6xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 15 pic18f87j50 family portc is a bidirectional i/o port. rc0/t1oso/t13cki rc0 t1oso t13cki 30 i/o o i st ? st digital i/o. timer1 oscillator output. timer1/timer3 external clock input. rc1/t1osi/eccp2/p2a rc1 t1osi eccp2 (1) p2a (1) 29 i/o i i/o o st cmos st ? digital i/o. timer1 oscillator input. capture 2 input/compare 2 output/pwm2 output. eccp2 pwm output a. rc2/eccp1/p1a rc2 eccp1 p1a 33 i/o i/o o st st ? digital i/o. capture 1 input/compare 1 output/pwm1 output. eccp1 pwm output a. rc3/sck1/scl1 rc3 sck1 scl1 34 i/o i/o i/o st st st digital i/o. synchronous serial clock input/output for spi mode. synchronous serial clock input/output for i 2 c? mode. rc4/sdi1/sda1 rc4 sdi1 sda1 35 i/o i i/o st st st digital i/o. spi data in. i 2 c data i/o. rc5/sdo1/c2out rc5 sdo1 c2out 36 i/o o o st ? ttl digital i/o. spi data out. comparator 2 output. rc6/tx1/ck1 rc6 tx1 ck1 31 i/o o i/o st ? st digital i/o. eusart1 asynchronous transmit. eusart1 synchronous clock (see related rx1/dt1). rc7/rx1/dt1 rc7 rx1 dt1 32 i/o i i/o st st st digital i/o. eusart1 asynchronous receive. eusart1 synchronous data (see related tx1/ck1). table 1-3: pic18f6xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 16 preliminary ? 2007 microchip technology inc. portd is a bidirectional i/o port. rd0/pmd0 rd0 pmd0 58 i/o i/o st ttl digital i/o. parallel master port data. rd1/pmd1 rd1 pmd1 55 i/o i/o st ttl digital i/o. parallel master port data. rd2/pmd2 rd2 pmd2 54 i/o i/o st ttl digital i/o. parallel master port data. rd3/pmd3 rd3 pmd3 53 i/o i/o st ttl digital i/o. parallel master port data. rd4/pmd4/sdo2 rd4 pmd4 sdo2 52 i/o i/o o st ttl ? digital i/o. parallel master port data. spi data out. rd5/pmd5/sdi2/sda2 rd5 pmd5 sdi2 sda2 51 i/o i/o i i/o st ttl st st digital i/o. parallel master port data. spi data in. i 2 c? data i/o. rd6/pmd6/sck2/scl2 rd6 pmd6 sck2 scl2 50 i/o i/o i/o i/o st ttl st st digital i/o. parallel master port data. synchronous serial clock input/output for spi mode. synchronous serial clock input/output for i 2 c mode. rd7/pmd7/ss2 rd7 pmd7 ss2 49 i/o i/o i st ttl ttl digital i/o. parallel master port data. spi slave select input. table 1-3: pic18f6xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 17 pic18f87j50 family porte is a bidirectional i/o port. re0/pmrd/p2d re0 pmrd p2d 2 i/o i/o o st ? ? digital i/o. parallel master port read strobe. eccp2 pwm output d. re1/pmwr/p2c re1 pmwr p2c 1 i/o i/o o st ? ? digital i/o. parallel master port write strobe. eccp2 pwm output c. re2/pmbe/p2b re2 pmbe p2b 64 i/o o o st ? ? digital i/o. parallel master port byte enable eccp2 pwm output b. re3/pma13/p3c/refo re3 pma13 p3c refo 63 i/o o o o st ? ? ? digital i/o. parallel master port address. eccp3 pwm output c. reference clock out. re4/pma12/p3b re4 pma12 p3b 62 i/o o o st ? ? digital i/o. parallel master port address. eccp3 pwm output b. re5/pma11/p1c re5 pma11 p1c 61 i/o o o st ? ? digital i/o. parallel master port address. eccp1 pwm output c. re6/pma10/p1b re6 pma10 p1b 60 i/o o o st ? ? digital i/o. parallel master port address. eccp1 pwm output b. re7/pma9/eccp2/p2a re7 pma9 eccp2 (2) p2a (2) 59 i/o o i/o o st ? st ? digital i/o. parallel master port address. capture 2 input/compare 2 output/pwm2 output. eccp2 pwm output a. table 1-3: pic18f6xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 18 preliminary ? 2007 microchip technology inc. portf is a bidirectional i/o port. rf2/pma5/an7/c2inb rf2 pma5 an7 c2inb 16 i/o o i i st ? analog analog digital i/o. parallel master port address. analog input 7. comparator 2 input b. rf3/d- rf3 d- 15 i i/o st ? digital input. usb differential minus line (input/output). rf4/d+ rf4 d+ 14 i i/o st ? digital input. usb differential plus line (input/output). rf5/an10/c1inb/cv ref rf5 an10 c1inb cv ref 13 i i i o st analog analog analog digital input. analog input 10. comparator 1 input b. comparator reference voltage output. rf6/an11/c1ina rf6 an11 c1ina 12 i/o i i st analog analog digital i/o. analog input 11. comparator 1 input a. rf7/ss1 /c1out rf7 ss1 c1out 11 i/o i o st ttl ttl digital i/o. spi slave select input. comparator 1 output. table 1-3: pic18f6xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 19 pic18f87j50 family portg is a bidirectional i/o port. rg0/pma8/eccp3/p3a rg0 pma8 eccp3 p3a 3 i/o o i/o o st ? ? ? digital i/o. parallel master port address. capture 3 input/compare 3 output/pwm3 output. eccp3 pwm output a. rg1/pma7/tx2/ck2 rg1 pma7 tx2 ck2 4 i/o o o i/o st ? ? st digital i/o. parallel master port address. eusart2 asynchronous transmit. eusart2 synchronous clock (see related rx2/dt2). rg2/pma6/rx2/dt2 rg2 pma6 rx2 dt2 5 i/o o i i/o st ? st st digital i/o. parallel master port address. eusart2 asynchronous receive. eusart2 synchronous data (see related tx2/ck2). rg3/pmcs1/ccp4/p3d rg3 pmcs1 ccp4 p3d 6 i/o o i/o o st ? st ? digital i/o. parallel master port chip select 1. capture 4 input/compare 4 output/pwm4 output. eccp3 pwm output d. rg4/pmcs2/ccp5/p1d rg4 pmcs2 ccp5 p1d 8 i/o o i/o o st ? st ? digital i/o. parallel master port chip select 2. capture 5 input/compare 5 output/pwm5 output. eccp1 pwm output d. v ss 9, 25, 41, 56 p ? ground reference for logic and i/o pins. v dd 26, 38, 57 p ? positive supply for peripheral digital logic and i/o pins. av ss 20 p ? ground reference for analog modules. av dd 19 p ? positive supply for analog modules. envreg 18 i st enable for on-chip voltage regulator. v ddcore /v cap v ddcore v cap 10 p p ? ? core logic power or external filter capacitor connection. positive supply for microcontroller core logic (regulator disabled). external filter capacitor connection (regulator enabled). v usb 17 p ? usb voltage input pin. table 1-3: pic18f6xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 64-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. 2: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared. 3: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 20 preliminary ? 2007 microchip technology inc. table 1-4: pic18f8xj5x pi nout i/o descriptions pin name pin number pin type buffer type description 80-tqfp mclr 9 i st master clear (reset) input. this pin is an active-low reset to the device. osc1/clki/ra7 osc1 clki ra7 (8) 49 i i i/o st cmos ttl oscillator crystal or external clock input. oscillator crystal input or external clock source input. st buffer when configured in rc mode; cmos otherwise. main oscillator input connection. external clock source input. always associated with pin function osc1. (see related osc1/clki, osc2/clko pins.) main clock input connection. general purpose i/o pin. osc2/clko/ra6 osc2 clko ra6 (8) 50 o o i/o ? ? ttl oscillator crystal or clock output. oscillator crystal output. connects to crystal or resonator in crystal oscillator mode. main oscillator feedback output connection. in rc mode, osc2 pin outputs clko which has 1/4 the frequency of osc1 and denotes the instruction cycle rate. system cycle clock output (f osc /4). general purpose i/o pin. legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 21 pic18f87j50 family porta is a bidirectional i/o port. ra0/an0 ra0 an0 30 i/o i ttl analog digital i/o. analog input 0. ra1/an1 ra1 an1 29 i/o i ttl analog digital i/o. analog input 1. ra2/an2/v ref - ra2 an2 v ref - 28 i/o i i ttl analog analog digital i/o. analog input 2. a/d reference voltage (low) input. ra3/an3/v ref + ra3 an3 v ref + 27 i/o i i ttl analog analog digital i/o. analog input 3. a/d reference voltage (high) input. ra4/pmd5/t0cki ra4 pmd5 (7) t0cki 34 i/o i/o i st ttl st digital i/o. parallel master port data. timer0 external clock input. ra5/pmd4/an4/c2ina ra5 pmd4 (7) an4 c2ina 33 i/o i/o i i ttl ttl analog analog digital i/o. parallel master port data. analog input 4. comparator 2 input a. ra6 ra7 ? ? ? ? ? ? see the osc2/clko/ra6 pin. see the osc1/clki/ra7 pin. table 1-4: pic18f8xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 22 preliminary ? 2007 microchip technology inc. portb is a bidirectional i/o port. portb can be software programmed for internal weak pull-ups on all inputs. rb0/flt0/int0 rb0 flt0 int0 58 i/o i i ttl st st digital i/o. eccp1/2/3 fault input. external interrupt 0. rb1/int1/pma4 rb1 int1 pma4 57 i/o i o ttl st ? digital i/o. external interrupt 1. parallel master port address. rb2/int2/pma3 rb2 int2 pma3 56 i/o i o ttl st ? digital i/o. external interrupt 2. parallel master port address. rb3/int3/eccp2/ p2a/pma2 rb3 int3 eccp2 (1) p2a (1) pma2 55 i/o i i/o o o ttl st st ? ? digital i/o. external interrupt 3. capture 2 input/compare 2 output/pwm2 output. eccp2 pwm output a. parallel master port address. rb4/kbi0/pma1 rb4 kbi0 pma1 54 i/o i i/o ttl ttl ? digital i/o. interrupt-on-change pin. parallel master port address. rb5/kbi1/pma0 rb5 kbi1 pma0 53 i/o i i/o ttl ttl ? digital i/o. interrupt-on-change pin. parallel master port address. rb6/kbi2/pgc rb6 kbi2 pgc 52 i/o i i/o ttl ttl st digital i/o. interrupt-on-change pin. in-circuit debugger and icsp? programming clock pin. rb7/kbi3/pgd rb7 kbi3 pgd 47 i/o i i/o ttl ttl st digital i/o. interrupt-on-change pin. in-circuit debugger and icsp programming data pin. table 1-4: pic18f8xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 23 pic18f87j50 family portc is a bidirectional i/o port. rc0/t1oso/t13cki rc0 t1oso t13cki 36 i/o o i st ? st digital i/o. timer1 oscillator output. timer1/timer3 external clock input. rc1/t1osi/eccp2/p2a rc1 t1osi eccp2 (2) p2a (2) 35 i/o i i/o o st cmos st ? digital i/o. timer1 oscillator input. capture 2 input/compare 2 output/pwm2 output. eccp2 pwm output a. rc2/eccp1/p1a rc2 eccp1 p1a 43 i/o i/o o st st ? digital i/o. capture 1 input/compare 1 output/pwm1 output. eccp1 pwm output a. rc3/sck1/scl1 rc3 sck1 scl1 44 i/o i/o i/o st st st digital i/o. synchronous serial clock input/output for spi mode. synchronous serial clock input/output for i 2 c? mode. rc4/sdi1/sda1 rc4 sdi1 sda1 45 i/o i i/o st st st digital i/o. spi data in. i 2 c data i/o. rc5/sdo1/c2out rc5 sdo1 c2out 46 i/o o o st ? ttl digital i/o. spi data out. comparator 2 output. rc6/tx1/ck1 rc6 tx1 ck1 37 i/o o i/o st ? st digital i/o. eusart1 asynchronous transmit. eusart1 synchronous clock (see related rx1/dt1). rc7/rx1/dt1 rc7 rx1 dt1 38 i/o i i/o st st st digital i/o. eusart1 asynchronous receive. eusart1 synchronous data (see related tx1/ck1). table 1-4: pic18f8xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 24 preliminary ? 2007 microchip technology inc. portd is a bidirectional i/o port. rd0/ad0/pmd0 rd0 ad0 pmd0 (6) 72 i/o i/o i/o st ttl ttl digital i/o. external memory address/data 0. parallel master port data. rd1/ad1/pmd1 rd1 ad1 pmd1 (6) 69 i/o i/o i/o st ttl ttl digital i/o. external memory address/data 1. parallel master port data. rd2/ad2/pmd2 rd2 ad2 pmd2 (6) 68 i/o i/o i/o st ttl ttl digital i/o. external memory address/data 2. parallel master port data. rd3/ad3/pmd3 rd3 ad3 pmd3 (6) 67 i/o i/o i/o st ttl ttl digital i/o. external memory address/data 3. parallel master port data. rd4/ad4/pmd4/ sdo2 rd4 ad4 pmd4 (6) sdo2 66 i/o i/o i/o o st ttl ttl ? digital i/o. external memory address/data 4. parallel master port data. spi data out. rd5/ad5/pmd5/ sdi2/sda2 rd5 ad5 pmd5 (6) sdi2 sda2 65 i/o i/o i/o i i/o st ttl ttl st st digital i/o. external memory address/data 5. parallel master port data. spi data in. i 2 c? data i/o. table 1-4: pic18f8xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 25 pic18f87j50 family portd is a bidirectional i/o port (continued). rd6/ad6/pmd6/ sck2/scl2 rd6 ad6 pmd6 (6) sck2 scl2 64 i/o i/o i/o i/o i/o st ttl ttl st st digital i/o. external memory address/data 6. parallel master port data. synchronous serial clock input/output for spi mode. synchronous serial clock input/output for i 2 c? mode. rd7/ad7/pmd7/ss2 rd7 ad7 pmd7 (6) ss2 63 i/o i/o i/o i st ttl ttl ttl digital i/o. external memory address/data 7. parallel master port data. spi slave select input. table 1-4: pic18f8xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 26 preliminary ? 2007 microchip technology inc. porte is a bidirectional i/o port. re0/ad8/pmrd/p2d re0 ad8 pmrd (6) p2d 4 i/o i/o i/o o st ttl ? ? digital i/o. external memory address/data 8. parallel master port read strobe. eccp2 pwm output d. re1/ad9/pmwr/p2c re1 ad9 pmwr (6) p2c 3 i/o i/o i/o o st ttl ? ? digital i/o. external memory address/data 9. parallel master port write strobe. eccp2 pwm output c. re2/ad10/pmbe/p2b re2 ad10 pmbe (6) p2b 78 i/o i/o o o st ttl ? ? digital i/o. external memory address/data 10. parallel master port byte enable. eccp2 pwm output b. re3/ad11/pma13/ p3c/refo re3 ad11 pma13 p3c (3) refo 77 i/o i/o o o o st ttl ? ? ? digital i/o. external memory address/data 11. parallel master port address. eccp3 pwm output c. reference clock out. re4/ad12/pma12/p3b re4 ad12 pma12 p3b (3) 76 i/o i/o o o st ttl ? ? digital i/o. external memory address/data 12. parallel master port address. eccp3 pwm output b. re5/ad13/pma11/p1c re5 ad13 pma11 p1c (3) 75 i/o i/o o o st ttl ? ? digital i/o. external memory address/data 13. parallel master port address. eccp1 pwm output c. table 1-4: pic18f8xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 27 pic18f87j50 family porte is a bidirectional i/o port (continued). re6/ad14/pma10/p1b re6 ad14 pma10 p1b (3) 74 i/o i/o o o st ttl ? ? digital i/o. external memory address/data 14. parallel master port address. eccp1 pwm output b. re7/ad15/pma9/ eccp2/p2a re7 ad15 pma9 eccp2 (4) p2a (4) 73 i/o i/o o i/o o st ttl ? st ? digital i/o. external memory address/data 15. parallel master port address. capture 2 input/compare 2 output/pwm2 output. eccp2 pwm output a. table 1-4: pic18f8xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 28 preliminary ? 2007 microchip technology inc. portf is a bidirectional i/o port. rf2/pma5/an7/c2inb rf2 pma5 an7 c2inb 18 i/o o i i st ? analog analog digital i/o. parallel master port address. analog input 7. comparator 2 input b. rf3/d- rf3 d- 17 i/o i/o st ? digital i/o. analog input 8. rf4/d+ rf4 d+ 16 i/o i/o st ? digital i/o. analog input 9. rf5/pmd2/an10/ c1inb/cv ref rf5 pmd2 (7) an10 c1inb cv ref 15 i/o i/o i i o st ttl analog analog analog digital i/o. parallel master port address. analog input 10. comparator 1 input b. comparator reference voltage output. rf6/pmd1/an11/c1ina rf6 pmd1 (7) an11 c1ina 14 i/o i/o i i st ttl analog analog digital i/o. parallel master port address. analog input 11. comparator 1 input a. rf7/pmd0/ss1 /c1out rf7 pmd0 (7) ss1 c1out 13 i/o i/o i o st ttl ttl ? digital i/o. parallel master port address. spi slave select input. comparator 1 output. table 1-4: pic18f8xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 29 pic18f87j50 family portg is a bidirectional i/o port. rg0/pma8/eccp3/p3a rg0 pma8 eccp3 p3a 5 i/o o i/o o st ? st ? digital i/o. parallel master port address. capture 3 input/compare 3 output/pwm3 output. eccp3 pwm output a. rg1/pma7/tx2/ck2 rg1 pma7 tx2 ck2 6 i/o o o i/o st ? ? st digital i/o. parallel master port address. eusart2 asynchronous transmit. eusart2 synchronous clock (see related rx2/dt2). rg2/pma6/rx2/dt2 rg2 pma6 rx2 dt2 7 i/o i/o i i/o st ? st st digital i/o. parallel master port address. eusart2 asynchronous receive. eusart2 synchronous data (see related tx2/ck2). rg3/pmcs1/ccp4/p3d rg3 pmcs1 ccp4 p3d 8 i/o i/o i/o o st ? st ? digital i/o. parallel master port chip select 1. capture 4 input/compare 4 output/pwm4 output. eccp3 pwm output d. rg4/pmcs2/ccp5/p1d rg4 pmcs2 ccp5 p1d 10 i/o o i/o o st ? st ? digital i/o. parallel master port chip select 2. capture 5 input/compare 5 output/pwm5 output. eccp1 pwm output d. table 1-4: pic18f8xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 30 preliminary ? 2007 microchip technology inc. porth is a bidirectional i/o port. rh0/a16 rh0 a16 79 i/o o st ttl digital i/o. external memory address/data 16. rh1/a17 rh1 a17 80 i/o o st ttl digital i/o. external memory address/data 17. rh2/a18/pmd7 rh2 a18 pmd7 (7) 1 i/o o i/o st ttl ttl digital i/o. external memory address/data 18. parallel master port data. rh3/a19/pmd6 rh3 a19 pmd6 (7) 2 i/o o i/o st ttl ttl digital i/o. external memory address/data 19. parallel master port data. rh4/pmd3/an12/ p3c/c2inc rh4 pmd3 (7) an12 p3c (5) c2inc 22 i/o i/o i o i st ttl analog ? analog digital i/o. parallel master port address. analog input 12. eccp3 pwm output c. comparator 2 input c. rh5/pmbe/an13/ p3b/c2ind rh5 pmbe (7) an13 p3b (5) c2ind 21 i/o o i o i st ? analog ? analog digital i/o. parallel master port byte enable. analog input 13. eccp3 pwm output b. comparator 2 input d. rh6/pmrd/an14/ p1c/c1inc rh6 pmrd (7) an14 p1c (5) c1inc 20 i/o i/o i o i st ? analog ? analog digital i/o. parallel master port read strobe. analog input 14. eccp1 pwm output c. comparator 1 input c. table 1-4: pic18f8xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 31 pic18f87j50 family porth is a bidirectional i/o port (continued). rh7/pmwr/an15/p1b rh7 pmwr (7) an15 p1b (5) 19 i/o i/o i o st ? analog ? digital i/o. parallel master port write strobe. analog input 15. eccp1 pwm output b. table 1-4: pic18f8xj5 x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
pic18f87j50 family ds39775b-page 32 preliminary ? 2007 microchip technology inc. portj is a bidirectional i/o port. rj0/ale rj0 ale 62 i/o o st ? digital i/o. external memory address latch enable. rj1/oe rj1 oe 61 i/o o st ? digital i/o. external memory output enable. rj2/wrl rj2 wrl 60 i/o o st ? digital i/o. external memory write low control. rj3/wrh rj3 wrh 59 i/o o st ? digital i/o. external memory write high control. rj4/ba0 rj4 ba0 39 i/o o st ? digital i/o. external memory byte address 0 control. rj5/ce rj5 ce 40 i/o o st ? digital i/o external memory chip enable control. rj6/lb rj6 lb 41 i/o o st ? digital i/o. external memory low byte control. rj7/ub rj7 ub 42 i/o o st ? digital i/o. external memory high byte control. v ss 11, 31, 51, 70 p ? ground reference for logic and i/o pins. v dd 32, 48, 71 p ? positive supply for peripheral digital logic and i/o pins. av ss 26 p ? ground reference for analog modules. av dd 25 p ? positive supply for analog modules. envreg 24 i st enable for on-chip voltage regulator. v ddcore /v cap v ddcore v cap 12 p p ? ? core logic power or external filter capacitor connection. positive supply for microcontroller core logic (regulator disabled). external filter capacitor connection (regulator enabled). v usb 23 p ? usb voltage input pin. table 1-4: pic18f8xj5x pinout i/o descriptions (continued) pin name pin number pin type buffer type description 80-tqfp legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels analog = analog input i = input o = output p = power od = open-drain (no p diode to v dd ) note 1: alternate assignment for eccp2/p2a when ccp2mx configuration bit is cleared (extended microcontroller mode). 2: default assignment for eccp2/p2a for all devices in all operating modes (ccp2mx is set). 3: default assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is set). 4: alternate assignment for eccp2/p2a when ccp2mx is cleared (microcontroller mode). 5: alternate assignments for p1b/p1c/p3b/p3c (eccpmx configuration bit is cleared). 6: pin placement when pmpmx = 1 . 7: pin placement when pmpmx = 0 . 8: ra7 and ra6 will be disabled if osc1 and osc2 are used for the clock function.
? 2007 microchip technology inc. preliminary ds39775b-page 33 pic18f87j50 family 2.0 oscillator configurations 2.1 overview devices in the pic18f87j50 family incorporate a different oscillator and microcontroller clock system than general purpose pic18f devices. the addition of the usb module, with its unique requirements for a stable clock source, make it necessary to provide a separate clock source that is compliant with both usb low-speed and full-speed specifications. the pic18f87j50 family has additional prescalers and postscalers which have been added to accommodate a wide range of oscillator frequencies. an overview of the oscillator structure is shown in figure 2-1. other oscillator features used in pic18 enhanced microcontrollers, such as the internal oscillator block and clock switching, remain the same. they are discussed later in this chapter. 2.1.1 oscillator control the operation of the oscillator in pic18f87j50 family devices is controlled through three configuration regis- ters and two control register s. configuration registers, config1l, config1h and config2l, select the oscillator mode, pll prescaler and cpu divider options. as configuration bits, these are set when the device is programmed and left in that configuration until the device is reprogrammed. the osccon register (register 2-2) selects the active clock mode; it is primarily used in controlling clock switching in power-managed modes. its use is discussed in section 2.4.1 ?oscillator control register? . the osctune register (register 2-1) is used to trim the intosc frequency source, as well as select the low-frequency clock source that drives several special features. the osctune register is also used to activate or disable the pll. its use is described in section 2.2.5.1 ?osctune register? . 2.2 oscillator types pic18f87j50 family devices can be operated in eight distinct oscillator modes. users can program the fosc2:fosc0 configuration bits to select one of the modes listed in table 2-1. for oscillator modes which produce a clock output, ?clko?, on pin ra6, the output frequency will be one fourth of the peripheral clock frequency. the clock output will stop when in sleep mode, but will continue during idle mode (see figure 2-1). table 2-1: oscillator modes mode description ecpll external clock input mode, the pll can be enabled or disabled, clko on ra6, apply external clock signal to ra7 ec external clock input mode, the pll is always disabled, clko on ra6, apply external clock signal to ra7 hspll high-speed crystal/resonator mode, pll can be enabled or disabled, crystal/ resonator connected between ra6 and ra7 hs high-speed crystal/resonator mode, pll always disabled, crystal/resonator connected between ra6 and ra7 intoscpllo internal oscillator mode, pll can be enabled or disabled, clko on ra6, port function on ra7, the internal oscillator block is used to derive both the primary clock source and the postscaled internal clock intoscpll internal oscillator mode, pll can be enabled or disabled, port function on ra6 and ra7, the internal oscillator block is used to derive both the primary clock source and the postscaled internal clock intosco internal oscillator mode, pll is always disabled, clko on ra6, port function on ra7, the output of the intosc postscaler serves as both the postscaled internal clock and the primary clock source intosc internal oscillator mode, pll is always disabled, port function on ra6 and ra7, the output of the intosc postscaler serves as both the postscaled internal clock and the primary clock source
pic18f87j50 family ds39775b-page 34 preliminary ? 2007 microchip technology inc. 2.2.1 oscillator modes and usb operation because of the unique requirements of the usb module, a different approach to clock operation is necessary. in order to use the usb module, a fixed 6 mhz or 48 mhz clock must be internally provided to the usb module for operation in either low-speed or full-speed mode, respectively. the microcontroller core need not be clocked at the same frequency as the usb module. a network of muxes, clock dividers and a fixed 96 mhz output pll have been provided which can be used to derive various microcontroller core and usb module frequencies. the oscillator structure of the pic18f87j50 family of devices is best understood by referring to figure 2-1. figure 2-1: pic18f87j50 family clock diagram osc1 osc2 primary oscillator cpu peripherals idle intosc postscaler 8 mhz 4 mhz 2 mhz 1 mhz 500 khz 125 khz 250 khz 111 110 101 100 011 010 001 000 31 khz intrc 31 khz internal oscillator block 8 mhz 8 mhz 0 1 osctune<7> plldiv2:plldiv0 cpu divider 1 2 3 6 usb module 4 mhz wdt, pwrt, fscm and two-speed start-up osccon<6:4> pllen 1 0 fosc2 1 0 pll prescaler 96 mhz pll (1) 2 1 0 fsen 8 10 11 4 cpdiv1:cpdiv0 00 01 10 11 cpdiv1:cpdiv0 (note 2) 00 fosc2:fosc1 other 00 01 osccon<1:0> 11 4 ra6 clko enabled modes timer1 clock (3) postscaled internal clock t1osi t1oso secondary oscillator t1oscen clock needs 48 mhz for fs needs 6 mhz for ls note 1: the pll requires a 4 mhz input and it produces a 96 mhz output. the pll will not be available until the pllen bit in the osctune register is set. once the pllen bit is set, the pll requires up to 2 ms to lock. 2: in order to use the usb module in full-speed mode, this node must be run at 48 mhz. for low-speed mode, this node may be run at either 48 mhz or 24 mhz, but the cpdiv bi ts must be set such that the usb module is clocked at 6 mhz. 3: selecting the timer1 clock or postscaled internal clock wi ll turn off the primary oscillator (unless required by the reference clock of section 2.5 ?reference clock output? ) and pll. 4: the usb module cannot be used to communicate unless the primary clock source is selected. 12 10 6 5 4 3 2 1 000 001 010 011 100 101 110 111 48 mhz primary clock source (4)
? 2007 microchip technology inc. preliminary ds39775b-page 35 pic18f87j50 family 2.2.2 crystal oscillator/ceramic resonators in hs and hspll oscillator modes, a crystal or ceramic resonator is connected to the osc1 and osc2 pins to establish oscillation. figure 2-2 shows the pin connections. the oscillator design requires the use of a parallel cut crystal. figure 2-2: crystal/ceramic resonator operation (xt, hs or hspll configuration) table 2-2: capacitor selection for ceramic resonators table 2-3: capacitor selection for crystal oscillator an internal postscaler allows users to select a clock frequency other than that of the crystal or resonator. frequency division is determined by the cpdiv configuration bits. users may select a clock frequency of the oscillator frequency, or 1/2, 1/3 or 1/6 of the frequency. an external clock may also be used when the micro- controller is in hs oscillator mode. in this case, the osc2/clko pin is left open (figure 2-3). note: use of a series cut crystal may give a fre- quency out of the crystal manufacturer?s specifications. typical capacitor values used: mode freq osc1 osc2 hs 8.0 mhz 16.0 mhz 27 pf 22 pf 27 pf 22 pf capacitor values are for design guidance only. these capacitors were tested with the resonators listed below for basic start-up and operation. these values are not optimized . different capacitor values may be required to produce acceptable oscillator operation. the user should test the performance of the oscillator over the expected v dd and temperature range for the application. see the notes following table 2-3 for additional information. resonators used: 4.0 mhz 8.0 mhz 16.0 mhz note 1: see table 2-2 and table 2-3 for initial values of c1 and c2. 2: a series resistor (r s ) may be required for at strip cut crystals. 3: r f varies with the oscillator mode chosen. c1 (1) c2 (1) xtal osc2 osc1 r f (3) sleep to logic pic18f87j50 r s (2) internal osc type crystal freq typical capacitor values tested: c1 c2 hs 4 mhz 27 pf 27 pf 8 mhz 22 pf 22 pf 20 mhz 15 pf 15 pf capacitor values are for design guidance only. these capacitors were tested with the crystals listed below for basic start-up and operation. these values are not optimized. different capacitor values may be required to produce acceptable oscillator operation. the user should test the performance of the oscillator over the expected v dd and temperature range for the application. see the notes following this table for additional information. crystals used: 4 mhz 8 mhz 20 mhz note 1: higher capacitance increases the stability of oscillator but also increases the start-up time. 2: when operating below 3v v dd , or when using certain ceramic resonators at any voltage, it may be necessary to use the hs mode or switch to a crystal oscillator. 3: since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropriate values of external components. 4: rs may be required to avoid overdriving crystals with low drive level specification. 5: always verify oscillator performance over the v dd and temperature range that is expected for the application.
pic18f87j50 family ds39775b-page 36 preliminary ? 2007 microchip technology inc. figure 2-3: extern al clock input operation (hs osc configuration) 2.2.3 external clock input the ec and ecpll oscillator modes require an exter- nal clock source to be connected to the osc1 pin. there is no oscillator start-up time required after a power-on reset or after an exit from sleep mode. in the ec and ecpll oscillator modes, the oscillator frequency divided by 4 is available on the osc2 pin. this signal may be used for test purposes or to synchronize other logic. figure 2-4 shows the pin connections for the ec oscillator mode. figure 2-4: extern al clock input operation (ec and ecpll configuration) 2.2.4 pll frequency multiplier pic18f87j50 family devices include a phase locked loop (pll) circuit. this is provided specifically for usb applications with lower speed oscillators and can also be used as a microcontroller clock source. the pll can be enabled in hspll, ecpll, intoscpll and intoscpllo oscillator modes by setting the pllen bit (osctune<6>). it is designed to produce a fixed 96 mhz reference clock from a fixed 4 mhz input. the output can then be divided and used for both the usb and the microcontroller core clock. because the pll has a fixed frequency input and output, there are eight prescaling options to match the oscillator input frequency to the pll. this prescaler allows the pll to be used with crystals, res- onators and external clocks, which are integer multiple frequencies of 4 mhz. for example, a 12 mhz crystal could be used in a prescaler divide by three mode to drive the pll. there is also a cpu divider which can be used to derive the microcontroller clock from the pll. this allows the usb peripheral and microcontroller to use the same oscillator input and still operate at different clock speeds. the cpu divider can reduce the incoming frequency by a factor of 1, 2, 3 or 6. 2.2.5 internal oscillator block the pic18f87j50 family devices include an internal oscillator block which generates two different clock sig- nals; either can be used as the microcontroller?s clock source. the internal oscillator may eliminate the need for external oscillator circuits on the osc1 and/or osc2 pins. the main output (intosc) is an 8 mhz clock source which can be used to directly drive the device clock. it also drives the intosc postscaler which can provide a range of clock frequencies from 31 khz to 8 mhz. additionally, the intosc may be used in conjunction with the pll to generate clock frequencies up to 48 mhz. the other clock source is the internal rc oscillator (intrc) which provides a nominal 31 khz output. intrc is enabled if it is selected as the device clock source. it is also enabled automatically when any of the following are enabled: ? power-up timer ? fail-safe clock monitor ? watchdog timer ? two-speed start-up these features are discussed in greater detail in section 25.0 ?special features of the cpu? . the clock source frequency (intosc direct, intrc direct or intosc postscaler) is selected by configuring the ircf bits of the osccon register (page 42). osc1 osc2 open clock from ext. system pic18f87j50 (hs mode) osc1/clki osc2/clko f osc /4 clock from ext. system pic18f87j50
? 2007 microchip technology inc. preliminary ds39775b-page 37 pic18f87j50 family 2.2.5.1 osctune register the internal oscillator?s output has been calibrated at the factory but can be adjusted in the user?s applica- tion. this is done by writing to the osctune register (register 2-1). the tuning sensitivity is constant throughout the tuning range. when the osctune register is modified, the intosc and intrc frequencies will begin shifting to the new frequency. the intrc clock will reach the new frequency within 8 clock cycles (approximately, 8*32 s = 256 s). the intosc clock will stabilize within 1 ms. code execution continues during this shift. there is no indication that the shift has occurred. the osctune register also contains the intsrc bit. the intsrc bit allows users to select which internal oscillator provides the clock source when the 31 khz frequency option is selected. this is covered in greater detail in section 2.4.1 ?oscillator control register? . the pllen bit, contained in the osctune register, can be used to enable or disable the internal 96 mhz pll when running in one of the pll type oscillator modes (e.g., intoscpll). oscillator modes that do not contain ?pll? in their name cannot be used with the pll. in these modes, the pll is always disabled regardless of the setting of the pllen bit. when configured for one of the pll enabled modes, setting the pllen bit does not immediately switch the device clock to the pll output. the pll requires up to two milliseconds to start up and lock during which time the device continues to be clocked. once the pll out- put is ready, the microcontroller core will automatically switch to the pll derived frequency. 2.2.5.2 internal oscillator output frequency and drift the internal oscillator block is calibrated at the factory to produce an intosc output frequency of 8.0 mhz. however, this frequency may drift as v dd or tempera- ture changes, which can affect the controller operation in a variety of ways. the low-frequency intrc oscillator operates indepen- dently of the intosc source. any changes in intosc across voltage and temperature are not necessarily reflected by changes in intrc and vice versa. 2.2.5.3 compensating for intosc drift it is possible to adjust the intosc frequency by modifying the value in the osctune register. this has no effect on the intrc clock source frequency. tuning the intosc source requires knowing when to make the adjustment, in which direction it should be made and in some cases, how large a change is needed. when using the eusart, for example, an adjustment may be required when it begins to generate framing errors or receives data with errors while in asynchronous mode. framing errors indicate that the device clock frequency is too high; to adjust for this, decrement the value in osctune to reduce the clock frequency. on the other hand, errors in data may sug- gest that the clock speed is too low; to compensate, increment osctune to increase the clock frequency. it is also possible to verify device clock speed against a reference clock. two timers may be used: one timer is clocked by the peripheral clock, while the other is clocked by a fixed reference source, such as the timer1 oscillator. both timers are cleared but the timer clocked by the reference generates interrupts. when an interrupt occurs, the internally clocked timer is read and both timers are cleared. if the internally clocked timer value is greater than expected, then the internal oscillator block is running too fast. to adjust for this, decrement the osctune register. finally, a ccp module can use free-running timer1 (or timer3), clocked by the internal oscillator block and an external event with a known period (i.e., ac power frequency). the time of the first event is captured in the ccprxh:ccprxl registers and is recorded for use later. when the second event causes a capture, the time of the first event is subtracted from the time of the second event. since the period of the external event is known, the time difference between events can be calculated. if the measured time is much greater than the calcu- lated time, the internal oscillator block is running too fast; to compensate, decrement the osctune register. if the measured time is much less than the calculated time, the internal oscillator block is running too slow; to compensate, increment the osctune register.
pic18f87j50 family ds39775b-page 38 preliminary ? 2007 microchip technology inc. 2.3 oscillator settings for usb when the pic18f87j50 family is used for usb connectivity, a 6 mhz or 48 mhz clock must be provided to the usb module for operation in either low-speed or full-speed modes, respectively. this may require some forethought in selecting an oscillator frequency and programming the device. the full range of possible oscillator configurations compatible with usb operation is shown in table 2-5. 2.3.1 low-speed operation the usb clock for low-speed mode is derived from the primary oscillator or from the 96 mhz pll. in order to operate the usb module in low-speed mode, a 6 mhz clock must be provided to the usb module. due to the way the clock dividers have been implemented in the pic18f87j50 family, the microcontroller core must run at 24 mhz in order for the usb module to get the 6 mhz clock needed for low-speed usb operation. several clocking schemes could be used to meet these two required conditions. see table 2-4 and table 2-5 for possible combinations which can be used for low-speed usb operation. table 2-4: clock for low-speed usb register 2-1: osctune: osci llator tuning register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 intsrc pllen tun5 tun4 tun3 tun2 tun1 tun0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 intsrc: internal oscillator low-frequency source select bit 1 = 31.25 khz device clock derived from 8 mhz intosc source (divide-by-256 enabled) 0 = 31 khz device clock derived directly from intrc internal oscillator bit 6 pllen: frequency multiplier enable bit 1 = 96 mhz pll is enabled 0 = 96 mhz pll is disabled bit 5-0 tun5:tun0: frequency tuning bits 011111 = maximum frequency 011110 ? ? ? ? ? ? 000001 000000 = center frequency. oscillator module is running at the calibrated frequency. 111111 ? ? ? ? 100000 = minimum frequency clock input cpu clock cpdiv<1:0> usb clock 48 24 <1, 1> 48/8 = 6 mhz 24 24 <1, 0> 24/4 = 6 mhz
? 2007 microchip technology inc. preliminary ds39775b-page 39 pic18f87j50 family table 2-5: oscillator configurat ion options for usb operation input oscillator frequency pll division (plldiv2:plldiv0) clock mode (fosc2:fosc0) mcu clock division (cpdiv1:cpdiv0) microcontroller clock frequency 48 mhz n/a ec none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 48 mhz 12 ( 000 )ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 40 mhz 10 ( 001 )ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 24 mhz 6 ( 010 ) hspll, ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 24 mhz n/a (1) ec, hs none ( 11 ) 24 mhz 2 ( 10 )12mhz 3 ( 01 )8mhz 6 ( 00 )4mhz 20 mhz 5 ( 011 ) hspll, ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 16 mhz 4 ( 100 ) hspll, ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 12 mhz 3 ( 101) hspll, ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 8mhz 2 ( 110 ) hspll, ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz 4mhz 1 ( 111 ) hspll, ecpll none ( 11 )48mhz 2 ( 10 ) 24 mhz 3 ( 01 )16mhz 6 ( 00 )8mhz legend: all clock frequencies, except 24 mhz, are exclusively asso ciated with full-speed usb operation (usb clock of 48 mhz). bold is used to highlight clock selections that are compat ible with low-speed usb operation (system clock of 24 mhz, usb clock of 6 mhz). note 1: only valid for low-speed usb operation.
pic18f87j50 family ds39775b-page 40 preliminary ? 2007 microchip technology inc. 2.4 clock sources and oscillator switching like previous pic18 enhanced devices, the pic18f87j50 family includes a feature that allows the device clock source to be switched from the main oscillator to an alternate, low-frequency clock source. pic18f87j50 family devices offer two alternate clock sources. when an alternate clock source is enabled, the various power-managed operating modes are available. essentially, there are three clock sources for these devices: ? primary oscillators ? secondary oscillators ? internal oscillator block the primary clock sources include the external crystal and resonator modes, the external clock modes and the internal oscillator block. the particular mode is defined by the fosc2:fosc0 configuration bits. the details of these modes are covered earlier in this chapter. the secondary oscillators are those external sources not connected to the osc1 or osc2 pins. these sources may continue to operate even after the controller is placed in a power-managed mode. pic18f87j50 family devices offer the timer1 oscillator as a secondary oscillator. this oscillator, in all power-managed modes, is often the time base for functions such as a real-time clock (rtc). most often, a 32.768 khz watch crystal is connected between the rc0/t1oso/t13cki and rc1/t1osi/ eccp2/p2a pins. like the hs oscillator mode circuits, loading capacitors are also connected from each pin to ground. the timer1 oscillator is discussed in greater detail in section 13.3 ?timer1 oscillator? . in addition to being a primary clock source, the postscaled internal clock is available as a power-managed mode clock source. the intrc source is also used as the clock source for several special features, such as the wdt and fail-safe clock monitor. 2.4.1 oscillator control register the osccon register (register 2-2) controls several aspects of the device clock?s operation, both in full-power operation and in power-managed modes. the system clock select bits, scs1:scs0, select the clock source. the available clock sources are the primary clock (defined by the fosc2:fosc0 configu- ration bits), the secondary clock (timer1 oscillator) and the postscaled internal clock.the clock source changes immediately, after one or more of the bits is written to, following a brief clock transition interval. the scs bits are cleared on all forms of reset. the internal oscillator frequency select bits, ircf2:ircf0, select the frequency output provided on the postscaled internal clock line. the choices are the intrc source, the intosc source (8 mhz) or one of the frequencies derived from the intosc postscaler (31 khz to 4 mhz). if the postscaled internal clock is supplying the device clock, changing the states of these bits will have an immediate change on the internal oscil- lator?s output. on device resets, the default output frequency of the intosc postscaler is set at 4 mhz. when an output frequency of 31 khz is selected (ircf2:ircf0 = 000 ), users may choose which inter- nal oscillator acts as the source. this is done with the intsrc bit in the osctune register (osctune<7>). setting this bit selects intosc as a 31.25 khz clock source by enabling the divide-by-256 output of the intosc postscaler. clearing intsrc selects intrc (nominally 31 khz) as the clock source. this option allows users to select the tunable and more precise intosc as a clock source, while maintaining power savings with a very low clock speed. regardless of the setting of intsrc, intrc always remains the clock source for features such as the watchdog timer and the fail-safe clock monitor. the osts and t1run bits indicate which clock source is currently providing the device clock. the osts bit indicates that the oscillator start-up timer (ost) has timed out and the primary clock is providing the device clock in primary clock modes. the t1run bit (t1con<6>) indicates when the timer1 oscillator is providing the device clock in secondary clock modes. in power-managed modes, only one of these bits will be set at any time. if none of these bits are set, the intrc is providing the clock or the internal oscillator block has just started and is not yet stable. the idlen bit determines if the device goes into sleep mode, or one of the idle modes, when the sleep instruction is executed.
? 2007 microchip technology inc. preliminary ds39775b-page 41 pic18f87j50 family the use of the flag and control bits in the osccon register is discussed in more detail in section 3.0 ?power-managed modes? . 2.4.2 oscillator transitions pic18f87j50 family devices contain circuitry to prevent clock ?glitches? when switching between clock sources. a short pause in the device clock occurs dur- ing the clock switch. the length of this pause is the sum of two cycles of the old clock source and three to four cycles of the new clock source. this formula assumes that the new clock source is stable. clock transitions are discussed in greater detail in section 3.1.2 ?entering power-managed modes? . note 1: the timer1 oscillator must be enabled to select the timer1 clock. the timer1 oscil- lator is enabled by setting the t1oscen bit in the timer1 control register (t1con<3>). if the timer1 oscillator is not enabled, then any attempt to select the timer1 clock source will be ignored. 2: it is recommended that the timer1 oscillator be operating and stable prior to switching to it as the clock source; other- wise, a very long delay may occur while the timer1 oscillator starts.
pic18f87j50 family ds39775b-page 42 preliminary ? 2007 microchip technology inc. register 2-2: osccon: os cillator control register (1) r/w-0 r/w-1 r/w-1 r/w-0 r-1 (2) u-1 r/w-0 r/w-0 idlen ircf2 ircf1 ircf0 osts ?scs1scs0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 idlen: idle enable bit 1 = device enters idle mode on sleep instruction 0 = device enters sleep mode on sleep instruction bit 6-4 ircf2:ircf0: internal oscillator frequency select bits 111 = 8 mhz (intosc drives clock directly) 110 = 4 mhz (3) 101 = 2 mhz 100 = 1 mhz 011 = 500 khz 010 = 250 khz 001 = 125 khz 000 = 31 khz (from either intosc/256 or intrc directly) (4) bit 3 osts: oscillator start-up time-out status bit (2) 1 = oscillator start-up timer time-out has expired; primary oscillator is running 0 = oscillator start-up timer time-out is running; primary oscillator is not ready bit 2 unimplemented: read as ? 1 ? bit 1-0 scs1:scs0: system clock select bits 11 = postscaled internal clock (intrc/intosc derived) 10 = reserved 01 = timer1 oscillator 00 = primary clock source (intosc postscaler output when fosc2:fosc0 = 001 or 000 ) 00 = primary clock source (cpu divider output for other values of fosc2:fosc0) note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 2: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 3: default output frequency of intosc on reset (4 mhz). 4: source selected by the intsrc bit (osctune<7>), see text.
? 2007 microchip technology inc. preliminary ds39775b-page 43 pic18f87j50 family 2.5 reference clock output in addition to the peripheral clock/4 output in certain oscillator modes, the device clock in the pic18f87j50 family can also be configured to provide a reference clock output signal to a port pin. this feature is avail- able in all oscillator configurations and allows the user to select a greater range of clock submultiples to drive external devices in the application. this reference clock output is controlled by the refocon register (register 2-3). setting the roon bit (refocon<7>) makes the clock signal available on the refo (re3) pin. the rodiv3:rodiv0 bits enable the selection of 16 different clock divider options. the rosslp and rosel bits (refocon<5:4>) con- trol the availability of the reference output during sleep mode. the rosel bit determines if the oscillator on osc1 and osc2, or the current system clock source, is used for the reference clock output. the rosslp bit determines if the reference source is available on re3 when the device is in sleep mode. to use the reference clock output in sleep mode, both the rosslp and rosel bits must be set. the device clock must also be configured for an ec or hs mode; otherwise, the oscillator on osc1 and osc2 will be powered down when the device enters sleep mode. clearing the rosel bit allows the reference output frequency to change as the system clock changes during any clock switches. the refocon register is an alternate sfr and shares the same memory address as the osccon register. it is accessed by setting the adshr bit (wdtcon<4>) in the wdtcon register (see register 25-9). register 2-3: refocon: reference oscillator control register r/w-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 roon ? rosslp rosel rodiv3 rodiv2 rodiv1 rodiv0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 roon: reference oscillator output enable bit 1 = reference oscillator enabled on refo pin 0 = reference oscillator disabled bit 6 unimplemented: read as ? 0 ? bit 5 rosslp: reference oscillator output stop in sleep bit 1 = reference oscillator continues to run in sleep 0 = reference oscillator is disabled in sleep bit 4 rosel: reference oscillator source select bit 1 = primary oscillator used as the base clock. note that the crystal oscillator must be enabled using the fosc2:fosc0 bits; crystal maintains the operation in sleep mode. 0 = system clock used as the base clock; base clock reflects any clock switching of the device bit 3-0 rodiv3:rodiv0: reference oscillator divisor select bits 1111 = base clock value divided by 32,768 1110 = base clock value divided by 16,384 1101 = base clock value divided by 8,192 1100 = base clock value divided by 4,096 1011 = base clock value divided by 2,048 1010 = base clock value divided by 1,024 1001 = base clock value divided by 512 1000 = base clock value divided by 256 0111 = base clock value divided by 128 0110 = base clock value divided by 64 0101 = base clock value divided by 32 0100 = base clock value divided by 16 0011 = base clock value divided by 8 0010 = base clock value divided by 4 0001 = base clock value divided by 2 0000 = base clock value
pic18f87j50 family ds39775b-page 44 preliminary ? 2007 microchip technology inc. 2.6 effects of power-managed modes on the various clock sources when pri_idle mode is selected, the designated primary oscillator continues to run without interruption. for all other power-managed modes, the oscillator using the osc1 pin is disabled. unless the usb module is enabled, the osc1 pin (and osc2 pin if used by the oscillator) will stop oscillating. in secondary clock modes (sec_run and sec_idle), the timer1 oscillator is operating and providing the device clock. the timer1 oscillator may also run in all power-managed modes if required to clock timer1 or timer3. in internal oscillator modes (rc_run and rc_idle), the internal oscillator block provides the device clock source. the 31 khz intrc output can be used directly to provide the clock and may be enabled to support various special features regardless of the power-managed mode (see section 25.2 ?watchdog timer (wdt)? , section 25.4 ?two-speed start-up? and section 25.5 ?fail-safe clock monitor? for more information on wdt, fail-safe clock monitor and two-speed start-up). the intosc output at 8 mhz may be used directly to clock the device or may be divided down by the postscaler. the intosc output is disabled if the clock is provided directly from the intrc output. if the sleep mode is selected, all clock sources which are no longer required are stopped. since all the tran- sistor switching currents have been stopped, sleep mode achieves the lowest current consumption of the device (only leakage currents). sleep mode should not be invoked while the usb mod- ule is enabled and operating in full-power mode. before sleep mode is selected, the usb module should be put in the suspend state. this is accomplished by setting the suspnd bit in the ucon register. enabling any on-chip feature that will operate during sleep will increase the current consumed during sleep. the intrc is required to support wdt operation. the timer1 oscillator may be operating to support a real-time clock. other features may be operating that do not require a device clock source (i.e., mssp slave, pmp, intx pins and others). peripherals that may add significant current consumption are listed in section 28.2 ?dc characteristics: power-down and supply current? . 2.7 power-up delays power-up delays are controlled by two timers so that no external reset circuitry is required for most applications. the delays ensure that the device is kept in reset until the device power supply is stable under normal circum- stances and the primary clock is operating and stable. for additional information on power-up delays, see section 4.6 ?power-up timer (pwrt)? . the first timer is the power-up timer (pwrt), which provides a fixed delay on power-up (parameter 33, table 28-13). the second timer is the oscillator start-up timer (ost), intended to keep the chip in reset until the crystal oscillator is stable (hs mode). the ost does this by counting 1024 oscillator cycles before allowing the oscillator to clock the device. there is a delay of interval, t csd (parameter 38, table 28-13), following por, while the controller becomes ready to execute instructions. this delay runs concurrently with any other delays. this may be the only delay that occurs when any of the ec or internal oscillator modes are used as the primary clock source.
? 2007 microchip technology inc. preliminary ds39775b-page 45 pic18f87j50 family 3.0 power-managed modes the pic18f87j50 family devices provide the ability to manage power consumption by simply managing clock- ing to the cpu and the peripherals. in general, a lower clock frequency and a reduction in the number of circuits being clocked constitutes lower consumed power. for the sake of managing power in an application, there are three primary modes of operation: ? run mode ? idle mode ? sleep mode these modes define which portions of the device are clocked and at what speed. the run and idle modes may use any of the three available clock sources (primary, secondary or internal oscillator block); the sleep mode does not use a clock source. the power-managed modes include several power-saving features offered on previous pic ? devices. one is the clock switching feature, offered in other pic18 devices, allowing the controller to use the timer1 oscillator in place of the primary oscillator. also included is the sleep mode, offered by all pic devices, where all device clocks are stopped. 3.1 selecting power-managed modes selecting a power-managed mode requires two decisions: if the cpu is to be clocked or not and which clock source is to be used. the idlen bit (osccon<7>) controls cpu clocking, while the scs1:scs0 bits (osccon<1:0>) select the clock source. the individual modes, bit settings, clock sources and affected modules are summarized in table 3-1. 3.1.1 clock sources the scs1:scs0 bits allow the selection of one of three clock sources for power-managed modes. they are: ? the primary clock source, as defined by the fosc2:fosc0 configuration bits ? the timer1 clock (provided by the secondary oscillator) ? the postscaled internal clock (derived from the internal oscillator block) 3.1.2 entering power-managed modes switching from one power-managed mode to another begins by loading the osccon register. the scs1:scs0 bits select the clock source and determine which run or idle mode is to be used. changing these bits causes an immediate switch to the new clock source, assuming that it is running. the switch may also be subject to clock transition delays. these are discussed in section 3.1.3 ?clock transitions and status indicators? and subsequent sections. entry to the power-managed idle or sleep modes is triggered by the execution of a sleep instruction. the actual mode that results depends on the status of the idlen bit. depending on the current mode and the mode being switched to, a change to a power-managed mode does not always require setting all of these bits. many transitions may be done by changing the oscillator select bits, or changing the idlen bit, prior to issuing a sleep instruction. if the idlen bit is already configured correctly, it may only be necessary to perform a sleep instruction to switch to the desired mode. table 3-1: power- managed modes mode osccon<7,1:0> module clocking available clock and oscillator source idlen (1) scs1:scs0 cpu peripherals sleep 0 n/a off off none ? all clocks are disabled pri_run n/a 00 clocked clocked primary clock source (defined by fosc2:fosc0); this is the normal full-power execution mode sec_run n/a 01 clocked clocked secondary ? timer1 oscillator rc_run n/a 11 clocked clocked postscaled internal clock pri_idle 100 off clocked primary clock source (defined by fosc2:fosc0) sec_idle 101 off clocked secondary ? timer1 oscillator rc_idle 111 off clocked postscaled internal clock note 1: idlen reflects its value when the sleep instruction is executed.
pic18f87j50 family ds39775b-page 46 preliminary ? 2007 microchip technology inc. 3.1.3 clock transitions and status indicators the length of the transition between clock sources is the sum of two cycles of the old clock source and three to four cycles of the new clock source. this formula assumes that the new clock source is stable. two bits indicate the current clock source and its status: osts (osccon<3>) and t1run (t1con<6>). in general, only one of these bits will be set while in a given power-managed mode. when the osts bit is set, the primary clock is providing the device clock. when the t1run bit is set, the timer1 oscillator is providing the clock. if neither of these bits is set, intrc is clocking the device. 3.1.4 multiple sleep commands the power-managed mode that is invoked with the sleep instruction is determined by the setting of the idlen bit at the time the instruction is executed. if another sleep instruction is executed, the device will enter the power-managed mode specified by idlen at that time. if idlen has changed, the device will enter the new power-managed mode specified by the new setting. 3.2 run modes in the run modes, clocks to both the core and peripherals are active. the difference between these modes is the clock source. 3.2.1 pri_run mode the pri_run mode is the normal, full-power execu- tion mode of the microcontroller. this is also the default mode upon a device reset unless two-speed start-up is enabled (see section 25.4 ?two-speed start-up? for details). in this mode, the osts bit is set. (see section 2.4.1 ?oscillator control register? ). 3.2.2 sec_run mode the sec_run mode is the compatible mode to the ?clock switching? feature offered in other pic18 devices. in this mode, the cpu and peripherals are clocked from the timer1 oscillator. this gives users the option of lower power consumption while still using a high-accuracy clock source. sec_run mode is entered by setting the scs1:scs0 bits to ? 01 ?. the device clock source is switched to the timer1 oscillator (see figure 3-1), the primary oscilla- tor is shut down, the t1run bit (t1con<6>) is set and the osts bit is cleared. note: executing a sleep instruction does not necessarily place the device into sleep mode. it acts as the trigger to place the controller into either the sleep mode, or one of the idle modes, depending on the setting of the idlen bit.
? 2007 microchip technology inc. preliminary ds39775b-page 47 pic18f87j50 family on transitions from sec_run mode to pri_run mode, the peripherals and cpu continue to be clocked from the timer1 oscillator while the primary clock is started. when the primary clock becomes ready, a clock switch back to the primary clock occurs (see figure 3-2). when the clock switch is complete, the t1run bit is cleared, the osts bit is set and the primary clock is providing the clock. the idlen and scs bits are not affected by the wake-up; the timer1 oscillator continues to run. figure 3-1: transition timing for entry to sec_run mode figure 3-2: transition timing from sec_run mode to pri_run mode (hspll) note: the timer1 oscillator should already be running prior to entering sec_run mode. if the t1oscen bit is not set when the scs1:scs0 bits are set to ? 01 ?, entry to sec_run mode will not occur. if the timer1 oscillator is enabled, but not yet running, device clocks will be delayed until the oscillator has started. in such situa- tions, initial oscillator operation is far from stable and unpredictable operation may result. q4 q3 q2 osc1 peripheral program q1 t1osi q1 counter clock cpu clock pc + 2 pc 123 n-1 n clock transition q4 q3 q2 q1 q3 q2 pc + 4 q1 q3 q4 osc1 peripheral program pc t1osi pll clock q1 pc + 4 q2 output q3 q4 q1 cpu clock pc + 2 clock counter q2 q2 q3 note 1: t ost = 1024 t osc ; t pll = 2 ms (approx). these intervals are not shown to scale. scs1:scs0 bits changed t pll (1) 12 n-1n clock osts bit set transition t ost (1)
pic18f87j50 family ds39775b-page 48 preliminary ? 2007 microchip technology inc. 3.2.3 rc_run mode in rc_run mode, the cpu and peripherals are clocked from the internal oscillator; the primary clock is shut down. this mode provides the best power conser- vation of all the run modes while still executing code. it works well for user applications which are not highly timing sensitive or do not require high-speed clocks at all times. this mode is entered by setting the scs1:scs0 bits (osccon<1:0>) to ? 11 ?. when the clock source is switched to the internal oscillator block (see figure 3-3), the primary oscillator is shut down and the osts bit is cleared. on transitions from rc_run mode to pri_run mode, the device continues to be clocked from the intosc block while the primary clock is started. when the primary clock becomes ready, a clock switch to the primary clock occurs (see figure 3-4). when the clock switch is complete, the osts bit is set and the primary clock is providing the device clock. the idlen and scs bits are not affected by the switch. the intrc block source will continue to run if either the wdt or the fail-safe clock monitor is enabled. figure 3-3: transition timing to rc_run mode figure 3-4: transition timing fr om rc_run mode to pri_run mode q4 q3 q2 osc1 peripheral program q1 intrc q1 counter clock cpu clock pc + 2 pc 123 n-1n clock transition q4 q3 q2 q1 q3 q2 pc + 4 q1 q3 q4 osc1 peripheral program pc intrc pll clock q1 pc + 4 q2 output q3 q4 q1 cpu clock pc + 2 clock counter q2 q2 q3 note 1: t ost = 1024 t osc ; t pll = 2 ms (approx). these intervals are not shown to scale. scs1:scs0 bits changed t pll (1) 12 n-1n clock osts bit set transition t ost (1)
? 2007 microchip technology inc. preliminary ds39775b-page 49 pic18f87j50 family 3.3 sleep mode the power-managed sleep mode is identical to the leg- acy sleep mode offered in all other pic devices. it is entered by clearing the idlen bit (the default state on device reset) and executing the sleep instruction. this shuts down the selected oscillator (figure 3-5). all clock source status bits are cleared. entering the sleep mode from any other mode does not require a clock switch. this is because no clocks are needed once the controller has entered sleep. if the wdt is selected, the intrc source will continue to operate. if the timer1 oscillator is enabled, it will also continue to run. when a wake event occurs in sleep mode (by interrupt, reset or wdt time-out), the device will not be clocked until the clock source selected by the scs1:scs0 bits becomes ready (see figure 3-6), or it will be clocked from the internal oscillator if either the two-speed start-up or the fail-safe clock monitor are enabled (see section 25.0 ?special features of the cpu? ). in either case, the osts bit is set when the primary clock is providing the device clocks. the idlen and scs bits are not affected by the wake-up. 3.4 idle modes the idle modes allow the controller?s cpu to be selectively shut down while the peripherals continue to operate. selecting a particular idle mode allows users to further manage power consumption. if the idlen bit is set to ? 1 ? when a sleep instruction is executed, the peripherals will be clocked from the clock source selected using the scs1:scs0 bits; however, the cpu will not be clocked. the clock source status bits are not affected. setting idlen and executing a sleep instruction provides a quick method of switching from a given run mode to its corresponding idle mode. if the wdt is selected, the intrc source will continue to operate. if the timer1 oscillator is enabled, it will also continue to run. since the cpu is not executing instructions, the only exits from any of the idle modes are by interrupt, wdt time-out or a reset. when a wake event occurs, cpu execution is delayed by an interval of t csd (parameter 38, table 28-13) while it becomes ready to execute code. when the cpu begins executing code, it resumes with the same clock source for the current idle mode. for example, when waking from rc_idle mode, the internal oscillator block will clock the cpu and peripherals (in other words, rc_run mode). the idlen and scs bits are not affected by the wake-up. while in any idle mode or the sleep mode, a wdt time-out will result in a wdt wake-up to the run mode currently specified by the scs1:scs0 bits. figure 3-5: transition timi ng for entry to sleep mode figure 3-6: transition timing for wake from sleep (hspll) q4 q3 q2 osc1 peripheral sleep program q1 q1 counter clock cpu clock pc + 2 pc q3 q4 q1 q2 osc1 peripheral program pc pll clock q3 q4 output cpu clock q1 q2 q3 q4 q1 q2 clock counter pc + 6 pc + 4 q1 q2 q3 q4 wake event note1: t ost = 1024 t osc ; t pll = 2 ms (approx). these intervals are not shown to scale. t ost (1) t pll (1) osts bit set pc + 2
pic18f87j50 family ds39775b-page 50 preliminary ? 2007 microchip technology inc. 3.4.1 pri_idle mode this mode is unique among the three low-power idle modes, in that it does not disable the primary device clock. for timing sensitive applications, this allows for the fastest resumption of device operation with its more accurate primary clock source, since the clock source does not have to ?warm up? or transition from another oscillator. pri_idle mode is entered from pri_run mode by setting the idlen bit and executing a sleep instruc- tion. if the device is in another run mode, set idlen first, then set the scs bits to ? 00 ? and execute sleep . although the cpu is disabled, the peripherals continue to be clocked from the primary clock source specified by the fosc1:fosc0 configuration bits. the osts bit remains set (see figure 3-7). when a wake event occurs, the cpu is clocked from the primary clock source. a delay of interval t csd is required between the wake event and when code exe- cution starts. this is required to allow the cpu to become ready to execute instructions. after the wake-up, the osts bit remains set. the idlen and scs bits are not affected by the wake-up (see figure 3-8). 3.4.2 sec_idle mode in sec_idle mode, the cpu is disabled but the peripherals continue to be clocked from the timer1 oscillator. this mode is entered from sec_run by set- ting the idlen bit and executing a sleep instruction. if the device is in another run mode, set idlen first, then set scs1:scs0 to ? 01 ? and execute sleep . when the clock source is switched to the timer1 oscillator, the primary oscillator is shut down, the osts bit is cleared and the t1run bit is set. when a wake event occurs, the peripherals continue to be clocked from the timer1 oscillator. after an interval of t csd following the wake event, the cpu begins exe- cuting code being clocked by the timer1 oscillator. the idlen and scs bits are not affected by the wake-up; the timer1 oscillator continues to run (see figure 3-8). figure 3-7: transition timing for entry to idle mode figure 3-8: transition timing for wake from idle to run mode note: the timer1 oscillator should already be running prior to entering sec_idle mode. if the t1oscen bit is not set when the sleep instruction is executed, the sleep instruction will be ignored and entry to sec_idle mode will not occur. if the timer1 oscillator is enabled, but not yet running, peripheral clocks will be delayed until the oscillator has started. in such situations, initial oscillator operation is far from stable and unpredictable operation may result. q1 peripheral program pc pc + 2 osc1 q3 q4 q1 cpu clock clock counter q2 osc1 peripheral program pc cpu clock q1 q3 q4 clock counter q2 wake event t csd
? 2007 microchip technology inc. preliminary ds39775b-page 51 pic18f87j50 family 3.4.3 rc_idle mode in rc_idle mode, the cpu is disabled but the peripherals continue to be clocked from the internal oscillator block. this mode allows for controllable power conservation during idle periods. from rc_run, this mode is entered by setting the idlen bit and executing a sleep instruction. if the device is in another run mode, first set idlen, then clear the scs bits and execute sleep . when the clock source is switched to the intosc block, the primary oscillator is shut down and the osts bit is cleared. when a wake event occurs, the peripherals continue to be clocked from the internal oscillator block. after a delay of t csd following the wake event, the cpu begins executing code being clocked by the intrc. the idlen and scs bits are not affected by the wake-up. the intrc source will continue to run if either the wdt or the fail-safe clock monitor is enabled. 3.5 exiting idle and sleep modes an exit from sleep mode, or any of the idle modes, is triggered by an interrupt, a reset or a wdt time-out. this section discusses the triggers that cause exits from power-managed modes. the clocking subsystem actions are discussed in each of the power-managed modes sections (see section 3.2 ?run modes?, section 3.3 ?sleep mode? and section 3.4 ?idle modes? ). 3.5.1 exit by interrupt any of the available interrupt sources can cause the device to exit from an idle mode, or the sleep mode, to a run mode. to enable this functionality, an interrupt source must be enabled by setting its enable bit in one of the intcon or pie registers. the exit sequence is initiated when the corresponding interrupt flag bit is set. on all exits from idle or sleep modes by interrupt, code execution branches to the interrupt vector if the gie/gieh bit (intcon<7>) is set. otherwise, code execution continues or resumes without branching (see section 9.0 ?interrupts? ). a fixed delay of interval, t csd , following the wake event is required when leaving sleep and idle modes. this delay is required for the cpu to prepare for execution. instruction execution resumes on the first clock cycle following this delay. 3.5.2 exit by wdt time-out a wdt time-out will cause different actions depending on which power-managed mode the device is in when the time-out occurs. if the device is not executing code (all idle modes and sleep mode), the time-out will result in an exit from the power-managed mode (see section 3.2 ?run modes? and section 3.3 ?sleep mode? ). if the device is executing code (all run modes), the time-out will result in a wdt reset (see section 25.2 ?watchdog timer (wdt)? ). the watchdog timer and postscaler are cleared by one of the following events: ? executing a sleep or clrwdt instruction ? the loss of a currently selected clock source (if the fail-safe clock monitor is enabled) 3.5.3 exit by reset exiting an idle or sleep mode by reset automatically forces the device to run from the intrc. 3.5.4 exit without an oscillator start-up delay certain exits from power-managed modes do not invoke the ost at all. there are two cases: ? pri_idle mode, where the primary clock source is not stopped; and ? the primary clock source is either the ec or ecpll mode. in these instances, the primary clock source either does not require an oscillator start-up delay, since it is already running (pri_idle), or normally does not require an oscillator start-up delay (ec). however, a fixed delay of interval, t csd , following the wake event is still required when leaving sleep and idle modes to allow the cpu to prepare for execution. instruction execution resumes on the first clock cycle following this delay.
pic18f87j50 family ds39775b-page 52 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 53 pic18f87j50 family 4.0 reset the pic18f87j50 family of devices differentiate between various kinds of reset: a) power-on reset (por) b) mclr reset during normal operation c) mclr reset during power-managed modes d) watchdog timer (wdt) reset (during execution) e) configuration mismatch (cm) f) brown-out reset (bor) g) reset instruction h) stack full reset i) stack underflow reset this section discusses resets generated by mclr , por and bor, and covers the operation of the various start-up timers. stack reset events are covered in section 5.1.6.4 ?stack full and underflow resets? . wdt resets are covered in section 25.2 ?watchdog timer (wdt)? . a simplified block diagram of the on-chip reset circuit is shown in figure 4-1. 4.1 rcon register device reset events are tracked through the rcon register (register 4-1). the lower five bits of the register indicate that a specific reset event has occurred. in most cases, these bits can only be set by the event and must be cleared by the application after the event. the state of these flag bits, taken together, can be read to indicate the type of reset that just occurred. this is described in more detail in section 4.7 ?reset state of registers? . the rcon register also has a control bit for setting interrupt priority (ipen). interrupt priority is discussed in section 9.0 ?interrupts? . figure 4-1: simplified block diagram of on-chip reset circuit external reset mclr v dd wdt time-out v dd rise detect pwrt intrc por pulse chip_reset brown-out reset (1) reset instruction stack pointer stack full/underflow reset sleep ( )_idle 32 s note 1: the envreg pin must be tied high to enable brown-out reset. the brown-out reset is provided by the on-chip voltage regulator when there is insufficient source voltage to function properly. pwrt 11-bit ripple counter 66 ms s r q configuration word mismatch
pic18f87j50 family ds39775b-page 54 preliminary ? 2007 microchip technology inc. register 4-1: rcon: re set control register r/w-0 u-0 r/w-1 r/w-1 r-1 r-1 r/w-0 r/w-0 ipen ?cm ri to pd por bor bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ipen: interrupt priority enable bit 1 = enable priority levels on interrupts 0 = disable priority levels on interrupts (pic16cxxx compatibility mode) bit 6 unimplemented: read as ? 0 ? bit 5 cm: configuration mismatch flag bit 1 = a configuration mismatch reset has not occurred 0 = a configuration mismatch reset has occurred (must be set in software after a configuration mismatch reset occurs) bit 4 ri : reset instruction flag bit 1 = the reset instruction was not executed (set by firmware only) 0 = the reset instruction was executed causing a device reset (must be set in software after a brown-out reset occurs) bit 3 to : watchdog time-out flag bit 1 = set by power-up, clrwdt instruction or sleep instruction 0 = a wdt time-out occurred bit 2 pd : power-down detection flag bit 1 = set by power-up or by the clrwdt instruction 0 = set by execution of the sleep instruction bit 1 por : power-on reset status bit 1 = a power-on reset has not occurred (set by firmware only) 0 = a power-on reset occurred (must be set in software after a power-on reset occurs) bit 0 bor : brown-out reset status bit 1 = a brown-out reset has not occurred (set by firmware only) 0 = a brown-out reset occurred (must be set in software after a brown-out reset occurs) note 1: it is recommended that the por bit be set after a power-on reset has been detected, so that subsequent power-on resets may be detected. 2: if the on-chip voltage regulator is disabled, bor remains ? 0 ? at all times. see section 4.4.1 ?detecting bor? for more information. 3: brown-out reset is said to have occurred when bor is ? 0 ? and por is ? 1 ? (assuming that por was set to ? 1 ? by software immediately after a power-on reset).
? 2007 microchip technology inc. preliminary ds39775b-page 55 pic18f87j50 family 4.2 master clear (mclr ) the mclr pin provides a method for triggering a hard external reset of the device. a reset is generated by holding the pin low. pic18 extended microcontroller devices have a noise filter in the mclr reset path which detects and ignores small pulses. the mclr pin is not driven low by any internal resets, including the wdt. 4.3 power-on reset (por) a power-on reset condition is generated on-chip whenever v dd rises above a certain threshold. this allows the device to start in the initialized state when v dd is adequate for operation. to take advantage of the por circuitry, tie the mclr pin through a resistor (1 k to 10 k ) to v dd . this will eliminate external rc components usually needed to create a power-on reset delay. a minimum rise rate for v dd is specified (parameter d004). for a slow rise time, see figure 4-2. when the device starts normal operation (i.e., exits the reset condition), device operating parameters (voltage, frequency, temperature, etc.) must be met to ensure operation. if these conditions are not met, the device must be held in reset until the operating conditions are met. por events are captured by the por bit (rcon<1>). the state of the bit is set to ? 0 ? whenever a power-on reset occurs; it does not change for any other reset event. por is not reset to ? 1 ? by any hardware event. to capture multiple events, the user manually resets the bit to ? 1 ? in software following any power-on reset. 4.4 brown-out reset (bor) the pic18f87j50 family of devices incorporates a simple bor function when the internal regulator is enabled (envreg pin is tied to v dd ). any drop of v dd below v bor (parameter d005) for greater than time t bor (parameter 35) will reset the device. a reset may or may not occur if v dd falls below v bor for less than t bor . the chip will remain in brown-out reset until v dd rises above v bor . once a bor has occurred, the power-up timer will keep the chip in reset for t pwrt (parameter 33). if v dd drops below v bor while the power-up timer is running, the chip will go back into a brown-out reset and the power-up timer will be initialized. once v dd rises above v bor , the power-up timer will execute the additional time delay. figure 4-2: external power-on reset circuit (for slow v dd power-up) 4.4.1 detecting bor the bor bit always resets to ? 0 ? on any brown-out reset or power-on reset event. this makes it difficult to determine if a brown-out reset event has occurred just by reading the state of bor alone. a more reliable method is to simultaneously check the state of both por and bor . this assumes that the por bit is reset to ? 1 ? in software immediately after any power-on reset event. if bor is ? 0 ? while por is ? 1 ?, it can be reliably assumed that a brown-out reset event has occurred. if the voltage regulator is disabled, brown-out reset functionality is disabled. in this case, the bor bit cannot be used to determine a brown-out reset event. the bor bit is still cleared by a power-on reset event. 4.5 configuration mismatch (cm) the configuration mismatch (cm) reset is designed to detect and attempt to recover from random, memory corrupting events. these include electrostatic discharge (esd) events, which can cause widespread single-bit changes throughout the device, and result in catastrophic failure. in pic18fxxj flash devices, the device configuration registers (located in the configuration memory space) are continuously monitored during operation by com- paring their values to complimentary shadow registers. if a mismatch is detected between the two sets of registers, a cm reset automatically occurs. these events are captured by the cm bit (rcon<5>). the state of the bit is set to ? 0 ? whenever a cm event occurs; it does not change for any other reset event. note 1: external power-on reset circuit is required only if the v dd power-up slope is too slow. the diode d helps discharge the capacitor quickly when v dd powers down. 2: r < 40 k is recommended to make sure that the voltage drop across r does not violate the device?s electrical specification. 3: r1 1 k will limit any current flowing into mclr from external capacitor c, in the event of mclr /v pp pin breakdown, due to electrostatic discharge (esd) or electrical overstress (eos). c r1 r d v dd mclr pic18f87j50 v dd
pic18f87j50 family ds39775b-page 56 preliminary ? 2007 microchip technology inc. a cm reset behaves similarly to a master clear reset, reset instruction, wdt time-out or stack event resets. as with all hard and power reset events, the device configuration words are reloaded from the flash configuration words in program memory as the device restarts. 4.6 power-up timer (pwrt) pic18f87j50 family devices incorporate an on-chip power-up timer (pwrt) to help regulate the power-on reset process. the pwrt is always enabled. the main function is to ensure that the device voltage is stable before code is executed. the power-up timer (pwrt) of the pic18f87j50 fam- ily devices is an 11-bit counter which uses the intrc source as the clock input. this yields an approximate time interval of 2048 x 32 s = 66 ms. while the pwrt is counting, the device is held in reset. the power-up time delay depends on the intrc clock and will vary from chip-to-chip due to temperature and process variation. see dc parameter 33 for details. 4.6.1 time-out sequence the pwrt time-out is invoked after the por pulse has cleared. the total time-out will vary based on the status of the pwrt. figure 4-3, figure 4-4, figure 4-5 and figure 4-6 all depict time-out sequences on power-up with the power-up timer. since the time-outs occur from the por pulse, if mclr is kept low long enough, the pwrt will expire. bringing mclr high will begin execution immediately if a clock source is available (figure 4-5). this is useful for testing purposes, or to synchronize more than one pic18fxxxx device operating in parallel. figure 4-3: time-out sequ ence on power-up (mclr tied to v dd , v dd rise < t pwrt ) figure 4-4: time-out sequ ence on power-up (mclr not tied to v dd ): case 1 t pwrt v dd mclr internal por pwrt time-out internal reset t pwrt v dd mclr internal por pwrt time-out internal reset
? 2007 microchip technology inc. preliminary ds39775b-page 57 pic18f87j50 family figure 4-5: time-out sequ ence on power-up (mclr not tied to v dd ): case 2 figure 4-6: slow rise time (mclr tied to v dd , v dd rise > t pwrt ) v dd mclr internal por pwrt time-out internal reset t pwrt v dd mclr internal por pwrt time-out internal reset 0v 1v 3.3v t pwrt
pic18f87j50 family ds39775b-page 58 preliminary ? 2007 microchip technology inc. 4.7 reset state of registers most registers are unaffected by a reset. their status is unknown on por and unchanged by all other resets. the other registers are forced to a ?reset state? depending on the type of reset that occurred. most registers are not affected by a wdt wake-up, since this is viewed as the resumption of normal operation. status bits from the rcon register (cm , ri , to , pd , por and bor ) are set or cleared differently in different reset situations, as indicated in table 4-1. these bits are used in software to determine the nature of the reset. table 4-2 describes the reset states for all of the special function registers. these are categorized by power-on and brown-out resets, master clear and wdt resets and wdt wake-ups. table 4-1: status bits, their significance and the initialization condition for rcon register condition program counter (1) rcon register stkptr register cm ri to pd por bor stkful stkunf power-on reset 0000h 111100 0 0 reset instruction 0000h u0uuuu u u brown-out reset 0000h 1111u0 u u configuration mismatch reset 0000h 0uuuuu u u mclr reset during power-managed run modes 0000h uu1uuu u u mclr reset during power-managed idle modes and sleep mode 0000h uu10uu u u mclr reset during full-power execution 0000h uuuuuu u u stack full reset (stvren = 1 ) 0000h uuuuuu 1 u stack underflow reset (stvren = 1 ) 0000h uuuuuu u 1 stack underflow error (not an actual reset, stvren = 0 ) 0000h uuuuuu u 1 wdt time-out during full-power or power-managed run modes 0000h uu0uuu u u wdt time-out during power-managed idle or sleep modes pc + 2 uu00uu u u interrupt exit from power-managed modes pc + 2 uuu0uu u u legend: u = unchanged note 1: when the wake-up is due to an interrupt and the gieh or giel bit is set, the pc is loaded with the interrupt vector (0008h or 0018h).
? 2007 microchip technology inc. preliminary ds39775b-page 59 pic18f87j50 family table 4-2: initialization conditions for all registers register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt tosu pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---0 uuuu (1) tosh pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu (1) tosl pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu (1) stkptr pic18f6xj5x pic18f8xj5x 00-0 0000 uu-0 0000 uu-u uuuu (1) pclatu pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu pclath pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pcl pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 pc + 2 (2) tblptru pic18f6xj5x pic18f8xj5x --00 0000 --00 0000 --uu uuuu tblptrh pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu tblptrl pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu tablat pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu prodh pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu prodl pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu intcon pic18f6xj5x pic18f8xj5x 0000 000x 0000 000u uuuu uuuu (3) intcon2 pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu (3) intcon3 pic18f6xj5x pic18f8xj5x 1100 0000 1100 0000 uuuu uuuu (3) indf0 pic18f6xj5x pic18f8xj5x n/a n/a n/a postinc0 pic18f6xj5x pic18f8xj5x n/a n/a n/a postdec0 pic18f6xj5x pic18f8xj5x n/a n/a n/a preinc0 pic18f6xj5x pic18f8xj5x n/a n/a n/a plusw0 pic18f6xj5x pic18f8xj5x n/a n/a n/a fsr0h pic18f6xj5x pic18f8xj5x ---- xxxx ---- uuuu ---- uuuu fsr0l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu wreg pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu indf1 pic18f6xj5x pic18f8xj5x n/a n/a n/a postinc1 pic18f6xj5x pic18f8xj5x n/a n/a n/a postdec1 pic18f6xj5x pic18f8xj5x n/a n/a n/a preinc1 pic18f6xj5x pic18f8xj5x n/a n/a n/a plusw1 pic18f6xj5x pic18f8xj5x n/a n/a n/a fsr1h pic18f6xj5x pic18f8xj5x ---- xxxx ---- uuuu ---- uuuu fsr1l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu bsr pic18f6xj5x pic18f8xj5x ---- 0000 ---- 0000 ---- uuuu legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
pic18f87j50 family ds39775b-page 60 preliminary ? 2007 microchip technology inc. indf2 pic18f6xj5x pic18f8xj5x n/a n/a n/a postinc2 pic18f6xj5x pic18f8xj5x n/a n/a n/a postdec2 pic18f6xj5x pic18f8xj5x n/a n/a n/a preinc2 pic18f6xj5x pic18f8xj5x n/a n/a n/a plusw2 pic18f6xj5x pic18f8xj5x n/a n/a n/a fsr2h pic18f6xj5x pic18f8xj5x ---- xxxx ---- uuuu ---- uuuu fsr2l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu status pic18f6xj5x pic18f8xj5x ---x xxxx ---u uuuu ---u uuuu tmr0h pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu tmr0l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu t0con pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu osccon pic18f6xj5x pic18f8xj5x 0110 q100 0110 q100 0110 q10u refocon pic18f6xj5x pic18f8xj5x 0-00 0000 u-uu uuuu u-uu uuuu cm1con pic18f6xj5x pic18f8xj5x 0001 1111 uuuu uuuu uuuu uuuu cm2con pic18f6xj5x pic18f8xj5x 0001 1111 uuuu uuuu uuuu uuuu rcon (4) pic18f6xj5x pic18f8xj5x 0-11 1100 0-qq qquu u-qq qquu tmr1h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu odcon1 pic18f6xj5x pic18f8xj5x ---0 0000 ---u uuuu ---u uuuu tmr1l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu odcon2 pic18f6xj5x pic18f8xj5x ---- --00 ---- --uu ---- --uu t1con pic18f6xj5x pic18f8xj5x 0000 0000 u0uu uuuu uuuu uuuu odcon3 pic18f6xj5x pic18f8xj5x ---- --00 ---- --uu ---- --uu tmr2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu padcfg1 pic18f6xj5x pic18f8xj5x ---- ---0 ---- ---u ---- ---u pr2 pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 1111 1111 memcon pic18f6xj5x pic18f8xj5x 0-00 --00 0-00 --00 u-uu --uu t2con pic18f6xj5x pic18f8xj5x -000 0000 -000 0000 -uuu uuuu ssp1buf pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ssp1add pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ssp1msk pic18f6xj5x pic18f8xj5x 1111 1111 uuuu uuuu uuuu uuuu ssp1stat pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ssp1con1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ssp1con2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu table 4-2: initialization conditi ons for all registers (continued) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
? 2007 microchip technology inc. preliminary ds39775b-page 61 pic18f87j50 family adresh pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu adresl pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu adcon0 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu adcon1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ancon0 pic18f6xj5x pic18f8xj5x 0--0 0000 u--u uuuu u--u uuuu ancon1 pic18f6xj5x pic18f8xj5x 0000 00-- uuuu uu-- uuuu uu-- wdtcon pic18f6xj5x pic18f8xj5x 0x-0 ---0 0x-u ---0 ux-u ---u eccp1as pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu eccp1del pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ccpr1h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccpr1l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccp1con pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu eccp2as pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu eccp2del pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ccpr2h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccpr2l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccp2con pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu eccp3as pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu eccp3del pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ccpr3h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccpr3l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccp3con pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu spbrg1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu rcreg1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu txreg1 pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu txsta1 pic18f6xj5x pic18f8xj5x 0000 0010 0000 0010 uuuu uuuu rcsta1 pic18f6xj5x pic18f8xj5x 0000 000x 0000 000x uuuu uuuu spbrg2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu rcreg2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu txreg2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu txsta2 pic18f6xj5x pic18f8xj5x 0000 0010 0000 0010 uuuu uuuu eecon2 pic18f6xj5x pic18f8xj5x ---- ---- ---- ---- ---- ---- eecon1 pic18f6xj5x pic18f8xj5x --00 x00- --00 u00- --00 u00- table 4-2: initialization conditions for all registers (continued) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
pic18f87j50 family ds39775b-page 62 preliminary ? 2007 microchip technology inc. ipr3 pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu pir3 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu (3) pie3 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ipr2 pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu pir2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu (3) pie2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ipr1 pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu pir1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu (3) pie1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu rcsta2 pic18f6xj5x pic18f8xj5x 0000 000x 0000 000x uuuu uuuu osctune pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu trisj pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu trish pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu trisg pic18f6xj5x pic18f8xj5x ---1 1111 ---1 1111 ---u uuuu trisf pic18f6xj5x pic18f8xj5x 111- -1-- 111- -1-- uuu- -u-- trise pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu trisd pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu trisc pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu trisb pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu trisa pic18f6xj5x pic18f8xj5x --11 1111 --11 1111 --uu uuuu latj pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu lath pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu latg pic18f6xj5x pic18f8xj5x ---x xxxx ---u uuuu ---u uuuu latf pic18f6xj5x pic18f8xj5x xxxx xx-- uuuu uu-- uuuu uu-- late pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu latd pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu latc pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu latb pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu lata pic18f6xj5x pic18f8xj5x --xx xxxx --uu uuuu --uu uuuu table 4-2: initialization conditi ons for all registers (continued) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
? 2007 microchip technology inc. preliminary ds39775b-page 63 pic18f87j50 family portj pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu porth pic18f6xj5x pic18f8xj5x 0000 xxxx uuuu uuuu uuuu uuuu portg pic18f6xj5x pic18f8xj5x 000x xxxx 000u uuuu uuuu uuuu portf pic18f6xj5x pic18f8xj5x x00x x0-- u00u u0-- u00u u0-- porte pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu portd pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu portc pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu portb pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu porta pic18f6xj5x pic18f8xj5x --0x 0000 --0u 0000 --uu uuuu spbrgh1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu baudcon1 pic18f6xj5x pic18f8xj5x 0100 0-00 0100 0-00 uuuu u-uu spbrgh2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu baudcon2 pic18f6xj5x pic18f8xj5x 0100 0-00 0100 0-00 uuuu u-uu tmr3h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu tmr3l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu t3con pic18f6xj5x pic18f8xj5x 0000 0000 uuuu uuuu uuuu uuuu tmr4 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pr4 pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 1111 1111 cvrcon pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu t4con pic18f6xj5x pic18f8xj5x -000 0000 -000 0000 -uuu uuuu ccpr4h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccpr4l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccp4con pic18f6xj5x pic18f8xj5x --00 0000 --00 0000 --uu uuuu ccpr5h pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccpr5l pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ccp5con pic18f6xj5x pic18f8xj5x --00 0000 --00 0000 --uu uuuu ssp2buf pic18f6xj5x pic18f8xj5x xxxx xxxx uuuu uuuu uuuu uuuu ssp2add pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ssp2msk pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ssp2stat pic18f6xj5x pic18f8xj5x 1111 1111 1111 1111 uuuu uuuu ssp2con1 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ssp2con2 pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu cmstat pic18f6xj5x pic18f8xj5x ---- --11 ---- --11 ---- --uu table 4-2: initialization conditions for all registers (continued) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
pic18f87j50 family ds39775b-page 64 preliminary ? 2007 microchip technology inc. pmaddrh pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdout1h pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmaddrl pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdout1l pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdin1h pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdin1l pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu ucon pic18f6xj5x pic18f8xj5x -0x0 000- -0x0 000- -uuu uuu- ustat pic18f6xj5x pic18f8xj5x -xxx xxx- -xxx xxx- -uuu uuu- ueir pic18f6xj5x pic18f8xj5x 0--0 0000 0--0 0000 u--u uuuu uir pic18f6xj5x pic18f8xj5x -000 0000 -000 0000 -uuu uuuu ufrmh pic18f6xj5x pic18f8xj5x ---- -xxx ---- -xxx ---- -uuu ufrml pic18f6xj5x pic18f8xj5x xxxx xxxx xxxx xxxx uuuu uuuu ucfg pic18f6xj5x pic18f8xj5x 00-0 0000 00-0 0000 uu-u uuuu uaddr pic18f6xj5x pic18f8xj5x -000 0000 -uuu uuuu -uuu uuuu ueie pic18f6xj5x pic18f8xj5x 0--0 0000 0--0 0000 u--u uuuu uie pic18f6xj5x pic18f8xj5x -000 0000 -000 0000 -uuu uuuu uep15 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep14 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep13 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep12 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep11 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep10 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep9 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep8 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep7 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep6 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep5 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep4 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep3 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep2 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep1 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu uep0 pic18f6xj5x pic18f8xj5x ---0 0000 ---0 0000 ---u uuuu pmconh pic18f6xj5x pic18f8xj5x 0-00 0000 0-00 0000 u-uu uuuu table 4-2: initialization conditi ons for all registers (continued) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
? 2007 microchip technology inc. preliminary ds39775b-page 65 pic18f87j50 family pmconl pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmmodeh pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmmodel pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdout2h pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdout2l pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdin2h pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmdin2l pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmeh pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmel pic18f6xj5x pic18f8xj5x 0000 0000 0000 0000 uuuu uuuu pmstath pic18f6xj5x pic18f8xj5x 00-- 0000 00-- 0000 uu-- uuuu pmstatl pic18f6xj5x pic18f8xj5x 10-- 1111 10-- 1111 uu-- uuuu table 4-2: initialization conditions for all registers (continued) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets cm resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition. shaded cells indicate conditions do not apply for the designated device. note 1: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hardware stack. 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector (0008h or 0018h). 3: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 4: see table 4-1 for reset value for specific condition.
pic18f87j50 family ds39775b-page 66 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 67 pic18f87j50 family 5.0 memory organization there are two types of memory in pic18 flash microcontroller devices: ? program memory ? data ram as harvard architecture devices, the data and program memories use separate busses; this allows for concurrent access of the two memory spaces. additional detailed information on the operation of the flash program memory is provided in section 6.0 ?flash program memory? . 5.1 program memory organization pic18 microcontrollers implement a 21-bit program counter which is capable of addressing a 2-mbyte program memory space. accessing a location between the upper boundary of the physically implemented memory and the 2-mbyte address will return all ? 0 ?s (a nop instruction). the entire pic18f87j50 family offers a range of on-chip flash program memory sizes, from 64 kbytes (up to 16,384 single-word instructions) to 128 kbytes (65,536 single-word instructions). the program memory maps for individual family members are shown in figure 5-3. figure 5-1: memory maps for pic18f87j50 family devices note: sizes of memory areas are not to scale. sizes of program memory areas ar e enhanced to show detail. unimplemented read as ? 0 ? unimplemented read as ? 0 ? unimplemented read as ? 0 ? 000000h 1ffffff pic18fx5j50 pic18fx6j50 pic18fx6j55 pic18fx7j50 007fffh 00ffffh 017fffh pc<20:0> stack level 1 ? stack level 31 ? ? call, callw, rcall, return, retfie, retlw, 21 user memory space on-chip memory on-chip memory on-chip memory on-chip memory addulnk, subulnk config. words config. words config. words config. words 01ffffh unimplemented read as ? 0 ?
pic18f87j50 family ds39775b-page 68 preliminary ? 2007 microchip technology inc. 5.1.1 hard memory vectors all pic18 devices have a total of three hard-coded return vectors in their program memory space. the reset vector address is the default value to which the program counter returns on all device resets; it is located at 0000h. pic18 devices also have two interrupt vector addresses for the handling of high-priority and low-priority interrupts. the high-priority interrupt vector is located at 0008h and the low-priority interrupt vector is at 0018h. their locations in relation to the program memory map are shown in figure 5-2. figure 5-2: hard vector and configuration word locations for pic18f87j50 family devices 5.1.2 flash configuration words because pic18f87j50 family devices do not have per- sistent configuration memory, the top four words of on-chip program memory are reserved for configuration information. on reset, the configuration information is copied into the configuration registers. the configuration words are stored in their program memory location in numerical order, starting with the lower byte of config1 at the lowest address and end- ing with the upper byte of config4. for these devices, only configuration words, config1 through config3, are used; config4 is reserved. the actual addresses of the flash configuration word for devices in the pic18f87j50 family are shown in table 5-1. their location in the memory map is shown with the other memory vectors in figure 5-2. additional details on the device configuration words are provided in section 25.1 ?configuration bits? . table 5-1: flash configuration word for pic18f87j50 family devices reset vector low-priority interrupt vector 0000h 0018h on-chip program memory high-priority interrupt vector 0008h 1fffffh (top of memory) (top of memory-7) flash configuration words read as ? 0 ? legend: (top of memory) represents upper boundary of on-chip program memory space (see figure 5-1 for device-specific values). shaded area represents unimplemented memory. areas are not shown to scale. device program memory (kbytes) configuration word addresses pic18f65j50 32 7ff8h to 7fffh pic18f85j50 pic18f66j50 64 fff8h to ffffh PIC18F86J50 pic18f66j55 96 17ff8h to 17fffh pic18f86j55 pic18f67j50 128 1fff8h to 1ffffh pic18f87j50
? 2007 microchip technology inc. preliminary ds39775b-page 69 pic18f87j50 family 5.1.3 pic18f87j50 family program memory modes the 80-pin devices in this family can address up to a total of 2 mbytes of program memory. this is achieved through the external memory bus. there are two distinct operating modes available to the controllers: ? microcontroller (mc) ? extended microcontroller (emc) the program memory mode is determined by setting the emb configuration bits (config3l<5:4>), as shown in register 5-1. (see also section 25.1 ?configuration bits? for additional details on the device configuration bits.) the program memory modes operate as follows: ?the microcontroller mode accesses only on-chip flash memory. attempts to read above the top of on-chip memory causes a read of all ? 0 ?s (a nop instruction). the microcontroller mode is also the only operating mode available to 64-pin devices. ?the extended microcontroller mode allows access to both internal and external program memories as a single block. the device can access its entire on-chip program memory; above this, the device accesses external program memory up to the 2-mbyte program space limit. execution automatically switches between the two memories as required. the setting of the emb configuration bits also controls the address bus width of the external memory bus. this is covered in more detail in section 7.0 ?external memory bus? . in all modes, the microcontroller has complete access to data ram. figure 5-3 compares the memory maps of the different program memory modes. the differences between on-chip and external memory access limitations are more fully explained in table 5-2. register 5-1: config3l: co nfiguration register 3 low r/wo-1 r/wo-1 r/wo-1 r/wo-1 r/wo-1 u-0 u-0 u-0 wait (1) bw (1) emb1 (1) emb0 (1) eashft (1) ? ? ? bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 wait: external bus wait enable bit (1) 1 = wait states on the external bus are disabled 0 = wait states on the external bus are enabled and selected by memcon<5:4> bit 6 bw: data bus width select bit (1) 1 = 16-bit data width modes 0 = 8-bit data width modes bit 5-4 emb1:emb0: external memory bus configuration bits (1) 11 = microcontroller mode, external bus disabled 10 = extended microcontroller mode, 12-bit address width for external bus 01 = extended microcontroller mode, 16-bit address width for external bus 00 = extended microcontroller mode, 20-bit address width for external bus bit 3 eashft: external address bus shift enable bit (1) 1 = address shifting enabled ? external address bus is shifted to start at 000000h 0 = address shifting disabled ? external address bus reflects the pc value bit 2-0 unimplemented: read as ? 0 ? note 1: implemented only on 80-pin devices.
pic18f87j50 family ds39775b-page 70 preliminary ? 2007 microchip technology inc. 5.1.4 extended microcontroller mode and address shifting by default, devices in extended microcontroller mode directly present the program counter value on the external address bus for those addresses in the range of the external memory space. in practical terms, this means addresses in the external memory device below the top of on-chip memory are unavailable. to avoid this, the extended microcontroller mode implements an address shifting option to enable auto- matic address translation. in this mode, addresses presented on the external bus are shifted down by the size of the on-chip program memory and are remapped to start at 0000h. this allows the complete use of the external memory device?s memory space. figure 5-3: memory maps for pic18f87j50 family program memory modes table 5-2: memory access for pic18f 8xj5x program memory modes external memory on-chip program memory microcontroller mode (1) 000000h on-chip program memory 1fffffh reads ? 0 ?s external on-chip memory memory (top of memory) (top of memory) + 1 legend: (top of memory) represents upper boundary of on-chip program memory space (see figure 5-1 for device-specific values). shaded areas represent unimplement ed, or inaccessible areas, depending on the mode. note 1: this mode is the only available mode on 64 -pin devices and the default on 80-pin devices. 2: these modes are only ava ilable on 80-pin devices. 3: addresses starting at the top of the program memory are translated to start at 0000h of the external device whenever the eashft configuration bit is set. extended microcontroller mode (2) 000000h 1fffffh (top of memory) (top of memory) + 1 external memory on-chip program memory 000000h 1fffffh (top of memory) (top of memory) + 1 (3) no access space on-chip memory space external on-chip memory memory space mapped to external memory space space space mapped to external memory space (top of memory) extended microcontroller mode with address shifting (2) 1fffffh ? operating mode internal program memory external program memory execution from table read from table write to execution from table read from table write to microcontroller yes yes yes no access no access no access extended microcontroller yes yes yes yes yes yes
? 2007 microchip technology inc. preliminary ds39775b-page 71 pic18f87j50 family 5.1.5 program counter the program counter (pc) specifies the address of the instruction to fetch for execution. the pc is 21 bits wide and is contained in three separate 8-bit registers. the low byte, known as the pcl register, is both readable and writable. the high byte, or pch register, contains the pc<15:8> bits; it is not directly readable or writable. updates to the pch register are performed through the pclath register. the upper byte is called pcu. this register contains the pc<20:16> bits; it is also not directly readable or writable. updates to the pcu register are performed through the pclatu register. the contents of pclath and pclatu are transferred to the program counter by any operation that writes pcl. similarly, the upper two bytes of the program counter are transferred to pclath and pclatu by an operation that reads pcl. this is useful for computed offsets to the pc (see section 5.1.8.1 ?computed goto? ). the pc addresses bytes in the program memory. to prevent the pc from becoming misaligned with word instructions, the least significant bit of pcl is fixed to a value of ? 0 ?. the pc increments by 2 to address sequential instructions in the program memory. the call , rcall , goto and program branch instructions write to the program counter directly. for these instructions, the contents of pclath and pclatu are not transferred to the program counter. 5.1.6 return address stack the return address stack allows any combination of up to 31 program calls and interrupts to occur. the pc is pushed onto the stack when a call or rcall instruc- tion is executed, or an interrupt is acknowledged. the pc value is pulled off the stack on a return, retlw or a retfie instruction (and on addulnk and subulnk instructions if the extended instruction set is enabled). pclatu and pclath are not affected by any of the return or call instructions. the stack operates as a 31-word by 21-bit ram and a 5-bit stack pointer, stkptr. the stack space is not part of either program or data space. the stack pointer is readable and writable and the address on the top of the stack is readable and writable through the top-of-stack special function registers. data can also be pushed to, or popped from the stack, using these registers. a call type instruction causes a push onto the stack. the stack pointer is first incremented and the location pointed to by the stack pointer is written with the contents of the pc (already pointing to the instruction following the call ). a return type instruction causes a pop from the stack. the contents of the location pointed to by the stkptr are transferred to the pc and then the stack pointer is decremented. the stack pointer is initialized to ? 00000 ? after all resets. there is no ram associated with the location corresponding to a stack pointer value of ? 00000 ?; this is only a reset value. status bits indicate if the stack is full, has overflowed or has underflowed. 5.1.6.1 top-of-stack access only the top of the return address stack (tos) is read- able and writable. a set of three registers, tosu:tosh:tosl, hold the contents of the stack location pointed to by the stkptr register (figure 5-4). this allows users to implement a software stack if necessary. after a call, rcall or interrupt (and addulnk and subulnk instructions if the extended instruction set is enabled), the software can read the pushed value by reading the tosu:tosh:tosl registers. these values can be placed on a user-defined software stack. at return time, the software can return these values to tosu:tosh:tosl and do a return. the user must disable the global interrupt enable bits while accessing the stack to prevent inadvertent stack corruption. figure 5-4: return address stack and associated registers 00011 001a34h 11111 11110 11101 00010 00001 00000 00010 return address stack <20:0> to p - o f - st a c k 000d58h tosl tosh tosu 34h 1ah 00h stkptr<4:0> top-of-stack registers stack pointer
pic18f87j50 family ds39775b-page 72 preliminary ? 2007 microchip technology inc. 5.1.6.2 return stack pointer (stkptr) the stkptr register (register 5-2) contains the stack pointer value, the stkful (stack full) status bit and the stkunf (stack underflow) status bits. the value of the stack pointer can be 0 through 31. the stack pointer increments before values are pushed onto the stack and decrements after values are popped off the stack. on reset, the stack pointer value will be zero. the user may read and write the stack pointer value. this feature can be used by a real-time operating system (rtos) for return stack maintenance. after the pc is pushed onto the stack 31 times (without popping any values off the stack), the stkful bit is set. the stkful bit is cleared by software or by a por. the action that takes place when the stack becomes full depends on the state of the stvren (stack over- flow reset enable) configuration bit. (refer to section 25.1 ?configuration bits? for a description of the device configuration bits.) if stvren is set (default), the 31st push will push the (pc + 2) value onto the stack, set the stkful bit and reset the device. the stkful bit will remain set and the stack pointer will be set to zero. if stvren is cleared, the stkful bit will be set on the 31st push and the stack pointer will increment to 31. any additional pushes will not overwrite the 31st push and the stkptr will remain at 31. when the stack has been popped enough times to unload the stack, the next pop will return a value of zero to the pc and set the stkunf bit, while the stack pointer remains at zero. the stkunf bit will remain set until cleared by software or until a por occurs. 5.1.6.3 push and pop instructions since the top-of-stack is readable and writable, the ability to push values onto the stack and pull values off the stack, without disturbing normal program execu- tion, is a desirable feature. the pic18 instruction set includes two instructions, push and pop , that permit the tos to be manipulated under software control. tosu, tosh and tosl can be modified to place data or a return address on the stack. the push instruction places the current pc value onto the stack. this increments the stack pointer and loads the current pc value onto the stack. the pop instruction discards the current tos by decrementing the stack pointer. the previous value pushed onto the stack then becomes the tos value. note: returning a value of zero to the pc on an underflow has the effect of vectoring the program to the reset vector, where the stack conditions can be verified and appropriate actions can be taken. this is not the same as a reset, as the contents of the sfrs are not affected. register 5-2: stkptr: stack pointer register r/c-0 r/c-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 stkful (1) stkunf (1) ? sp4 sp3 sp2 sp1 sp0 bit 7 bit 0 legend: c = clearable only bit r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 stkful: stack full flag bit (1) 1 = stack became full or overflowed 0 = stack has not become full or overflowed bit 6 stkunf: stack underflow flag bit (1) 1 = stack underflow occurred 0 = stack underflow did not occur bit 5 unimplemented: read as ? 0 ? bit 4-0 sp4:sp0: stack pointer location bits note 1: bit 7 and bit 6 are cleared by user software or by a por.
? 2007 microchip technology inc. preliminary ds39775b-page 73 pic18f87j50 family 5.1.6.4 stack full and underflow resets device resets on stack overflow and stack underflow conditions are enabled by setting the stvren bit in configuration register 1l. when stvren is set, a full or underflow condition will set the appropriate stkful or stkunf bit and then cause a device reset. when stvren is cleared, a full or underflow condition will set the appropriate stkful or stkunf bit, but not cause a device reset. the stkful or stkunf bits are cleared by the user software or a power-on reset. 5.1.7 fast register stack a fast register stack is provided for the status, wreg and bsr registers to provide a ?fast return? option for interrupts. this stack is only one level deep and is neither readable nor writable. it is loaded with the current value of the corresponding register when the processor vectors for an interrupt. all interrupt sources will push values into the stack registers. the values in the registers are then loaded back into the working registers if the retfie, fast instruction is used to return from the interrupt. if both low and high-priority interrupts are enabled, the stack registers cannot be used reliably to return from low-priority interrupts. if a high-priority interrupt occurs while servicing a low-priority interrupt, the stack register values stored by the low-priority interrupt will be overwritten. in these cases, users must save the key registers in software during a low-priority interrupt. if interrupt priority is not used, all interrupts may use the fast register stack for returns from interrupt. if no interrupts are used, the fast register stack can be used to restore the status, wreg and bsr registers at the end of a subroutine call. to use the fast register stack for a subroutine call, a call label, fast instruction must be executed to save the status, wreg and bsr registers to the fast register stack. a return, fast instruction is then executed to restore these registers from the fast register stack. example 5-1 shows a source code example that uses the fast register stack during a subroutine call and return. example 5-1: fast register stack code example 5.1.8 look-up tables in program memory there may be programming situations that require the creation of data structures, or look-up tables, in program memory. for pic18 devices, look-up tables can be implemented in two ways: ? computed goto ? table reads 5.1.8.1 computed goto a computed goto is accomplished by adding an offset to the program counter. an example is shown in example 5-2. a look-up table can be formed with an addwf pcl instruction and a group of retlw nn instructions. the w register is loaded with an offset into the table before executing a call to that table. the first instruction of the called routine is the addwf pcl instruction. the next instruction executed will be one of the retlw nn instructions that returns the value ? nn ? to the calling function. the offset value (in wreg) specifies the number of bytes that the program counter should advance and should be multiples of 2 (lsb = 0 ). in this method, only one data byte may be stored in each instruction location and room on the return address stack is required. example 5-2: computed goto using an offset value 5.1.8.2 table reads a better method of storing data in program memory allows two bytes of data to be stored in each instruction location. look-up table data may be stored two bytes per program word while programming. the table pointer (tblptr) specifies the byte address and the table latch (tablat) contains the data that is read from the program memory. data is transferred from program memory one byte at a time. table read operation is discussed further in section 6.1 ?table reads and table writes? . call sub1, fast ;status, wreg, bsr ;saved in fast register ;stack ? ? sub1 ? ? return fast ;restore values saved ;in fast register stack movf offset, w call table org nn00h table addwf pcl retlw nnh retlw nnh retlw nnh . . .
pic18f87j50 family ds39775b-page 74 preliminary ? 2007 microchip technology inc. 5.2 pic18 instruction cycle 5.2.1 clocking scheme the microcontroller clock input, whether from an internal or external source, is internally divided by four to generate four non-overlapping quadrature clocks (q1, q2, q3 and q4). internally, the program counter is incremented on every q1; the instruction is fetched from the program memory and latched into the instruc- tion register (ir) during q4. the instruction is decoded and executed during the following q1 through q4. the clocks and instruction execution flow are shown in figure 5-5. 5.2.2 instruction flow/pipelining an ?instruction cycle? consists of four q cycles, q1 through q4. the instruction fetch and execute are pipe- lined in such a manner that a fetch takes one instruction cycle, while the decode and execute takes another instruction cycle. however, due to the pipelining, each instruction effectively executes in one cycle. if an instruction causes the program counter to change (e.g., goto ), then two cycles are required to complete the instruction (example 5-3). a fetch cycle begins with the program counter (pc) incrementing in q1. in the execution cycle, the fetched instruction is latched into the instruction register (ir) in cycle q1. this instruction is then decoded and executed during the q2, q3 and q4 cycles. data memory is read during q2 (operand read) and written during q4 (destination write). figure 5-5: clock/ instruction cycle example 5-3: instruction pipeline flow q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 q1 q2 q3 q4 pc osc2/clko (rc mode) pc pc + 2 pc + 4 fetch inst (pc) execute inst (pc ? 2) fetch inst (pc + 2) execute inst (pc) fetch inst (pc + 4) execute inst (pc + 2) internal phase clock all instructions are single cycle, except for any program branches. these take two cycles since the fetch instruction is ?flushed? from the pipeline while the new instruction is being fetched and then executed. t cy 0t cy 1t cy 2t cy 3t cy 4t cy 5 1. movlw 55h fetch 1 execute 1 2. movwf portb fetch 2 execute 2 3. bra sub_1 fetch 3 execute 3 4. bsf porta, bit3 (forced nop) fetch 4 flush ( nop ) 5. instruction @ address sub_1 fetch sub_1 execute sub_1
? 2007 microchip technology inc. preliminary ds39775b-page 75 pic18f87j50 family 5.2.3 instructions in program memory the program memory is addressed in bytes. instruc- tions are stored as two bytes or four bytes in program memory. the least significant byte of an instruction word is always stored in a program memory location with an even address (lsb = 0 ). to maintain alignment with instruction boundaries, the pc increments in steps of 2 and the lsb will always read ? 0 ? (see section 5.1.5 ?program counter? ). figure 5-6 shows an example of how instruction words are stored in the program memory. the call and goto instructions have the absolute program memory address embedded into the instruc- tion. since instructions are always stored on word boundaries, the data contained in the instruction is a word address. the word address is written to pc<20:1> which accesses the desired byte address in program memory. instruction #2 in figure 5-6 shows how the instruction, goto 0006h , is encoded in the program memory. program branch instructions, which encode a relative address offset, operate in the same manner. the offset value stored in a branch instruction represents the number of single-word instructions that the pc will be offset by. section 26.0 ?instruction set summary? provides further details of the instruction set. figure 5-6: instructions in program memory 5.2.4 two-word instructions the standard pic18 instruction set has four two-word instructions: call , movff , goto and lsfr . in all cases, the second word of the instructions always has ? 1111 ? as its four most significant bits; the other 12 bits are literal data, usually a data memory address. the use of ? 1111 ? in the 4 msbs of an instruction specifies a special form of nop . if the instruction is executed in proper sequence ? immediately after the first word ? the data in the second word is accessed and used by the instruction sequence. if the first word is skipped for some reason and the second word is executed by itself, a nop is executed instead. this is necessary for cases when the two-word instruction is preceded by a conditional instruction that changes the pc. example 5-4 shows how this works. example 5-4: two- word instructions word address lsb = 1 lsb = 0 program memory byte locations 000000h 000002h 000004h 000006h instruction 1: movlw 055h 0fh 55h 000008h instruction 2: goto 0006h efh 03h 00000ah f0h 00h 00000ch instruction 3: movff 123h, 456h c1h 23h 00000eh f4h 56h 000010h 000012h 000014h note: see section 5.5 ?program memory and the extended instruction set? for information on two-word instructions in the extended instruction set. case 1: object code source code 0110 0110 0000 0000 tstfsz reg1 ; is ram location 0? 1100 0001 0010 0011 movff reg1, reg2 ; no, skip this word 1111 0100 0101 0110 ; execute this word as a nop 0010 0100 0000 0000 addwf reg3 ; continue code case 2: object code source code 0110 0110 0000 0000 tstfsz reg1 ; is ram location 0? 1100 0001 0010 0011 movff reg1, reg2 ; yes, execute this word 1111 0100 0101 0110 ; 2nd word of instruction 0010 0100 0000 0000 addwf reg3 ; continue code
pic18f87j50 family ds39775b-page 76 preliminary ? 2007 microchip technology inc. 5.3 data memory organization the data memory in pic18 devices is implemented as static ram. each register in the data memory has a 12-bit address, allowing up to 4096 bytes of data memory. the memory space is divided into as many as 16 banks that contain 256 bytes each. the pic18f87j50 family implements all available banks and provides 3904 bytes of data memory available to the user. figure 5-7 shows the data memory organization for the devices. the data memory contains special function registers (sfrs) and general purpose registers (gprs). the sfrs are used for control and status of the controller and peripheral functions, while gprs are used for data storage and scratchpad operations in the user?s application. any read of an unimplemented location will read as ? 0 ?s. the instruction set and architecture allow operations across all banks. the entire data memory may be accessed by direct, indirect or indexed addressing modes. addressing modes are discussed later in this section. to ensure that commonly used registers (select sfrs and select gprs) can be accessed in a single cycle, pic18 devices implement an access bank. this is a 256-byte memory space that provides fast access to select sfrs and the lower portion of gpr bank 0 with- out using the bsr. section 5.3.3 ?access bank? provides a detailed description of the access ram. 5.3.1 usb ram the entire data memory is actually mapped to a special dual access ram. when the usb module is disabled, the gprs in these banks are used like any other gpr in the data memory space. when the usb module is enabled, the memory in these banks is allocated as buffer ram for usb operation. this area is shared between the microcontroller core and the usb serial interface engine (sie) and is used to transfer data directly between the two. it is theoretically possible to use the areas of usb ram that are not allocated as usb buffers for normal scratchpad memory or other variable storage. in practice, the dynamic nature of buffer allocation makes this risky at best. additionally, bank 4 is used for usb buffer management when the module is enabled and should not be used for any other purposes during that time. additional information on usb ram and buffer operation is provided in section 22.0 ?universal serial bus (usb)? 5.3.2 bank select register large areas of data memory require an efficient addressing scheme to make rapid access to any address possible. ideally, this means that an entire address does not need to be provided for each read or write operation. for pic18 devices, this is accom- plished with a ram banking scheme. this divides the memory space into 16 contiguous banks of 256 bytes. depending on the instruction, each location can be addressed directly by its full 12-bit address, or an 8-bit low-order address and a 4-bit bank pointer. most instructions in the pic18 instruction set make use of the bank pointer, known as the bank select register (bsr). this sfr holds the 4 most significant bits of a location?s address; the instruction itself includes the 8 least significant bits. only the four lower bits of the bsr are implemented (bsr3:bsr0). the upper four bits are unused; they will always read ? 0 ? and cannot be written to. the bsr can be loaded directly by using the movlb instruction. the value of the bsr indicates the bank in data mem- ory. the 8 bits in the instruction show the location in the bank and can be thought of as an offset from the bank?s lower boundary. the relationship between the bsr?s value and the bank division in data memory is shown in figure 5-8. since up to 16 registers may share the same low-order address, the user must always be careful to ensure that the proper bank is selected before performing a data read or write. for example, writing what should be program data to an 8-bit address of f9h while the bsr is 0fh, will end up resetting the program counter. while any bank can be selected, only those banks that are actually implemented can be read or written to. writes to unimplemented banks are ignored, while reads from unimplemented banks will return ? 0 ?s. even so, the status register will still be affected as if the operation was successful. the data memory map in figure 5-7 indicates which banks are implemented. in the core pic18 instruction set, only the movff instruction fully specifies the 12-bit address of the source and target registers. this instruction ignores the bsr completely when it executes. all other instructions include only the low-order address as an operand and must use either the bsr or the access bank to locate their target registers. note: the operation of some aspects of data memory are changed when the pic18 extended instruction set is enabled. see section 5.6 ?data memory and the extended instruction set? for more information.
? 2007 microchip technology inc. preliminary ds39775b-page 77 pic18f87j50 family figure 5-7: data memory map fo r pic18f87j50 family devices bank 0 bank 1 bank 14 bank 15 data memory map bsr<3:0> = 0000 = 0001 = 1111 060h 05fh f5fh fffh 00h 5fh 60h ffh access bank when a = 0 : the bsr is ignored and the access bank is used. the first 96 bytes are general purpose ram (from bank 0). the remaining 160 bytes are special function registers (from bank 15). when a = 1 : the bsr specifies the bank used by the instruction. f3fh f00h effh 1ffh 100h 0ffh 000h access ram ffh 00h ffh 00h ffh 00h gpr (1) gpr (1) sfr (2) access ram high access ram low bank 2 = 0010 (sfrs) 2ffh 200h bank 3 ffh 00h gpr (1) ffh = 0011 = 1101 gpr (1) gpr, bdt (1) gpr (1) gpr (1) gpr (1) gpr (1) gpr (1) gpr (1) gpr (1) gpr (1) gpr (1) 4ffh 400h 5ffh 500h 3ffh 300h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h 00h gpr (1) gpr (1) = 0110 = 0111 = 1010 = 1100 = 1000 = 0101 = 1001 = 1011 = 0100 bank 4 bank 5 bank 6 bank 7 bank 8 bank 9 bank 10 bank 11 bank 12 bank 13 = 1110 6ffh 600h 7ffh 700h 8ffh 800h 9ffh 900h affh a00h bffh b00h cffh c00h dffh d00h e00h note 1: these banks also serve as ram buffers for usb operation. see section 5.3.1 ?usb ram? for more information. 2: addresses, f40h through f5fh, are not part of the acce ss bank, therefore, specifying a bsr should be used to access these registers. 40h 60h access ram
pic18f87j50 family ds39775b-page 78 preliminary ? 2007 microchip technology inc. figure 5-8: use of the bank select register (direct addressing) 5.3.3 access bank while the use of the bsr with an embedded 8-bit address allows users to address the entire range of data memory, it also means that the user must always ensure that the correct bank is selected. otherwise, data may be read from or written to the wrong location. this can be disastrous if a gpr is the intended target of an operation, but an sfr is written to instead. verifying and/or changing the bsr for each read or write to data memory can become very inefficient. to streamline access for the most commonly used data memory locations, the data memory is configured with an access bank, which allows users to access a mapped block of memory without specifying a bsr. the access bank consists of the first 96 bytes of memory (00h-5fh) in bank 0 and the last 160 bytes of memory (60h-ffh) in bank 15. the lower half is known as the ?access ram? and is composed of gprs. the upper half is where the device?s sfrs are mapped. these two areas are mapped contiguously in the access bank and can be addressed in a linear fashion by an 8-bit address (figure 5-7). the access bank is used by core pic18 instructions that include the access ram bit (the ?a? parameter in the instruction). when ?a? is equal to ? 1 ?, the instruction uses the bsr and the 8-bit address included in the opcode for the data memory address. when ?a? is ? 0 ?, however, the instruction is forced to use the access bank address map; the current value of the bsr is ignored entirely. using this ?forced? addressing allows the instruction to operate on a data address in a single cycle without updating the bsr first. for 8-bit addresses of 60h and above, this means that users can evaluate and operate on sfrs more efficiently. the access ram below 60h is a good place for data values that the user might need to access rapidly, such as immediate computational results or common program variables. access ram also allows for faster and more code efficient context saving and switching of variables. the mapping of the access bank is slightly different when the extended instruction set is enabled (xinst configuration bit = 1 ). this is discussed in more detail in section 5.6.3 ?mapping the access bank in indexed literal offset mode? . 5.3.4 general purpose register file pic18 devices may have banked memory in the gpr area. this is data ram which is available for use by all instructions. gprs start at the bottom of bank 0 (address 000h) and grow upwards towards the bottom of the sfr area. gprs are not initialized by a power-on reset and are unchanged on all other resets. note 1: the access ram bit of the instruction can be used to force an override of the selected bank (bsr<3:0>) to the registers of the access bank. 2: the movff instruction embeds the entire 12-bit address in the instruction. data memory bank select (2) 7 0 from opcode (2) 0000 000h 100h 200h 300h f00h e00h fffh bank 0 bank 1 bank 2 bank 14 bank 15 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh bank 3 through bank 13 0010 11111111 7 0 bsr (1) 11111111
? 2007 microchip technology inc. preliminary ds39775b-page 79 pic18f87j50 family 5.3.5 special function registers the special function registers (sfrs) are registers used by the cpu and peripheral modules for controlling the desired operation of the device. these registers are implemented as static ram. sfrs start at the top of data memory (fffh) and extend downward to occupy more than the top half of bank 15 (f40h to fffh). a list of these registers is given intable 5-3, table 5-4 and table 5-5. the sfrs can be classified into two sets: those associated with the ?core? device functionality (alu, resets and interrupts) and those related to the peripheral functions. the reset and interrupt registers are described in their respective chapters, while the alu?s status register is described later in this section. registers related to the operation of the peripheral features are described in the chapter for that peripheral. the sfrs are typically distributed among the peripherals whose functions they control. unused sfr locations are unimplemented and read as ? 0 ?s note: addresses, f40h through f5fh, are not part of the access bank, therefore specify- ing a bsr should be used to access these registers. table 5-3: special function register map for pic18f87j50 family devices address name address name address name address name address name address name fffh tosu fdfh indf2 (1) fbfh eccp1as f9fh ipr1 f7fh spbrgh1 f5fh ucfg ffeh tosh fdeh postinc2 (1) fbeh eccp1del f9eh pir1 f7eh baudcon1 f5eh uaddr ffdh tosl fddh postdec2 (1) fbdh ccpr1h f9dh pie1 f7dh spbrgh2 f5dh ueie ffch stkptr fdch preinc2 (1) fbch ccpr1l f9ch rcsta2 f7ch baudcon2 f5ch uie ffbh pclatu fdbh plusw2 (1) fbbh ccp1con f9bh osctune f7bh tmr3h f5bh uep15 ffah pclath fdah fsr2h fbah eccp2as f9ah trisj (2) f7ah tmr3l f5ah uep14 ff9h pcl fd9h fsr2l fb9h eccp2del f99h trish (2) f79h t3con f59h uep13 ff8h tblptru fd8h status fb8h ccpr2h f98h trisg f78h tmr4 f58h uep12 ff7h tblptrh fd7h tmr0h fb7h ccpr2l f97h trisf f77h pr4 (3) f57h uep11 ff6h tblptrl fd6h tmr0l fb6h ccp2con f96h trise f76h t4con f56h uep10 ff5h tablat fd5h t0con fb5h eccp3as f95h trisd f75h ccpr4h f55h uep9 ff4h prodh fd4h fb4h eccp3del f94h trisc f74h ccpr4l f54h uep8 ff3h prodl fd3h osccon (3) fb3h ccpr3h f93h trisb f73h ccp4con f53h uep7 ff2h intcon fd2h cm1con fb2h ccpr3l f92h trisa f72h ccpr5h f52h uep6 ff1h intcon2 fd1h cm2con fb1h ccp3con f91h latj (2) f71h ccpr5l f51h uep5 ff0h intcon3 fd0h rcon fb0h spbrg1 f90h lath (2) f70h ccp5con f50h uep4 fefh indf0 (1) fcfh tmr1h (3) fafh rcreg1 f8fh latg f6fh ssp2buf f4fh uep3 feeh postinc0 (1) fceh tmr1l (3) faeh txreg1 f8eh latf f6eh ssp2add f4eh uep2 fedh postdec0 (1) fcdh t1con (3) fadh txsta1 f8dh late f6dh ssp2stat f4dh uep1 fech preinc0 (1) fcch tmr2 (3) fach rcsta1 f8ch latd f6ch ssp2con1 f4ch uep0 febh plusw0 (1) fcbh pr2 (3) fabh spbrg2 f8bh latc f6bh ssp2con2 f4bh pmconh feah fsr0h fcah t2con faah rcreg2 f8ah latb f6ah cmstat f4ah pmconl fe9h fsr0l fc9h ssp1buf fa9h txreg2 f89h lata f69h pmaddrh (4) f49h pmmodeh fe8h wreg fc8h ssp1add fa8h txsta2 f88h portj (2) f68h pmaddrl (4) f48h pmmodel fe7h indf1 (1) fc7h ssp1stat fa7h eecon2 f87h porth (2) f67h pmdin1h f47h pmdout2h fe6h postinc1 (1) fc6h ssp1con1 fa6h eecon1 f86h po rtg f66h pmdin1l f46h pmdout2l fe5h postdec1 (1) fc5h ssp1con2 fa5h ipr3 f85h portf f65h ucon f45h pmdin2h fe4h preinc1 (1) fc4h adresh fa4h pir3 f84h porte f64h ustat f44h pmdin2l fe3h plusw1 (1) fc3h adresl fa3h pie3 f83h portd f63h ueir f43h pmeh fe2h fsr1h fc2h adcon0 (3) fa2h ipr2 f82h portc f62h uir f42h pmel fe1h fsr1l fc1h adcon1 (3) fa1h pir2 f81h portb f61h ufrmh f41h pmstath fe0h bsr fc0h wdtcon fa0h pie2 f80h porta f60h ufrml f40h pmstatl note 1: this is not a physical register. 2: this register is not available on 64-pin devices. 3: this register shares the same address with another register (see table 5-4 for alternate register). 4: pmaddrh and pmdouth share the same address and pmaddrl and pm doutl share the same address. pmaddrx is used in master modes and pmdoutx is used in slave modes.
pic18f87j50 family ds39775b-page 80 preliminary ? 2007 microchip technology inc. 5.3.5.1 shared address sfrs in several locations in the sfr bank, a single address is used to access two different hardware registers. in these cases, a ?legacy? register of the standard pic18 sfr set (such as osccon, t1con, etc.) shares its address with an alternate register. these alternate reg- isters are associated with enhanced configuration options for peripherals, or with new device features not included in the standard pic18 sfr map. a complete list of shared register addresses and the registers associated with them is provided in table 5-4. access to the alternate registers is enabled in software by setting the adshr bit in the wdtcon register (register 5-3). adshr must be manually set or cleared to access the alternate or legacy registers, as required. since the bit remains in a given state until changed, users should always verify the state of adshr before writing to any of the shared sfr addresses. 5.3.5.2 context defined sfrs in addition to the shared address sfrs, there are sev- eral registers that share the same address in the sfr space, but are not accessed with the adshr bit. instead, the register?s definition and use depends on the operating mode of its associated peripheral. these registers are: ? sspxadd and sspxmsk: these are two sepa- rate hardware registers, accessed through a single sfr address. the operating mode of the mssp modules determines which register is being accessed. see section 19.4.3.4 ?7-bit address masking mode? for additional details. ? pmaddrh/l and pmdout2h/l: in this case, these named buffer pairs are actually the same physical registers. the pmp module?s operating mode determines what function the registers take on. see section 11.1.2 ?data registers? for additional details. table 5-4: shared sfr addresses for pic18f87j50 family devices address name address name address name fd3h (d) osccon fcdh (d) t1con fc2h (d) adcon0 (a) refocon (a) odcon3 (a) ancon1 fcfh (d) tmr1h fcch (d) tmr2 fc1h (d) adcon1 (a) odcon1 (a) padcfg1 (a) ancon0 fceh (d) tmr1l fcbh (d) pr2 f77h (d) pr4 (a) odcon2 (a) memcon (1) (a) cvrcon legend: (d) = default sfr, accessible only when adshr = 0 ; (a) = alternate sfr, accessible only when adshr = 1 . note 1: implemented in 80-pin devices only. register 5-3: wdtcon: wat chdog timer control register r/w-0 r-x u-0 r/w-0 u-0 u-0 u-0 u-0 regslp lvdstat ? adshr ? ? ?swdten bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 regslp: voltage regulator low-power operation enable bit for details of bit operation, see register 25-9 on page 357. bit 6 lvdstat: low-voltage detect status bit 1 = v ddcore > 2.45v nominal 0 = v ddcore < 2.45v nominal bit 5 unimplemented : read as ? 0 ? bit 4 adshr: shared address sfr select bit 1 = alternate sfr is selected 0 = default (legacy) sfr is selected bit 3-1 unimplemented : read as ? 0 ? bit 0 swdten: software controlled watchdog timer enable bit for details of bit operation, see register 25-9.
? 2007 microchip technology inc. preliminary ds39775b-page 81 pic18f87j50 family table 5-5: register file summary (pic18f87j50 family) file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: tosu ? ? ? top-of-stack upper byte (tos<20:16>) ---0 0000 59, 71 tosh top-of-stack high byte (tos<15:8>) 0000 0000 59, 71 tosl top-of-stack low byte (tos<7:0>) 0000 0000 59, 71 stkptr stkful stkunf ? sp4 sp3 sp2 sp1 sp0 00-0 0000 59, 72 pclatu ? ?bit 21 (1) holding register for pc<20:16> ---0 0000 59, 71 pclath holding register for pc<15:8> 0000 0000 59, 71 pcl pc low byte (pc<7:0>) 0000 0000 59, 71 tblptru ? ? bit 21 program memory table pointer upper byte (tblptr<20:16>) --00 0000 59, 104 tblptrh program memory table pointer high byte (tblptr<15:8>) 0000 0000 59, 104 tblptrl program memory table pointer low byte (tblptr<7:0>) 0000 0000 59, 104 tablat program memory table latch 0000 0000 59, 104 prodh product register high byte xxxx xxxx 59, 117 prodl product register low byte xxxx xxxx 59, 117 intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 59, 121 intcon2 rbpu intedg0 intedg1 intedg2 intedg3 tmr0ip int3ip rbip 1111 1111 59, 121 intcon3 int2ip int1ip int3ie int2ie int1ie int3if int2if int1if 1100 0000 59, 121 indf0 uses contents of fsr0 to address data memory ? value of fsr0 not changed (not a physical register) n/a 59, 89 postinc0 uses contents of fsr0 to address data memory ? value of fsr0 post-incremented (not a physical register) n/a 59, 90 postdec0 uses contents of fsr0 to address data memory ? value of fsr0 post-decremented (not a physical register) n/a 59, 90 preinc0 uses contents of fsr0 to address data memory ? value of fsr0 pre-incremented (not a physical register) n/a 59, 90 plusw0 uses contents of fsr0 to address data memory ? value of fsr0 pre-incremented (not a physical register) ? value of fsr0 offset by w n/a 59, 90 fsr0h ? ? ? ? indirect data memory address pointer 0 high byte ---- xxxx 59, 89 fsr0l indirect data memory address pointer 0 low byte xxxx xxxx 59, 89 wreg working register xxxx xxxx 59, 73 indf1 uses contents of fsr1 to address data memory ? value of fsr1 not changed (not a physical register) n/a 59, 89 postinc1 uses contents of fsr1 to address data memory ? value of fsr1 post-incremented (not a physical register) n/a 59, 90 postdec1 uses contents of fsr1 to address data memory ? value of fsr1 post-decremented (not a physical register) n/a 59, 90 preinc1 uses contents of fsr1 to address data memory ? value of fsr1 pre-incremented (not a physical register) n/a 59, 90 plusw1 uses contents of fsr1 to address data memory ? value of fsr1 pre-incremented (not a physical register) ? value of fsr1 offset by w n/a 59, 90 fsr1h ? ? ? ? indirect data memory address pointer 1 high byte ---- xxxx 59, 89 fsr1l indirect data memory address pointer 1 low byte xxxx xxxx 59, 89 bsr ? ? ? ? bank select register ---- 0000 59, 76 indf2 uses contents of fsr2 to address data memory ? value of fsr2 not changed (not a physical register) n/a 60, 89 postinc2 uses contents of fsr2 to address data memory ? value of fsr2 post-incremented (not a physical register) n/a 60, 90 postdec2 uses contents of fsr2 to address data memory ? value of fsr2 post-decremented (not a physical register) n/a 60, 90 preinc2 uses contents of fsr2 to address data memory ? value of fsr2 pre-incremented (not a physical register) n/a 60, 90 plusw2 uses contents of fsr2 to address data memory ? value of fsr2 pre-incremented (not a physical register) ? value of fsr2 offset by w n/a 60, 90 fsr2h ? ? ? ? indirect data memory address pointer 2 high byte ---- xxxx 60, 89 legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. bold indicates shared-access sfrs. note 1: bit 21 of the pc is only available in serial programming modes. 2: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 3: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 4: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 5: the sspxmsk registers are only accessible when sspxcon2<3:0> = 1001 . 6: alternate names and definitions for these bits when the mssp module is operating in i 2 c? slave mode. see section 19.4.3.2 ?address masking modes? for details 7: these bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ? 0 ?. reset values are shown for 80-pin devices. 8: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. see section 11.1.2 ?data registers? for more information.
pic18f87j50 family ds39775b-page 82 preliminary ? 2007 microchip technology inc. fsr2l indirect data memory address pointer 2 low byte xxxx xxxx 60, 89 status ? ? ?novzdcc ---x xxxx 60, 87 tmr0h timer0 register high byte 0000 0000 60, 191 tmr0l timer0 register low byte xxxx xxxx 60, 191 t0con tmr0on t08bit t0cs t0se psa t0ps2 t0ps1 t0ps0 1111 1111 60, 190 osccon (2) / idlen ircf2 ircf1 ircf0 osts (4) ? scs1 scs0 0110 q100 60, 42 refocon (3) roon ? rosslp rosel rodiv3 rodiv2 rodiv1 rodiv0 0-00 0000 60, 43 cm1con con coe cpol evpol1 evpol0 cref cch1 cch0 0001 1111 60, 343 cm2con con coe cpol evpol1 evpol0 cref cch1 cch0 0001 1111 60, 343 rcon ipen ?cm ri to pd por bor 0-11 1100 58, 60, 133 tmr1h (2) / timer1 register high byte xxxx xxxx 60, 194 odcon1 (3) ? ? ? ccp5od ccp4od eccp3od eccp2od eccp1od ---0 0000 60, 137 tmr1l (2) / timer1 register low byte xxxx xxxx 60, 194 odcon2 (3) ? ? ? ? ? ? u2od u1od ---- --00 60, 137 t1con (2) / rd16 t1run t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 0000 0000 60, 194 odcon3 (3) ? ? ? ? ? ? spi2od spi1od ---- --00 60, 137 tmr2 (2) / timer2 register 0000 0000 60, 199 padcfg1 (3) ? ? ? ? ? ? ?pmpttl ---- ---0 60, 138 pr2 (2) / timer2 period register 1111 1111 60, 199 memcon (3) edbis ?wait1wait0 ? ?wm1wmo 0-00 --00 60, 106 t2con ? t2outps3 t2outps2 t2outps1 t2outps0 tmr2on t2ckps1 t2ckps0 -000 0000 60, 199 ssp1buf mssp1 receive buffer/transmit register xxxx xxxx 60, 241, 276 ssp1add/ mssp1 address register (i 2 c? slave mode), mssp1 baud rate reload register (i 2 c? master mode) 0000 0000 60, 246 ssp1msk (5) msk7 msk6 msk5 msk4 msk3 msk2 msk1 msk0 1111 1111 60, 248 ssp1stat smp cke d/a psr/w ua bf 0000 0000 60, 231, 242 ssp1con1 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 60, 231, 243 ssp1con2 gcen ackstat ackdt acken rcen pen rsen sen 0000 0000 60, 231, 244 gcen ackstat admsk5 (6) admsk4 (6) admsk3 (6) admsk2 (6) admsk1 (6) sen adresh a/d result register high byte xxxx xxxx 61, 308 adresl a/d result register low byte xxxx xxxx 61, 308 adcon0 (2) / vcfg1 vcfg0 chs3 chs2 chs1 chs0 go/done adon 0000 0000 61, 299 ancon1 (3) pcfg15 pcfg14 pcfg13 pcfg12 pcfg11 pcfg10 ? ? 0000 00-- 61, 299 adcon1 (2) / adfm adcal acqt2 acqt1 acqt0 adcs2 adcs1 adcs0 0000 0000 61, 299 ancon0 (3) pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 0--0 0000 61, 299 wdtcon regslp lvdstat ?adshr ? ? ?swdten 0x-0 ---0 61, 356 table 5-5: register file summary (pic18f87j50 family) (continued) file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. bold indicates shared-access sfrs. note 1: bit 21 of the pc is only available in serial programming modes. 2: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 3: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 4: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 5: the sspxmsk registers are only accessible when sspxcon2<3:0> = 1001 . 6: alternate names and definitions for these bits when the mssp module is operating in i 2 c? slave mode. see section 19.4.3.2 ?address masking modes? for details 7: these bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ? 0 ?. reset values are shown for 80-pin devices. 8: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. see section 11.1.2 ?data registers? for more information.
? 2007 microchip technology inc. preliminary ds39775b-page 83 pic18f87j50 family eccp1as eccp1ase eccp1as2 eccp1as1 eccp1as0 pss1ac1 pss1ac0 pss1bd1 pss1bd0 0000 0000 61, 230 eccp1del p1rsen p1dc6 p1dc5 p1dc4 p1dc3 p1dc2 p1dc1 p1dc0 0000 0000 61, 230 ccpr1h capture/compare/pwm register 1 high byte xxxx xxxx 61, 230 ccpr1l capture/compare/pwm register 1 low byte xxxx xxxx 61, 230 ccp1con p1m1 p1m0 dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 0000 0000 61, 230 eccp2as eccp2ase eccp2as2 eccp2as1 eccp2as0 pss2ac1 pss2ac0 pss2bd1 pss2bd0 0000 0000 61, 230 eccp2del p2rsen p2dc6 p2dc5 p2dc4 p2dc3 p2dc2 p2dc1 p2dc0 0000 0000 61, 230 ccpr2h capture/compare/pwm register 2 high byte xxxx xxxx 61, 230 ccpr2l capture/compare/pwm register 2 low byte xxxx xxxx 61, 230 ccp2con p2m1 p2m0 dc2b1 dc2b0 ccp2m3 ccp2m2 ccp2m1 ccp2m0 0000 0000 61, 230 eccp3as eccp3ase eccp3as2 eccp3as1 eccp3as0 pss3ac1 pss3ac0 pss3bd1 pss3bd0 0000 0000 61, 230 eccp3del p3rsen p3dc6 p3dc5 p3dc4 p3dc3 p3dc2 p3dc1 p3dc0 0000 0000 61, 230 ccpr3h capture/compare/pwm register 3 high byte xxxx xxxx 61, 230 ccpr3l capture/compare/pwm register 3 low byte xxxx xxxx 61, 230 ccp3con p3m1 p3m0 dc3b1 dc3b0 ccp3m3 ccp3m2 ccp3m1 ccp3m0 0000 0000 61, 230 spbrg1 eusart1 baud rate generator register low byte 0000 0000 61, 281 rcreg1 eusart1 receive register 0000 0000 61, 289, 290 txreg1 eusart1 transmit register xxxx xxxx 61, 287, 288 txsta1 csrc tx9 txen sync sendb brgh trmt tx9d 0000 0010 61, 287 rcsta1 spen rx9 sren cren adden ferr oerr rx9d 0000 000x 61, 289 spbrg2 eusart2 baud rate generator register low byte 0000 0000 61, 281 rcreg2 eusart2 receive register 0000 0000 61, 289, 290 txreg2 eusart2 transmit register 0000 0000 61, 287, 288 txsta2 csrc tx9 txen sync sendb brgh trmt tx9d 0000 0010 61, 287 eecon2 program memory control register 2 (not a physical register) ---- ---- 61, 96 eecon1 ? ? wprog free wrerr wren wr ? --00 x00- 61, 96 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 1111 1111 62, 130 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 0000 0000 62, 124 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 0000 0000 62, 127 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 1111 1111 62, 130 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 0000 0000 62, 124 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 0000 0000 62, 127 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 1111 1111 62, 130 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 0000 0000 62, 124 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 0000 0000 62, 127 rcsta2 spen rx9 sren cren adden ferr oerr rx9d 0000 000x 62, 289 osctune intsrc pllen tun5 tun4 tun3 tun2 tun1 tun0 0000 0000 62, 37 table 5-5: register file summary (pic18f87j50 family) (continued) file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. bold indicates shared-access sfrs. note 1: bit 21 of the pc is only available in serial programming modes. 2: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 3: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 4: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 5: the sspxmsk registers are only accessible when sspxcon2<3:0> = 1001 . 6: alternate names and definitions for these bits when the mssp module is operating in i 2 c? slave mode. see section 19.4.3.2 ?address masking modes? for details 7: these bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ? 0 ?. reset values are shown for 80-pin devices. 8: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. see section 11.1.2 ?data registers? for more information.
pic18f87j50 family ds39775b-page 84 preliminary ? 2007 microchip technology inc. trisj (7) trisj7 trisj6 trisj5 trisj4 trisj3 trisj2 trisj1 trisj0 1111 1111 62, 163 trish (7) trish7 trish6 trish5 trish4 trish3 trish2 trish1 trish0 1111 1111 62, 161 trisg ? ? ? trisg4 trisg3 tri sg2trisg1trisg0 ---1 1111 62, 158 trisf trisf7 trisf6 trisf 5 trisf4 trisf3 trisf2 ? ? 111- -1-- 62, 155 trise trise7 trise6 trise5 trise4 trise3 trise2 trise1 trise0 1111 1111 62, 152 trisd trisd7 trisd6 trisd5 trisd 4 trisd3 trisd2 trisd1 trisd0 1111 1111 62, 149 trisc trisc7 trisc6 trisc5 trisc 4 trisc3 trisc2 trisc1 trisc0 1111 1111 62, 146 trisb trisb7 trisb6 trisb5 trisb4 trisb3 trisb2 trisb1 trisb0 1111 1111 62, 143 trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 --11 1111 62, 140 latj (7) latj7latj6latj5latj4latj3latj2latj1latj0 xxxx xxxx 62, 163 lath (7) lath7 lath6 lath5 lath4 lath3 lath2 lath1 lath0 xxxx xxxx 62, 161 latg ? ? ? latg4 latg3 latg2 latg1 latg0 ---x xxxx 62, 158 latf latf7 latf6 latf5 latf4 latf3 latf2 ? ? xxxx xx-- 62, 155 late late7 late6 late5 late4 late3 late2 late1 late0 xxxx xxxx 62, 152 latd latd7 latd6 latd5 latd4 latd3 latd2 latd1 latd0 xxxx xxxx 62, 149 latc latc7 latc6 latc5 latc4 latc3 latc2 latc1 latc0 xxxx xxxx 62, 146 latb latb7 latb6 latb5 latb4 latb3 latb2 latb1 latb0 xxxx xxxx 62, 143 lata ? ? lata5 lata4 lata3 lata2 lata1 lata0 --xx xxxx 62, 140 portj (7) rj7 rj6 rj5 rj4 rj3 rj2 rj1 rj0 xxxx xxxx 63, 163 porth (7) rh7 rh6 rh5 rh4 rh3 rh2 rh1 rh0 0000 xxxx 63, 161 portg rdpu repu rjpu (7) rg4 rg3 rg2 rg1 rg0 000x xxxx 63, 158 portf rf7 rf6 rf5 rf4 rf3 rf2 ? ? x00x x0-- 63, 155 porte re7 re6 re5 re4 re3 re2 re1 re0 xxxx xxxx 63, 152 portd rd7 rd6 rd5 rd4 rd3 rd2 rd1 rd0 xxxx xxxx 63, 149 portc rc7 rc6 rc5 rc4 rc3 rc2 rc1 rc0 xxxx xxxx 63, 146 portb rb7 rb6 rb5 rb4 rb3 rb2 rb1 rb0 xxxx xxxx 63, 143 porta ? ? ra5 ra4 ra3 ra2 ra1 ra0 --0x 0000 63, 140 spbrgh1 eusart1 baud rate generator register high byte 0000 0000 63, 281 baudcon1 abdovf rcidl dtrxp sckp brg16 ? wue abden 0100 0-00 63, 281 spbrgh2 eusart2 baud rate generator register high byte 0000 0000 63, 281 baudcon2 abdovf rcidl dtrxp sckp brg16 ? wue abden 0100 0-00 63, 281 tmr3h timer3 register high byte xxxx xxxx 63, 206 tmr3l timer3 register low byte xxxx xxxx 63, 206 t3con rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on 0000 0000 63, 206 tmr4 timer4 register 0000 0000 63, 205 pr4 (2) / timer4 period register 1111 1111 63, 206 cvrcon (3) cvren cvroe cvrr cvrss cvr3 cvr2 cvr1 cvr0 0000 0000 63, 344 t4con ? t4outps3 t4outps2 t4outps1 t4outps0 tmr4on t4ckps1 t4ckps0 -000 0000 63, 205 table 5-5: register file summary (pic18f87j50 family) (continued) file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. bold indicates shared-access sfrs. note 1: bit 21 of the pc is only available in serial programming modes. 2: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 3: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 4: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 5: the sspxmsk registers are only accessible when sspxcon2<3:0> = 1001 . 6: alternate names and definitions for these bits when the mssp module is operating in i 2 c? slave mode. see section 19.4.3.2 ?address masking modes? for details 7: these bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ? 0 ?. reset values are shown for 80-pin devices. 8: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. see section 11.1.2 ?data registers? for more information.
? 2007 microchip technology inc. preliminary ds39775b-page 85 pic18f87j50 family ccpr4h capture/compare/pwm register 4 high byte xxxx xxxx 63, 208 ccpr4l capture/compare/pwm register 4 low byte xxxx xxxx 63, 208 ccp4con ? ? dc4b1 dc4b0 ccp4m3 ccp4m2 ccp4m1 ccp4m0 --00 0000 63, 208 ccpr5h capture/compare/pwm register 5 high byte xxxx xxxx 63, 208 ccpr5l capture/compare/pwm register 5 low byte xxxx xxxx 63, 208 ccp5con ? ? dc5b1 dc5b0 ccp5m3 ccp5m2 ccp5m1 ccp5m0 --00 0000 63, 208 ssp2buf mssp2 receive buffer/transmit register xxxx xxxx 63, 241, 276 ssp2add/ mssp2 address register (i 2 c? slave mode), mssp2 baud rate reload register (i 2 c master mode) 0000 0000 63, 241 ssp2msk (5) msk7 msk6 msk5 msk4 msk3 msk2 msk1 msk0 0000 0000 63, 248 ssp2stat smp cke d/a psr/w ua bf 1111 1111 63, 231, 242 ssp2con1 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 63, 231, 243 ssp2con2 gcen ackstat ackdt acken rcen pen rsen sen 0000 0000 63, 231, 243 gcen ackstat admsk5 (6) admsk4 (6) admsk3 (6) admsk2 (6) admsk1 (6) sen cmstat ? ? ? ? ? ? cout2 cout1 ---- --11 63, 337 pmaddrh/ cs2 cs1 parallel master port address high byte 0000 0000 64, 172 pmdout1h (8) parallel port out data high byte (buffer 1) 0000 0000 64, 175 pmaddrl/ parallel master port address low byte 0000 0000 64, 172 pmdout1l (8) parallel port out data low byte (buffer 0) 0000 0000 64, 172 pmdin1h parallel port in data high byte (buffer 1) 0000 0000 64, 172 pmdin1l parallel port in data low byte (buffer 0) 0000 0000 64, 172 ucon ? ppbrst se0 pktdis usben resume suspnd ? -0x0 000- 64, 310 ustat ? endp3 endp2 endp1 endp0 dir ppbi ? -xxx xxx- 64, 314 ueir btsef ? ? btoef dfn8ef crc16ef crc5ef pidef 0--0 0000 64, 327 uir ? sofif stallif idleif trnif actvif uerrif urstif -000 0000 64, 324 ufrmh ? ? ? ? ? frm10 frm9 frm8 ---- -xxx 64, 316 ufrml frm7 frm6 frm5 frm4 frm3 frm2 frm1 frm0 xxxx xxxx 64, 316 ucfg uteye ? ? upuen utrdis fsen ppb1 ppb0 00-0 0000 64, 311 uaddr ? addr6 addr5 addr4 addr3 addr2 addr1 addr0 -000 0000 64, 316 ueie btsee ? ? btoee dfn8ee crc16ee crc5ee pidee 0--0 0000 64, 328 uie ? sofie stallie idleie trnie actvie uerrie urstie -000 0000 64, 326 uep15 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep14 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep13 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep12 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep11 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep10 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep9 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep8 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 table 5-5: register file summary (pic18f87j50 family) (continued) file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. bold indicates shared-access sfrs. note 1: bit 21 of the pc is only available in serial programming modes. 2: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 3: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 4: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 5: the sspxmsk registers are only accessible when sspxcon2<3:0> = 1001 . 6: alternate names and definitions for these bits when the mssp module is operating in i 2 c? slave mode. see section 19.4.3.2 ?address masking modes? for details 7: these bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ? 0 ?. reset values are shown for 80-pin devices. 8: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. see section 11.1.2 ?data registers? for more information.
pic18f87j50 family ds39775b-page 86 preliminary ? 2007 microchip technology inc. uep7 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep6 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep5 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep4 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep3 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep2 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep1 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 uep0 ? ? ? ephshk epcondis epouten epinen epstall ---0 0000 64, 315 pmconh pmpen ? psidl adrmux1 adrmux0 ptbeen ptwren ptrden 0-00 0000 64, 166 pmconl csf1 csf0 alp cs2p cs1p bep wrsp rdsp 0000 0000 65, 167 pmmodeh busy irqm1 irqm0 incm1 incm0 mode16 mode1 mode0 0000 0000 65, 168 pmmodel waitb1 waitb0 waitm3 waitm2 waitm1 waitm0 waite1 waite0 0000 0000 65, 169 pmdout2h parallel port out data high byte (buffer 3) 0000 0000 65, 172 pmdout2l parallel port out data low byte (buffer 2) 0000 0000 65, 172 pmdin2h parallel port in data high byte (buffer 3) 0000 0000 65, 172 pmdin2l parallel port in data low byte (buffer 2) 0000 0000 65, 172 pmeh pten15 pten14 pten13 pten12 pten11 pten10 pten9 pten8 0000 0000 65, 169 pmel pten7 pten6 pten5 pten4 pten3 pten2 pten1 pten0 0000 0000 65, 170 pmstath ibf ibov ? ? ib3f ib2f ib1f ib0f 00-- 0000 65, 170 pmstatl obe obuf ? ? ob3e ob2e ob1e ob0e 10-- 1111 65, 171 table 5-5: register file summary (pic18f87j50 family) (continued) file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition. bold indicates shared-access sfrs. note 1: bit 21 of the pc is only available in serial programming modes. 2: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 3: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 4: reset value is ? 0 ? when two-speed start-up is enabled and ? 1 ? if disabled. 5: the sspxmsk registers are only accessible when sspxcon2<3:0> = 1001 . 6: alternate names and definitions for these bits when the mssp module is operating in i 2 c? slave mode. see section 19.4.3.2 ?address masking modes? for details 7: these bits and/or registers are only available in 80-pin devices; otherwise, they are unimplemented and read as ? 0 ?. reset values are shown for 80-pin devices. 8: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. see section 11.1.2 ?data registers? for more information.
? 2007 microchip technology inc. preliminary ds39775b-page 87 pic18f87j50 family 5.3.6 status register the status register, shown in register 5-4, contains the arithmetic status of the alu. the status register can be the operand for any instruction, as with any other register. if the status register is the destination for an instruction that affects the z, dc, c, ov or n bits, then the write to these five bits is disabled. these bits are set or cleared according to the device logic. therefore, the result of an instruction with the status register as destination may be different than intended. for example, clrf status will set the z bit but leave the other bits unchanged. the status register then reads back as ? 000u u1uu ?. it is recom- mended, therefore, that only bcf, bsf, swapf, movff and movwf instructions are used to alter the status register because these instructions do not affect the z, c, dc, ov or n bits in the status register. for other instructions not affecting any status bits, see the instruction set summaries in table 26-2 and table 26-3. note: the c and dc bits operate as a borrow and digit borrow bit respectively, in subtraction. register 5-4: status register u-0 u-0 u-0 r/w-x r/w-x r/w-x r/w-x r/w-x ? ? ?novzdc (1) c (2) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-5 unimplemented: read as ? 0 ? bit 4 n: negative bit this bit is used for signed arithmetic (2?s complement). it indicates whether the result was negative (alu msb = 1 ). 1 = result was negative 0 = result was positive bit 3 ov: overflow bit this bit is used for signed arithmetic (2?s complement). it indicates an overflow of the 7-bit magnitude which causes the sign bit (bit 7) to change state. 1 = overflow occurred for signed arithmetic (in this arithmetic operation) 0 = no overflow occurred bit 2 z: zero bit 1 = the result of an arithmetic or logic operation is zero 0 = the result of an arithmetic or logic operation is not zero bit 1 dc: digit carry/borrow bit (1) for addwf, addlw, sublw and subwf instructions: 1 = a carry-out from the 4th low-order bit of the result occurred 0 = no carry-out from the 4th low-order bit of the result bit 0 c: carry/borrow bit (2) for addwf, addlw, sublw and subwf instructions: 1 = a carry-out from the most significant bit of the result occurred 0 = no carry-out from the most significant bit of the result occurred note 1: for borrow, the polarity is reversed. a subtraction is executed by adding the 2?s complement of the second operand. for rotate ( rrf, rlf ) instructions, this bit is loaded with either bit 4 or bit 3 of the source register. 2: for borrow, the polarity is reversed. a subtraction is executed by adding the 2?s complement of the second operand. for rotate ( rrf, rlf ) instructions, this bit is loaded with either the high or low-order bit of the source register.
pic18f87j50 family ds39775b-page 88 preliminary ? 2007 microchip technology inc. 5.4 data addressing modes while the program memory can be addressed in only one way ? through the program counter ? information in the data memory space can be addressed in several ways. for most instructions, the addressing mode is fixed. other instructions may use up to three modes, depending on which operands are used and whether or not the extended instruction set is enabled. the addressing modes are: ? inherent ? literal ?direct ?indirect an additional addressing mode, indexed literal offset, is available when the extended instruction set is enabled (xinst configuration bit = 1 ). its operation is discussed in greater detail in section 5.6.1 ?indexed addressing with literal offset? . 5.4.1 inherent and literal addressing many pic18 control instructions do not need any argument at all; they either perform an operation that globally affects the device, or they operate implicitly on one register. this addressing mode is known as inherent addressing. examples include sleep , reset and daw . other instructions work in a similar way, but require an additional explicit argument in the opcode. this is known as literal addressing mode, because they require some literal value as an argument. examples include addlw and movlw , which respectively, add or move a literal value to the w register. other examples include call and goto , which include a 20-bit program memory address. 5.4.2 direct addressing direct addressing specifies all or part of the source and/or destination address of the operation within the opcode itself. the options are specified by the arguments accompanying the instruction. in the core pic18 instruction set, bit-oriented and byte-oriented instructions use some version of direct addressing by default. all of these instructions include some 8-bit literal address as their least significant byte. this address specifies either a register address in one of the banks of data ram ( section 5.3.4 ?general purpose register file? ), or a location in the access bank ( section 5.3.3 ?access bank? ) as the data source for the instruction. the access ram bit ?a? determines how the address is interpreted. when ?a? is ? 1 ?, the contents of the bsr ( section 5.3.2 ?bank select register? ) are used with the address to determine the complete 12-bit address of the register. when ?a? is ? 0 ?, the address is interpreted as being a register in the access bank. addressing that uses the access ram is sometimes also known as direct forced addressing mode. a few instructions, such as movff , include the entire 12-bit address (either source or destination) in their opcodes. in these cases, the bsr is ignored entirely. the destination of the operation?s results is determined by the destination bit ?d?. when ?d? is ? 1 ?, the results are stored back in the source register, overwriting its origi- nal contents. when ?d? is ? 0 ?, the results are stored in the w register. instructions without the ?d? argument have a destination that is implicit in the instruction; their destination is either the target register being operated on or the w register. 5.4.3 indirect addressing indirect addressing allows the user to access a location in data memory without giving a fixed address in the instruction. this is done by using file select registers (fsrs) as pointers to the locations to be read or written to. since the fsrs are themselves located in ram as special function registers, they can also be directly manipulated under program control. this makes fsrs very useful in implementing data structures such as tables and arrays in data memory. the registers for indirect addressing are also implemented with indirect file operands (indfs) that permit automatic manipulation of the pointer value with auto-incrementing, auto-decrementing or offsetting with another value. this allows for efficient code using loops, such as the example of clearing an entire ram bank in example 5-5. it also enables users to perform indexed addressing and other stack pointer operations for program memory in data memory. example 5-5: how to clear ram (bank 1) using indirect addressing note: the execution of some instructions in the core pic18 instruction set are changed when the pic18 extended instruction set is enabled. see section 5.6 ?data memory and the extended instruction set? for more information. lfsr fsr0, 100h ; next clrf postinc0 ; clear indf ; register then ; inc pointer btfss fsr0h, 1 ; all done with ; bank1? bra next ; no, clear next continue ; yes, continue
? 2007 microchip technology inc. preliminary ds39775b-page 89 pic18f87j50 family 5.4.3.1 fsr registers and the indf operand at the core of indirect addressing are three sets of registers: fsr0, fsr1 and fsr2. each represents a pair of 8-bit registers, fsrnh and fsrnl. the four upper bits of the fsrnh register are not used, so each fsr pair holds a 12-bit value. this represents a value that can address the entire range of the data memory in a linear fashion. the fsr register pairs, then, serve as pointers to data memory locations. indirect addressing is accomplished with a set of indirect file operands, indf0 through indf2. these can be thought of as ?virtual? registers: they are mapped in the sfr space but are not physically imple- mented. reading or writing to a particular indf register actually accesses its corresponding fsr register pair. a read from indf1, for example, reads the data at the address indicated by fsr1h:fsr1l. instructions that use the indf registers as operands actually use the contents of their corresponding fsr as a pointer to the instruction?s target. the indf operand is just a convenient way of using the pointer. because indirect addressing uses a full 12-bit address, data ram banking is not necessary. thus, the current contents of the bsr and the access ram bit have no effect on determining the target address. figure 5-9: indirect addressing fsr1h:fsr1l 0 7 data memory 000h 100h 200h 300h f00h e00h fffh bank 0 bank 1 bank 2 bank 14 bank 15 bank 3 through bank 13 addwf, indf1, 1 0 7 using an instruction with one of the indirect addressing registers as the operand.... ...uses the 12-bit address stored in the fsr pair associated with that register.... ...to determine the data memory location to be used in that operation. in this case, the fsr1 pair contains fcch. this means the contents of location fcch will be added to that of the w register and stored back in fcch. xxxx 1111 11001100
pic18f87j50 family ds39775b-page 90 preliminary ? 2007 microchip technology inc. 5.4.3.2 fsr registers and postinc, postdec, preinc and plusw in addition to the indf operand, each fsr register pair also has four additional indirect operands. like indf, these are ?virtual? registers that cannot be indirectly read or written to. accessing these registers actually accesses the associated fsr register pair, but also performs a specific action on its stored value. they are: ? postdec: accesses the fsr value, then automatically decrements it by ? 1 ? afterwards ? postinc: accesses the fsr value, then automatically increments it by ? 1 ? afterwards ? preinc: increments the fsr value by ? 1 ?, then uses it in the operation ? plusw: adds the signed value of the w register (range of -127 to 128) to that of the fsr and uses the new value in the operation in this context, accessing an indf register uses the value in the fsr registers without changing them. similarly, accessing a plusw register gives the fsr value offset by the value in the w register; neither value is actually changed in the operation. accessing the other virtual registers changes the value of the fsr registers. operations on the fsrs with postdec, postinc and preinc affect the entire register pair; that is, roll- overs of the fsrnl register from ffh to 00h carry over to the fsrnh register. on the other hand, results of these operations do not change the value of any flags in the status register (e.g., z, n, ov, etc.). the plusw register can be used to implement a form of indexed addressing in the data memory space. by manipulating the value in the w register, users can reach addresses that are fixed offsets from pointer addresses. in some applications, this can be used to implement some powerful program control structure, such as software stacks, inside of data memory. 5.4.3.3 operations by fsrs on fsrs indirect addressing operations that target other fsrs or virtual registers represent special cases. for exam- ple, using an fsr to point to one of the virtual registers will not result in successful operations. as a specific case, assume that fsr0h:fsr0l contains fe7h, the address of indf1. attempts to read the value of the indf1, using indf0 as an operand, will return 00h. attempts to write to indf1, using indf0 as the operand, will result in a nop . on the other hand, using the virtual registers to write to an fsr pair may not occur as planned. in these cases, the value will be written to the fsr pair but without any incrementing or decrementing. thus, writing to indf2 or postdec2 will write the same value to the fsr2h:fsr2l. since the fsrs are physical registers mapped in the sfr space, they can be manipulated through all direct operations. users should proceed cautiously when working on these registers, particularly if their code uses indirect addressing. similarly, operations by indirect addressing are gener- ally permitted on all other sfrs. users should exercise the appropriate caution that they do not inadvertently change settings that might affect the operation of the device. 5.5 program memory and the extended instruction set the operation of program memory is unaffected by the use of the extended instruction set. enabling the extended instruction set adds five additional two-word commands to the existing pic18 instruction set: addfsr , callw , movsf , movss and subfsr . these instructions are executed as described in section 5.2.4 ?two-word instructions? .
? 2007 microchip technology inc. preliminary ds39775b-page 91 pic18f87j50 family 5.6 data memory and the extended instruction set enabling the pic18 extended instruction set (xinst configuration bit = 1 ) significantly changes certain aspects of data memory and its addressing. specifi- cally, the use of the access bank for many of the core pic18 instructions is different. this is due to the intro- duction of a new addressing mode for the data memory space. this mode also alters the behavior of indirect addressing using fsr2 and its associated operands. what does not change is just as important. the size of the data memory space is unchanged, as well as its linear addressing. the sfr map remains the same. core pic18 instructions can still operate in both direct and indirect addressing mode; inherent and literal instructions do not change at all. indirect addressing with fsr0 and fsr1 also remains unchanged. 5.6.1 indexed addressing with literal offset enabling the pic18 extended instruction set changes the behavior of indirect addressing using the fsr2 register pair and its associated file operands. under the proper conditions, instructions that use the access bank ? that is, most bit-oriented and byte-oriented instructions ? can invoke a form of indexed addressing using an offset specified in the instruction. this special addressing mode is known as indexed addressing with literal offset, or indexed literal offset mode. when using the extended instruction set, this addressing mode requires the following: ? the use of the access bank is forced (?a? = 0 ); and ? the file address argument is less than or equal to 5fh. under these conditions, the file address of the instruction is not interpreted as the lower byte of an address (used with the bsr in direct addressing) or as an 8-bit address in the access bank. instead, the value is interpreted as an offset value to an address pointer specified by fsr2. the offset and the contents of fsr2 are added to obtain the target address of the operation. 5.6.2 instructions affected by indexed literal offset mode any of the core pic18 instructions that can use direct addressing are potentially affected by the indexed literal offset addressing mode. this includes all byte-oriented and bit-oriented instructions, or almost one-half of the standard pic18 instruction set. instruc- tions that only use inherent or literal addressing modes are unaffected. additionally, byte-oriented and bit-oriented instructions are not affected if they use the access bank (access ram bit is ? 1 ?) or include a file address of 60h or above. instructions meeting these criteria will continue to execute as before. a comparison of the different possi- ble addressing modes when the extended instruction set is enabled is shown in figure 5-10. those who desire to use byte-oriented or bit-oriented instructions in the indexed literal offset mode should note the changes to assembler syntax for this mode. this is described in more detail in section 26.2.1 ?extended instruction syntax? .
pic18f87j50 family ds39775b-page 92 preliminary ? 2007 microchip technology inc. figure 5-10: comparing addressing options for bit-oriented and byte-oriented instructions (extended instruction set enabled) example instruction: addwf, f, d, a (opcode: 0010 01da ffff ffff ) when a = 0 and f 60h: the instruction executes in direct forced mode. ?f? is interpreted as a location in the access ram between 060h and fffh. this is the same as locations f60h to fffh (bank 15) of data memory. locations below 060h are not available in this addressing mode. when a = 0 and f 5fh: the instruction executes in indexed literal offset mode. ?f? is interpreted as an offset to the address value in fsr2. the two are added together to obtain the address of the target register for the instruction. the address can be anywhere in the data memory space. note that in this mode, the correct syntax is now: addwf [k], d where ?k? is the same as ?f?. when a = 1 (all values of f): the instruction executes in direct mode (also known as direct long mode). ?f? is interpreted as a location in one of the 16 banks of the data memory space. the bank is designated by the bank select register (bsr). the address can be in any implemented bank in the data memory space. 000h 060h 100h f00h f60h fffh valid range 00h 60h ffh data memory access ram bank 0 bank 1 through bank 14 bank 15 sfrs 000h 060h 100h f00h f60h fffh data memory bank 0 bank 1 through bank 14 bank 15 sfrs fsr2h fsr2l ffffffff 001001da ffffffff 001001da 000h 060h 100h f00h f60h fffh data memory bank 0 bank 1 through bank 14 bank 15 sfrs for ?f? bsr 00000000
? 2007 microchip technology inc. preliminary ds39775b-page 93 pic18f87j50 family 5.6.3 mapping the access bank in indexed literal offset mode the use of indexed literal offset addressing mode effectively changes how the lower part of access ram (00h to 5fh) is mapped. rather than containing just the contents of the bottom part of bank 0, this mode maps the contents from bank 0 and a user-defined ?window? that can be located anywhere in the data memory space. the value of fsr2 establishes the lower bound- ary of the addresses mapped into the window, while the upper boundary is defined by fsr2 plus 95 (5fh). addresses in the access ram above 5fh are mapped as previously described (see section 5.3.3 ?access bank? ). an example of access bank remapping in this addressing mode is shown in figure 5-11. remapping of the access bank applies only to opera- tions using the indexed literal offset mode. operations that use the bsr (access ram bit is ? 1 ?) will continue to use direct addressing as before. any indirect or indexed addressing operation that explicitly uses any of the indirect file operands (including fsr2) will con- tinue to operate as standard indirect addressing. any instruction that uses the access bank, but includes a register address of greater than 05fh, will use direct addressing and the normal access bank map. 5.6.4 bsr in indexed literal offset mode although the access bank is remapped when the extended instruction set is enabled, the operation of the bsr remains unchanged. direct addressing, using the bsr to select the data memory bank, operates in the same manner as previously described. figure 5-11: remapping the access bank with indexed literal offset addressing data memory 000h 100h 200h f60h f00h fffh bank 1 bank 15 bank 2 through bank 14 sfrs 05fh addwf f, d, a fsr2h:fsr2l = 120h locations in the region from the fsr2 pointer (120h) to the pointer plus 05fh (17fh) are mapped to the bottom of the access ram (000h-05fh). special function registers at f60h through fffh are mapped to 60h through ffh, as usual. bank 0 addresses below 5fh are not available in this mode. they can still be addressed by using the bsr. access bank 00h ffh bank 0 sfrs bank 1 ?window? not accessible window example situation: 120h 17fh 5fh 60h
pic18f87j50 family ds39775b-page 94 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 95 pic18f87j50 family 6.0 flash program memory the flash program memory is readable, writable and erasable during normal operation over the entire v dd range. a read from program memory is executed on one byte at a time. a write to program memory is executed on blocks of 64 bytes at a time or two bytes at a time. pro- gram memory is erased in blocks of 1024 bytes at a time. a bulk erase operation may not be issued from user code. writing or erasing program memory will cease instruction fetches until the operation is complete. the program memory cannot be accessed during the write or erase, therefore, code cannot execute. an internal programming timer terminates program memory writes and erases. a value written to program memory does not need to be a valid instruction. executing a program memory location that forms an invalid instruction results in a nop . 6.1 table reads and table writes in order to read and write program memory, there are two operations that allow the processor to move bytes between the program memory space and the data ram: ? table read ( tblrd ) ? table write ( tblwt ) the program memory space is 16 bits wide, while the data ram space is 8 bits wide. table reads and table writes move data between these two memory spaces through an 8-bit register (tablat). table read operations retrieve data from program memory and place it into the data ram space. figure 6-1 shows the operation of a table read with program memory and data ram. table write operations store data from the data memory space into holding registers in program memory. the procedure to write the contents of the holding registers into program memory is detailed in section 6.5 ?writing to flash program memory? . figure 6-2 shows the operation of a table write with program memory and data ram. table operations work with byte entities. a table block containing data, rather than program instructions, is not required to be word-aligned. therefore, a table block can start and end at any byte address. if a table write is being used to write executable code into program memory, program instructions will need to be word-aligned. figure 6-1: table read operation table pointer (1) table latch (8-bit) program memory tblptrh tblptrl tablat tblptru instruction: tblrd * note 1: table pointer register points to a byte in program memory. program memory (tblptr)
pic18f87j50 family ds39775b-page 96 preliminary ? 2007 microchip technology inc. figure 6-2: table wr ite operation 6.2 control registers several control registers are used in conjunction with the tblrd and tblwt instructions. these include the: ? eecon1 register ? eecon2 register ? tablat register ? tblptr registers 6.2.1 eecon1 and eecon2 registers the eecon1 register (register 6-1) is the control register for memory accesses. the eecon2 register is not a physical register; it is used exclusively in the memory write and erase sequences. reading eecon2 will read all ? 0 ?s. the wprog bit, when set, will allow programming two bytes per word on the execution of the wr com- mand. if this bit is cleared, the wr command will result in programming on a block of 64 bytes. the free bit, when set, will allow a program memory erase operation. when free is set, the erase operation is initiated on the next wr command. when free is clear, only writes are enabled. the wren bit, when set, will allow a write operation. on power-up, the wren bit is clear. the wrerr bit is set in hardware when the wr bit is set and cleared when the internal programming timer expires and the write operation is complete. the wr control bit initiates write operations. the bit cannot be cleared, only set, in software. it is cleared in hardware at the completion of the write operation. table pointer (1) table latch (8-bit) tblptrh tblptrl tablat program memory (tblptr) tblptru instruction: tblwt * note 1: table pointer actually points to one of 64 holding registers, the address of which is determined by tblptrl<5:0>. the process for physically writing dat a to the program memory array is discussed in section 6.5 ?writing to flash program memory? . holding registers program memory note: during normal operation, the wrerr is read as ? 1 ?. this can indicate that a write operation was prematurely terminated by a reset, or a write operation was attempted improperly.
? 2007 microchip technology inc. preliminary ds39775b-page 97 pic18f87j50 family register 6-1: eecon1: eepr om control register 1 u-0 u-0 r/w-0 r/w-0 r/w-x r/w-0 r/s-0 u-0 ? ? wprog free wrerr (1) wren wr ? bit 7 bit 0 legend: s = settable only bit (cannot be cleared in software) r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 unimplemented: read as ? 0 ? bit 5 wprog: one word-wide program bit 1 = program 2 bytes on the next wr command 0 = program 64 bytes on the next wr command bit 4 free: flash row erase enable bit 1 = erase the program memory row addressed by tblptr on the next wr command (cleared by completion of erase operation) 0 = perform write only bit 3 wrerr: flash program error flag bit (1) 1 = a write operation is prematurely terminated (any reset during self-timed programming in normal operation, or an improper write attempt) 0 = the write operation completed bit 2 wren: flash program write enable bit 1 = allows write cycles to flash program memory 0 = inhibits write cycles to flash program memory bit 1 wr: write control bit 1 = initiates a program memory erase cycle or write cycle (the operation is self-timed and the bit is cleared by hardware once write is complete. the wr bit can only be set (not cleared) in software.) 0 = write cycle is complete bit 0 unimplemented: read as ? 0 ? note 1: when a wrerr occurs, the eepgd and cfgs bits are not cleared. this allows tracing of the error condition.
pic18f87j50 family ds39775b-page 98 preliminary ? 2007 microchip technology inc. 6.2.2 table latch register (tablat) the table latch (tablat) is an 8-bit register mapped into the sfr space. the table latch register is used to hold 8-bit data during data transfers between program memory and data ram. 6.2.3 table pointer register (tblptr) the table pointer (tblptr) register addresses a byte within the program memory. the tblptr is comprised of three sfr registers: table pointer upper byte, table pointer high byte and table pointer low byte (tblptru:tblptrh:tblptrl). these three regis- ters join to form a 22-bit wide pointer. the low-order 21 bits allow the device to address up to 2 mbytes of program memory space. the 22nd bit allows access to the device id, the user id and the configuration bits. the table pointer register, tblptr, is used by the tblrd and tblwt instructions. these instructions can update the tblptr in one of four ways based on the table operation. these operations are shown in table 6-1. these operations on the tblptr only affect the low-order 21 bits. 6.2.4 table pointer boundaries tblptr is used in reads, writes and erases of the flash program memory. when a tblrd is executed, all 22 bits of the tblptr determine which byte is read from program memory into tablat. when a tblwt is executed, the seven lsbs of the table pointer register (tblptr<6:0>) determine which of the 64 program memory holding registers is written to. when the timed write to program memory begins (via the wr bit), the 12 msbs of the tblptr (tblptr<21:10>) determine which program memory block of 1024 bytes is written to. for more detail, see section 6.5 ?writing to flash program memory? . when an erase of program memory is executed, the 12 msbs of the table pointer register point to the 1024-byte block that will be erased. the least significant bits are ignored. figure 6-3 describes the relevant boundaries of tblptr based on flash program memory operations. table 6-1: table pointer operations with tblrd and tblwt instructions figure 6-3: table pointer bo undaries based on operation example operation on table pointer tblrd* tblwt* tblptr is not modified tblrd*+ tblwt*+ tblptr is incremented after the read/write tblrd*- tblwt*- tblptr is decremented after the read/write tblrd+* tblwt+* tblptr is incremented before the read/write 21 16 15 87 0 erase: tblptr<20:10> table write: tblptr<20:6> table read: tblptr<21:0> tblptrl tblptrh tblptru
? 2007 microchip technology inc. preliminary ds39775b-page 99 pic18f87j50 family 6.3 reading the flash program memory the tblrd instruction is used to retrieve data from program memory and places it into data ram. table reads from program memory are performed one byte at a time. tblptr points to a byte address in program space. executing tblrd places the byte pointed to into tablat. in addition, tblptr can be modified automatically for the next table read operation. the internal program memory is typically organized by words. the least significant bit of the address selects between the high and low bytes of the word. figure 6-4 shows the interface between the internal program memory and the tablat. figure 6-4: reads from flash program memory example 6-1: reading a flash program memory word (even byte address) program memory (odd byte address) tblrd tablat tblptr = xxxxx1 fetch instruction register (ir) read register tblptr = xxxxx0 movlw code_addr_upper ; load tblptr with the base movwf tblptru ; address of the word movlw code_addr_high movwf tblptrh movlw code_addr_low movwf tblptrl read_word tblrd*+ ; read into tablat and increment movf tablat, w ; get data movwf word_even tblrd*+ ; read into tablat and increment movf tablat, w ; get data movwf word_odd
pic18f87j50 family ds39775b-page 100 preliminary ? 2007 microchip technology inc. 6.4 erasing flash program memory the minimum erase block is 512 words or 1024 bytes. only through the use of an external programmer, or through icsp control, can larger blocks of program memory be bulk erased. word erase in the flash array is not supported. when initiating an erase sequence from the micro- controller itself, a block of 1024 bytes of program memory is erased. the most significant 12 bits of the tblptr<21:10> point to the block being erased. tblptr<9:0> are ignored. the eecon1 register commands the erase operation. the wren bit must be set to enable write operations. the free bit is set to select an erase operation. for protection, the write initiate sequence for eecon2 must be used. a long write is necessary for erasing the internal flash. instruction execution is halted while in a long write cycle. the long write will be terminated by the internal programming timer. 6.4.1 flash program memory erase sequence the sequence of events for erasing a block of internal program memory location is: 1. load table pointer register with address of row being erased. 2. set the wren and free bits (eecon1<2,4>) to enable the erase operation. 3. disable interrupts. 4. write 55h to eecon2. 5. write 0aah to eecon2. 6. set the wr bit. this will begin the row erase cycle. 7. the cpu will stall for duration of the erase for t iw (see parameter d133a). 8. re-enable interrupts. example 6-2: erasing a flash program memory row movlw code_addr_upper ; load tblptr with the base movwf tblptru ; address of the memory block movlw code_addr_high movwf tblptrh movlw code_addr_low movwf tblptrl erase_row bsf eecon1, wren ; enable write to memory bsf eecon1, free ; enable row erase operation bcf intcon, gie ; disable interrupts required movlw 55h sequence movwf eecon2 ; write 55h movlw 0aah movwf eecon2 ; write 0aah bsf eecon1, wr ; start erase (cpu stall) bsf intcon, gie ; re-enable interrupts
? 2007 microchip technology inc. preliminary ds39775b-page 101 pic18f87j50 family 6.5 writing to flash program memory the programming block is 32 words or 64 bytes. programming one word or two bytes at a time is also supported. table writes are used internally to load the holding registers needed to program the flash memory. there are 64 holding registers used by the table writes for programming. since the table latch (tablat) is only a single byte, the tblwt instruction may need to be executed 64 times for each programming operation (if wprog = 0 ). all of the table write operations will essentially be short writes because only the holding registers are written. at the end of updating the 64 holding registers, the eecon1 register must be written to in order to start the programming operation with a long write. the long write is necessary for programming the inter- nal flash. instruction execution is halted while in a long write cycle. the long write will be terminated by the internal programming timer. the on-chip timer controls the write time. the write/erase voltages are generated by an on-chip charge pump, rated to operate over the voltage range of the device. figure 6-5: table writes to flash program memory 6.5.1 flash program memory write sequence the sequence of events for programming an internal program memory location should be: 1. read 1024 bytes into ram. 2. update data values in ram as necessary. 3. load table pointer register with address being erased. 4. execute the row erase procedure. 5. load table pointer register with address of first byte being written, minus 1. 6. write the 64 bytes into the holding registers with auto-increment. 7. set the wren bit (eecon1<2>) to enable byte writes. 8. disable interrupts. 9. write 55h to eecon2. 10. write 0aah to eecon2. 11. set the wr bit. this will begin the write cycle. 12. the cpu will stall for duration of the write for t iw (see parameter d133a). 13. re-enable interrupts. 14. repeat steps 6 through 13 until all 1024 bytes are written to program memory. 15. verify the memory (table read). an example of the required code is shown in example 6-3 on the following page. note 1: unlike previous pic ? devices, members of the pic18f87j50 family do not reset the holding registers after a write occurs. the holding registers must be cleared or overwritten before a programming sequence. 2: to maintain the endurance of the program memory cells, each flash byte should not be programmed more than one time between erase operations. before attempting to modify the contents of the target cell a second time, a row erase of the target row, or a bulk erase of the entire memory, must be performed. tablat tblptr = xxxx3f tblptr = xxxxx1 tblptr = xxxxx0 write register tblptr = xxxxx2 program memory holding register holding register holding register holding register 8 8 8 8 note: before setting the wr bit, the table pointer address needs to be within the intended address range of the 64 bytes in the holding register.
pic18f87j50 family ds39775b-page 102 preliminary ? 2007 microchip technology inc. example 6-3: writing to flash program memory movlw code_addr_upper ; load tblptr with the base address movwf tblptru ; of the memory block, minus 1 movlw code_addr_high movwf tblptrh movlw code_addr_low movwf tblptrl erase_block bsf eecon1, wren ; enable write to memory bsf eecon1, free ; enable row erase operation bcf intcon, gie ; disable interrupts movlw 55h movwf eecon2 ; write 55h movlw 0aah movwf eecon2 ; write 0aah bsf eecon1, wr ; start erase (cpu stall) bsf intcon, gie ; re-enable interrupts movlw d'16' movwf write_counter ; need to write 16 blocks of 64 to write ; one erase block of 1024 restart_buffer movlw d'64' movwf counter movlw buffer_addr_high ; point to buffer movwf fsr0h movlw buffer_addr_low movwf fsr0l fill_buffer ... ; read the new data from i2c, spi, ; psp, usart, etc. write_buffer movlw d?64 ; number of bytes in holding register movwf counter write_byte_to_hregs movff postinc0, wreg ; get low byte of buffer data movwf tablat ; present data to table latch tblwt+* ; write data, perform a short write ; to internal tblwt holding register. decfsz counter ; loop until buffers are full bra write_byte_to_hregs program_memory bsf eecon1, wren ; enable write to memory bcf intcon, gie ; disable interrupts movlw 55h required movwf eecon2 ; write 55h sequence movlw 0aah movwf eecon2 ; write 0aah bsf eecon1, wr ; start program (cpu stall) bsf intcon, gie ; re-enable interrupts bcf eecon1, wren ; disable write to memory decfsz write_counter ; done with one write cycle bra restart_buffer ; if not done replacing the erase block
? 2007 microchip technology inc. preliminary ds39775b-page 103 pic18f87j50 family 6.5.2 flash program memory write sequence (word proramming). the pic18f87j50 family of devices have a feature that allows programming a single word (two bytes). this feature is enabled when the wprog bit is set. if the memory location is already erased, the following sequence is required to enable this feature: 1. load the table pointer register with the address of the data to be written. (it must be an even address.) 2. write the 2 bytes into the holding registers by performing table writes. (do not post-increment on the second table write.) 3. set the wren bit (eecon1<2>) to enable writes and the wprog bit (eecon1<5>) to select word write mode. 4. disable interrupts. 5. write 55h to eecon2. 6. write aah to eecon2. 7. set the wr bit. this will begin the write cycle. 8. the cpu will stall for duration of the write for t iw (see parameter d133a). 9. re-enable interrupts. example 6-4: single word write to flash program memory movlw code_addr_upper ; load tblptr with the base address movwf tblptru movlw code_addr_high movwf tblptrh movlw code_addr_low ; the table pointer must be loaded with an even address movwf tblptrl movlw data0 ; lsb of word to be written movwf tablat tblwt*+ movlw data1 ; msb of word to be written movwf tablat tblwt* ; the last table write must not increment the table pointer! the table pointer needs to point to the msb before starting the write operation. program_memory bsf eecon1, wprog ; enable single word write bsf eecon1, wren ; enable write to memory bcf intcon, gie ; disable interrupts movlw 55h required movwf eecon2 ; write 55h sequence movlw 0aah movwf eecon2 ; write 0aah bsf eecon1, wr ; start program (cpu stall) bsf intcon, gie ; re-enable interrupts bcf eecon1, wprog ; disable single word write bcf eecon1, wren ; disable write to memory
pic18f87j50 family ds39775b-page 104 preliminary ? 2007 microchip technology inc. 6.5.3 write verify depending on the application, good programming practice may dictate that the value written to the memory should be verified against the original value. this should be used in applications where excessive writes can stress bits near the specification limit. 6.5.4 unexpected termination of write operation if a write is terminated by an unplanned event, such as loss of power or an unexpected reset, the memory location just programmed should be verified and repro- grammed if needed. if the write operation is interrupted by a mclr reset or a wdt time-out reset during normal operation, the user can check the wrerr bit and rewrite the location(s) as needed. 6.6 flash program operation during code protection see section 25.6 ?program verification and code protection? for details on code protection of flash program memory. table 6-2: registers associated with program flash memory name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: tblptru ? ? bit 21 program memory table pointer upper byte (tblptr<20:16>) 59 tbpltrh program memory table pointer high byte (tblptr<15:8>) 59 tblptrl program memory table pointer low byte (tblptr<7:0>) 59 tablat program memory table latch 59 intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 eecon2 program memory control register 2 (not a physical register) 61 eecon1 ? ? wprog free wrerr wren wr ?61 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used during flash program memory access.
? 2007 microchip technology inc. preliminary ds39775b-page 105 pic18f87j50 family 7.0 external memory bus the external memory bus (emb) allows the device to access external memory devices (such as flash, eprom, sram, etc.) as program or data memory. it supports both 8 and 16-bit data width modes and three address widths of up to 20 bits. the bus is implemented with 28 pins, multiplexed across four i/o ports. three ports (portd, porte and porth) are multiplexed with the address/data bus for a total of 20 available lines, while portj is multiplexed with the bus control signals. a list of the pins and their functions is provided in table 7-1. table 7-1: pic18f87j50 family exte rnal bus ? i/o port functions note: the external memory bus is not implemented on 64-pin devices. name port bit external memory bus function rd0/ad0 portd 0 address bit 0 or data bit 0 rd1/ad1 portd 1 address bit 1 or data bit 1 rd2/ad2 portd 2 address bit 2 or data bit 2 rd3/ad3 portd 3 address bit 3 or data bit 3 rd4/ad4 portd 4 address bit 4 or data bit 4 rd5/ad5 portd 5 address bit 5 or data bit 5 rd6/ad6 portd 6 address bit 6 or data bit 6 rd7/ad7 portd 7 address bit 7 or data bit 7 re0/ad8 porte 0 address bit 8 or data bit 8 re1/ad9 porte 1 address bit 9 or data bit 9 re2/ad10 porte 2 address bit 10 or data bit 10 re3/ad11 porte 3 address bit 11 or data bit 11 re4/ad12 porte 4 address bit 12 or data bit 12 re5/ad13 porte 5 address bit 13 or data bit 13 re6/ad14 porte 6 address bit 14 or data bit 14 re7/ad15 porte 7 address bit 15 or data bit 15 rh0/a16 porth 0 address bit 16 rh1/a17 porth 1 address bit 17 rh2/a18 porth 2 address bit 18 rh3/a19 porth 3 address bit 19 rj0/ale portj 0 address latch enable (ale) control pin rj1/oe portj 1 output enable (oe ) control pin rj2/wrl portj 2 write low (wrl ) control pin rj3/wrh portj 3 write high (wrh ) control pin rj4/ba0 portj 4 byte address bit 0 (ba0) rj5/ce portj 5 chip enable (ce ) control pin rj6/lb portj 6 lower byte enable (lb ) control pin rj7/ub portj 7 upper byte enable (ub ) control pin note: for the sake of clarity, only i/o port and external bus assignments are shown here. one or more additional multiplexed features may be available on some pins.
pic18f87j50 family ds39775b-page 106 preliminary ? 2007 microchip technology inc. 7.1 external memory bus control the operation of the interface is controlled by the memcon register (register 7-1). this register is available in all program memory operating modes except microcontroller mode. in this mode, the register is disabled and cannot be written to. the ebdis bit (memcon<7>) controls the operation of the bus and related port functions. clearing ebdis enables the interface and disables the i/o functions of the ports, as well as any other functions multiplexed to those pins. setting the bit enables the i/o ports and other functions, but allows the interface to override everything else on the pins when an external memory operation is required. by default, the external bus is always enabled and disables all other i/o. the operation of the ebdis bit is also influenced by the program memory mode being used. this is discussed in more detail in section 7.5 ?program memory modes and the external memory bus? . the wait bits allow for the addition of wait states to external memory operations. the use of these bits is discussed in section 7.3 ?wait states? . the wm bits select the particular operating mode used when the bus is operating in 16-bit data width mode. these are discussed in more detail in section 7.6 ?16-bit data width modes? . these bits have no effect when an 8-bit data width mode is selected. the memcon register (see register 7-1) shares the same memory space as the pr2 register and can be alternately selected based on the designation of the adshr bit in the wdtcon register (see register 25-9). register 7-1: memcon: external memory bus control register r/w-0 u-0 r/w-0 r/w-0 u-0 u-0 r/w-0 r/w-0 ebdis ?wait1wait0 ? ?wm1wm0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ebdis : external bus disable bit 1 = external bus enabled when microcontroller accesses external memory; otherwise, all external bus drivers are mapped as i/o ports 0 = external bus always enabled, i/o ports are disabled bit 6 unimplemented : read as ? 0 ? bit 5-4 wait1:wait0: table reads and writes bus cycle wait count bits 11 = table reads and writes will wait 0 t cy 10 = table reads and writes will wait 1 t cy 01 = table reads and writes will wait 2 t cy 00 = table reads and writes will wait 3 t cy bit 3-2 unimplemented : read as ? 0 ? bit 1-0 wm1:wm0: tblwt operation with 16-bit data bus width select bits 1x = word write mode: tablat word output, wrh active when tablat is written 01 = byte select mode: tablat data copied on both msb and lsb, wrh and (ub or lb ) will activate 00 = byte write mode: tablat data copied on both msb and lsb, wrh or wrl will activate
? 2007 microchip technology inc. preliminary ds39775b-page 107 pic18f87j50 family 7.2 address and data width the pic18f87j50 family of devices can be indepen- dently configured for different address and data widths on the same memory bus. both address and data width are set by configuration bits in the config3l register. as configuration bits, this means that these options can only be configured by programming the device and are not controllable in software. the bw bit selects an 8-bit or 16-bit data bus width. setting this bit (default) selects a data width of 16 bits. the emb1:emb0 bits determine both the program memory operating mode and the address bus width. the available options are 20-bit, 16-bit and 12-bit, as well as microcontroller mode (external bus disabled). selecting a 16-bit or 12-bit width makes a correspond- ing number of high-order lines available for i/o functions. these pins are no longer affected by the setting of the ebdis bit. for example, selecting a 16-bit addressing mode (emb1:emb0 = 01 ) disables a19:a16 and allows porth<3:0> to function without interruptions from the bus. using the smaller address widths allows users to tailor the memory bus to the size of the external memory space for a particular design while freeing up pins for dedicated i/o operation. because the emb bits have the effect of disabling pins for memory bus operations, it is important to always select an address width at least equal to the data width. if a 12-bit address width is used with a 16-bit data width, the upper four bits of data will not be available on the bus. all combinations of address and data widths require multiplexing of address and data information on the same lines. the address and data multiplexing, as well as i/o ports made available by the use of smaller address widths, are summarized in table 7-2. 7.2.1 address shifting on the external bus by default, the address presented on the external bus is the value of the pc. in practical terms, this means that addresses in the external memory device below the top of on-chip memory are unavailable to the micro- controller. to access these physical locations, the glue logic between the microcontroller and the external memory must somehow translate addresses. to simplify the interface, the external bus offers an extension of extended microcontroller mode that automatically performs address shifting. this feature is controlled by the eashft configuration bit. setting this bit offsets addresses on the bus by the size of the microcontroller?s on-chip program memory and sets the bottom address at 0000h. this allows the device to use the entire range of physical addresses of the external memory. 7.2.2 21-bit addressing as an extension of 20-bit address width operation, the external memory bus can also fully address a 2-mbyte memory space. this is done by using the bus address bit 0 (ba0) control line as the least significant bit of the address. the ub and lb control signals may also be used with certain memory devices to select the upper and lower bytes within a 16-bit wide data word. this addressing mode is available in both 8-bit and certain 16-bit data width modes. additional details are provided in section 7.6.3 ?16-bit byte select mode? and section 7.7 ?8-bit data width mode? . table 7-2: address and data lines for different address and data widths data width address width multiplexed data and address lines (and corresponding ports) address only lines (and corresponding ports) ports available for i/o 8-bit 12-bit ad7:ad0 (portd<7:0>) ad11:ad8 (porte<3:0>) porte<7:4>, all of porth 16-bit ad15:ad8 (porte<7:0>) all of porth 20-bit a19:a16, ad15:ad8 (porth<3:0>, porte<7:0>) ? 16-bit 16-bit ad15:ad0 (portd<7:0>, porte<7:0>) ? all of porth 20-bit a19:a16 (porth<3:0>) ?
pic18f87j50 family ds39775b-page 108 preliminary ? 2007 microchip technology inc. 7.3 wait states while it may be assumed that external memory devices will operate at the microcontroller clock rate, this is often not the case. in fact, many devices require longer times to write or retrieve data than the time allowed by the execution of table read or table write operations. to compensate for this, the external memory bus can be configured to add a fixed delay to each table opera- tion using the bus. wait states are enabled by setting the wait configuration bit. when enabled, the amount of delay is set by the wait1:wait0 bits (memcon<5:4>). the delay is based on multiples of microcontroller instruction cycle time and are added following the instruction cycle when the table operation is executed. the range is from no delay to 3 t cy (default value). 7.4 port pin weak pull-ups with the exception of the upper address lines, a19:a16, the pins associated with the external memory bus are equipped with weak pull-ups. the pull-ups are controlled by the upper three bits of the portg register (portg<7:5>). they are named rdpu, repu and rjpu and control pull-ups on portd, porte and portj, respectively. setting one of these bits enables the corresponding pull-ups for that port. all pull-ups are disabled by default on all device resets. in extended microcontroller mode, the port pull-ups can be useful in preserving the memory state on the external bus while the bus is temporarily disabled (ebdis = ? 1 ?). 7.5 program memory modes and the external memory bus the pic18f87j50 family of devices is capable of operating in one of two program memory modes, using combinations of on-chip and external program memory. the functions of the multiplexed port pins depend on the program memory mode selected, as well as the setting of the ebdis bit. in microcontroller mode, the bus is not active and the pins have their port functions only. writes to the memcom register are not permitted. the reset value of ebdis (? 0 ?) is ignored and emb pins behave as i/o ports. in extended microcontroller mode, the external program memory bus shares i/o port functions on the pins. when the device is fetching or doing table read/table write operations on the external program memory space, the pins will have the external bus function. if the device is fetching and accessing internal program memory locations only, the ebdis control bit will change the pins from external memory to i/o port functions. when ebdis = 0 , the pins function as the external bus. when ebdis = 1 , the pins function as i/o ports. if the device fetches or accesses external memory while ebdis = 1 , the pins will switch to external bus. if the ebdis bit is set by a program executing from exter- nal memory, the action of setting the bit will be delayed until the program branches into the internal memory. at that time, the pins will change from external bus to i/o ports. if the device is executing out of internal memory when ebdis = 0 , the memory bus address/data and control pins will not be active. they will go to a state where the active address/data pins are tri-state; the ce , oe , wrh , wrl , ub and lb signals are ? 1 ? and ale and ba0 are ? 0 ?. note that only those pins associated with the current address width are forced to tri-state; the other pins continue to function as i/o. in the case of 16-bit address width, for example, only ad<15:0> (portd and porte) are affected; a19:a16 (porth<3:0>) continue to function as i/o. in all external memory modes, the bus takes priority over any other peripherals that may share pins with it. this includes the parallel master port and serial communication modules which would otherwise take priority over the i/o port. 7.6 16-bit data width modes in 16-bit data width mode, the external memory interface can be connected to external memories in three different configurations: ? 16-bit byte write ? 16-bit word write ? 16-bit byte select the configuration to be used is determined by the wm1:wm0 bits in the memcon register (memcon<1:0>). these three different configurations allow the designer maximum flexibility in using both 8-bit and 16-bit devices with 16-bit data. for all 16-bit modes, the address latch enable (ale) pin indicates that the address bits, ad<15:0>, are avail- able on the external memory interface bus. following the address latch, the output enable signal (oe ) will enable both bytes of program memory at once to form a 16-bit instruction word. the chip enable signal (ce ) is active at any time that the microcontroller accesses external memory, whether reading or writing; it is inactive (asserted high) whenever the device is in sleep mode. in byte select mode, jedec standard flash memories will require ba0 for the byte address line and one i/o line to select between byte and word mode. the other 16-bit modes do not need ba0. jedec standard static ram memories will use the ub or lb signals for byte selection.
? 2007 microchip technology inc. preliminary ds39775b-page 109 pic18f87j50 family 7.6.1 16-bit byte write mode figure 7-1 shows an example of 16-bit byte write mode for pic18f87j50 family devices. this mode is used for two separate 8-bit memories connected for 16-bit operation. this generally includes basic eprom and flash devices. it allows table writes to byte-wide external memories. during a tblwt instruction cycle, the tablat data is presented on the upper and lower bytes of the ad15:ad0 bus. the appropriate wrh or wrl control line is strobed on the lsb of the tblptr. figure 7-1: 16-bit byte write mode example ad<7:0> a<19:16> (1) ale d<15:8> 373 a d<7:0> a<19:0> a d<7:0> 373 oe wrh oe oe wr (2) wr (2) ce ce note 1: upper order address li nes are used only for 20-bit address widths. 2: this signal only applies to table writes. see section 6.1 ?table reads and table writes? . wrl d<7:0> (lsb) (msb) pic18f87j50 d<7:0> ad<15:8> address bus data bus control lines ce
pic18f87j50 family ds39775b-page 110 preliminary ? 2007 microchip technology inc. 7.6.2 16-bit word write mode figure 7-2 shows an example of 16-bit word write mode for pic18f87j50 family devices. this mode is used for word-wide memories which include some of the eprom and flash-type memories. this mode allows opcode fetches and table reads from all forms of 16-bit memory and table writes to any type of word-wide external memories. this method makes a distinction between tblwt cycles to even or odd addresses. during a tblwt cycle to an even address (tblptr<0> = 0 ), the tablat data is transferred to a holding latch and the external address data bus is tri-stated for the data portion of the bus cycle. no write signals are activated. during a tblwt cycle to an odd address (tblptr<0> = 1 ), the tablat data is presented on the upper byte of the ad15:ad0 bus. the contents of the holding latch are presented on the lower byte of the ad15:ad0 bus. the wrh signal is strobed for each write cycle; the wrl pin is unused. the signal on the ba0 pin indicates the lsb of the tblptr, but it is left unconnected. instead, the ub and lb signals are active to select both bytes. the obvious limitation to this method is that the table write must be done in pairs on a specific word boundary to correctly write a word location. figure 7-2: 16-bit word write mode example ad<7:0> pic18f87j50 ad<15:8> ale 373 a<20:1> 373 oe wrh a<19:16> (1) a d<15:0> oe wr (2) ce d<15:0> jedec word eprom memory address bus data bus control lines note 1: upper order address lines are used only for 20-bit address widths. 2: this signal only applies to table writes. see section 6.1 ?table reads and table writes? . ce
? 2007 microchip technology inc. preliminary ds39775b-page 111 pic18f87j50 family 7.6.3 16-bit byte select mode figure 7-3 shows an example of 16-bit byte select mode. this mode allows table write operations to word-wide external memories with byte selection capability. this generally includes both word-wide flash and sram devices. during a tblwt cycle, the tablat data is presented on the upper and lower byte of the ad15:ad0 bus. the wrh signal is strobed for each write cycle; the wrl pin is not used. the ba0 or ub /lb signals are used to select the byte to be written, based on the least significant bit of the tblptr register. flash and sram devices use different control signal combinations to implement byte select mode. jedec standard flash memories require that a controller i/o port pin be connected to the memory?s byte/word pin to provide the select signal. they also use the ba0 signal from the controller as a byte address. jedec standard static ram memories, on the other hand, use the ub or lb signals to select the byte. figure 7-3: 16-bit byte select mode example ad<7:0> pic18f87j50 ad<15:8> ale 373 a<20:1> 373 oe wrh a<19:16> (2) wrl ba0 jedec word a d<15:0> a<20:1> ce d<15:0> i/o oe wr (1) a0 byte/word flash memory jedec word a d<15:0> ce d<15:0> oe wr (1) lb ub sram memory lb ub 138 (3) address bus data bus control lines note 1: this signal only applies to table writes. see section 6.1 ?table reads and table writes? . 2: upper order address lines are used only for 20-bit address width. 3: demultiplexing is only required when mu ltiple memory devices are accessed.
pic18f87j50 family ds39775b-page 112 preliminary ? 2007 microchip technology inc. 7.6.4 16-bit mode timing the presentation of control signals on the external memory bus is different for the various operating modes. typical signal timing diagrams are shown in figure 7-4 and figure 7-5. figure 7-4: external me mory bus timing for tblrd (extended microcontroller mode) figure 7-5: external me mory bus timing for sleep (extended microcontroller mode) q2 q1 q3 q4 q2 q1 q3 q4 q2 q1 q3 q4 a<19:16> ale oe ad<15:0> ce opcode fetch opcode fetch opcode fetch tblrd * tblrd cycle 1 addlw 55h from 000100h q2 q1 q3 q4 0ch cf33h tblrd 92h from 199e67h 9256h from 000104h memory cycle instruction execution inst(pc ? 2) tblrd cycle 2 movlw 55h from 000102h movlw q2 q1 q3 q4 q2 q1 q3 q4 a<19:16> ale oe 3aaah ad<15:0> 00h 00h ce opcode fetch opcode fetch sleep sleep from 007554h q1 bus inactive 0003h 3aabh 0e55h memory cycle instruction execution inst(pc ? 2) sleep mode, movlw 55h from 007556h
? 2007 microchip technology inc. preliminary ds39775b-page 113 pic18f87j50 family 7.7 8-bit data width mode in 8-bit data width mode, the external memory bus operates only in multiplexed mode; that is, data shares the 8 least significant bits of the address bus. figure 7-6 shows an example of 8-bit multiplexed mode for 80-pin devices. this mode is used for a single 8-bit memory connected for 16-bit operation. the instructions will be fetched as two 8-bit bytes on a shared data/address bus. the two bytes are sequen- tially fetched within one instruction cycle (t cy ). therefore, the designer must choose external memory devices according to timing calculations based on 1/2 t cy (2 times the instruction rate). for proper mem- ory speed selection, glue logic propagation delay times must be considered, along with setup and hold times. the address latch enable (ale) pin indicates that the address bits, ad<15:0>, are available on the external memory interface bus. the output enable signal (oe ) will enable one byte of program memory for a portion of the instruction cycle, then ba0 will change and the second byte will be enabled to form the 16-bit instruc- tion word. the least significant bit of the address, ba0, must be connected to the memory devices in this mode. the chip enable signal (ce ) is active at any time that the microcontroller accesses external memory, whether reading or writing. it is inactive (asserted high) whenever the device is in sleep mode. this generally includes basic eprom and flash devices. it allows table writes to byte-wide external memories. figure 7-6: 8-bit multiplexed mode example ad<7:0> a<19:16> (1) ale d<15:8> 373 a<19:0> a d<7:0> oe oe wr (2) ce note 1: upper order address bits are only used for 20-bit address width. the upper ad byte is used for all address widths except 8-bit. 2: this signal only applies to table writes. see section 6.1 ?table reads and table writes? . wrl d<7:0> pic18f87j50 ad<15:8> (1) address bus data bus control lines ce a0 ba0
pic18f87j50 family ds39775b-page 114 preliminary ? 2007 microchip technology inc. 7.7.1 8-bit mode timing the presentation of control signals on the external memory bus is different for the various operating modes. typical signal timing diagrams are shown in figure 7-7 and figure 7-8. figure 7-7: external me mory bus timing for tblrd (extended microcontroller mode) figure 7-8: external me mory bus timing for sleep (extended microcontroller mode) q2 q1 q3 q4 q2 q1 q3 q4 q2 q1 q3 q4 a<19:16> ale oe ad<7:0> ce opcode fetch opcode fetch opcode fetch tblrd * tblrd cycle 1 addlw 55h from 000100h q2 q1 q3 q4 0ch 33h tblrd 92h from 199e67h 92h from 000104h memory cycle instruction execution inst(pc ? 2) tblrd cycle 2 movlw 55h from 000102h movlw ad<15:8> cfh q2 q1 q3 q4 q2 q1 q3 q4 a<19:16> ale oe aah ad<7:0> 00h 00h ce opcode fetch opcode fetch sleep sleep from 007554h q1 bus inactive 00h abh 55h memory cycle instruction execution inst(pc ? 2) sleep mode, movlw 55h from 007556h ad<15:8> 3ah 3ah 03h 0eh ba0
? 2007 microchip technology inc. preliminary ds39775b-page 115 pic18f87j50 family 7.8 operation in power-managed modes in alternate, power-managed run modes, the external bus continues to operate normally. if a clock source with a lower speed is selected, bus operations will run at that speed. in these cases, excessive access times for the external memory may result if wait states have been enabled and added to external memory opera- tions. if operations in a lower power run mode are anticipated, users should provide in their applications for adjusting memory access times at the lower clock speeds. in sleep and idle modes, the microcontroller core does not need to access data; bus operations are suspended. the state of the external bus is frozen, with the address/data pins and most of the control pins hold- ing at the same state they were in when the mode was invoked. the only potential changes are the ce , lb and ub pins, which are held at logic high.
pic18f87j50 family ds39775b-page 116 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 117 pic18f87j50 family 8.0 8 x 8 hardware multiplier 8.1 introduction all pic18 devices include an 8 x 8 hardware multiplier as part of the alu. the multiplier performs an unsigned operation and yields a 16-bit result that is stored in the product register pair, prodh:prodl. the multiplier?s operation does not affect any flags in the status register. making multiplication a hardware operation allows it to be completed in a single instruction cycle. this has the advantages of higher computational throughput and reduced code size for multiplication algorithms and allows the pic18 devices to be used in many applica- tions previously reserved for digital signal processors. a comparison of various hardware and software multiply operations, along with the savings in memory and execution time, is shown in table 8-1. 8.2 operation example 8-1 shows the instruction sequence for an 8 x 8 unsigned multiplication. only one instruction is required when one of the arguments is already loaded in the wreg register. example 8-2 shows the sequence to do an 8 x 8 signed multiplication. to account for the sign bits of the argu- ments, each argument?s most significant bit (msb) is tested and the appropriate subtractions are done. example 8-1: 8 x 8 unsigned multiply routine example 8-2: 8 x 8 signed multiply routine table 8-1: performance comparison for v arious multiply operations movf arg1, w ; mulwf arg2 ; arg1 * arg2 -> ; prodh:prodl movf arg1, w mulwf arg2 ; arg1 * arg2 -> ; prodh:prodl btfsc arg2, sb ; test sign bit subwf prodh, f ; prodh = prodh ; - arg1 movf arg2, w btfsc arg1, sb ; test sign bit subwf prodh, f ; prodh = prodh ; - arg2 routine multiply method program memory (words) cycles (max) time @ 48 mhz @ 10 mhz @ 4 mhz 8 x 8 unsigned without hardware multiply 13 69 5.7 s27.6 s69 s hardware multiply 1 1 83.3 ns 400 ns 1 s 8 x 8 signed without hardware multiply 33 91 7.5 s36.4 s91 s hardware multiply 6 6 500 ns 2.4 s6 s 16 x 16 unsigned without hardware multiply 21 242 20.1 s96.8 s242 s hardware multiply 28 28 2.3 s 11.2 s28 s 16 x 16 signed without hardware multiply 52 254 21.6 s 102.6 s254 s hardware multiply 35 40 3.3 s16.0 s40 s
pic18f87j50 family ds39775b-page 118 preliminary ? 2007 microchip technology inc. example 8-3 shows the sequence to do a 16 x 16 unsigned multiplication. equation 8-1 shows the algorithm that is used. the 32-bit result is stored in four registers (res3:res0). equation 8-1: 16 x 16 unsigned multiplication algorithm example 8-3: 16 x 16 unsigned multiply routine example 8-4 shows the sequence to do a 16 x 16 signed multiply. equation 8-2 shows the algorithm used. the 32-bit result is stored in four registers (res3:res0). to account for the sign bits of the arguments, the msb for each argument pair is tested and the appropriate subtractions are done. equation 8-2: 16 x 16 signed multiplication algorithm example 8-4: 16 x 16 signed multiply routine res3:res0 = arg1h:arg1l ? arg2h:arg2l = (arg1h ? arg2h ? 2 16 ) + (arg1h ? arg2l ? 2 8 ) + (arg1l ? arg2h ? 2 8 ) + (arg1l ? arg2l) movf arg1l, w mulwf arg2l ; arg1l * arg2l-> ; prodh:prodl movff prodh, res1 ; movff prodl, res0 ; ; movf arg1h, w mulwf arg2h ; arg1h * arg2h-> ; prodh:prodl movff prodh, res3 ; movff prodl, res2 ; ; movf arg1l, w mulwf arg2h ; arg1l * arg2h-> ; prodh:prodl movf prodl, w ; addwf res1, f ; add cross movf prodh, w ; products addwfc res2, f ; clrf wreg ; addwfc res3, f ; ; movf arg1h, w ; mulwf arg2l ; arg1h * arg2l-> ; prodh:prodl movf prodl, w ; addwf res1, f ; add cross movf prodh, w ; products addwfc res2, f ; clrf wreg ; addwfc res3, f ; res3:res0 = arg1h:arg1l ? arg2h:arg2l = (arg1h ? arg2h ? 2 16 ) + (arg1h ? arg2l ? 2 8 ) + (arg1l ? arg2h ? 2 8 ) + (arg1l ? arg2l) + (-1 ? arg2h<7> ? arg1h:arg1l ? 2 16 ) + (-1 ? arg1h<7> ? arg2h:arg2l ? 2 16 ) movf arg1l, w mulwf arg2l ; arg1l * arg2l -> ; prodh:prodl movff prodh, res1 ; movff prodl, res0 ; ; movf arg1h, w mulwf arg2h ; arg1h * arg2h -> ; prodh:prodl movff prodh, res3 ; movff prodl, res2 ; ; movf arg1l, w mulwf arg2h ; arg1l * arg2h -> ; prodh:prodl movf prodl, w ; addwf res1, f ; add cross movf prodh, w ; products addwfc res2, f ; clrf wreg ; addwfc res3, f ; ; movf arg1h, w ; mulwf arg2l ; arg1h * arg2l -> ; prodh:prodl movf prodl, w ; addwf res1, f ; add cross movf prodh, w ; products addwfc res2, f ; clrf wreg ; addwfc res3, f ; ; btfss arg2h, 7 ; arg2h:arg2l neg? bra sign_arg1 ; no, check arg1 movf arg1l, w ; subwf res2 ; movf arg1h, w ; subwfb res3 ; sign_arg1 btfss arg1h, 7 ; arg1h:arg1l neg? bra cont_code ; no, done movf arg2l, w ; subwf res2 ; movf arg2h, w ; subwfb res3 ; cont_code :
? 2007 microchip technology inc. preliminary ds39775b-page 119 pic18f87j50 family 9.0 interrupts members of the pic18f87j50 family of devices have multiple interrupt sources and an interrupt priority feature that allows most interrupt sources to be assigned a high-priority level or a low-priority level. the high-priority interrupt vector is at 0008h and the low-priority interrupt vector is at 0018h. high-priority interrupt events will interrupt any low-priority interrupts that may be in progress. there are thirteen registers which are used to control interrupt operation. these registers are: ? rcon ?intcon ? intcon2 ? intcon3 ? pir1, pir2, pir3 ? pie1, pie2, pie3 ? ipr1, ipr2, ipr3 it is recommended that the microchip header files supplied with mplab ? ide be used for the symbolic bit names in these registers. this allows the assembler/compiler to automatically take care of the placement of these bits within the specified register. in general, interrupt sources have three bits to control their operation. they are: ? flag bit to indicate that an interrupt event occurred ? enable bit that allows program execution to branch to the interrupt vector address when the flag bit is set ? priority bit to select high priority or low priority the interrupt priority feature is enabled by setting the ipen bit (rcon<7>). when interrupt priority is enabled, there are two bits which enable interrupts globally. setting the gieh bit (intcon<7>) enables all interrupts that have the priority bit set (high priority). setting the giel bit (intcon<6>) enables all interrupts that have the priority bit cleared (low priority). when the interrupt flag, enable bit and appropriate global interrupt enable bit are set, the interrupt will vector immediately to address 0008h or 0018h, depending on the priority bit setting. individual interrupts can be disabled through their corresponding enable bits. when the ipen bit is cleared (default state), the interrupt priority feature is disabled and interrupts are compatible with pic ? mid-range devices. in compatibility mode, the interrupt priority bits for each source have no effect. intcon<6> is the peie bit which enables/disables all peripheral interrupt sources. intcon<7> is the gie bit which enables/disables all interrupt sources. all interrupts branch to address 0008h in compatibility mode. when an interrupt is responded to, the global interrupt enable bit is cleared to disable further interrupts. if the ipen bit is cleared, this is the gie bit. if interrupt priority levels are used, this will be either the gieh or giel bit. high-priority interrupt sources can interrupt a low-priority interrupt. low-priority interrupts are not processed while high-priority interrupts are in progress. the return address is pushed onto the stack and the pc is loaded with the interrupt vector address (0008h or 0018h). once in the interrupt service routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. the interrupt flag bits must be cleared in software before re-enabling interrupts to avoid recursive interrupts. the ?return from interrupt? instruction, retfie , exits the interrupt routine and sets the gie bit (gieh or giel if priority levels are used) which re-enables interrupts. for external interrupt events, such as the intx pins or the portb input change interrupt, the interrupt latency will be three to four instruction cycles. the exact latency is the same for one or two-cycle instructions. individual interrupt flag bits are set regardless of the status of their corresponding enable bit or the gie bit. note: do not use the movff instruction to modify any of the interrupt control registers while any interrupt is enabled. doing so may cause erratic microcontroller behavior.
pic18f87j50 family ds39775b-page 120 preliminary ? 2007 microchip technology inc. figure 9-1: pic18f87j50 family interrupt logic tmr0ie gie/gieh peie/giel wake-up if in interrupt to cpu vector to location 0008h int2if int2ie int2ip int1if int1ie int1ip tmr0if tmr0ie tmr0ip rbif rbie rbip ipen tmr0if tmr0ip int1if int1ie int1ip int2if int2ie int2ip rbif rbie rbip int0if int0ie peie/giel interrupt to cpu vector to location ipen ipen 0018h pir1<7:0> pie1<7:0> ipr1<7:0> high-priority interrupt generation low-priority interrupt generation idle or sleep modes gie/gieh int3if int3ie int3ip int3if int3ie int3ip pir2<7:0> pie2<7:0> ipr2<7:0> pir3<7:0> pie3<7:0> ipr3<7:0> pir1<7:0> pie1<7:0> ipr1<7:0> pir2<7:0> pie2<7:0> ipr2<7: 0 > pir3<7:0> pie3<7:0> ipr3< 7 :0 > ipen
? 2007 microchip technology inc. preliminary ds39775b-page 121 pic18f87j50 family 9.1 intcon registers the intcon registers are readable and writable registers which contain various enable, priority and flag bits. note: interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global interrupt enable bit. user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. this feature allows for software polling. register 9-1: intcon: interrupt control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-x gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif (1) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 gie/gieh: global interrupt enable bit when ipen = 0 : 1 = enables all unmasked interrupts 0 = disables all interrupts when ipen = 1 : 1 = enables all high-priority interrupts 0 = disables all interrupts bit 6 peie/giel: peripheral interrupt enable bit when ipen = 0 : 1 = enables all unmasked peripheral interrupts 0 = disables all peripheral interrupts when ipen = 1 : 1 = enables all low-priority peripheral interrupts 0 = disables all low-priority peripheral interrupts bit 5 tmr0ie: tmr0 overflow interrupt enable bit 1 = enables the tmr0 overflow interrupt 0 = disables the tmr0 overflow interrupt bit 4 int0ie: int0 external interrupt enable bit 1 = enables the int0 external interrupt 0 = disables the int0 external interrupt bit 3 rbie: rb port change interrupt enable bit 1 = enables the rb port change interrupt 0 = disables the rb port change interrupt bit 2 tmr0if: tmr0 overflow interrupt flag bit 1 = tmr0 register has overflowed (must be cleared in software) 0 = tmr0 register did not overflow bit 1 int0if: int0 external interrupt flag bit 1 = the int0 external interrupt occurred (must be cleared in software) 0 = the int0 external interrupt did not occur bit 0 rbif: rb port change interrupt flag bit (1) 1 = at least one of the rb7:rb4 pins changed state (must be cleared in software) 0 = none of the rb7:rb4 pins have changed state note 1: a mismatch condition will continue to set this bit. reading portb will end the mismatch condition and allow the bit to be cleared.
pic18f87j50 family ds39775b-page 122 preliminary ? 2007 microchip technology inc. register 9-2: intcon2: in terrupt control register 2 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 rbpu intedg0 intedg1 intedg2 intedg3 tmr0ip int3ip rbip bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 rbpu : portb pull-up enable bit 1 = all portb pull-ups are disabled 0 = portb pull-ups are enabled by individual port latch values bit 6 intedg0: external interrupt 0 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 5 intedg1: external interrupt 1 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 4 intedg2: external interrupt 2 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 3 intedg3: external interrupt 3 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 2 tmr0ip: tmr0 overflow interrupt priority bit 1 =high priority 0 = low priority bit 1 int3ip: int3 external interrupt priority bit 1 =high priority 0 = low priority bit 0 rbip: rb port change interrupt priority bit 1 =high priority 0 = low priority note: interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global interrupt enable bit. user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. this feature allows for software polling.
? 2007 microchip technology inc. preliminary ds39775b-page 123 pic18f87j50 family register 9-3: intcon3: in terrupt control register 3 r/w-1 r/w-1 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 int2ip int1ip int3ie int2ie int1ie int3if int2if int1if bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 int2ip: int2 external interrupt priority bit 1 =high priority 0 = low priority bit 6 int1ip: int1 external interrupt priority bit 1 =high priority 0 = low priority bit 5 int3ie: int3 external interrupt enable bit 1 = enables the int3 external interrupt 0 = disables the int3 external interrupt bit 4 int2ie: int2 external interrupt enable bit 1 = enables the int2 external interrupt 0 = disables the int2 external interrupt bit 3 int1ie: int1 external interrupt enable bit 1 = enables the int1 external interrupt 0 = disables the int1 external interrupt bit 2 int3if: int3 external interrupt flag bit 1 = the int3 external interrupt occurred (must be cleared in software) 0 = the int3 external interrupt did not occur bit 1 int2if: int2 external interrupt flag bit 1 = the int2 external interrupt occurred (must be cleared in software) 0 = the int2 external interrupt did not occur bit 0 int1if: int1 external interrupt flag bit 1 = the int1 external interrupt occurred (must be cleared in software) 0 = the int1 external interrupt did not occur note: interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global interrupt enable bit. user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. this feature allows for software polling.
pic18f87j50 family ds39775b-page 124 preliminary ? 2007 microchip technology inc. 9.2 pir registers the pir registers contain the individual flag bits for the peripheral interrupts. due to the number of peripheral interrupt sources, there are three peripheral interrupt request (flag) registers (pir1, pir2, pir3). note 1: interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global interrupt enable bit, gie (intcon<7>). 2: user software should ensure the appropriate interrupt flag bits are cleared prior to enabling an interrupt and after servicing that interrupt. register 9-4: pir1: peripheral interrupt request (flag) register 1 r/w-0 r/w-0 r-0 r-0 r/w-0 r/w-0 r/w-0 r/w-0 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 pmpif: parallel master port read/write interrupt flag bit 1 = a read or a write operation has taken place (must be cleared in software) 0 =no read or write has occurred bit 6 adif: a/d converter interrupt flag bit 1 = an a/d conversion completed (must be cleared in software) 0 = the a/d conversion is not complete bit 5 rc1if: eusart1 receive interrupt flag bit 1 = the eusart1 receive buffer, rcreg1, is full (cleared when rcreg1 is read) 0 = the eusart1 receive buffer is empty bit 4 tx1if: eusart1 transmit interrupt flag bit 1 = the eusart1 transmit buffer, txreg1, is empty (cleared when txreg1 is written) 0 = the eusart1 transmit buffer is full bit 3 ssp1if: master synchronous serial port interrupt flag bit (mssp1 module) 1 = the transmission/reception is complete (must be cleared in software) 0 = waiting to transmit/receive bit 2 ccp1if: eccp1 interrupt flag bit capture mode: 1 = a tmr1/tmr3 register capture occurred (must be cleared in software) 0 = no tmr1/tmr3 register capture occurred compare mode: 1 = a tmr1/tmr3 register compare match occurred (must be cleared in software) 0 = no tmr1/tmr3 register compare match occurred pwm mode: unused in this mode. bit 1 tmr2if: tmr2 to pr2 match interrupt flag bit 1 = tmr2 to pr2 match occurred (must be cleared in software) 0 = no tmr2 to pr2 match occurred bit 0 tmr1if: tmr1 overflow interrupt flag bit 1 = tmr1 register overflowed (must be cleared in software) 0 = tmr1 register did not overflow
? 2007 microchip technology inc. preliminary ds39775b-page 125 pic18f87j50 family register 9-5: pir2: peripheral interrupt request (flag) register 2 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 oscfif: oscillator fail interrupt flag bit 1 = device oscillator failed, clock input has changed to intosc (must be cleared in software) 0 = device clock operating bit 6 cm2if: comparator 2 interrupt flag bit 1 = comparator input has changed (must be cleared in software) 0 = comparator input has not changed bit 5 cm1if: comparator 1 interrupt flag bit 1 = comparator input has changed (must be cleared in software) 0 = comparator input has not changed bit 4 usbif: usb interrupt flag bit 1 = usb has requested an interrupt (must be cleared in software) 0 = no usb interrupt request bit 3 bcl1if: bus collision interrupt flag bit (mssp1 module) 1 = a bus collision occurred (must be cleared in software) 0 = no bus collision occurred bit 2 lvdif: low-voltage detect interrupt flag bit 1 = a low-voltage condition occurred (must be cleared in software) 0 =device v ddcore voltage is above the regulator low-voltage trip point (above 2.45v) bit 1 tmr3if: tmr3 overflow interrupt flag bit 1 = tmr3 register overflowed (must be cleared in software) 0 = tmr3 register did not overflow bit 0 ccp2if: eccp2 interrupt flag bit capture mode: 1 = a tmr1/tmr3 register capture occurred (must be cleared in software) 0 = no tmr1/tmr3 register capture occurred compare mode: 1 = a tmr1/tmr3 register compare match occurred (must be cleared in software) 0 = no tmr1/tmr3 register compare match occurred pwm mode: unused in this mode.
pic18f87j50 family ds39775b-page 126 preliminary ? 2007 microchip technology inc. register 9-6: pir3: peripheral interrupt request (flag) register 3 r/w-0 r/w-0 r-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ssp2if: master synchronous serial port 2 interrupt flag bit 1 = the transmission/reception is complete (must be cleared in software) 0 = waiting to transmit/receive bit 6 bcl2if: bus collision interrupt flag bit (mssp2 module) 1 = a bus collision occurred (must be cleared in software) 0 = no bus collision occurred bit 5 rc2if: eusart2 receive interrupt flag bit 1 = the eusart2 receive buffer, rcreg2, is full (cleared when rcreg2 is read) 0 = the eusart2 receive buffer is empty bit 4 tx2if: eusart2 transmit interrupt flag bit 1 = the eusart2 transmit buffer, txreg2, is empty (cleared when txreg2 is written) 0 = the eusart2 transmit buffer is full bit 3 tmr4if: tmr4 to pr4 match interrupt flag bit 1 = tmr4 to pr4 match occurred (must be cleared in software) 0 = no tmr4 to pr4 match occurred bit 2 ccp5if: ccp5 interrupt flag bit capture mode: 1 = a tmr1/tmr3 register capture occurred (must be cleared in software) 0 = no tmr1/tmr3 register capture occurred compare mode: 1 = a tmr1/tmr3 register compare match occurred (must be cleared in software) 0 = no tmr1/tmr3 register compare match occurred pwm mode: unused in this mode. bit 1 ccp4if: ccp4 interrupt flag bit capture mode: 1 = a tmr1/tmr3 register capture occurred (must be cleared in software) 0 = no tmr1/tmr3 register capture occurred compare mode: 1 = a tmr1/tmr3 register compare match occurred (must be cleared in software) 0 = no tmr1/tmr3 register compare match occurred pwm mode: unused in this mode. bit 0 ccp3if: eccp3 interrupt flag bit capture mode: 1 = a tmr1/tmr3 register capture occurred (must be cleared in software) 0 = no tmr1/tmr3 register capture occurred compare mode: 1 = a tmr1/tmr3 register compare match occurred (must be cleared in software) 0 = no tmr1/tmr3 register compare match occurred pwm mode: unused in this mode.
? 2007 microchip technology inc. preliminary ds39775b-page 127 pic18f87j50 family 9.3 pie registers the pie registers contain the individual enable bits for the peripheral interrupts. due to the number of peripheral interrupt sources, there are three peripheral interrupt enable registers (pie1, pie2, pie3). when ipen = 0 , the peie bit must be set to enable any of these peripheral interrupts. register 9-7: pie1: peripheral interrupt enable register 1 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 pmpie: parallel master port read/write interrupt enable bit 1 = enables the pm read/write interrupt 0 = disables the pm read/write interrupt bit 6 adie: a/d converter interrupt enable bit 1 = enables the a/d interrupt 0 = disables the a/d interrupt bit 5 rc1ie: eusart1 receive interrupt enable bit 1 = enables the eusart1 receive interrupt 0 = disables the eusart1 receive interrupt bit 4 tx1ie: eusart1 transmit interrupt enable bit 1 = enables the eusart1 transmit interrupt 0 = disables the eusart1 transmit interrupt bit 3 ssp1ie: master synchronous serial port interrupt enable bit (mssp1 module) 1 = enables the mssp1 interrupt 0 = disables the mssp1 interrupt bit 2 ccp1ie: eccp1 interrupt enable bit 1 = enables the eccp1 interrupt 0 = disables the eccp1 interrupt bit 1 tmr2ie: tmr2 to pr2 match interrupt enable bit 1 = enables the tmr2 to pr2 match interrupt 0 = disables the tmr2 to pr2 match interrupt bit 0 tmr1ie: tmr1 overflow interrupt enable bit 1 = enables the tmr1 overflow interrupt 0 = disables the tmr1 overflow interrupt
pic18f87j50 family ds39775b-page 128 preliminary ? 2007 microchip technology inc. register 9-8: pie2: peripheral interrupt enable register 2 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 oscfie: oscillator fail interrupt enable bit 1 = enabled 0 = disabled bit 6 cm2ie: comparator 2 interrupt enable bit 1 = enabled 0 = disabled bit 5 cm1ie: comparator 1 interrupt enable bit 1 = enabled 0 = disabled bit 4 usbie: usb interrupt enable bit 1 = enabled 0 = disabled bit 3 bcl1ie: bus collision interrupt enable bit (mssp1 module) 1 = enabled 0 = disabled bit 2 lvdie: low-voltage detect interrupt enable bit 1 = enabled 0 = disabled bit 1 tmr3ie: tmr3 overflow interrupt enable bit 1 = enabled 0 = disabled bit 0 ccp2ie: eccp2 interrupt enable bit 1 = enabled 0 = disabled
? 2007 microchip technology inc. preliminary ds39775b-page 129 pic18f87j50 family register 9-9: pie3: peripheral interrupt enable register 3 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ssp2ie: master synchronous serial port 2 interrupt enable bit 1 = enabled 0 = disabled bit 6 bcl2ie: bus collision interrupt enable bit (mssp2 module) 1 = enabled 0 = disabled bit 5 rc2ie: eusart2 receive interrupt enable bit 1 = enabled 0 = disabled bit 4 tx2ie: eusart2 transmit interrupt enable bit 1 = enabled 0 = disabled bit 3 tmr4ie: tmr4 to pr4 match interrupt enable bit 1 = enabled 0 = disabled bit 2 ccp5ie: ccp5 interrupt enable bit 1 = enabled 0 = disabled bit 1 ccp4ie : ccp4 interrupt enable bit 1 = enabled 0 = disabled bit 0 ccp3ie: eccp3 interrupt enable bit 1 = enabled 0 = disabled
pic18f87j50 family ds39775b-page 130 preliminary ? 2007 microchip technology inc. 9.4 ipr registers the ipr registers contain the individual priority bits for the peripheral interrupts. due to the number of peripheral interrupt sources, there are three peripheral interrupt priority registers (ipr1, ipr2, ipr3). using the priority bits requires that the interrupt priority enable (ipen) bit be set. register 9-10: ipr1: peripheral interrupt priority register 1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 pmpip: parallel master port read/write interrupt priority bit 1 =high priority 0 = low priority bit 6 adip: a/d converter interrupt priority bit 1 =high priority 0 = low priority bit 5 rc1ip: eusart1 receive interrupt priority bit 1 =high priority 0 = low priority bit 4 tx1ip: eusart1 transmit interrupt priority bit 1 =high priority 0 = low priority bit 3 ssp1ip: master synchronous serial port interrupt priority bit (mssp1 module) 1 =high priority 0 = low priority bit 2 ccp1ip: eccp1 interrupt priority bit 1 =high priority 0 = low priority bit 1 tmr2ip: tmr2 to pr2 match interrupt priority bit 1 =high priority 0 = low priority bit 0 tmr1ip: tmr1 overflow interrupt priority bit 1 =high priority 0 = low priority
? 2007 microchip technology inc. preliminary ds39775b-page 131 pic18f87j50 family register 9-11: ipr2: peripheral interrupt priority register 2 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 oscfip: oscillator fail interrupt priority bit 1 =high priority 0 = low priority bit 6 cm2ip: comparator 2 interrupt priority bit 1 =high priority 0 = low priority bit 5 c12ip: comparator 1 interrupt priority bit 1 =high priority 0 = low priority bit 4 usbip: usb interrupt priority bit 1 =high priority 0 = low priority bit 3 bcl1ip: bus collision interrupt priority bit (mssp1 module) 1 =high priority 0 = low priority bit 2 lvdip: low-voltage detect interrupt priority bit 1 =high priority 0 = low priority bit 1 tmr3ip: tmr3 overflow interrupt priority bit 1 =high priority 0 = low priority bit 0 ccp2ip: eccp2 interrupt priority bit 1 =high priority 0 = low priority
pic18f87j50 family ds39775b-page 132 preliminary ? 2007 microchip technology inc. register 9-12: ipr3: peripheral interrupt priority register 3 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ssp2ip: master synchronous serial port 2 interrupt priority bit 1 =high priority 0 = low priority bit 6 bcl2ip: bus collision interrupt priority bit (mssp2 module) 1 =high priority 0 = low priority bit 5 rc2ip: eusart2 receive interrupt priority bit 1 =high priority 0 = low priority bit 4 tx2ip: eusart2 transmit interrupt priority bit 1 =high priority 0 = low priority bit 3 tmr4ie: tmr4 to pr4 interrupt priority bit 1 =high priority 0 = low priority bit 2 ccp5ip: ccp5 interrupt priority bit 1 =high priority 0 = low priority bit 1 ccp4ip: ccp4 interrupt priority bit 1 =high priority 0 = low priority bit 0 ccp3ip: eccp3 interrupt priority bit 1 =high priority 0 = low priority
? 2007 microchip technology inc. preliminary ds39775b-page 133 pic18f87j50 family 9.5 rcon register the rcon register contains bits used to determine the cause of the last reset or wake-up from idle or sleep modes. rcon also contains the bit that enables interrupt priorities (ipen). register 9-13: rcon: re set control register r/w-0 u-0 r/w-1 r/w-1 r-1 r-1 r/w-0 r/w-0 ipen ?cm ri to pd por bor bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ipen: interrupt priority enable bit 1 = enable priority levels on interrupts 0 = disable priority levels on interrupts (pic16cxxx compatibility mode) bit 6 unimplemented: read as ? 0 ? bit 5 cm: configuration mismatch flag bit for details of bit operation, see register 4-1. bit 4 ri : reset instruction flag bit for details of bit operation, see register 4-1. bit 3 to : watchdog timer time-out flag bit for details of bit operation, see register 4-1. bit 2 pd : power-down detection flag bit for details of bit operation, see register 4-1. bit 1 por : power-on reset status bit for details of bit operation, see register 4-1. bit 0 bor : brown-out reset status bit for details of bit operation, see register 4-1.
pic18f87j50 family ds39775b-page 134 preliminary ? 2007 microchip technology inc. 9.6 intx pin interrupts external interrupts on the rb0/int0, rb1/int1, rb2/int2 and rb3/int3 pins are edge-triggered. if the corresponding intedgx bit in the intcon2 register is set (= 1 ), the interrupt is triggered by a rising edge; if the bit is clear, the trigger is on the falling edge. when a valid edge appears on the rbx/intx pin, the corresponding flag bit, intxif, is set. this interrupt can be disabled by clearing the corresponding enable bit, intxie. flag bit, intxif, must be cleared in software in the interrupt service routine before re-enabling the interrupt. all external interrupts (int0, int1, int2 and int3) can wake-up the processor from the power-managed modes if bit intxie was set prior to going into the power-managed modes. if the global interrupt enable bit, gie, is set, the processor will branch to the interrupt vector following wake-up. interrupt priority for int1, int2 and int3 is determined by the value contained in the interrupt priority bits, int1ip (intcon3<6>), int2ip (intcon3<7>) and int3ip (intcon2<1>). there is no priority bit associated with int0. it is always a high-priority interrupt source. 9.7 tmr0 interrupt in 8-bit mode (which is the default), an overflow in the tmr0 register (ffh 00h) will set flag bit, tmr0if. in 16-bit mode, an overflow in the tmr0h:tmr0l register pair (ffffh 0000h) will set tmr0if. the interrupt can be enabled/disabled by setting/clearing enable bit, tmr0ie (intcon<5>). interrupt priority for timer0 is determined by the value contained in the interrupt prior- ity bit, tmr0ip (intcon2<2>). see section 12.0 ?timer0 module? for further details on the timer0 module. 9.8 portb interrupt-on-change an input change on portb<7:4> sets flag bit, rbif (intcon<0>). the interrupt can be enabled/disabled by setting/clearing enable bit, rbie (intcon<3>). interrupt priority for portb interrupt-on-change is determined by the value contained in the interrupt priority bit, rbip (intcon2<0>). 9.9 context saving during interrupts during interrupts, the return pc address is saved on the stack. additionally, the wreg, status and bsr registers are saved on the fast return stack. if a fast return from interrupt is not used (see section 5.3 ?data memory organization? ), the user may need to save the wreg, status and bsr registers on entry to the interrupt service routine. depending on the user?s application, other registers may also need to be saved. example 9-1 saves and restores the wreg, status and bsr registers during an interrupt service routine. example 9-1: saving status, wreg and bsr registers in ram movwf w_temp ; w_temp is in virtual bank movff status, status_temp ; status_temp located anywhere movff bsr, bsr_temp ; bsr_tmep located anywhere ; ; user isr code ; movff bsr_temp, bsr ; restore bsr movf w_temp, w ; restore wreg movff status_temp, status ; restore status
? 2007 microchip technology inc. preliminary ds39775b-page 135 pic18f87j50 family 10.0 i/o ports depending on the device selected and features enabled, there are up to nine ports available. some pins of the i/o ports are multiplexed with an alternate function from the peripheral features on the device. in general, when a peripheral is enabled, that pin may not be used as a general purpose i/o pin. each port has three memory-mapped registers for its operation: ? tris register (data direction register) ? port register (reads the levels on the pins of the device) ? lat register (output latch register) reading the port register reads the current status of the pins, whereas writing to the port register writes to the output latch (lat) register. setting a tris bit (= 1 ) makes the corresponding port pin an input (i.e., put the corresponding output driver in a high-impedance mode). clearing a tris bit (= 0 ) makes the corresponding port pin an output (i.e., put the contents of the corresponding lat bit on the selected pin). the data latch (lat register) is useful for read-modify-write operations on the value that the i/o pins are driving. read-modify-write operations on the lat register read and write the latched output value for port register. a simplified model of a generic i/o port, without the interfaces to other peripherals, is shown in figure 10-1. figure 10-1: generic i/o port operation 10.1 i/o port pin capabilities when developing an application, the capabilities of the port pins must be considered. outputs on some pins have higher output drive strength than others. similarly, some pins can tolerate higher than v dd input levels. 10.1.1 input pins and voltage considerations the voltage tolerance of pins used as device inputs is dependent on the pin?s input function. pins that are used as digital only inputs are able to handle dc voltages up to 5.5v, a level typical for digital logic circuits. in contrast, pins that also have analog input functions of any kind (such as a/d and comparator inputs) can only tolerate voltages up to v dd . voltage excursions beyond v dd on these pins should be avoided. table 10-1 summarizes the input capabilities. refer to section 28.0 ?electrical characteristics? for more details. table 10-1: input voltage levels 10.1.2 pin output drive when used as digital i/o, the output pin drive strengths vary for groups of pins intended to meet the needs for a variety of applications. in general, there are three classes of output pins in terms of drive capability. portb and portc, as well as porta<7:6>, are designed to drive higher current loads, such as leds. portd, porte and portj are capable of driving digital circuits associated with external memory devices. they can also drive leds, but only those with smaller current requirements. portf, portg and porth, along with porta<5:0>, have the lowest drive level, but are capable of driving normal digital circuit loads with a high input impedance. data bus wr lat wr tris rd port data latch tris latch rd tris input buffer i/o pin q d ck q d ck en qd en rd lat or port port or pin tolerated input description porta<5:0> v dd only v dd input levels tolerated. portc<1:0> portf<6:1> porth<7:4> (1) portb<7:0> 5.5v tolerates input levels above v dd , useful for most standard logic. portc<7:2> portd<7:0> porte<7:0> portf<7> portg<4:0> porth<3:0> (1) portj<7:0> (1) note 1: these ports are not available on 64-pin devices.
pic18f87j50 family ds39775b-page 136 preliminary ? 2007 microchip technology inc. table 10-2 summarizes the output capabilities of the ports. refer to the ?absolute maximum ratings? in section 28.0 ?electrical characteristics? for more details. table 10-2: output drive levels 10.1.3 pull-up configuration four of the i/o ports (portb, portd, porte and portj) implement configurable weak pull-ups on all pins. these are internal pull-ups that allow floating digital input signals to be pulled to a consistent level, without the use of external resistors. the pull-ups are enabled with a single bit for each of the ports: rbpu (intcon2<7>) for portb, and rdpu, repu and rjpu (portg<7:5>) for the other ports. 10.1.4 open-drain outputs the output pins for several peripherals are also equipped with a configurable open-drain output option. this allows the peripherals to communicate with external digital logic operating at a higher voltage level, without the use of level translators. the open-drain option is implemented on port pins specifically associated with the data and clock outputs of the eusarts, the mssp modules (in spi mode) and the ccp and eccp modules. it is selectively enabled by setting the open-drain control bit for the correspond- ing module in the odcon registers (register 10-1, register 10-2 and register 10-3). their configuration is discussed in more detail with the individual port where these peripherals are multiplexed. the odcon registers all reside in the sfr configuration space, and share the same sfr addresses as the timer1 registers (see section 5.3.5.1 ?shared address sfrs? for more details). the odcon registers are accessed by setting the adshr bit (wdtcon<4>). when the open-drain option is required, the output pin must also be tied through an external pull-up resistor provided by the user to a higher voltage level, up to 5.5v (figure 10-2). when a digital logic high signal is output, it is pulled up to the higher voltage level. figure 10-2: using the open-drain output (usart shown as example) 10.1.5 ttl input buffer option many of the digital i/o ports use schmitt trigger (st) input buffers. while this form of buffering works well with many types of input, some applications may require ttl level signals to interface with external logic devices. this is particularly true with the emb and the parallel master port (pmp), which are particularly likely to be interfaced to ttl level logic or memory devices. the inputs for the pmp can be optionally configured for ttl buffers with the pmpttl bit in the padcfg1 reg- ister (register 10-4). setting this bit configures all data and control input pins for the pmp to use ttl buffers. by default, these pmp inputs use the port?s st buffers. as with the odcon registers, the padcfg1 register resides in the sfr configuration space; it shares the same memory address as the tmr2 register. padcfg1 is accessed by setting the adshr bit (wdtcon<4>). port drive description porta minimum intended for indication. portf portg porth (1) portd medium sufficient drive levels for external memory interfacing as well as indication. porte portj (1) portb high suitable for direct led drive levels. portc note 1: these ports are not available on 64-pin devices. note: rjpu is implemented on 80-pin devices only. tx x pic18f87j50 +5v (at logic ? 1 ?) 3.3v v dd 5v
? 2007 microchip technology inc. preliminary ds39775b-page 137 pic18f87j50 family register 10-1: odcon1: peripheral open-drain control register 1 u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? ? ccp5od ccp4od eccp3od eccp2od eccp1od bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-5 unimplemented: read as ? 0 ? bit 4-3 ccp5od:ccp4od: ccpx open-drain output enable bits 1 = open-drain output on ccpx pin (capture/pwm modes) enabled 0 = open-drain output disabled bit 2-0 eccp3od:eccp1od: eccpx open-drain output enable bits 1 = open-drain output on eccpx pin (capture mode) enabled 0 = open-drain output disabled register 10-2: odcon2: peripheral open-drain control register 2 u-0 u-0 u-0 u-0 u-0 u-0 r/w-0 r/w-0 ? ? ? ? ? ? u2od u1od bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-2 unimplemented: read as ? 0 ? bit 1-0 u2od:u1od: eusartx open-drain output enable bits 1 = open-drain output on txx/ckx pin enabled 0 = open-drain output disabled register 10-3: odcon3: peripheral open-drain control register 3 u-0 u-0 u-0 u-0 u-0 u-0 r/w-0 r/w-0 ? ? ? ? ? ? spi2od spi1od bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-2 unimplemented: read as ? 0 ? bit 1-0 spi2od:spi1od: spi open-drain output enable bits 1 = open-drain output on sdox pin enabled 0 = open-drain output disabled
pic18f87j50 family ds39775b-page 138 preliminary ? 2007 microchip technology inc. 10.2 porta, trisa and lata registers porta is a 6-bit wide, bidirectional port. the corresponding data direction register is trisa. the corresponding output latch register is lata. the ra4 pin is multiplexed with the timer0 module clock input to become the ra4/t0cki pin. it is also multi- plexed as the parallel master port data pin. the other porta pins are multiplexed with the analog v ref + and v ref - inputs. the operation of pins ra5:ra0 as a/d converter inputs is selected by clearing or setting the control bits in the ancon0 register. the ra4/t0cki pin is a schmitt trigger input. all other porta pins have ttl input levels and full cmos output drivers. the trisa register controls the direction of the porta pins, even when they are being used as analog inputs. the user must ensure the bits in the trisa register are maintained set when using them as analog inputs. osc2/clko/ra6 and osc1/clki/ra7 normally serve as the external circuit connections for the external (primary) oscillator circuit (hs and hspll oscillator modes), or the external clock input (ec and ecpll oscillator modes). in these cases, ra6 and ra7 are not available as digital i/o and their corresponding tris and lat bits are read as ? 0 ?. for intoscx and intoscpllx oscillator modes (fosc2 configuration bit is ? 0 ?), either ra7, or both ra6 and ra7, automatically become available as digi- tal i/o, depending on the oscillator mode selected. when ra6 is not configured as a digital i/o, in these cases, it provides a clock output at f osc /4. a list of the possible configurations for ra6 and ra7, based on oscillator mode, is provided in register 10-3. for these pins, the corresponding porta, trisa and lata bits are only defined when the pins are configured as i/o. table 10-3: function of ra7:ra6 in intosc and intoscpll modes example 10-1: initia lizing porta register 10-4: padcfg1: pad conf iguration control register 1 u-0 u-0 u-0 u-0 u-0 u-0 u-0 r/w-0 ? ? ? ? ? ? ? pmpttl bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-1 unimplemented: read as ? 0 ? bit 0 pmpttl: pmp module ttl input buffer select bit 1 = pmp module uses ttl input buffers 0 = pmp module uses schmitt trigger input buffers note 1: the ra5 (ra5/pmd4/an4/c2ina) pin is a multiplexed a/d convertor, parallel master port data and also a comparator 2 input a. (pmp pin placement depends on the pmpmx configuration bit.) 2: ra5 and ra3:ra0 are configured as analog inputs on any reset and are read as ? 0 ?. ra4 is configured as a digital input. oscillator mode (fosc2:fosc0 configuration bits) ra6 ra7 intoscpllo ( 011 ) clko i/o intoscpll ( 010 ) i/o i/o intosco ( 001 ) clko i/o intosc ( 000 ) i/o i/o legend: clko = f osc /4 clock output; i/o = digital port. clrf porta ; initialize porta by ; clearing output ; data latches clrf lata ; alternate method to ; clear data latches bsf wdtcon,adshr ; enable write/read to ; the shared sfr movlw 1fh ; configure a/d movwf ancon0 ; for digital inputs bcf wdtcon,adshr ; disable write/read ; to the shared sfr movlw 0cfh ; value used to ; initialize ; data direction movwf trisa ; set ra<3:0> as inputs, ; ra<5:4> as outputs
? 2007 microchip technology inc. preliminary ds39775b-page 139 pic18f87j50 family table 10-4: porta functions pin name function tris setting i/o i/o type description ra0/an0 ra0 0 o dig lata<0> data output; not affected by analog input. 1 i ttl porta<0> data input; disabled when analog input enabled. an0 1 i ana a/d input channel 0. default input configuration on por; does not affect digital output. ra1/an1 ra1 0 o dig lata<1> data output; not affected by analog input. 1 i ttl porta<1> data input; disabled when analog input enabled. an1 1 i ana a/d input channel 1. default input configuration on por; does not affect digital output. ra2/an2/v ref -ra2 0 o dig lata<2> data output; not affected by analog input. disabled when cv ref output enabled. 1 i ttl porta<2> data input. disabled when analog functions enabled; disabled when cv ref output enabled. an2 1 i ana a/d input channel 2 . default input configuration on por; not affected by analog output. v ref - 1 i ana a/d low reference voltage input. ra3/an3/v ref +ra3 0 o dig lata<3> data output; not affected by analog input. 1 i ttl porta<3> data input; disabled when analog input enabled. an3 1 i ana a/d input channel 3. default input configuration on por. v ref + 1 i ana a/d high reference voltage input. ra4/t0cki/ pmd5 ra4 0 o dig lata<4> data output. 1 i st porta<4> data input; default configuration on por. t0cki x i st timer0 clock input. pmd5 (1,2) x o dig parallel master port data output. x i ttl parallel master port data output. ra5/pmd4/ an4/c2ina ra5 0 o dig lata<5> data output; not affected by analog input. 1 i ttl porta<5> data input; disabled when analog input enabled. pmd4 (1,2) x o dig parallel master port data output. x i ttl parallel master port data output. an4 1 i ana a/d input channel 4. default configuration on por. c2ina 1 i ana comparator2 input a. legend: o = output, i = input, ana = analog signal, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: when pmpmx = 0 . 2: available on 80-pin devices only.
pic18f87j50 family ds39775b-page 140 preliminary ? 2007 microchip technology inc. table 10-5: summary of regist ers associated with porta name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: porta ? ? ra5 ra4 ra3 ra2 ra1 ra0 63 lata ? ? lata5 lata4 lata3 lata2 lata1 lata0 62 trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 62 ancon0 (1) pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 61 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by porta. note 1: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
? 2007 microchip technology inc. preliminary ds39775b-page 141 pic18f87j50 family 10.3 portb, trisb and latb registers portb is an 8-bit wide, bidirectional port. the corre- sponding data direction register is trisb. all pins on portb are digital only and tolerate voltages up to 5.5v. each of the portb pins has a weak internal pull-up. a single control bit can turn on all the pull-ups. this is performed by clearing bit, rbpu (intcon2<7>). the weak pull-up is automatically turned off when the port pin is configured as an output. the pull-ups are disabled on a power-on reset. four of the portb pins (rb7:rb4) have an interrupt-on-change feature. only pins configured as inputs can cause this interrupt to occur (i.e., any rb7:rb4 pin configured as an output is excluded from the interrupt-on-change comparison). the input pins (of rb7:rb4) are compared with the old value latched on the last read of portb. the ?mismatch? outputs of rb7:rb4 are ored together to generate the rb port change interrupt with flag bit, rbif (intcon<0>). this interrupt can wake the device from power-managed modes. the user, in the interrupt service routine, can clear the interrupt in the following manner: a) any read or write of portb (except with the movff (any), portb instruction). this will end the mismatch condition. b) clear flag bit, rbif. a mismatch condition will continue to set flag bit, rbif. reading portb will end the mismatch condition and allow flag bit, rbif, to be cleared. the interrupt-on-change feature is recommended for wake-up on key depression operation and operations where portb is only used for the interrupt-on-change feature. polling of portb is not recommended while using the interrupt-on-change feature. for 80-pin devices, rb3 can be configured as the alternate peripheral pin for the eccp2 module and enhanced pwm output 2a by clearing the ccp2mx configuration bit. this applies only to 80-pin devices operating in extended microcontroller mode. if the device is in microcontroller mode, the alternate assignment for eccp2 is re7. as with other eccp2 configurations, the user mu st ensure that the trisb<3> bit is set appropriately for the intended operation. ports, rb1, rb2, rb3, rb4 and rb5, are multiplexed with the parallel master port address. example 10-2: init ializing portb clrf portb ; initialize portb by ; clearing output ; data latches clrf latb ; alternate method to clear ; output data latches movlw 0cfh ; value used to initialize ; data direction movwf trisb ; set rb<3:0> as inputs ; rb<5:4> as outputs ; rb<7:6> as inputs
pic18f87j50 family ds39775b-page 142 preliminary ? 2007 microchip technology inc. table 10-6: portb functions pin name function tris setting i/o i/o type description rb0/flt0/int0 rb0 0 o dig latb<0> data output. 1 i ttl portb<0> data input; weak pull-up when rbpu bit is cleared. flt0 1 i st enhanced pwm fault input (eccp1 module); enabled in software. int0 1 i st external interrupt 0 input. rb1/int1/ pma4 rb1 0 o dig latb<1> data output. 1 i ttl portb<1> data input; weak pull-up when rbpu bit is cleared. int1 1 i st external interrupt 1 input. pma4 x o ? parallel master port address out. rb2/int2/ pma3 rb2 0 o dig latb<2> data output. 1 i ttl portb<2> data input; weak pull-up when rbpu bit is cleared. int2 1 i st external interrupt 2 input. pma3 x o ? parallel master port address out. rb3/int3/ eccp2/p2a/ pma2 rb3 0 o dig latb<3> data output. 1 i ttl portb<3> data input; weak pull-up when rbpu bit is cleared. int3 1 i st external interrupt 3 input. eccp2 (1) 0 o dig eccp2 compare output and eccp2 pwm output; takes priority over port data. 1 i st eccp2 capture input. p2a (1) 0 o dig eccp2 enhanced pwm output, channel a. may be configured for tri-state during enhanced pwm shutdown events. takes priority over port data. pma2 x o ? parallel master port address out. rb4/kbi0/ pma1 rb4 0 o dig latb<4> data output. 1 i ttl portb<4> data input; weak pull-up when rbpu bit is cleared. kbi0 i ttl interrupt-on-pin change. pma1 x o ? parallel master port address out. rb5/kbi1/ pma0 rb5 0 o dig latb<5> data output. 1 i ttl portb<5> data input; weak pull-up when rbpu bit is cleared. kbi1 i ttl interrupt-on-pin change. pma0 x o ? parallel master port address out. rb6/kbi2/pgc rb6 0 o dig latb<6> data output. 1 i ttl portb<6> data input; weak pull-up when rbpu bit is cleared. kbi2 1 i ttl interrupt-on-pin change. pgc x i st serial execution (icsp?) clock input for icsp and icd operation. (2) rb7/kbi3/pgd rb7 0 o dig latb<7> data output. 1 i ttl portb<7> data input; weak pull-up when rbpu bit is cleared. kbi3 1 i ttl interrupt-on-pin change. pgd x o dig serial execution data output for icsp and icd operation. (2) x i st serial execution data input for icsp and icd operation. (2) legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: alternate assignment for eccp2/p2a when the ccp2mx config uration bit is cleared (extended microcontroller mode, 80-pin devices only). default assignment is rc1. 2: all other pin functions are dis abled when icsp? or icd are enabled.
? 2007 microchip technology inc. preliminary ds39775b-page 143 pic18f87j50 family table 10-7: summary of regist ers associated with portb name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: portb rb7 rb6 rb5 rb4 rb3 rb2 rb1 rb0 63 latb latb7 latb6 latb5 latb4 latb3 latb2 latb1 latb0 62 trisb trisb7 trisb6 trisb5 trisb4 trisb3 trisb2 trisb1 trisb0 62 intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 intcon2 rbpu intedg0 intedg1 intedg2 intedg3 tmr0ip int3ip rbip 59 intcon3 int2ip int1ip int3ie int2ie int1ie int3if int2if int1if 59 legend: shaded cells are not used by portb.
pic18f87j50 family ds39775b-page 144 preliminary ? 2007 microchip technology inc. 10.4 portc, trisc and latc registers portc is an 8-bit wide, bidirectional port. only portc pins, rc2 through rc7, are digital only pins and can tolerate input voltages up to 5.5v. portc is multiplexed with ccp, mssp and eusart peripheral functions (table 10-8). the pins have schmitt trigger input buffers. the pins for ccp, spi and eusart are also configurable for open-drain out- put whenever these functions are active. open-drain configuration is selected by setting the spixod, eccpxod and uxod control bits in the odcon regis- ters (see section 10.1.3 ?pull-up configuration? for more information). rc1 is normally configured as the default peripheral pin for the eccp2 module. assignment of eccp2 is controlled by configuration bit, ccp2mx (default state, ccp2mx = 1 ). when enabling peripheral functions, care should be taken in defining tris bits for each portc pin. some peripherals override the tris bit to make a pin an output, while other peripherals override the tris bit to make a pin an input. the user should refer to the corresponding peripheral section for the correct tris bit settings. the contents of the trisc register are affected by peripheral overrides. reading trisc always returns the current contents, even though a peripheral device may be overriding one or more of the pins. example 10-3: initializing portc note: these pins are configured as digital inputs on any device reset. clrf portc ; initialize portc by ; clearing output ; data latches clrf latc ; alternate method to clear ; output data latches movlw 0cfh ; value used to initialize ; data direction movwf trisc ; set rc<3:0> as inputs ; rc<5:4> as outputs ; rc<7:6> as inputs
? 2007 microchip technology inc. preliminary ds39775b-page 145 pic18f87j50 family table 10-8: portc functions pin name function tris setting i/o i/o type description rc0/t1oso/ t13cki rc0 0 o dig latc<0> data output. 1 i st portc<0> data input. t1oso x o ana timer1 oscillator output; enabled when timer1 oscillator enabled. disables digital i/o. t13cki 1 i st timer1/timer3 counter input. rc1/t1osi/ eccp2/p2a rc1 0 o dig latc<1> data output. 1 i st portc<1> data input. t1osi x i ana timer1 oscillator input; enabled when timer1 oscillator enabled. disables digital i/o. eccp2 (1) 0 o dig eccp2 compare output and eccp2 pwm output; takes priority over port data. 1 i st eccp2 capture input. p2a (1) 0 o dig eccp2 enhanced pwm output, channel a. may be configured for tri-state during enhanced pwm shutdown events. takes priority over port data. rc2/eccp1/ p1a rc2 0 o dig latc<2> data output. 1 i st portc<2> data input. eccp1 0 o dig eccp1 compare output and eccp1 pwm output; takes priority over port data. 1 i st eccp1 capture input. p1a 0 o dig eccp1 enhanced pwm output, channel a. may be configured for tri-state during enhanced pwm shutdown events. takes priority over port data. rc3/sck1/ scl1 rc3 0 o dig latc<3> data output. 1 i st portc<3> data input. sck1 0 o dig spi clock output (mssp1 module); takes priority over port data. 1 i st spi clock input (mssp1 module). scl1 0 odigi 2 c? clock output (mssp1 module); takes priority over port data. 1 isti 2 c clock input (mssp1 module); input type depends on module setting. rc4/sdi1/ sda1 rc4 0 o dig latc<4> data output. 1 i st portc<4> data input. sdi1 1 i st spi data input (mssp1 module). sda1 1 odigi 2 c data output (mssp1 module); takes priority over port data. 1 isti 2 c data input (mssp1 module); input type depends on module setting. rc5/sdo1/ c2out rc5 0 o dig latc<5> data output. 1 i st portc<5> data input. sdo1 0 o dig spi data output (mssp1 module); takes priority over port data. c2out x o dig comparator 2 output. rc6/tx1/ck1 rc6 0 o dig latc<6> data output. 1 i st portc<6> data input. tx1 1 o dig synchronous serial data output (eusart1 module); takes priority over port data. ck1 1 o dig synchronous serial data input (eusar t1 module). user must configure as an input. 1 i st synchronous serial clock input (eusart1 module). legend: o = output, i = input, ana = analog signal, dig = digital output, st = schmitt buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set.
pic18f87j50 family ds39775b-page 146 preliminary ? 2007 microchip technology inc. table 10-9: summary of register s associated with portc rc7/rx1/dt1 rc7 0 o dig latc<7> data output. 1 i st portc<7> data input. rx1 1 i st asynchronous serial receive data input (eusart1 module). dt1 1 o dig synchronous serial data output (eusart1 module); takes priority over port data. 1 i st synchronous serial data input (eusar t1 module). user must configure as an input. table 10-8: portc functions (continued) pin name function tris setting i/o i/o type description legend: o = output, i = input, ana = analog signal, dig = digital output, st = schmitt buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: default assignment for eccp2/p2a when ccp2mx configuration bit is set. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: portc rc7 rc6 rc5 rc4 rc3 rc2 rc1 rc0 63 latc latc7 latbc6 latc5 latcb4 latc3 latc2 latc1 latc0 62 trisc trisc7 trisc6 trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 62
? 2007 microchip technology inc. preliminary ds39775b-page 147 pic18f87j50 family 10.5 portd, trisd and latd registers portd is an 8-bit wide, bidirectional port. all pins on portd are digital only and tolerate voltages up to 5.5v. all pins on portd are implemented with schmitt trigger input buffers. each pin is individually configurable as an input or output. on 80-pin devices, portd is multiplexed with the system bus as part of the external memory interface. i/o port and other functions are only available when the interface is disabled by setting the ebdis bit (memcon<7>). when the interface is enabled, portd is the low-order byte of the multiplexed address/data bus (ad7:ad0). the trisd bits are also overridden. portd can also be configured to function as an 8-bit wide parallel master port data. in this mode, parallel master port takes priority over the other digital i/o (but not the external memory interface). this multiplexing is available when pmpmx = 1 . when the parallel master port is active, the input buffers are ttl. for more information, refer to section 11.0 ?parallel master port? each of the portd pins has a weak internal pull-up. the pull-ups are provided to keep the inputs at a known state for the external memory interface while powering up. a single control bit can turn off all the pull-ups. this is performed by clearing bit, rdpu (portg<7>). the weak pull-up is automatically turned off when the port pin is configured as an output. the pull-ups are disabled on all device resets. example 10-4: initializing portd note: these pins are configured as digital inputs on any device reset. clrf portd ; initialize portd by ; clearing output ; data latches clrf latd ; alternate method to clear ; output data latches movlw 0cfh ; value used to initialize ; data direction movwf trisd ; set rd<3:0> as inputs ; rd<5:4> as outputs ; rd<7:6> as inputs
pic18f87j50 family ds39775b-page 148 preliminary ? 2007 microchip technology inc. table 10-10: portd functions pin name function tris setting i/o i/o type description rd0/ad0/ pmd0 rd0 0 o dig latd<0> data output. 1 i st portd<0> data input. ad0 (2) x o dig external memory interface, address/data bit 0 output. (1) x i ttl external memory interface, data bit 0 input. (1) pmd0 (3) x o dig parallel master port data out. x i ttl parallel master port data input. rd1/ad1/ pmd1 rd1 0 o dig latd<1> data output. 1 i st portd<1> data input. ad1 (2) x o dig external memory interface, address/data bit 1 output. (1) x i ttl external memory interface, data bit 1 input. (1) pmd1 (3) x o dig parallel master port data out. x i ttl parallel master port data input. rd2/ad2/ pmd2 rd2 0 o dig latd<2> data output. 1 i st portd<2> data input. ad2 (2) x o dig external memory interface, address/data bit 2 output. (1) x i ttl external memory interface, data bit 2 input. (1) pmd2 (3) x o dig parallel master port data out. x i ttl parallel master port data input. rd3/ad3/ pmd3 rd3 0 o dig latd<3> data output. 1 i st portd<3> data input. ad3 (2) x o dig external memory interface, address/data bit 3 output. (1) x i ttl external memory interface, data bit 3 input. (1) pmd3 (3) x o dig parallel master port data out. x i ttl parallel master port data input. rd4/ad4/ pmd4/sdo2 rd4 0 o dig latd<4> data output. 1 i st portd<4> data input. ad4 (2) x o dig external memory interface, address/data bit 4 output. (1) x i ttl external memory interface, data bit 4 input. (1) pmd4 (3) x o dig parallel master port data out. x i ttl parallel master port data input. sdo2 0 o dig spi data output (mssp2 module); takes priority over port data. rd5/ad5/ pmd5/sdi2/ sda2 rd5 0 o dig latd<5> data output. 1 i st portd<5> data input. ad5 (2) x o dig external memory interface, address/data bit 5 output. (1) x i ttl external memory interface, data bit 5 input. (1) pmd5 (3) x o dig parallel master port data out. x i ttl parallel master port data input. sdi2 1 i st spi data input (mssp2 module). sda2 1 odigi 2 c? data output (mssp2 module); takes priority over port data. 1 isti 2 c data input (mssp2 module); input type depends on module setting. legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: external memory interface i/o takes priority over all other digital and pmp i/o. 2: available on 80-pin devices only. 3: when pmpmx = 1 .
? 2007 microchip technology inc. preliminary ds39775b-page 149 pic18f87j50 family table 10-11: summary of register s associated with portd rd6/ad6/ pmd6/sck2/ scl2 rd6 0 o dig latd<6> data output. 1 i st portd<6> data input. ad6 (2) x o dig-3 external memory interface, address/data bit 6 output. (1) x i ttl external memory interface, data bit 6 input. (1) pmd6 (3) x o dig parallel master port data out. x i ttl parallel master port data input. sck2 0 o dig spi clock output (mssp2 module); takes priority over port data. 1 i st spi clock input (mssp2 module). scl2 0 odigi 2 c? clock output (mssp2 module); takes priority over port data. 1 isti 2 c clock input (mssp2 module); input type depends on module setting. rd7/ad7/ pmd7/ss2 rd7 0 o dig latd<7> data output. 1 i st portd<7> data input. ad7 (2) x o dig external memory interface, address/data bit 7 output. (1) x i ttl external memory interface, data bit 7 input. (1) pmd7 (3) x o dig parallel master port data out. x i ttl parallel master port data input. ss2 x i ttl slave select input for mssp (mssp2 module). table 10-10: portd fu nctions (continued) pin name function tris setting i/o i/o type description legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: external memory interface i/o takes priority over all other digital and pmp i/o. 2: available on 80-pin devices only. 3: when pmpmx = 1 . name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: portd rd7 rd6 rd5 rd4 rd3 rd2 rd1 rd0 63 latd latd7 latd6 latd5 latd4 latd3 latd2 latd1 latd0 62 trisd trisd7 trisd6 trisd5 trisd 4trisd3trisd2trisd1trisd0 62 portg rdpu repu rjpu (1) rg4 rg3 rg2 rg1 rg0 63 legend: shaded cells are not used by portd. note 1: unimplemented on 64-pin devices, read as ? 0 ?.
pic18f87j50 family ds39775b-page 150 preliminary ? 2007 microchip technology inc. 10.6 porte, trise and late registers porte is an 8-bit wide, bidirectional port. all pins on porte are digital only and tolerate voltages up to 5.5v. all pins on porte are implemented with schmitt trigger input buffers. each pin is individually configurable as an input or output. on 80-pin devices, porte is multiplexed with the system bus as part of the external memory interface. i/o port and other functions are only available when the interface is disabled, by setting the ebdis bit (memcon<7>). when the interface is enabled, porte is the high-order byte of the multiplexed address/data bus (ad15:ad8). the trise bits are also overridden. each of the porte pins has a weak internal pull-up. a single control bit can turn off all the pull-ups. this is performed by clearing bit repu (portg<6>). the weak pull-up is automatically turned off when the port pin is configured as an output. the pull-ups are disabled on any device reset. porte is also multiplexed with enhanced pwm outputs b and c for eccp1 and eccp3 and outputs b, c and d for eccp2. for all devices, their default assignments are on porte<6:3>. on 80-pin devices, the multiplexing for the outputs of eccp1 and eccp3 is controlled by the eccpmx configuration bit. clearing this bit reassigns the p1b/p1c and p3b/p3c outputs to porth. for devices operating in microcontroller mode, pin re7 can be configured as the alternate peripheral pin for the eccp2 module and enhanced pwm output 2a. this is done by clearing the ccp2mx configuration bit. porte is also multiplexed with the parallel master port address lines. when pmpmx = 0, re1 and re0 are multiplexed with the control signals, pmpwr and pmprd. re3 can also be configured as the reference clock output (refo) from the system clock. for further details on this, refer to section 2.5 ?reference clock output? . example 10-5: initializing porte note: these pins are configured as digital inputs on any device reset. clrf porte ; initialize porte by ; clearing output ; data latches clrf late ; alternate method to clear ; output data latches movlw 03h ; value used to initialize ; data direction movwf trise ; set re<1:0> as inputs ; re<7:2> as outputs
? 2007 microchip technology inc. preliminary ds39775b-page 151 pic18f87j50 family table 10-12: porte functions pin name function tris setting i/o i/o type description re0/ad8/ pmrd/p2d re0 0 o dig late<0> data output. 1 i st porte<0> data input. ad8 (3) x o dig external memory interface, address/data bit 8 output. (2) x i ttl external memory interface, data bit 8 input. (2) pmrd (5) x o dig parallel master port read strobe pin. x i ttl parallel master port read pin. p2d 0 o dig eccp2 enhanced pwm output, channel d; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. re1/ad9/ pmwr/p2c re1 0 o dig late<1> data output. 1 i st porte<1> data input. ad9 (3) x o dig external memory interface, address/data bit 9 output. (2) x i ttl external memory interface, data bit 9 input. (2) pmwr (5) x o dig parallel master port write strobe pin. x i ttl parallel master port write pin. p2c 0 o dig eccp2 enhanced pwm output, channel c; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. re2/ad10/ pmbe/p2b re2 0 o dig late<2> data output. 1 i st porte<2> data input. ad10 (3) x o dig external memory interface, address/data bit 10 output. (2) x i ttl external memory interface, data bit 10 input. (2) pmbe (5) x o dig parallel master port byte enable. p2b 0 o dig eccp2 enhanced pwm output, channel b; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. re3/ad11/ pma13/p3c/ refo re3 0 o dig late<3> data output. 1 i st porte<3> data input. ad11 (3) x o dig external memory interface, address/data bit 11 output. (2) x i ttl external memory interface, data bit 11 input. (2) pma13 x o dig parallel master port address. p3c (1) 0 o dig eccp3 enhanced pwm output, channel c; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. refo x o dig reference output clock. re4/ad12/ pma12/p3b re4 0 o dig late<4> data output. 1 i st porte<4> data input. ad12 (3) x o dig external memory interface, address/data bit 12 output. (2) x i ttl external memory interface, data bit 12 input. (2) pma12 x o dig parallel master port address. p3b (1) 0 o dig eccp3 enhanced pwm output, channel b; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: default assignments for p1b/p1c and p3b/p3c when eccpmx configuration bit is set (80-pin devices only). 2: external memory interface i/o takes priority over all other digital and pmp i/o. 3: available on 80-pin devices only. 4: alternate assignment for eccp2/p2a when eccp2mx confi guration bit is cleared (all devices in microcontroller mode). 5: default configuration for pmp (pmpmx configuration bit = 1) .
pic18f87j50 family ds39775b-page 152 preliminary ? 2007 microchip technology inc. table 10-13: summary of registers associated with porte re5/ad13/ pma11/p1c re5 0 o dig late<5> data output. 1 i st porte<5> data input. ad13 (3) x o dig external memory interface, address/data bit 13 output. (2) x i ttl external memory interface, data bit 13 input. (2) pma11 x o dig parallel master port address. p1c (1) 0 o dig eccp1 enhanced pwm output, channel c; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. re6/ad14/ pma10/p1b re6 0 o dig late<6> data output. 1 i st porte<6> data input. ad14 (3) x o dig external memory interface, address/data bit 14 output. (2) x i ttl external memory interface, data bit 14 input. (2) pma10 x o dig parallel master port address. p1b (1) 0 o dig eccp1 enhanced pwm output, channel b; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. re7/ad15/ pma9/eccp2/ p2a re7 0 o dig late<7> data output. 1 i st porte<7> data input. ad15 (3) x o dig external memory interface, address/data bit 15 output. (2) x i ttl external memory interface, data bit 15 input. (2) pma9 x o dig parallel master port address. eccp2 (4) 0 o dig eccp2 compare output and eccp2 pwm output; takes priority over port data. 1 i st eccp2 capture input. p2a (4) 0 o dig eccp2 enhanced pwm output, channel a; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. table 10-12: porte functions (continued) pin name function tris setting i/o i/o type description legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: default assignments for p1b/p1c and p3b/p3c when eccpmx configuration bit is set (80-pin devices only). 2: external memory interface i/o takes priority over all other digital and pmp i/o. 3: available on 80-pin devices only. 4: alternate assignment for eccp2/p2a when eccp2mx configur ation bit is cleared (all devices in microcontroller mode). 5: default configuration for pmp (pmpmx configuration bit = 1) . name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: porte re7 re6 re5 re4 re3 re2 re1 re0 63 late late7 late6 late5 late4 late3 late2 late1 late0 62 trise trise7 trise6 trise5 trise4 trise3 trise2 trise1 trise0 62 portg rdpu repu rjpu (1) rg4 rg3 rg2 rg1 rg0 63 legend: shaded cells are not used by porte. note 1: unimplemented on 64-pin devices, read as ? 0 ?.
? 2007 microchip technology inc. preliminary ds39775b-page 153 pic18f87j50 family 10.7 portf, latf and trisf registers portf is a 6-bit wide, bidirectional port. rf2, rf5 and rf6 are analog inputs. these ports are configured as analog inputs on a device reset. all pins on portf are implemented with schmitt trig- ger input buffers. each pin is individually configurable as an input or output. pins, rf3 and rf4, are multiplexed with the usb mod- ule. depending on the configuration of the module, they can serve as the differential data lines for the on-chip usb transceiver. both rf3 and rf4 have schmitt trigger input buffers. as digital ports, they can only function as digital inputs; the on-chip usb transceiver must be disabled (utrdis (ucfg<3>) bit = 1 ) to use the pin as digital inputs. when configured for usb oper- ation, the data direction is determined automatically by the configuration and status of the usb module at any given time. when configuration bit, pmpmx = 0 , portf is multi- plexed with parallel master data port. this multiplexing is available only in 80 pin devices. example 10-6: initializing portf note 1: on device resets, pins rf2, rf5 and rf6 are configured as analog inputs and are read as ? 0 ?. 2: to configure portf as digital i/o, set the corresponding bits in ancon0 and ancon1. clrf portf ; initialize portf by ; clearing output ; data latches clrf latf ; alternate method to ; clear output latches bsf wdtcon,adshr ; enable write/read to ; the shared sfr movlw 80h ; make rf2 digital movwf ancon0 ; movlw 0ch ; make rf<6:5> digital movwf ancon1 ; bcf wdtcon,adshr ; disable write/read to ; the shared sfr movlw c0h ; movwf trisf ; set rf5:rf2 as outputs, ; rf<7:6> as inputs
pic18f87j50 family ds39775b-page 154 preliminary ? 2007 microchip technology inc. table 10-14: portf functions pin name function tris setting i/o i/o type description rf2/pma5/ an7/c2inb rf2 0 o dig latf<2> data output; not affected by analog input. 1 i st portf<2> data input; disabled when analog input enabled. pma5 x o dig parallel master port address. an7 1 i ana a/d input channel 7. default configuration on por. c2inb x i ana comparator 2 input b. rf3/d- rf3 1 i st portf<3> data input; disabled when analog input enabled. d- o xvcr usb bus differential minus line output (internal transceiver). i xvcr usb bus differential minus line input (internal transceiver). rf4/d+ rf4 1 i st portf<4> data input; disabled when analog input enabled. d+ o xvcr usb bus differential plus line output (internal transceiver). i xvcr usb bus differential plus line input (internal transceiver). rf5/pmd2/ an10/c1inb/ cv ref rf5 0 o dig latf<5> data output; not affected by analog input. disabled when cv ref output enabled. 1 i st portf<5> data input; disabled when analog input enabled. disabled when cv ref output enabled. pmd2 (1) x o dig parallel master port data out. x i ttl parallel master port data input. an10 1 i ana a/d input channel 10 and comparator c1+ input. default input configuration on por. c1inb x i ana comparator 1 input b. cv ref x o ana comparator voltage reference out put. enabling this feature disables digital i/o. rf6/pmd1/ an11/c1ina rf6 0 o dig latf<6> data output; not affected by analog input. 1 i st portf<6> data input; disabled when analog input enabled. pmd1 (1) x o dig parallel master port data out. x i ttl parallel master port data input. an11 1 i ana a/d input channel 11 and comparator c1- input. default input configuration on por; does not affect digital output. c1ina x i ana comparator 1 input a. rf7/pmd0/ s s1 /c1out rf7 0 o dig latf<7> data output. 1 i st portf<7> data input. pmd0 (1) x o dig parallel master port data out. x i ttl parallel master port data input. ss1 1 i ttl slave select input for mssp1. c1out x o dig comparator 1 output. legend: o = output, i = input, ana = analog signal, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, xvcr = usb transceiver, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: alternate pmp configuration when the pmpmx configuration bit = 0 ; available on 80-pin devices only.
? 2007 microchip technology inc. preliminary ds39775b-page 155 pic18f87j50 family table 10-15: summary of registers associated with portf name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: portf rf7 rf6 rf5 rf4 rf3 rf2 ? ?63 latf latf7 latf6 latf5 latf4 latf3 latf2 ? ?62 trisf trisf7 trisf6 trisf5 trisf4 trisf3 trisf2 ? ?62 ancon0 (1) pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 61 ancon1 (1) pcfg15 pcfg14 pcfg13 pcfg12 pcfg 11 pcfg10 ? ?61 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by portf. note 1: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
pic18f87j50 family ds39775b-page 156 preliminary ? 2007 microchip technology inc. 10.8 portg, trisg and latg registers portg is a 5-bit wide, bidirectional port. the corre- sponding data direction register is trisg. all pins on portg are digital only and tolerate voltages up to 5.5v. portg is multiplexed with eusart2 functions (table 10-16). portg pins have schmitt trigger input buffers. portg has pins multiplexed with the parallel master port. when enabling peripheral functions, care should be taken in defining tris bits for each portg pin. some peripherals override the tris bit to make a pin an output, while other peripherals override the tris bit to make a pin an input. the user should refer to the corresponding peripheral section for the correct tris bit settings. the pin override value is not loaded into the tris register. this allows read-modify-write of the tris register without concern due to peripheral overrides. although the port itself is only five bits wide, portg<7:5> bits are still implemented. these are used to control the weak pull-ups on the i/o ports associated with the external memory bus (portd, porte and portj). setting these bits enables the pull-ups. since these are control bits and are not associated with port i/o, the corresponding trisg and latg bits are not implemented. example 10-7: initializing portg clrf portg ; initialize portg by ; clearing output ; data latches clrf latg ; alternate method to clear ; output data latches movlw 04h ; value used to initialize ; data direction movwf trisg ; set rg1:rg0 as outputs ; rg2 as input ; rg4:rg3 as outputs
? 2007 microchip technology inc. preliminary ds39775b-page 157 pic18f87j50 family table 10-16: portg functions pin name function tris setting i/o i/o type description rg0/pma8/ eccp3/p3a rg0 0 o dig latg<0> data output. 1 i st portg<0> data input. pma8 x o dig parallel master port address. eccp3 o dig eccp3 compare and pwm output; takes priority over port data. i st eccp3 capture input. p3a 0 o dig eccp3 enhanced pwm output, channel a; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. rg1/pma7/ tx2/ck2/ rg1 0 o dig latg<1> data output. 1 i st portg<1> data input. pma7 x o dig parallel master port address. tx2 1 o dig synchronous serial data output (eusart2 module); takes priority over port data. ck2 1 o dig synchronous serial data input (eusart2 module). user must configure as an input. 1 i st synchronous serial clock input (eusart2 module). rg2/pma6/ rx2/dt2 rg2 0 o dig latg<2> data output. 1 i st portg<2> data input. pma6 x o dig parallel master port address. rx2 1 i st asynchronous serial receive data input (eusart2 module). dt2 1 o dig synchronous serial data output (eusart2 module); takes priority over port data. 1 i st synchronous serial data input (eusart2 module). user must configure as an input. rg3/pmcs1/ ccp4/p3d rg3 0 o dig latg<3> data output. 1 i st portg<3> data input. pmcs1 x o dig parallel master port address chip select 1 x i ttl parallel master port address chip select 1 in. ccp4 0 o dig ccp4 compare output and ccp4 pwm output; takes priority over port data. 1 i st ccp4 capture input. p3d 0 o dig eccp3 enhanced pwm output, channel d; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. rg4/pmcs2/ ccp5/p1d rg4 0 o dig latg<4> data output. 1 i st portg<4> data input. pmcs2 x o dig parallel master port address chip select 2 ccp5 0 o dig ccp5 compare output and ccp5 pwm output; takes priority over port data. 1 i st ccp5 capture input. p1d 0 o dig eccp1 enhanced pwm output, channel d; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option).
pic18f87j50 family ds39775b-page 158 preliminary ? 2007 microchip technology inc. table 10-17: summary of registers associated with portg name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: portg rdpu repu rjpu (1) rg4 rg3 rg2 rg1 rg0 63 latg ? ? ? latg4 latg3 latg2 latg1 latg0 62 trisg ? ? ? trisg4 trisg3 trisg2 trisg1 trisg0 62 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by portg. note 1: unimplemented on 64-pin devices, read as ? 0 ?.
? 2007 microchip technology inc. preliminary ds39775b-page 159 pic18f87j50 family 10.9 porth, lath and trish registers porth is an 8-bit wide, bidirectional i/o port. porth pins <3:0> are digital only and tolerate voltages up to 5.5v. all pins on porth are implemented with schmitt trigger input buffers. each pin is individually configurable as an input or output. when the external memory interface is enabled, four of the porth pins function as the high-order address lines for the interface. the address output from the interface takes priority over other digital i/o. the corresponding trish bits are also overridden. porth pins, rh4 through rh7, are multiplexed with analog converter inputs. the operation of these pins as analog inputs is selected by clearing or setting the corresponding bits in the ancon1 register. rh3 to rh6 is multiplexed with parallel master port and rh4 to rh6 are multiplexed as comparator pins. porth can also be configured as the alternate enhanced pwm output channels b and c for the eccp1 and eccp3 modules. this is done by clearing the eccpmx configuration bit. example 10-8: initializing porth note: porth is available only on 80-pin devices. clrf porth ; initialize porth by ; clearing output ; data latches clrf lath ; alternate method to ; clear output latches bsf wdtcon,adshr; enable write/read to ; the shared sfr movlw f0h ; configure porth as movwf ancon1 ; digital i/o bcf wdtcon,adshr; disable write/read to ; the shared sfr movlw 0cfh ; value used to initialize ; data direction movwf trish ; set rh3:rh0 as inputs ; rh5:rh4 as outputs ; rh7:rh6 as inputs
pic18f87j50 family ds39775b-page 160 preliminary ? 2007 microchip technology inc. table 10-18: porth functions pin name function tris setting i/o i/o type description rh0/a16 rh0 0 o dig lath<0> data output. 1 i st porth<0> data input. a16 x o dig external memory interface, address line 16. takes priority over port data. rh1/a17 rh1 0 o dig lath<1> data output. 1 i st porth<1> data input. a17 x o dig external memory interface, address line 17. takes priority over port data. rh2/a18/ pmd7 rh2 0 o dig lath<2> data output. 1 i st porth<2> data input. a18 x o dig external memory interface, address line 18. takes priority over port data. pmd7 (2) x o dig parallel master port data out. x i ttl parallel master port data input. rh3/a19/ pmd6 rh3 0 o dig lath<3> data output. 1 i st porth<3> data input. a19 x o dig external memory interface, address line 19. takes priority over port data. pmd6 (2) x o dig parallel master port data out. x i ttl parallel master port data input. rh4/pmd3/ an12/p3c/ c2inc rh4 0 o dig lath<4> data output. 1 i st porth<4> data input. pmd3 (2) x i ttl parallel master port data out. x o dig parallel master port data input. an12 i ana a/d input channel 12. default input configuration on por; does not affect digital output. p3c (1) 0 o dig eccp3 enhanced pwm output, channel c; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. c2inc x i ana comparator 2 input c. rh5/pmbe/ an13/p3b/ c2ind rh5 0 o dig lath<5> data output. 1 i st porth<5> data input. pmbe (2) x o dig parallel master port data byte enable. an13 i ana a/d input channel 13. default input configuration on por; does not affect digital output. p3b (1) 0 o dig eccp3 enhanced pwm output, channel b; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. c2ind x i ana comparator 2 input d. rh6/pmrd/ an14/p1c/ c1inc rh6 0 o dig lath<6> data output. 1 i st porth<6> data input. pmrd (2) x o dig parallel master port read strobe. x i ttl parallel master port read in. an14 i ana a/d input channel 14. default input configuration on por; does not affect digital output. p1c (1) 0 o dig eccp1 enhanced pwm output, channel c; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. c1inc x i ana comparator 1 input c. legend: o = output, i = input, ana = analog signal, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: alternate assignments for p1b/p1c and p3b/p3c when eccpmx configuration bit is clear ed. default assignments are porte<6:3>. 2: when pmpmx = 0 .
? 2007 microchip technology inc. preliminary ds39775b-page 161 pic18f87j50 family table 10-19: summary of regist ers associated with porth rh7/pmwr/ an15/p1b/ rh7 0 o dig lath<7> data output. 1 i st porth<7> data input. pmwr (2) x o dig parallel master port write strobe. x i ttl parallel master port write in. an15 i ana a/d input channel 15. default input configuration on por; does not affect digital output. p1b (1) 0 o dig eccp1 enhanced pwm output, channel b; takes priority over port and pmp data. may be configured for tri-state during enhanced pwm shutdown events. table 10-18: porth fu nctions (continued) pin name function tris setting i/o i/o type description legend: o = output, i = input, ana = analog signal, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). note 1: alternate assignments for p1b/p1c and p3b/p3c when eccpmx configuration bit is clear ed. default assignments are porte<6:3>. 2: when pmpmx = 0 . name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: porth (1) rh7 rh6 rh5 rh4 rh3 rh2 rh1 rh0 62 lath (1) lath7 lath6 lath5 lath4 lath3 lath2 lath1 lath0 63 trish (1) trish7 trish6 trish5 trish4 trish3 trish2 trish1 trish0 62 ancon1 (2) pcfg15 pcfg14 pcfg13 pcfg12 pcfg11 pcfg10 ? ?61 legend: shaded cells are not used by porth. note 1: unimplemented on 64-pin devices, read as ? 0 ?. 2: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
pic18f87j50 family ds39775b-page 162 preliminary ? 2007 microchip technology inc. 10.10 portj, trisj and latj registers portj is an 8-bit wide, bidirectional port. all pins on portj are digital only and tolerate voltages up to 5.5v. all pins on portj are implemented with schmitt trigger input buffers. each pin is individually configurable as an input or output. when the external memory interface is enabled, all of the portj pins function as control outputs for the interface. this occurs automatically when the interface is enabled by clearing the ebdis control bit (memcon<7>). the trisj bits are also overridden. each of the portj pins has a weak internal pull-up. the pull-ups are provided to keep the inputs at a known state for the external memory interface while powering up. a single control bit can turn off all the pull-ups. this is performed by clearing bit rjpu (portg<5>). the weak pull-up is automatically turned off when the port pin is configured as an output. the pull-ups are disabled on any device reset. example 10-9: initializing portj note: portj is available only on 80-pin devices. note: these pins are configured as digital inputs on any device reset. clrf portj ; initialize portg by ; clearing output ; data latches clrf latj ; alternate method to clear ; output data latches movlw 0cfh ; value used to initialize ; data direction movwf trisj ; set rj3:rj0 as inputs ; rj5:rj4 as output ; rj7:rj6 as inputs
? 2007 microchip technology inc. preliminary ds39775b-page 163 pic18f87j50 family table 10-20: port j functions table 10-21: summary of register s associated with portj pin name function tris setting i/o i/o type description rj0/ale rj0 0 o dig latj<0> data output. 1 i st portj<0> data input. ale x o dig external memory interface address latch enable control output; takes priority over digital i/o. rj1/oe rj1 0 o dig latj<1> data output. 1 i st portj<1> data input. oe x o dig external memory interface output enable control output; takes priority over digital i/o. rj2/wrl rj2 0 o dig latj<2> data output. 1 i st portj<2> data input. wrl x o dig external memory bus write low byte control; takes priority over digital i/o. rj3/wrh rj3 0 o dig latj<3> data output. 1 i st portj<3> data input. wrh x o dig external memory interface write high byte control output; takes priority over digital i/o. rj4/ba0 rj4 0 o dig latj<4> data output. 1 i st portj<4> data input. ba0 x o dig external memory interface byte address 0 control output; takes priority over digital i/o. rj5/ce rj5 0 o dig latj<5> data output. 1 i st portj<5> data input. ce x o dig external memory interface chip enable control output; takes priority over digital i/o. rj6/lb rj6 0 o dig latj<6> data output. 1 i st portj<6> data input. lb x o dig external memory interface lower byte enable control output; takes priority over digital i/o. rj7/ub rj7 0 o dig latj<7> data output. 1 i st portj<7> data input. ub x o dig external memory interface upper byte enable control output; takes priority over digital i/o. legend: o = output, i = input, dig = digital output, st = schmitt buffer input, ttl = ttl buffer input, x = don?t care (tris bit does not affect port direction or is overridden for this option). name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: portj (1) rj7 rj6 rj5 rj4 rj3 rj2 rj1 rj0 63 latj (1) latj7 latj6 latj5 latj4 latj3 latj2 latj1 latj0 62 trisj (1) trisj7 trisj6 trisj5 trisj4 trisj3 tris j2 trisj1 trisj0 62 portg rdpu repu rjpu (1) rg4 rg3 rg2 rg1 rg0 63 legend: shaded cells are not used by portj. note 1: unimplemented on 64-pin devices, read as ? 0 ?.
pic18f87j50 family ds39775b-page 164 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 165 pic18f87j50 family 11.0 parallel master port the parallel master port module (pmp) is a parallel, 8-bit i/o module, specifically designed to communicate with a wide variety of parallel devices, such as commu- nication peripherals, lcds, external memory devices and microcontrollers. because the interface to parallel peripherals varies significantly, the pmp is highly configurable. the pmp module can be configured to serve as either a parallel master port or as a parallel slave port. key features of the pmp module include: ? up to 16 programmable address lines ? up to two chip select lines ? programmable strobe options - individual read and write strobes or; - read/write strobe with enable strobe ? address auto-increment/auto-decrement ? programmable address/data multiplexing ? programmable polarity on control signals ? legacy parallel slave port support ? enhanced parallel slave support - address support - 4-byte deep, auto-incrementing buffer ? programmable wait states ? selectable input voltage levels figure 11-1: pmp module overview pma<0> pma<14> pma<15> pmbe pmrd pmwr pmd<7:0> pmenb pmrd/pmwr pmcs1 pma<1> pma<13:2> pmall pmalh pma<7:0> pma<15:8> pmcs2 eeprom address bus data bus control lines pic18 lcd fifo microcontroller 8-bit data up to 16-bit address parallel master port buffer
pic18f87j50 family ds39775b-page 166 preliminary ? 2007 microchip technology inc. 11.1 module registers the pmp module has a total of 14 special function registers for its operation, plus one additional register to set configuration options. of these, 8 registers are used for control and 6 are used for pmp data transfer. 11.1.1 control registers the eight pmp control registers are: ? pmconh and pmconl ? pmmodeh and pmmodel ? pmstatl and pmstath ? pmeh and pmel the pmcon registers (register 11-1 and register 11-2) control basic module operations, includ- ing turning the module on or off. they also configure address multiplexing and control strobe configuration. the pmmode registers (register 11-3 and register 11-4) configure the various master and slave operating modes, the data width and interrupt generation. the pmeh and pmel registers (register 11-5 and register 11-6) configure the module?s operation at the hardware (i/o pin) level. the pmstat registers (register 11-5 and register 11-6) provide status flags for the module?s input and output buffers, depending on the operating mode. register 11-1: pmconh: parallel po rt control register high byte r/w-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pmpen ? psidl adrmux1 adrmux0 ptbeen ptwren ptrden bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 pmpen: parallel master port enable bit 1 = pmp enabled 0 = pmp disabled, no off-chip access performed bit 6 unimplemented: read as ? 0 ? bit 5 psidl: stop in idle mode bit 1 = discontinue module operation when device enters idle mode 0 = continue module operation in idle mode bit 4-3 adrmux1:adrmux0: address/data multiplexing selection bits 11 = reserved 10 = all 16 bits of address are multiplexed on pmd<7:0> pins 01 = lower 8 bits of address are multiplexed on pmd<7:0> pins, upper 8 bits are on pma<15:8> 00 = address and data appear on separate pins bit 2 ptbeen: byte enable port enable bit (16-bit master mode) 1 = pmbe port enabled 0 = pmbe port disabled bit 1 ptwren: write enable strobe port enable bit 1 = pmwr/pmenb port enabled 0 = pmwr/pmenb port disabled bit 0 ptrden: read/write strobe port enable bit 1 = pmrd/pmwr port enabled 0 = pmrd/pmwr port disabled
? 2007 microchip technology inc. preliminary ds39775b-page 167 pic18f87j50 family register 11-2: pmconl: parallel port control register low byte r/w-0 r/w-0 r/w-0 (1) r/w-0 (1) r/w-0 (1) r/w-0 r/w-0 r/w-0 csf1 csf0 alp cs2p cs1p bep wrsp rdsp bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 csf1:csf0: chip select function bits 11 = reserved 10 = pmcs1 and pmcs2 function as chip select 01 = pmcs2 functions as chip select, pmcs1 used as address bit 14 (pmaddrh address bit 6) 00 = pmcs2 and pmcs1 used as address bits 15 and 14 (pmaddrh address bits 7 and 6) bit 5 alp: address latch polarity bit (1) 1 = active-high (pmall and pmalh) 0 = active-low (pmall and pmalh ) bit 4 cs2p: chip select 2 polarity bit (1) 1 = active-high (pmcs2) 0 =active-low (pmcs2 ) bit 3 cs1p: chip select 1 polarity bit (1) 1 = active-high (pmcs1/pmcs) 0 =active-low (pmcs1 /pmcs ) bit 2 bep: byte enable polarity bit 1 = byte enable active-high (pmbe) 0 = byte enable active-low (pmbe ) bit 1 wrsp: write strobe polarity bit for slave modes and master mode 2 (pmmodeh<1:0> = 00,01,10 ) : 1 = write strobe active-high (pmwr) 0 = write strobe active-low (pmwr ) for master mode 1 (pmmodeh<1:0> = 11 ) : 1 = enable strobe active-high (pmenb) 0 = enable strobe active-low (pmenb ) bit 0 rdsp: read strobe polarity bit for slave modes and master mode 2 (pmmodeh<1:0> = 00,01,10 ) : 1 = read strobe active-high (pmrd) 0 = read strobe active-low (pmrd ) for master mode 1 (pmmodeh<1:0> = 11 ) : 1 = read/write strobe active-high (pmrd/pmwr) 0 = read/write strobe active-low (pmrd /pmwr ) note 1: these bits have no effect when their corresponding pins are used as address lines.
pic18f87j50 family ds39775b-page 168 preliminary ? 2007 microchip technology inc. register 11-3: pmmodeh: parallel port mode register high byte r-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 busy irqm1 irqm0 incm1 incm0 mode16 mode1 mode0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 busy: busy bit (master mode only) 1 = port is busy 0 = port is not busy bit 6-5 irqm1:irqm0: interrupt request mode bits 11 = interrupt generated when read buffer 3 is read or write buffer 3 is written (buffered psp mode) or on a read or write operation when pma<1:0> = 11 (addressable psp mode only) 10 = no interrupt generated, processor stall activated 01 = interrupt generated at the end of the read/write cycle 00 = no interrupt generated bit 4-3 incm1:incm0: increment mode bits 11 = psp read and write buffers auto-increment (legacy psp mode only) 10 = decrement addr<15,13:0> by 1 every read/write cycle 01 = increment addr<15,13:0> by 1 every read/write cycle 00 = no increment or decrement of address bit 2 mode16: 8/16-bit mode bit 1 = 16-bit mode: data register is 16 bits, a read or write to the data register invokes two 8-bit transfers 0 = 8-bit mode: data register is 8 bits, a read or write to the data register invokes one 8-bit transfer bit 1-0 mode1:mode0: parallel port mode select bits 11 = master mode 1 (pmcsx, pmrd/pmwr, pmenb, pmbe, pma and pmd<7:0>) 10 = master mode 2 (pmcsx, pmrd, pmwr, pmbe, pma and pmd<7:0>) 01 = enhanced psp, control signals (pmrd, pmwr, pmcs, pmd<7:0> and pma<1:0>) 00 = legacy parallel slave port, control signals (pmrd, pmwr, pmcs and pmd<7:0>)
? 2007 microchip technology inc. preliminary ds39775b-page 169 pic18f87j50 family register 11-4: pmmodel: parallel port mode register low byte r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 waitb1 (1) waitb0 (1) waitm3 waitm2 waitm1 waitm0 waite1 (1) waite0 (1) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 waitb1:waitb0: data setup to read/write wait state configuration bits (1) 11 = data wait of 4 t cy ; multiplexed address phase of 4 t cy 10 = data wait of 3 t cy ; multiplexed address phase of 3 t cy 01 = data wait of 2 t cy ; multiplexed address phase of 2 t cy 00 = data wait of 1 t cy ; multiplexed address phase of 1 t cy bit 5-2 waitm3:waitm0: read to byte enable strobe wait state configuration bits 1111 = wait of additional 15 t cy ... 0001 = wait of additional 1 t cy 0000 = no additional wait cycles (operation forced into one t cy ) bit 1-0 waite1:waite0: data hold after strobe wait state configuration bits (1) 11 = wait of 4 t cy 10 = wait of 3 t cy 01 = wait of 2 t cy 00 = wait of 1 t cy note 1: waitb and waite bits are ignored whenever waitm3:waitm0 = 0000 . register 11-5: pmeh: parallel port enable register high byte r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pten15 pten14 pten13 pten12 pten11 pten10 pten9 pten8 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 pten15:pten14: pmcsx strobe enable bits 1 = pma15 and pma14 function as either pma<15:14> or pmcs2 and pmcs1 0 = pma15 and pma14 function as port i/o bit 5-0 pten13:pten8: pmp address port enable bits 1 = pma<13:8> function as pmp address lines 0 = pma<13:8> function as port i/o
pic18f87j50 family ds39775b-page 170 preliminary ? 2007 microchip technology inc. register 11-6: pmel: parallel port enable register low byte r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pten7 pten6 pten5 pten4 pten3 pten2 pten1 pten0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-2 pten7:pten2: pmp address port enable bits 1 = pma<7:2> function as pmp address lines 0 = pma<7:2> function as port i/o bit 1-0 pten1:pten0: pmalh/pmall strobe enable bits 1 = pma1 and pma0 function as either pma<1:0> or pmalh and pmall 0 = pma1 and pma0 pads functions as port i/o register 11-7: pmstath: parallel po rt status register high byte r-0 r/w-0 u-0 u-0 r-0 r-0 r-0 r-0 ibf ibov ? ? ib3f ib2f ib1f ib0f bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ibf: input buffer full status bit 1 = all writable input buffer registers are full 0 = some or all of the writable input buffer registers are empty bit 6 ibov: input buffer overflow status bit 1 = a write attempt to a full input byte register occurred (must be cleared in software) 0 = no overflow occurred bit 5-4 unimplemented: read as ? 0 ? bit 3-0 ib3f:ib0f: input buffer x status full bits 1 = input buffer contains data that has not been read (reading buffer will clear this bit) 0 = input buffer does not contain any unread data
? 2007 microchip technology inc. preliminary ds39775b-page 171 pic18f87j50 family register 11-8: pmstatl: parallel port status register low byte r-1 r/w-0 u-0 u-0 r-1 r-1 r-1 r-1 obe obuf ? ? ob3e ob2e ob1e ob0e bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 obe: output buffer empty status bit 1 = all readable output buffer registers are empty 0 = some or all of the readable output buffer registers are full bit 6 obuf: output buffer underflow status bit 1 = a read occurred from an empty output byte register (must be cleared in software) 0 = no underflow occurred bit 5-4 unimplemented: read as ? 0 ? bit 3-0 ob3e:ob0e: output buffer x status empty bits 1 = output buffer is empty (writing data to the buffer will clear this bit) 0 = output buffer contains data that has not been transmitted
pic18f87j50 family ds39775b-page 172 preliminary ? 2007 microchip technology inc. 11.1.2 data registers the pmp module uses 6 registers for transferring data into and out of the microcontroller. they are arranged as three pairs to allow the option of 16-bit data operations: ? pmdin1h and pmdin1l ? pmdin2h and pmdin2l ? pmaddrh/pmdout1h and pmaddrl/pmdout1l ? pmdout2h and pmdout2l the pmdin1 register is used for incoming data in slave modes, and both input and output data in master modes. the pmdin2 register is used for buffering input data in select slave modes. the pmaddrx/pmdout1x registers are actually a single register pair; the name and function is dictated by the module?s operating mode. in master modes, the registers functions as the pmaddrh and pmaddrl registers, and contain the address of any incoming or outgoing data. in slave modes, the registers function as pmdout1h and pmdout1l and are used for outgoing data. pmaddrh differs from pmaddrl in that it can also have limited pmp control functions. when the module is operating in select master mode configurations, the upper two bits of the register can be used to determine the operation of chip select signals. if chip select signals are not used, pmaddr simply functions to hold the upper 8 bits of the address. the function of the individual bits in pmaddrh is shown in register 11-9. the pmdout2h and pmdout2l registers are only used in buffered slave modes and serve as a buffer for outgoing data. 11.1.3 pad config uration control register in addition to the module level configuration options, the pmp module can also be configured at the i/o pin for electrical operation. this option allows users to select either the normal schmitt trigger input buffer on digital i/o pins shared with the pmp, or use ttl level compatible buffers instead. buffer configuration is controlled by the pmpttl bit in the padcfg1 register. the padcfg1 register is one of the shared address sfrs, and has the same address as the tmr2 regis- ter. padcfg1 is accessed by setting the adshr bit (wdtcon<4>). refer to section 5.3.5.1 ?shared address sfrs? for more information. register 11-9: pmaddrh: parallel port address register, high byte (master modes only) (1) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 cs2 cs1 addr<13:8> bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 cs2: chip select 2 bit if pmcon<7:6> = 10 or 01 : 1 = chip select 2 is active 0 = chip select 2 is inactive if pmcon<7:6> = 11 or 00 : bit functions as addr<15>. bit 6 cs1: chip select 1 bit if pmcon<7:6> = 10 : 1 = chip select 1 is active 0 = chip select 1 is inactive if pmcon<7:6> = 11 or 0x : bit functions as addr<14>. bit 5-0 addr5:addr0: parallel port destination address bits note 1: in enhanced slave mode, pmaddrh functions as pmdout1h, one of the output data buffer registers.
? 2007 microchip technology inc. preliminary ds39775b-page 173 pic18f87j50 family 11.1.4 pmp multiplexing options(80-pins devices) by default, the pmp and the external memory bus (emb) multiplex some of their signals to the same i/o pins on portd and porte. it is possible that some applications may require the use of both modules at the same time. for these instances, the 80-pin devices can be configured to multiplex the pmp to different i/o ports. pmp configuration is determined by the pmpmx configuration bit setting; by default, the pmp and emb modules share portd and porte. the optional pin configuration is shown in table 11-1. table 11-1: pmp pin multiplexing 80-pin devices 11.2 slave port modes the primary mode of operation for the module is con- figured using the mode1:mode0 bits in the pmmodeh register. the setting affects whether the module acts as a slave or a master and it determines the usage of the control pins. 11.2.1 legacy mode (psp) in legacy mode (pmmodeh<1:0> = 00 and pmpen = 1 ), the module is configured as a parallel slave port with the associated enabled module pins dedicated to the module. in this mode, an external device, such as another microcontroller or micro- processor, can asynchronously read and write data using the 8-bit data bus (pmd<7:0>), the read (pmrd), write (pmwr) and chip select (pmcs1) inputs. it acts as a slave on the bus and responds to the read/write control signals. figure 11-2 shows the connection of the parallel slave port. when chip select is active and a write strobe occurs (pmcs = 1 and pmwr = 1 ), the data from pmd<7:0> is captured into the pmdin1l register. figure 11-2: legacy parallel slave port example pmp function pin assignment pmpmx = 1 pmpmx= 0 pmd0 portd<0> portf<7> pmd1 portd<1> portf<6> pmd2 portd<2> portf<5> pmd3 portd<3> porth<4> pmd4 portd<4> porta<5> pmd5 portd<5> porta<4> pmd6 portd<6> porth<3> pmd7 portd<7> porth<2> pmbe porte<2> porth<5> pmwr porte<1> porth<7> pmrd porte<0> porth<6> pmd<7:0> pmrd pmwr master address bus data bus control lines pmcs pmd<7:0> pmrd pmwr pic18 slave pmcs1
pic18f87j50 family ds39775b-page 174 preliminary ? 2007 microchip technology inc. 11.2.2 write to slave port when chip select is active and a write strobe occurs (pmcs = 1 and pmwr = 1 ), the data from pmd<7:0> is captured into the lower pmdin1l register. the pmpif and ibf flag bits are set when the write ends.the timing for the control signals in write mode is shown in figure 11-3. the polarity of the control signals are configurable. 11.2.3 read from slave port when chip select is active and a read strobe occurs (pmcs = 1 and pmrd = 1 ), the data from the pmdoutl1 register (pmdoutl1<7:0>) is presented onto pmd<7:0>.the timing for the control signals in read mode is shown in figure 11-4. figure 11-3: parallel slave port write waveforms figure 11-4: parallel slave port read waveforms pmcs1 | q4 | q1 | q2 | q3 | q4 pmwr pmrd pmd<7:0> ibf obe pmpif pmcs1 | q4 | q1 | q2 | q3 | q4 pmwr pmrd pmd<7:0> ibf obe pmpif
? 2007 microchip technology inc. preliminary ds39775b-page 175 pic18f87j50 family 11.2.4 buffered parallel slave port mode buffered parallel slave port mode is functionally iden- tical to the legacy parallel slave port mode with one exception: the implementation of 4-level read and write buffers. buffered psp mode is enabled by setting the incm bits in the pmmodeh register. if the incm<1:0> bits are set to ? 11 ?, the pmp module will act as the buffered parallel slave port. when the buffered mode is active, the pmdin1l, pmdin1h, pmdin2l and pmdin2h registers become the write buffers and the pmdout1l, pmdout1h, pmdout2l and pmdout2h registers become the read buffers. buffers are numbered 0 through 3, start- ing with the lower byte of pmdin1l to pmdin2h as the read buffers and pmdout1l to pmdout2h as the write buffers. 11.2.4.1 read from slave port for read operations, the bytes will be sent out sequen- tially, starting with buffer 0 (pmdout1l<7:0>) and ending with buffer 3 (pmdout2h<7:0>) for every read strobe. the module maintains an internal pointer to keep track of which buffer is to be read. each of the buffers has a corresponding read status bit, obxe, in the pmstatl register. this bit is cleared when a buffer contains data that has not been written to the bus, and is set when data is written to the bus. if the current buffer location being read from is empty, a buffer under- flow is generated, and the buffer overflow flag bit obuf is set. if all four obxe status bits are set, then the output buffer empty flag (obe) will also be set. 11.2.4.2 write to slave port for write operations, the data is be stored sequentially, starting with buffer 0 (pmdin1l<7:0>) and ending with buffer 3 (pmdin2h<7:0). as with read operations, the module maintains an internal pointer to the buffer that is to be written next. the input buffers have their own write status bits, ibxf in the pmstath register. the bit is set when the buffer contains unread incoming data, and cleared when the data has been read. the flag bit is set on the write strobe. if a write occurs on a buffer when its associated ibxf bit is set, the buffer overflow flag, ibov, is set; any incoming data in the buffer will be lost. if all four ibxf flags are set, the input buffer full flag (ibf) is set. in buffered slave mode, the module can be configured to generate an interrupt on every read or write strobe (irqm1:irqm0 = 01 ). it can be configured to generate an interrupt on a read from read buffer 3 or a write to write buffer 3, which is essentially an interrupt every fourth read or write strobe (rqm1:irqm0 = 11 ). when interrupting every fourth byte for input data, all input buffer registers should be read to clear the ibxf flags. if these flags are not cleared, then there is a risk of hitting an overflow condition. figure 11-5: parallel master/slave connection buffered example pmd<7:0> pmrd pmwr pmcs data bus control lines pmrd pmwr pic18 slave pmcs1 pmdout1l (0) pmdout1h (1) pmdout2l (2) pmdout2h (3) pmdin1l (0) pmdin1h (1) pmdin2l (2) pmdin2h (3) pmd<7:0> write address pointer read address pointer master
pic18f87j50 family ds39775b-page 176 preliminary ? 2007 microchip technology inc. 11.2.5 addressable parallel slave port mode in the addressable parallel slave port mode ( pmmodeh<1:0> = 01 ), the module is configured with two extra inputs, pma<1:0>, which are the address lines 1 and 0. this makes the 4-byte buffer space directly addressable as fixed pairs of read and write buffers. as with legacy buffered mode, data is output from pmdout1l, pmdout1h, pmdout2l and pmdout2h, and is read in pmdin1l, pmdin1h, pmdin2l and pmdin2h. table 11-2 shows the buffer addressing for the incoming address to the input and output registers. table 11-2: slave mode buffer addressing figure 11-6: parallel master/slave connection addressed buffer example pmaddr<1:0> output register (buffer) input register (buffer) 00 pmdout1l (0) pmdin1l (0) 01 pmdout1h (1) pmdin1h (1) 10 pmdout2l (2) pmdin2l (2) 11 pmdout2h((3) pmdin2h (3) pmd<7:0> pmrd pmwr master pmcs pma<1:0> address bus data bus control lines pmrd pmwr pic18f slave pmcs1 pmdout1l (0) pmdout1h (1) pmdout2l (2) pmdout2h (3) pmdin1l (0) pmdin1h (1) pmdin2l (2) pmdin2h (3) pmd<7:0> write address decode read address decode pma<1:0>
? 2007 microchip technology inc. preliminary ds39775b-page 177 pic18f87j50 family 11.2.5.1 read from slave port when chip select is active and a read strobe occurs (pmcs = 1 and pmrd = 1 ), the data from one of the four output bytes is presented onto pmd<7:0>. which byte is read depends on the 2-bit address placed on addr[1:0]. table 11-2 shows the corresponding output registers and their associated address. when an output buffer is read, the corresponding obxe bit is set. the obxe flag bit is set when all the buffers are empty. if any buffer is already empty, obxe = 1 , the next read to that buffer will generate an obuf event. figure 11-7: parallel slave port read waveforms 11.2.5.2 write to slave port when chip select is active and a write strobe occurs (pmcs = 1 and pmwr = 1 ), the data from pmd<7:0> is captured into one of the four input buffer bytes. which byte is written depends on the 2-bit address placed on addrl[1:0]. table 11-2 shows the corre- sponding input registers and their associated address. when an input buffer is written, the corresponding ibxf bit is set. the ibf flag bit is set when all the buffers are written. if any buffer is already written (ibxf = 1 ), the next write strobe to that buffer will generate an obuf event and the byte will be discarded. figure 11-8: parallel slave port write waveforms pmcs | q4 | q1 | q2 | q3 | q4 pmwr pmrd pmd<7:0> pma<1:0> obe pmpif pmcs | q4 | q1 | q2 | q3 | q4 pmwr pmrd pmd<7:0> ibf pmpif pma<1:0>
pic18f87j50 family ds39775b-page 178 preliminary ? 2007 microchip technology inc. 11.3 master port modes in its master modes, the pmp module provides an 8-bit data bus, up to 16 bits of address, and all the necessary control signals to operate a variety of external parallel devices, such as memory devices, peripherals and slave microcontrollers. to use the pmp as a master, the module must be enabled (pmpen = 1 ) and the mode must be set to one of the two possible master modes (pmmodeh<1:0> = 10 or 11 ). because there are a number of parallel devices with a variety of control methods, the pmp module is designed to be extremely flexible to accommodate a range of configurations. some of these features include: ? 8 and 16-bit data modes on an 8-bit data bus ? configurable address/data multiplexing ? up to two chip select lines ? up to 16 selectable address lines ? address auto-increment and auto-decrement ? selectable polarity on all control lines ? configurable wait states at different stages of the read/write cycle 11.3.1 pmp and i/o pin control multiple control bits are used to configure the presence or absence of control and address signals in the mod- ule. these bits are ptbeen, ptwren, ptrden, and pten<15:0>. they give the user the ability to conserve pins for other functions and allow flexibility to control the external address. when any one of these bits is set, the associated function is present on its associated pin; when clear, the associated pin reverts to its defined i/o port function. setting a pten bit will enable the associated pin as an address pin and drive the corresponding data con- tained in the pmaddr register. clearing the ptenx bit will force the pin to revert to its original i/o function. for the pins configured as chip select (pmcs1 or pmcs2) with the corresponding ptenx bit set. the pten0 and pten1 bits also control the pmall and pmalh signals. when multiplexing is used, the associated address latch signals should be enabled. 11.3.2 read/write control the pmp module supports two distinct read/write signaling methods. in master mode 1, read and write strobe are combined into a single control line, pmrd/pmwr. a second control line, pmenb, deter- mines when a read or write action is to be taken. in master mode 2, separate read and write strobes (pmrd and pmwr) are supplied on separate pins. all control signals (pmrd, pmwr, pmbe, pmenb, pmal and pmcsx) can be individually configured as either positive or negative polarity. configuration is controlled by separate bits in the pmconl register. note that the polarity of control signals that share the same output pin (for example, pmwr and pmenb) are controlled by the same bit; the configuration depends on which master port mode is being used. 11.3.3 data width the pmp supports data widths of both 8 and 16 bits. the data width is selected by the mode16 bit (pmmodeh<2>). because the data path into and out of the module is only 8 bits wide, 16-bit operations are always handled in a multiplexed fashion, with the least significant byte of data being presented first. to differ- entiate data bytes, the byte enable control strobe, pmbe, is used to signal when the most significant byte of data is being presented on the data lines. 11.3.4 address multiplexing in either of the master modes (pmmodeh<1:0> = 1x ), the user can configure the address bus to be multiplexed together with the data bus. this is accomplished using the adrmux1:adrmux0 bits (pmconh<4:3>). there are three address multiplexing modes available; typical pinout configurations for these modes are shown in figure 11-9, figure 11-10 and figure 11-11. in demultiplexed mode (pmconh<4:3> = 00 ), data and address information are completely separated. data bits are presented on pmd<7:0>, and address bits are presented on pmaddrh<7:0> and pmaddrl<7:0> in partially multiplexed mode (pmconh<4:3> = 01 ), the lower eight bits of the address are multiplexed with the data pins on pmd<7:0>. the upper eight bits of address are unaffected and are presented on pmaddrh<7:0>. the pma0 pin is used as an address latch, and presents the address latch low enable strobe (pmall). the read and write sequences are extended by a complete cpu cycle during which the address is presented on the pmd<7:0> pins. in fully multiplexed mode (pmconh<4:3> = 10 ), the entire 16 bits of the address are multiplexed with the data pins on pmd<7:0>. the pma0 and pma1 pins are used to present address latch low enable (pmall) and address latch high enable (pmalh) strobes, respectively. the read and write sequences are extended by two complete cpu cycles. during the first cycle, the lower eight bits of the address are presented on the pmd<7:0> pins with the pmall strobe active. during the second cycle, the upper eight bits of the address are presented on the pmd<7:0> pins with the pmalh strobe active. in the event the upper address bits are configured as chip select pins, the corresponding address bits are automatically forced to ? 0 ?.
? 2007 microchip technology inc. preliminary ds39775b-page 179 pic18f87j50 family figure 11-9: demultiplexed addressi ng mode (separate read and write strobes, two chip selects) figure 11-10: partially multiplexed addressing mode (separate read and write strobes, two chip selects) figure 11-11: fully multiplexed addre ssing mode (separate read and write strobes, two chip selects) pmrd pmwr pmd<7:0> pmcs1 pma<13:0> pmcs2 pic18f address bus data bus control lines pmrd pmwr pmd<7:0> pmcs1 pma<13:8> pmall pma<7:0> pmcs2 pic18f address bus multiplexed data and address bus control lines pmrd pmwr pmd<7:0> pmcs1 pmalh pma<13:8> pmcs2 pic18f multiplexed data and address bus control lines pmall
pic18f87j50 family ds39775b-page 180 preliminary ? 2007 microchip technology inc. 11.3.5 chip select features up to two chip select lines, pmcs1 and pmcs2, are available for the master modes of the pmp. the two chip select lines are multiplexed with the most signifi- cant bits of the address bus (pmaddrh<6> and pmaddrh<7>). when a pin is configured as a chip select, it is not included in any address auto-increment/ decrement. the function of the chip select signals is configured using the chip select function bits (pmconl<7:6>). 11.3.6 auto-increment/decrement while the module is operating in one of the master modes, the incm bits (pmmodeh<3:4>) control the behavior of the address value. the address can be made to automatically increment or decrement after each read and write operation. the address increments once each operation is completed and the busy bit goes to ? 0 ?. if the chip select signals are disabled and configured as address bits, the bits will participate in the increment and decrement operations; otherwise, the cs2 and cs1 bit values will be unaffected. 11.3.7 wait states in master mode, the user has control over the duration of the read, write and address cycles by configuring the module wait states. three portions of the cycle, the beginning, middle and end, are configured using the corresponding waitbx, waitmx and waitex bits in the pmmodel register. the waitb bits (pmmodel<7:6>) set the number of wait cycles for the data setup prior to the pmrd/pmwt strobe in mode 10, or prior to the pmenb strobe in mode 11. the waitm bits (pmmodel<5:2>) set the number of wait cycles for the pmrd/pmwt strobe in mode 10, or for the pmenb strobe in mode 11. when this wait state setting is 0 then waitb and waite have no effect. the waite bits (pmmodel<1:0>) define the number of wait cycles for the data hold time after the pmrd/pmwt strobe in mode 10, or after the pmenb strobe in mode 11. 11.3.8 read operation to perform a read on the parallel master port, the user reads the pmdin1l register. this causes the pmp to output the desired values on the chip select lines and the address bus. then the read line (pmrd) is strobed. the read data is placed into the pmdin1l register. if the 16-bit mode is enabled (mode16 = 1 ), the read of the low byte of the pmdin1l register will initiate two bus reads. the first read data byte is placed into the pmdin1l register, and the second read data is placed into the pmdin1h. note that the read data obtained from the pmdin1l register is actually the read value from the previous read operation. hence, the first user read will be a dummy read to initiate the first bus read and fill the read register. also, the requested read value will not be ready until after the busy bit is observed low. thus, in a back-to-back read operation, the data read from the register will be the same for both reads. the next read of the register will yield the new value. 11.3.9 write operation to perform a write onto the parallel bus, the user writes to the pmdin1l register. this causes the module to first output the desired values on the chip select lines and the address bus. the write data from the pmdin1l register is placed onto the pmd<7:0> data bus. then the write line (pmwr) is strobed. if the 16-bit mode is enabled (mode16 = 1 ), the write to the pmdin1l reg- ister will initiate two bus writes. first write will consist of the data contained in pmdin1l and the second write will contain the pmdin1h. 11.3.10 parallel master port status 11.3.10.1 the busy bit in addition to the pmp interrupt, a busy bit is provided to indicate the status of the module. this bit is only used in master mode. while any read or write operation is in progress, the busy bit is set for all but the very last cpu cycle of the operation. in effect, if a single-cycle read or write operation is requested, the busy bit will never be active. this allows back-to-back transfers. while the bit is set, any request by the user to initiate a new operation will be ignored (i.e., writing or reading the lower byte of the pmdin1l register will not initiate either a read nor a write). 11.3.10.2 interrupts when the pmp module interrupt is enabled for master mode, the module will interrupt on every completed read or write cycle; otherwise, the busy bit is available to query the status of the module.
? 2007 microchip technology inc. preliminary ds39775b-page 181 pic18f87j50 family 11.3.11 master mode timing this section contains a number of timing examples that represent the common master mode configuration options. these options vary from 8-bit to 16-bit data, fully demultiplexed to fully multiplexed address, as well as wait states. figure 11-12: read and write timing, 8-bit data, demultiplexed address figure 11-13: read timing, 8-bit data, partially multiplexed address figure 11-14: read timing, 8-bit data, wait states enabled, partially multiplexed address pmcs2 pmwr pmrd pmpif pmd<7:0> pmcs1 pma<13:0> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 busy q2 q3 q4 q1 pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 pma<13:8> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif busy address<7:0> data pmcs2 pmrd pmwr pmall pmd<7:0> pmcs1 pma<13:8> q1- - - pmpif q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - waitm<3:0> = 0010 waite<1:0> = 00 waitb<1:0> = 01 busy address<7:0> data
pic18f87j50 family ds39775b-page 182 preliminary ? 2007 microchip technology inc. figure 11-15: write timing, 8-bit data, partially multiplexed address figure 11-16: write timing, 8-bit data, wait states enabled, partially multiplexed address figure 11-17: read timing, 8-bit data, partially multiplexed address, enable strobe pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 pma<13:8> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif data busy address<7:0> pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 pma<13:8> q1- - - pmpif data q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - q1- - - waitm<3:0> = 0010 waite<1:0> = 00 waitb<1:0> = 01 busy address<7:0> pmcs2 pmrd/pmwr pmenb pmall pmd<7:0> pmcs1 pma<13:8> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif busy address<7:0> data
? 2007 microchip technology inc. preliminary ds39775b-page 183 pic18f87j50 family figure 11-18: write timing, 8-bit dat a, partially multiplexed address, enable strobe figure 11-19: read timing, 8-bit data, fully multiplexed 16-bit address figure 11-20: write timing, 8-bit dat a, fully multiplexed 16-bit address pmcs2 pmrd/pmwr pmenb pmall pmd<7:0> pmcs1 pma<13:8> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif data busy address<7:0> pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmalh data pmpif busy address<7:0> address<15:8> pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmalh data pmpif busy address<7:0> address<15:8>
pic18f87j50 family ds39775b-page 184 preliminary ? 2007 microchip technology inc. figure 11-21: read timing, 16-bit data, demultiplexed address figure 11-22: write timing, 16-bit data, demultiplexed address figure 11-23: read timing, 16-bit multiplexed data, partially multiplexed address pmcs2 pmwr pmrd pmd<7:0> pmcs1 pma<13:0> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif pmbe busy msb lsb pmcs2 pmwr pmrd pmd<7:0> pmcs1 pma<13:0> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif lsb msb pmbe busy pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 pma<13:8> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif pmbe busy address<7:0> lsb msb
? 2007 microchip technology inc. preliminary ds39775b-page 185 pic18f87j50 family figure 11-24: write timing, 16-bit multiplexed data, partially multiplexed address figure 11-25: read timing, 16-bit multiplexed data, fully multiplexed 16-bit address figure 11-26: write timing, 16-bit multiplexed data, fully multiplexed 16-bit address pmcs2 pmwr pmrd pmall pmd<7:0> pmcs1 pma<13:8> q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmpif lsb msb pmbe busy address<7:0> pmcs2 pmwr pmrd pmbe pmd<7:0> pmcs1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmalh pmpif pmall busy q2 q3 q4 q1 address<7:0> lsb address<15:8> msb pmcs2 pmwr pmrd pmbe pmd<7:0> pmcs1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 pmalh pmall msb lsb pmpif busy q2 q3 q4 q1 address<7:0> address<15:8>
pic18f87j50 family ds39775b-page 186 preliminary ? 2007 microchip technology inc. 11.4 application examples this section introduces some potential applications for the pmp module. 11.4.1 multiplexed memory or peripheral figure 11-27 demonstrates the hookup of a memory or another addressable peripheral in full multiplex mode. consequently, this mode achieves the best pin saving from the microcontroller perspective. however, for this configuration, there needs to be some external latches to maintain the address. figure 11-27: example of a multiplexed addressing application 11.4.2 partially multiplexed memory or peripheral partial multiplexing implies using more pins; however, for a few extra pins, some extra performance can be achieved. figure 11-28 shows an example of a mem- ory or peripheral that is partially multiplexed with an external latch. if the peripheral has internal latches, as shown in figure 11-29, then no extra circuitry is required except for the peripheral itself. figure 11-28: example of a partially multiplexed addressing application figure 11-29: example of an 8-bit mu ltiplexed address and data application pmd<7:0> pmalh d<7:0> 373 a<15:0> d<7:0> a<7:0> 373 pmrd pmwr oe wr ce pic18f address bus data bus control lines pmcs pmall a<15:8> pma<14:7> d<7:0> 373 a<14:0> d<7:0> a<7:0> pmrd pmwr oe wr ce pic18f address bus data bus control lines pmcs pmall a<14:8> pmd<7:0> ale pmrd pmwr rd wr cs pic18f address bus data bus control lines pmcs pmall ad<7:0> parallel peripheral pmd<7:0>
? 2007 microchip technology inc. preliminary ds39775b-page 187 pic18f87j50 family 11.4.3 parallel eeprom example figure 11-30 shows an example connecting parallel eeprom to the pmp. figure 11-31 shows a slight variation to this, configuring the connection for 16-bit data from a single eeprom. figure 11-30: parallel eeprom exampl e (up to 15-bit address, 8-bit data) figure 11-31: parallel eeprom example (up to 15-bit address, 16-bit data) 11.4.4 lcd controller example the pmp module can be configured to connect to a typical lcd controller interface, as shown in figure 11-32. in this case the pmp module is config- ured for active-high control signals since common lcd displays require active-high control. figure 11-32: lcd control ex ample (byte mode operation) pma a d<7:0> pmrd pmwr oe wr ce pic18f address bus data bus control lines pmcs pmd<7:0> parallel eeprom pma a d<7:0> pmrd pmwr oe wr ce pic18f address bus data bus control lines pmcs pmd<7:0> parallel eeprom pmbe a0 pmrd/pmwr d<7:0> pic18f address bus data bus control lines pma0 r/w rs e lcd controller pmcs pm<7:0>
pic18f87j50 family ds39775b-page 188 preliminary ? 2007 microchip technology inc. table 11-3: registers associated with pmp module name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pmconh pmpen ? psidl adrmux1 adrmux0 ptbeen ptwren ptrden 64 pmconl csf1 csf0 alp cs2p cs1p bep wrsp rdsp 65 pmaddrh (1) / cs2 cs1 parallel master port address, high byte 64 pmdout1h (1) parallel port out data, high byte (buffer 1) 64 pmaddrl (1) / parallel master port address, low byte 64 pmdout1l (1) parallel port out data, low byte (buffer 0) 64 pmdout2h parallel port out data, high byte (buffer 3) 64 pmdout2l parallel port out data, low byte (buffer 2) 64 pmdin1h parallel port in data, high byte (buffer 1) 64 pmdin1l parallel port in data, low byte (buffer 0) 64 pmdin2h parallel port in data, high byte (buffer 3) 65 pmdin2l parallel port in data, low byte (buffer 2) 65 pmmodeh busy irqm1 irqm0 incm1 incm0 mode16 mode1 mode0 65 pmmodel waitb1 waitb0 waitm3 waitm 2 waitm1 waitm0 waite1 waite0 65 pmeh pten15 pten14 pten13 pten12 pten11 pten10 pten9 pten8 65 pmel pten7 pten6 pten5 pten4 pten3 pten2 pten1 pten0 65 pmstath ibf ibov ? ? ib3f ib2f ib1f ib0f 65 pmstatl obe obuf ? ? ob3e ob2e ob1e ob0e 65 padcfg1 (2) ? ? ? ? ? ? ?pmpttl 60 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used during eccp operation. note 1: the pmaddrh/pmdout1h and pmaddrl/pmdout1l register pairs share the physical registers and addresses, but have different functions determined by the module?s operating mode. 2: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
? 2007 microchip technology inc. preliminary ds39775b-page 189 pic18f87j50 family 12.0 timer0 module the timer0 module incorporates the following features: ? software selectable operation as a timer or counter in both 8-bit or 16-bit modes ? readable and writable registers ? dedicated 8-bit, software programmable prescaler ? selectable clock source (internal or external) ? edge select for external clock ? interrupt-on-overflow the t0con register (register 12-1) controls all aspects of the module?s operation, including the prescale selection. it is both readable and writable. a simplified block diagram of the timer0 module in 8-bit mode is shown in figure 12-1. figure 12-2 shows a simplified block diagram of the timer0 module in 16-bit mode. register 12-1: t0con: ti mer0 control register r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 tmr0on t08bit t0cs t0se psa t0ps2 t0ps1 t0ps0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 tmr0on: timer0 on/off control bit 1 = enables timer0 0 = stops timer0 bit 6 t08bit : timer0 8-bit/16-bit control bit 1 = timer0 is configured as an 8-bit timer/counter 0 = timer0 is configured as a 16-bit timer/counter bit 5 t0cs : timer0 clock source select bit 1 = transition on t0cki pin 0 = internal instruction cycle clock (clko) bit 4 t0se : timer0 source edge select bit 1 = increment on high-to-low transition on t0cki pin 0 = increment on low-to-high transition on t0cki pin bit 3 psa : timer0 prescaler assignment bit 1 = timer0 prescaler is not assigned. timer0 clock input bypasses prescaler. 0 = timer0 prescaler is assigned. timer0 clock input comes from prescaler output. bit 2-0 t0ps2:t0ps0 : timer0 prescaler select bits 111 = 1:256 prescale value 110 = 1:128 prescale value 101 = 1:64 prescale value 100 = 1:32 prescale value 011 = 1:16 prescale value 010 = 1:8 prescale value 001 = 1:4 prescale value 000 = 1:2 prescale value
pic18f87j50 family ds39775b-page 190 preliminary ? 2007 microchip technology inc. 12.1 timer0 operation timer0 can operate as either a timer or a counter. the mode is selected with the t0cs bit (t0con<5>). in timer mode (t0cs = 0 ), the module increments on every clock by default unless a different prescaler value is selected (see section 12.3 ?prescaler? ). if the tmr0 register is written to, the increment is inhibited for the following two instruction cycles. the user can work around this by writing an adjusted value to the tmr0 register. the counter mode is selected by setting the t0cs bit (= 1 ). in this mode, timer0 increments either on every rising or falling edge of pin ra4/t0cki. the increment- ing edge is determined by the timer0 source edge select bit, t0se (t0con<4>); clearing this bit selects the rising edge. restrictions on the external clock input are discussed below. an external clock source can be used to drive timer0; however, it must meet certain requirements to ensure that the external clock can be synchronized with the internal phase clock (t osc ). there is a delay between synchronization and the onset of incrementing the timer/counter. 12.2 timer0 reads and writes in 16-bit mode tmr0h is not the actual high byte of timer0 in 16-bit mode. it is actually a buffered version of the real high byte of timer0 which is not directly readable nor writ- able (refer to figure 12-2). tmr0h is updated with the contents of the high byte of timer0 during a read of tmr0l. this provides the ability to read all 16 bits of timer0 without having to verify that the read of the high and low byte were valid, due to a rollover between successive reads of the high and low byte. similarly, a write to the high byte of timer0 must also take place through the tmr0h buffer register. the high byte is updated with the contents of tmr0h when a write occurs to tmr0l. this allows all 16 bits of timer0 to be updated at once. figure 12-1: timer0 block diagram (8-bit mode) figure 12-2: timer0 block di agram (16-bit mode) note: upon reset, timer0 is enabled in 8-bit mode with clock input from t0cki max. prescale. t0cki pin t0se 0 1 1 0 t0cs f osc /4 programmable prescaler sync with internal clocks tmr0l (2 t cy delay) internal data bus psa t0ps2:t0ps0 set tmr0if on overflow 3 8 8 note: upon reset, timer0 is enabled in 8-bit mode with clock input from t0cki max. prescale. t0cki pin t0se 0 1 1 0 t0cs f osc /4 sync with internal clocks tmr0l (2 t cy delay) internal data bus 8 psa t0ps2:t0ps0 set tmr0if on overflow 3 tmr0 tmr0h high byte 8 8 8 read tmr0l write tmr0l 8 programmable prescaler
? 2007 microchip technology inc. preliminary ds39775b-page 191 pic18f87j50 family 12.3 prescaler an 8-bit counter is available as a prescaler for the timer0 module. the prescaler is not directly readable or writable. its value is set by the psa and t0ps2:t0ps0 bits (t0con<3:0>) which determine the prescaler assignment and prescale ratio. clearing the psa bit assigns the prescaler to the timer0 module. when it is assigned, prescale values from 1:2 through 1:256 in power-of-2 increments are selectable. when assigned to the timer0 module, all instructions writing to the tmr0 register (e.g., clrf tmr0 , movwf tmr0 , bsf tmr0 , etc.) clear the prescaler count. 12.3.1 switching prescaler assignment the prescaler assignment is fully under software control and can be changed ?on-the-fly? during program execution. 12.4 timer0 interrupt the tmr0 interrupt is generated when the tmr0 register overflows from ffh to 00h in 8-bit mode, or from ffffh to 0000h in 16-bit mode. this overflow sets the tmr0if flag bit. the interrupt can be masked by clearing the tmr0ie bit (intcon<5>). before re-enabling the interrupt, the tmr0if bit must be cleared in software by the interrupt service routine. since timer0 is shut down in sleep mode, the tmr0 interrupt cannot awaken the processor from sleep. table 12-1: registers associated with timer0 note: writing to tmr0 when the prescaler is assigned to timer0 will clear the prescaler count but will not change the prescaler assignment. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: tmr0l timer0 register low byte 60 tmr0h timer0 register high byte 60 intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 t0con tmr0on t08bit t0cs t0se psa t0ps2 t0ps1 t0ps0 60 trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 62 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by timer0.
pic18f87j50 family ds39775b-page 192 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 193 pic18f87j50 family 13.0 timer1 module the timer1 timer/counter module incorporates these features: ? software selectable operation as a 16-bit timer or counter ? readable and writable 8-bit registers (tmr1h and tmr1l) ? selectable clock source (internal or external) with device clock or timer1 oscillator internal options ? interrupt on overflow ? reset on ccp special event trigger ? device clock status flag (t1run) a simplified block diagram of the timer1 module is shown in figure 13-1. a block diagram of the module?s operation in read/write mode is shown in figure 13-2. the module incorporates its own low-power oscillator to provide an additional clocking option. the timer1 oscillator can also be used as a low-power clock source for the microcontroller in power-managed operation. timer1 can also be used to provide real-time clock (rtc) functionality to applications with only a minimal addition of external components and code overhead. timer1 is controlled through the t1con control register (register 13-1). it also contains the timer1 oscillator enable bit (t1oscen). timer1 can be enabled or disabled by setting or clearing control bit, tmr1on (t1con<0>). register 13-1: t1con: ti mer1 control register (1) r/w-0 r-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 rd16 t1run t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 rd16: 16-bit read/write mode enable bit 1 = enables register read/write of timer1 in one 16-bit operation 0 = enables register read/write of timer1 in two 8-bit operations bit 6 t1run: timer1 system clock status bit 1 = device clock is derived from timer1 oscillator 0 = device clock is derived from another source bit 5-4 t1ckps1:t1ckps0: timer1 input clock prescale select bits 11 = 1:8 prescale value 10 = 1:4 prescale value 01 = 1:2 prescale value 00 = 1:1 prescale value bit 3 t1oscen: timer1 oscillator enable bit 1 = timer1 oscillator is enabled 0 = timer1 oscillator is shut off the oscillator inverter and feedback resistor are turned off to eliminate power drain. bit 2 t1sync : timer1 external clock input synchronization select bit when tmr1cs = 1 : 1 = do not synchronize external clock input 0 = synchronize external clock input when tmr1cs = 0 : this bit is ignored. timer1 uses the internal clock when tmr1cs = 0 . bit 1 tmr1cs: timer1 clock source select bit 1 = external clock from pin rc0/t1oso/t13cki (on the rising edge) 0 = internal clock (f osc /4) bit 0 tmr1on: timer1 on bit 1 = enables timer1 0 =stops timer1 note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 .
pic18f87j50 family ds39775b-page 194 preliminary ? 2007 microchip technology inc. 13.1 timer1 operation timer1 can operate in one of these modes: ?timer ? synchronous counter ? asynchronous counter the operating mode is determined by the clock select bit, tmr1cs (t1con<1>). when tmr1cs is cleared (= 0 ), timer1 increments on every internal instruction cycle (f osc /4). when the bit is set, timer1 increments on every rising edge of the timer1 external clock input or the timer1 oscillator, if enabled. when timer1 is enabled, the rc1/t1osi and rc0/t1oso/t13cki pins become inputs. this means the values of trisc<1:0> are ignored and the pins are read as ? 0 ?. figure 13-1: timer1 block diagram figure 13-2: timer1 block diag ram (16-bit read/write mode) t1sync tmr1cs t1ckps1:t1ckps0 sleep input t1oscen (1) f osc /4 internal clock on/off prescaler 1, 2, 4, 8 synchronize detect 1 0 2 t1oso/t13cki t1osi 1 0 tmr1on tmr1l set tmr1if on overflow tmr1 high byte clear tmr1 (eccpx special event trigger) timer1 oscillator note 1: when enable bit, t1oscen, is cleared, the inverter and f eedback resistor are turned off to eliminate power drain. on/off timer1 timer1 clock input t1sync tmr1cs t1ckps1:t1ckps0 sleep input t1oscen (1) f osc /4 internal clock prescaler 1, 2, 4, 8 synchronize detect 1 0 2 t1oso/t13cki t1osi note 1: when enable bit, t1oscen, is cleared, the inverter and feed back resistor are turned off to eliminate power drain. 1 0 tmr1l internal data bus 8 set tmr1if on overflow tmr1 tmr1h high byte 8 8 8 read tmr1l write tmr1l 8 tmr1on clear tmr1 (eccpx special event trigger) timer1 oscillator on/off timer1 timer1 clock input
? 2007 microchip technology inc. preliminary ds39775b-page 195 pic18f87j50 family 13.2 timer1 16-bit read/write mode timer1 can be configured for 16-bit reads and writes (see figure 13-2). when the rd16 control bit, t1con<7>, is set, the address for tmr1h is mapped to a buffer register for the high byte of timer1. a read from tmr1l will load the contents of the high byte of timer1 into the timer1 high byte buffer register. this provides the user with the ability to accurately read all 16 bits of timer1 without having to determine whether a read of the high byte, followed by a read of the low byte, has become invalid due to a rollover between reads. a write to the high byte of timer1 must also take place through the tmr1h buffer register. the timer1 high byte is updated with the contents of tmr1h when a write occurs to tmr1l. this allows a user to write all 16 bits to both the high and low bytes of timer1 at once. the high byte of timer1 is not directly readable or writable in this mode. all reads and writes must take place through the timer1 high byte buffer register. writes to tmr1h do not clear the timer1 prescaler. the prescaler is only cleared on writes to tmr1l. 13.3 timer1 oscillator an on-chip crystal oscillator circuit is incorporated between pins t1osi (input) and t1oso (amplifier output). it is enabled by setting the timer1 oscillator enable bit, t1oscen (t1con<3>). the oscillator is a low-power circuit rated for 32 khz crystals. it will continue to run during all power-managed modes. the circuit for a typical lp oscillator is shown in figure 13-3. table 13-1 shows the capacitor selection for the timer1 oscillator. the user must provide a software time delay to ensure proper start-up of the timer1 oscillator. figure 13-3: external components for the timer1 lp oscillator table 13-1: capacitor selection for the timer oscillator (2,3,4) 13.3.1 using timer1 as a clock source the timer1 oscillator is also available as a clock source in power-managed modes. by setting the clock select bits, scs1:scs0 (osccon<1:0>), to ? 01 ?, the device switches to sec_run mode; both the cpu and peripherals are clocked from the timer1 oscillator. if the idlen bit (osccon<7>) is cleared and a sleep instruction is executed, the device enters sec_idle mode. additional details are available in section 3.0 ?power-managed modes? . whenever the timer1 oscillator is providing the clock source, the timer1 system clock status flag, t1run (t1con<6>), is set. this can be used to determine the controller?s current clocking mode. it can also indicate the clock source being currently used by the fail-safe clock monitor. if the clock monitor is enabled and the timer1 oscillator fails while providing the clock, polling the t1run bit will indicate whether the clock is being provided by the timer1 oscillator or another source. 13.3.2 timer1 oscillator layout considerations the timer1 oscillator circuit draws very little power during operation. due to the low-power nature of the oscillator, it may also be sensitive to rapidly changing signals in close proximity. the oscillator circuit, shown in figure 13-3, should be located as close as possible to the microcontroller. there should be no circuits passing within the oscillator circuit boundaries other than v ss or v dd . note: see the notes with table 13-1 for additional information about capacitor selection. c1 c2 xtal pic18f87j50 t1osi t1oso 32.768 khz 27 pf 27 pf oscillator type freq. c1 c2 lp 32 khz 27 pf (1) 27 pf (1) note 1: microchip suggests these values as a starting point in validating the oscillator circuit. 2: higher capacitance increases the stability of the oscillator but also increases the start-up time. 3: since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropriate values of external components. 4: capacitor values are for design guidance only.
pic18f87j50 family ds39775b-page 196 preliminary ? 2007 microchip technology inc. if a high-speed circuit must be located near the oscilla- tor (such as the eccp1 pin in output compare or pwm mode, or the primary oscillator using the osc2 pin), a grounded guard ring around the oscillator circuit, as shown in figure 13-4, may be helpful when used on a single-sided pcb or in addition to a ground plane. figure 13-4: oscillator circuit with grounded guard ring 13.4 timer1 interrupt the tmr1 register pair (tmr1h:tmr1l) increments from 0000h to ffffh and rolls over to 0000h. the timer1 interrupt, if enabled, is generated on overflow which is latched in interrupt flag bit, tmr1if (pir1<0>). this interrupt can be enabled or disabled by setting or clearing the timer1 interrupt enable bit, tmr1ie (pie1<0>). 13.5 resetting timer1 using the eccp special event trigger if eccp1 or eccp2 is configured to use timer1 and to generate a special event trigger in compare mode (ccpxm3:ccpxm0 = 1011 ), this signal will reset timer3. the trigger from eccp2 will also start an a/d conversion if the a/d module is enabled (see section 18.2.1 ?special event trigger? for more information). the module must be configured as either a timer or a synchronous counter to take advantage of this feature. when used this way, the ccprxh:ccprxl register pair effectively becomes a period register for timer1. if timer1 is running in asynchronous counter mode, this reset operation may not work. in the event that a write to timer1 coincides with a special event trigger, the write operation will take precedence. 13.6 using timer1 as a real-time clock adding an external lp oscillator to timer1 (such as the one described in section 13.3 ?timer1 oscillator? ) gives users the option to include rtc functionality to their applications. this is accomplished with an inex- pensive watch crystal to provide an accurate time base and several lines of application code to calculate the time. when operating in sleep mode and using a battery or supercapacitor as a power source, it can completely eliminate the need for a separate rtc device and battery backup. the application code routine, rtcisr , shown in example 13-1, demonstrates a simple method to increment a counter at one-second intervals using an interrupt service routine. incrementing the tmr1 register pair to overflow triggers the interrupt and calls the routine which increments the seconds counter by one. additional counters for minutes and hours are incremented as the previous counter overflows. since the register pair is 16 bits wide, counting up to overflow the register directly from a 32.768 khz clock would take 2 seconds. to force the overflow at the required one-second intervals, it is necessary to pre- load it. the simplest method is to set the msb of tmr1h with a bsf instruction. note that the tmr1l register is never preloaded or altered; doing so may introduce cumulative error over many cycles. for this method to be accurate, timer1 must operate in asynchronous mode and the timer1 overflow interrupt must be enabled (pie1<0> = 1 ) as shown in the routine, rtcinit . the timer1 oscillator must also be enabled and running at all times. 13.7 considerations in asynchronous counter mode following a timer1 interrupt and an update to the tmr1 registers, the timer1 module uses a falling edge on its clock source to trigger the next register update on the rising edge. if the update is completed after the clock input has fallen, the next rising edge will not be counted. if the application can reliably update tmr1 before the timer input goes low, no additional action is needed. otherwise, an adjusted update can be performed following a later timer1 increment. this can be done by monitoring tmr1l within the interrupt routine until it increments, and then updating the tmr1h:tmr1l reg- ister pair while the clock is low, or one-half of the period of the clock source. assuming that timer1 is being used as a real-time clock, the clock source is a 32.768 khz crystal oscillator. in this case, one-half period of the clock is 15.25 s. v dd osc1 v ss osc2 rc0 rc1 rc2 note: not drawn to scale. note: the special event triggers from the eccpx module will not set the tmr1if interrupt flag bit (pir1<0>).
? 2007 microchip technology inc. preliminary ds39775b-page 197 pic18f87j50 family the real-time clock application code in example 13-1 shows a typical isr for timer1, as well as the optional code required if the update cannot be done reliably within the required interval. example 13-1: implementing a real-time clock using a timer1 interrupt service rtcinit movlw 80h ; preload tmr1 register pair movwf tmr1h ; for 1 second overflow clrf tmr1l movlw b?00001111? ; configure for external clock, movwf t1con ; asynchronous operation, external oscillator clrf secs ; initialize timekeeping registers clrf mins ; movlw .12 movwf hours bsf pie1, tmr1ie ; enable timer1 interrupt return rtcisr ; insert the next 4 lines of code when tmr1 ; can not be reliably updated before clock pulse goes low btfsc tmr1l,0 ; wait for tmr1l to become clear bra $-2 ; (may already be clear) btfss tmr1l,0 ; wait for tmr1l to become set bra $-2 ; tmr1 has just incremented ; if tmr1 update can be completed before clock pulse goes low ; start isr here bsf tmr1h, 7 ; preload for 1 sec overflow bcf pir1, tmr1if ; clear interrupt flag incf secs, f ; increment seconds movlw .59 ; 60 seconds elapsed? cpfsgt secs return ; no, done clrf secs ; clear seconds incf mins, f ; increment minutes movlw .59 ; 60 minutes elapsed? cpfsgt mins return ; no, done clrf mins ; clear minutes incf hours, f ; increment hours movlw .23 ; 24 hours elapsed? cpfsgt hours return ; no, done clrf hours ; reset hours return ; done
pic18f87j50 family ds39775b-page 198 preliminary ? 2007 microchip technology inc. table 13-2: registers associated with timer1 as a timer/counter name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 tmr1l (1) timer1 register low byte 60 tmr1h (1) timer1 register high byte 60 t1con (1) rd16 t1run t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 60 legend: shaded cells are not used by the timer1 module. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 .
? 2007 microchip technology inc. preliminary ds39775b-page 199 pic18f87j50 family 14.0 timer2 module the timer2 module incorporates the following features: ? 8-bit timer and period registers (tmr2 and pr2, respectively) ? readable and writable (both registers) ? software programmable prescaler (1:1, 1:4 and 1:16) ? software programmable postscaler (1:1 through 1:16) ? interrupt on tmr2 to pr2 match ? optional use as the shift clock for the mssp modules the module is controlled through the t2con register (register 14-1) which enables or disables the timer and configures the prescaler and postscaler. timer2 can be shut off by clearing control bit, tmr2on (t2con<2>), to minimize power consumption. a simplified block diagram of the module is shown in figure 14-1. 14.1 timer2 operation in normal operation, tmr2 is incremented from 00h on each clock (f osc /4). a 4-bit counter/prescaler on the clock input gives direct input, divide-by-4 and divide-by-16 prescale options. these are selected by the prescaler control bits, t2ckps1:t2ckps0 (t2con<1:0>). the value of tmr2 is compared to that of the period register, pr2, on each clock cycle. when the two values match, the comparator generates a match signal as the timer output. this signal also resets the value of tmr2 to 00h on the next cycle and drives the output counter/postscaler (see section 14.2 ?timer2 interrupt? ). the tmr2 and pr2 registers are both directly readable and writable. the tmr2 register is cleared on any device reset, while the pr2 register initializes at ffh. both the prescaler and postscaler counters are cleared on the following events: ? a write to the tmr2 register ? a write to the t2con register ? any device reset (power-on reset, mclr reset, watchdog timer reset or brown-out reset) tmr2 is not cleared when t2con is written. register 14-1: t2con: ti mer2 control register u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? t2outps3 t2outps2 t2outps1 t2outps0 tmr2on t2ckps1 t2ckps0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 unimplemented: read as ? 0 ? bit 6-3 t2outps3:t2outps0: timer2 output postscale select bits 0000 = 1:1 postscale 0001 = 1:2 postscale ? ? ? 1111 = 1:16 postscale bit 2 tmr2on: timer2 on bit 1 = timer2 is on 0 = timer2 is off bit 1-0 t2ckps1:t2ckps0: timer2 clock prescale select bits 00 = prescaler is 1 01 = prescaler is 4 1x = prescaler is 16
pic18f87j50 family ds39775b-page 200 preliminary ? 2007 microchip technology inc. 14.2 timer2 interrupt timer2 can also generate an optional device interrupt. the timer2 output signal (tmr2 to pr2 match) pro- vides the input for the 4-bit output counter/postscaler. this counter generates the tmr2 match interrupt flag which is latched in tmr2if (pir1<1>). the interrupt is enabled by setting the tmr2 match interrupt enable bit, tmr2ie (pie1<1>). a range of 16 postscale options (from 1:1 through 1:16 inclusive) can be selected with the postscaler control bits, t2outps3:t2outps0 (t2con<6:3>). 14.3 timer2 output the unscaled output of tmr2 is available primarily to the eccp modules, where it is used as a time base for operations in pwm mode. timer2 can be optionally used as the shift clock source for the mssp modules operating in spi mode. additional information is provided in section 19.0 ?master synchronous serial port (mssp) module? . figure 14-1: timer2 block diagram table 14-1: registers associated with timer2 as a timer/counter name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 tmr2 (1) timer2 register 60 t2con ? t2outps3 t2outps2 t2outps1 t2outps0 tmr2on t2ckps1 t2ckps0 60 pr2 (1) timer2 period register 60 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the timer2 module. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . comparator tmr2 output tmr2 postscaler prescaler pr2 2 f osc /4 1:1 to 1:16 1:1, 1:4, 1:16 4 t2outps3:t2outps0 t2ckps1:t2ckps0 set tmr2if internal data bus 8 reset tmr2/pr2 8 8 (to pwm or msspx) match
? 2007 microchip technology inc. preliminary ds39775b-page 201 pic18f87j50 family 15.0 timer3 module the timer3 timer/counter module incorporates these features: ? software selectable operation as a 16-bit timer or counter ? readable and writable 8-bit registers (tmr3h and tmr3l) ? selectable clock source (internal or external) with device clock or timer1 oscillator internal options ? interrupt-on-overflow ? module reset on eccp special event trigger a simplified block diagram of the timer3 module is shown in figure 15-1. a block diagram of the module?s operation in read/write mode is shown in figure 15-2. the timer3 module is controlled through the t3con register (register 15-1). it also selects the clock source options for the ccp and eccp modules; see section 17.1.1 ?ccp modules and timer resources? for more information. register 15-1: t3con: ti mer3 control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 rd16: 16-bit read/write mode enable bit 1 = enables register read/write of timer3 in one 16-bit operation 0 = enables register read/write of timer3 in two 8-bit operations bit 6,3 t3ccp2:t3ccp1: timer3 and timer1 to eccpx/ccpx enable bits 11 = timer3 and timer4 are the clock sources for all eccp/ccp modules 10 = timer3 and timer4 are the clock sources for eccp3, ccp4 and ccp5; timer1 and timer2 are the clock sources for eccp1 and eccp2 01 = timer3 and timer4 are the clock sources for eccp2, eccp3, ccp4 and ccp5; timer1 and timer2 are the clock sources for eccp1 00 = timer1 and timer2 are the clock sources for all eccp/ccp modules bit 5-4 t3ckps1:t3ckps0 : timer3 input clock prescale select bits 11 = 1:8 prescale value 10 = 1:4 prescale value 01 = 1:2 prescale value 00 = 1:1 prescale value bit 2 t3sync : timer3 external clock input synchronization control bit (not usable if the device clock comes from timer1/timer3.) when tmr3cs = 1 : 1 = do not synchronize external clock input 0 = synchronize external clock input when tmr3cs = 0 : this bit is ignored. timer3 uses the internal clock when tmr3cs = 0 . bit 1 tmr3cs: timer3 clock source select bit 1 = external clock input from timer1 oscillator or t13cki (on the rising edge after the first falling edge) 0 = internal clock (f osc /4) bit 0 tmr3on: timer3 on bit 1 = enables timer3 0 = stops timer3
pic18f87j50 family ds39775b-page 202 preliminary ? 2007 microchip technology inc. 15.1 timer3 operation timer3 can operate in one of three modes: ?timer ? synchronous counter ? asynchronous counter the operating mode is determined by the clock select bit, tmr3cs (t3con<1>). when tmr3cs is cleared (= 0 ), timer3 increments on every internal instruction cycle (f osc /4). when the bit is set, timer3 increments on every rising edge of the timer1 external clock input or the timer1 oscillator, if enabled. as with timer1, the rc1/t1osi and rc0/t1oso/t13cki pins become inputs when the timer1 oscillator is enabled. this means the values of trisc<1:0> are ignored and the pins are read as ? 0 ?. figure 15-1: timer3 block diagram figure 15-2: timer3 block diag ram (16-bit read/write mode) t3sync tmr3cs t3ckps1:t3ckps0 sleep input t1oscen (1) f osc /4 internal clock prescaler 1, 2, 4, 8 synchronize detect 1 0 2 t1oso/t13cki t1osi 1 0 tmr3on tmr3l set tmr3if on overflow tmr3 high byte timer1 oscillator note 1: when enable bit, t1oscen, is cleared, the inverter and feedback resistor are turned off to eliminate power drain. on/off timer3 eccpx special event trigger eccpx select from t3con<6,3> clear tmr3 timer1 clock input t3sync tmr3cs t3ckps1:t3ckps0 sleep input t1oscen (1) f osc /4 internal clock prescaler 1, 2, 4, 8 synchronize detect 1 0 2 t13cki/t1oso t1osi note 1: when enable bit, t1oscen, is cleared, the inverter and feedback resistor are turned off to eliminate power drain. 1 0 tmr3l internal data bus 8 set tmr3if on overflow tmr3 tmr3h high byte 8 8 8 read tmr1l write tmr1l 8 tmr3on eccpx special event trigger timer1 oscillator on/off timer3 timer1 clock input eccpx select from t3con<6,3> clear tmr3
? 2007 microchip technology inc. preliminary ds39775b-page 203 pic18f87j50 family 15.2 timer3 16-bit read/write mode timer3 can be configured for 16-bit reads and writes (see figure 15-2). when the rd16 control bit (t3con<7>) is set, the address for tmr3h is mapped to a buffer register for the high byte of timer3. a read from tmr3l will load the contents of the high byte of timer3 into the timer3 high byte buffer register. this provides the user with the ability to accurately read all 16 bits of timer1 without having to determine whether a read of the high byte, followed by a read of the low byte, has become invalid due to a rollover between reads. a write to the high byte of timer3 must also take place through the tmr3h buffer register. the timer3 high byte is updated with the contents of tmr3h when a write occurs to tmr3l. this allows a user to write all 16 bits to both the high and low bytes of timer3 at once. the high byte of timer3 is not directly readable or writable in this mode. all reads and writes must take place through the timer3 high byte buffer register. writes to tmr3h do not clear the timer3 prescaler. the prescaler is only cleared on writes to tmr3l. 15.3 using the timer1 oscillator as the timer3 clock source the timer1 internal oscillator may be used as the clock source for timer3. the timer1 oscillator is enabled by setting the t1oscen (t1con<3>) bit. to use it as the timer3 clock source, the tmr3cs bit must also be set. as previously noted, this also configures timer3 to increment on every rising edge of the oscillator source. the timer1 oscillator is described in section 13.0 ?timer1 module? . 15.4 timer3 interrupt the tmr3 register pair (tmr3h:tmr3l) increments from 0000h to ffffh and overflows to 0000h. the timer3 interrupt, if enabled, is generated on overflow and is latched in interrupt flag bit, tmr3if (pir2<1>). this interrupt can be enabled or disabled by setting or clearing the timer3 interrupt enable bit, tmr3ie (pie2<1>). 15.5 resetting timer3 using the eccp special event trigger if eccp1 or eccp2 is configured to use timer3 and to generate a special event trigger in compare mode (ccpxm3:ccpxm0 = 1011 ), this signal will reset timer3. the trigger from eccp2 will also start an a/d conversion if the a/d module is enabled (see section 18.2.1 ?special event trigger? for more information). the module must be configured as either a timer or synchronous counter to take advantage of this feature. when used this way, the ccprxh:ccprxl register pair effectively becomes a period register for timer3. if timer3 is running in asynchronous counter mode, the reset operation may not work. in the event that a write to timer3 coincides with a special event trigger from an eccp module, the write will take precedence. table 15-1: registers associated with timer3 as a timer/counter note: the special event triggers from the eccpx module will not set the tmr3if interrupt flag bit (pir1<0>). name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 62 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 62 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 62 tmr3l timer3 register low byte 63 tmr3h timer3 register high byte 63 t1con (1) rd16 t1run t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 60 t3con rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the timer3 module. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 .
pic18f87j50 family ds39775b-page 204 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 205 pic18f87j50 family 16.0 timer4 module the timer4 timer module has the following features: ? 8-bit timer register (tmr4) ? 8-bit period register (pr4) ? readable and writable (both registers) ? software programmable prescaler (1:1, 1:4, 1:16) ? software programmable postscaler (1:1 to 1:16) ? interrupt on tmr4 match of pr4 timer4 has a control register shown in register 16-1. timer4 can be shut off by clearing control bit, tmr4on (t4con<2>), to minimize power consumption. the prescaler and postscaler selection of timer4 are also controlled by this register. figure 16-1 is a simplified block diagram of the timer4 module. 16.1 timer4 operation timer4 can be used as the pwm time base for the pwm mode of the eccp/ccp modules. the tmr4 register is readable and writable and is cleared on any device reset. the input clock (f osc /4) has a prescale option of 1:1, 1:4 or 1:16, selected by control bits t4ckps1:t4ckps0 (t4con<1:0>). the match out- put of tmr4 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a tmr4 interrupt, latched in flag bit, tmr4if (pir3<3>). the prescaler and postscaler counters are cleared when any of the following occurs: ? a write to the tmr4 register ? a write to the t4con register ? any device reset (power-on reset, mclr reset, watchdog timer reset or brown-out reset) tmr4 is not cleared when t4con is written. register 16-1: t4con: ti mer4 control register u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? t4outps3 t4outps2 t4outps1 t4outps0 tmr4on t4ckps1 t4ckps0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 unimplemented: read as ? 0 ? bit 6-3 t4outps3:t4outps0 : timer4 output postscale select bits 0000 = 1:1 postscale 0001 = 1:2 postscale ? ? ? 1111 = 1:16 postscale bit 2 tmr4on : timer4 on bit 1 = timer4 is on 0 = timer4 is off bit 1-0 t4ckps1:t4ckps0 : timer4 clock prescale select bits 00 = prescaler is 1 01 = prescaler is 4 1x = prescaler is 16
pic18f87j50 family ds39775b-page 206 preliminary ? 2007 microchip technology inc. 16.2 timer4 interrupt the timer4 module has an 8-bit period register, pr4, which is both readable and writable. timer4 increments from 00h until it matches pr4 and then resets to 00h on the next increment cycle. the pr4 register is initialized to ffh upon reset. 16.3 output of tmr4 the output of tmr4 (before the postscaler) is used only as a pwm time base for the eccp/ccp modules. it is not used as a baud rate clock for the mssp modules as is the timer2 output. figure 16-1: timer4 block diagram table 16-1: registers associated with timer4 as a timer/counter comparator tmr4 output tmr4 postscaler prescaler pr4 2 f osc /4 1:1 to 1:16 1:1, 1:4, 1:16 4 t4outps3:t4outps0 t4ckps1:t4ckps0 set tmr4if internal data bus 8 reset tmr4/pr4 8 8 (to pwm) match name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 tmr4 timer4 register 63 t4con ? t4outps3 t4outps2 t4outps1 t4outps0 tmr4on t4ckps1 t4ckps0 63 pr4 (1) timer4 period register 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the timer4 module. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 .
? 2007 microchip technology inc. preliminary ds39775b-page 207 pic18f87j50 family 17.0 capture/compare/pwm (ccp) modules members of the pic18f87j50 family of devices all have a total of five ccp (capture/compare/pwm) modules. two of these (ccp4 and ccp5) implement standard capture, compare and pulse-width modulation (pwm) modes and are discussed in this section. the other three modules (eccp1, eccp2, eccp3) implement standard capture and compare modes, as well as enhanced pwm modes. these are discussed in section 18.0 ?enhanced capture/compare/pwm (eccp) module? . each ccp/eccp module contains a 16-bit register which can operate as a 16-bit capture register, a 16-bit compare register or a pwm master/slave duty cycle register. for the sake of clarity, all ccp module opera- tion in the following sections is described with respect to ccp4, but is equally applicable to ccp5. capture and compare operations described in this chapter apply to all standard and enhanced ccp modules. the operations of pwm mode, described in section 17.4 ?pwm mode? , apply to ccp4 and ccp5 only. note: throughout this section and section 18.0 ?enhanced capture/compare/pwm (eccp) module? , references to register and bit names that may be associated with a specific ccp module are referred to generically by the use of ?x? or ?y? in place of the specific module number. thus, ?ccpxcon? might refer to the control register for eccp1, eccp2, eccp3, ccp4 or ccp5. register 17-1: ccpxcon: ccpx control re gister (ccp4 module, ccp5 module) u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? dcxb1 dcxb0 ccpxm3 ccpxm2 ccpxm1 ccpxm0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 unimplemented: read as ? 0 ? bit 5-4 dcxb1:dcxb0: pwm duty cycle bit 1 and bit 0 for ccpx module capture mode: unused. compare mode : unused. pwm mode: these bits are the two least significant bits (bit 1 and bit 0) of the 10-bit pwm duty cycle. the eight most significant bits (dcx9:dcx2) of the duty cycle are found in ccprxl. bit 3-0 ccpxm3:ccpxm0 : ccpx module mode select bits 0000 = capture/compare/pwm disabled (resets ccpx module) 0001 = reserved 0010 = compare mode: toggle output on match (ccpxif bit is set) 0011 = reserved 0100 = capture mode: every falling edge 0101 = capture mode: every rising edge 0110 = capture mode: every 4th rising edge 0111 = capture mode: every 16th rising edge 1000 = compare mode: initialize ccpx pin low; on compare match, force ccpx pin high (ccpxif bit is set) 1001 = compare mode: initialize ccpx pin high; on compare match, force ccpx pin low (ccpxif bit is set) 1010 = compare mode: generate software interrupt on compare match (ccpxif bit is set, ccpx pin reflects i/o state) 1011 = compare mode: trigger special event, reset timer, start a/d conversion on ccpx match (ccpxif bit is set) 11xx =pwm mode
pic18f87j50 family ds39775b-page 208 preliminary ? 2007 microchip technology inc. 17.1 ccp module configuration each capture/compare/pwm module is associated with a control register (generically, ccpxcon) and a data register (ccprx). the data register, in turn, is comprised of two 8-bit registers: ccprxl (low byte) and ccprxh (high byte). all registers are both readable and writable. 17.1.1 ccp modules and timer resources the eccp/ccp modules utilize timers 1, 2, 3 or 4, depending on the mode selected. timer1 and timer3 are available to modules in capture or compare modes, while timer2 and timer4 are available for modules in pwm mode. table 17-1: ccp mode ? timer resource the assignment of a particular timer to a module is determined by the timer to ccp enable bits in the t3con register (register 15-1, page 201). depending on the configuration selected, up to four timers may be active at once, with modules in the same configuration (capture/compare or pwm) sharing timer resources. the possible configurations are shown in figure 17-1. 17.1.2 open-drain output option when operating in output mode (i.e., in compare or pwm modes), the drivers for the ccpx pins can be optionally configured as open-drain outputs. this fea- ture allows the voltage level on the pin to be pulled to a higher level through an external pull-up resistor, and allows the output to communicate with external cir- cuits without the need for additional level shifters. for more information, see section 10.1.4 ?open-drain outputs? . the open-drain output option is controlled by the bits in the odcon1 register. setting the appropriate bit con- figures the pin for the corresponding module for open-drain operation. the odcon1 memory shares the same address space as tmr1h. the odcon1 register can be accessed by setting the adshr bit in the wdtcon register(wdtcon<4>). figure 17-1: eccp/ccp and time r interconnect configurations ccp mode timer resource capture compare pwm timer1 or timer3 timer1 or timer3 timer2 or timer4 tmr1 ccp5 tmr2 tmr3 tmr4 ccp4 eccp3 eccp2 eccp1 tmr1 tmr2 tmr3 ccp5 tmr4 ccp4 eccp3 eccp2 eccp1 tmr1 tmr2 tmr3 ccp5 tmr4 ccp4 eccp3 eccp2 eccp1 tmr1 tmr2 tmr3 ccp5 tmr4 ccp4 eccp3 eccp2 eccp1 t3ccp<2:1> = 00 t3ccp<2:1> = 01 t3ccp<2:1> = 10 t3ccp<2:1> = 11 timer1 is used for all capture and compare operations for all ccp modules. timer2 is used for pwm operations for all ccp modules. modules may share either timer resource as a common time base. timer3 and timer4 are not available. timer1 and timer2 are used for capture and compare or pwm operations for eccp1 only (depending on selected mode). all other modules use either timer3 or timer4. modules may share either timer resource as a common time base if they are in capture/compare or pwm modes. timer1 and timer2 are used for capture and compare or pwm operations for eccp1 and eccp2 only (depending on the mode selected for each module). both modules may use a timer as a common time base if they are both in capture/compare or pwm modes. the other modules use either timer3 or timer4. modules may share either timer resource as a common time base if they are in capture/compare or pwm modes. timer3 is used for all capture and compare operations for all ccp modules. timer4 is used for pwm operations for all ccp modules. modules may share either timer resource as a common time base. timer1 and timer2 are not available.
? 2007 microchip technology inc. preliminary ds39775b-page 209 pic18f87j50 family 17.2 capture mode in capture mode, the ccprxh:ccprxl register pair captures the 16-bit value of the tmr1 or tmr3 registers when an event occurs on the corresponding ccpx pin. an event is defined as one of the following: ? every falling edge ? every rising edge ? every 4th rising edge ? every 16th rising edge the event is selected by the mode select bits, ccpxm3:ccpxm0 (ccpxcon<3:0>). when a capture is made, the interrupt request flag bit, ccpxif, is set; it must be cleared in software. if another capture occurs before the value in register ccprx is read, the old captured value is overwritten by the new captured value. 17.2.1 ccpx pin configuration in capture mode, the appropriate ccpx pin should be configured as an input by setting the corresponding tris direction bit. 17.2.2 timer1/timer3 mode selection the timers that are to be used with the capture feature (timer1 and/or timer3) must be running in timer mode or synchronized counter mode. in asynchronous counter mode, the capture operation will not work. the timer to be used with each ccp module is selected in the t3con register (see section 17.1.1 ?ccp modules and timer resources? ). 17.2.3 software interrupt when the capture mode is changed, a false capture interrupt may be generated. the user should keep the ccpxie interrupt enable bit clear to avoid false interrupts. the interrupt flag bit, ccpxif, should also be cleared following any such change in operating mode. 17.2.4 ccp prescaler there are four prescaler settings in capture mode. they are specified as part of the operating mode selected by the mode select bits (ccpxm3:ccpxm0). whenever the ccpx module is turned off or capture mode is disabled, the prescaler counter is cleared. this means that any reset will clear the prescaler counter. switching from one capture prescaler to another may generate an interrupt. also, the prescaler counter will not be cleared; therefore, the first capture may be from a non-zero prescaler. example 17-1 shows the recommended method for switching between capture prescalers. this example also clears the prescaler counter and will not generate the ?false? interrupt. example 17-1: changing between capture prescalers (ccp5 shown) figure 17-2: capture mode operat ion block diagram note: if rg4/ccp5 is configured as an output, a write to the port can cause a capture condition. clrf ccp5con ; turn ccp module off movlw new_capt_ps ; load wreg with the ; new prescaler mode ; value and ccp on movwf ccp5con ; load ccp5con with ; this value ccpr4h ccpr4l tmr1h tmr1l set ccp4if tmr3 enable q1:q4 ccp4con<3:0> ccp4 pin prescaler 1, 4, 16 and edge detect tmr1 enable t3ccp2 t3ccp2 ccpr5h ccpr5l tmr1h tmr1l set ccp5if tmr3 enable ccp5con<3:0> ccp5 pin prescaler 1, 4, 16 tmr3h tmr3l tmr1 enable t3ccp2 t3ccp1 t3ccp2 t3ccp1 tmr3h tmr3l and edge detect 4 4 4
pic18f87j50 family ds39775b-page 210 preliminary ? 2007 microchip technology inc. 17.3 compare mode in compare mode, the 16-bit ccprx register value is constantly compared against either the tmr1 or tmr3 register pair value. when a match occurs, the ccpx pin can be: ? driven high ? driven low ? toggled (high-to-low or low-to-high) ? remains unchanged (that is, reflects the state of the i/o latch) the action on the pin is based on the value of the mode select bits (ccpxm3:ccpxm0). at the same time, the interrupt flag bit, ccpxif, is set. 17.3.1 ccpx pin configuration the user must configure the ccpx pin as an output by clearing the appropriate tris bit. 17.3.2 timer1/timer3 mode selection timer1 and/or timer3 must be running in timer mode or synchronized counter mode if the ccpx module is using the compare feature. in asynchronous counter mode, the compare operation may not work. 17.3.3 software interrupt mode when the generate software interrupt mode is chosen (ccpxm3:ccpxm0 = 1010 ), the corresponding ccpx pin is not affected. only a ccp interrupt is generated, if enabled and the ccpxie bit is set. figure 17-3: compare mode operat ion block diagram note: clearing the ccp5con register will force the rg4 compare output latch (depend- ing on device configuration) to the default low level. this is not the portb or portc i/o data latch. ccpr4h ccpr4l tmr1h tmr1l comparator q s r output logic set ccp4if ccp4 pin tris ccp4con<3:0> output enable tmr3h tmr3l ccpr5h ccpr5l comparator 1 0 t3ccp2 t3ccp1 set ccp5if 1 0 compare 4 q s r output logic ccp5 pin tris ccp5con<3:0> output enable 4 match compare match
? 2007 microchip technology inc. preliminary ds39775b-page 211 pic18f87j50 family table 17-2: registers associated with capture, compare, timer1 and timer3 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 rcon ipen ? cm ri to pd por bor 60 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 62 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 62 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 trisg ? ? ? trisg4 trisg3 trisg2 trisg1 trisg0 62 tmr1l (1) timer1 register low byte 60 tmr1h (1) timer1 register high byte 60 odcon1 (2) ? ? ? ccp5od ccp4od eccp3od eccp2od eccp1od 60 t1con (1) rd16 t1run t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 60 tmr3h timer3 register high byte 63 tmr3l timer3 register low byte 63 t3con rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on 63 ccpr4l capture/compare/pwm register 4 low byte 63 ccpr4h capture/compare/pwm register 4 high byte 63 ccpr5l capture/compare/pwm register 5 low byte 63 ccpr5h capture/compare/pwm register 5 high byte 63 ccp4con ? ? dc4b1 dc4b0 ccp4m3 ccp4m2 ccp4m1 ccp4m0 63 ccp5con ? ? dc5b1 dc5b0 ccp5m3 ccp5m2 ccp5m1 ccp5m0 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by capture/compare, timer1 or timer3. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 2: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
pic18f87j50 family ds39775b-page 212 preliminary ? 2007 microchip technology inc. 17.4 pwm mode in pulse-width modulation (pwm) mode, the ccpx pin produces up to a 10-bit resolution pwm output. since the ccp4 and ccp5 pins are multiplexed with a portg data latch, the appropriate trisg bit must be cleared to make the ccp4 or ccp5 pin an output. figure 17-4 shows a simplified block diagram of the ccp module in pwm mode. for a step-by-step procedure on how to set up a ccp module for pwm operation, see section 17.4.3 ?setup for pwm operation? . figure 17-4: simplified pwm block diagram a pwm output (figure 17-5) has a time base (period) and a time that the output stays high (duty cycle). the frequency of the pwm is the inverse of the period (1/period). figure 17-5: pwm output 17.4.1 pwm period the pwm period is specified by writing to the pr2 (pr4) register. the pwm period can be calculated using equation 17-1: equation 17-1: pwm frequency is defined as 1/[pwm period]. when tmr2 (tmr4) is equal to pr2 (pr4), the following three events occur on the next increment cycle: ? tmr2 (tmr4) is cleared ? the ccpx pin is set (exception: if pwm duty cycle = 0%, the ccpx pin will not be set) ? the pwm duty cycle is latched from ccprxl into ccprxh 17.4.2 pwm duty cycle the pwm duty cycle is specified by writing to the ccprxl register and to the ccpxcon<5:4> bits. up to 10-bit resolution is available. the ccprxl contains the eight msbs and the ccpxcon<5:4> contains the two lsbs. this 10-bit value is represented by ccprxl:ccpxcon<5:4>. equation 17-2 is used to calculate the pwm duty cycle in time. equation 17-2: ccprxl and ccpxcon<5:4> can be written to at any time, but the duty cycle value is not latched into ccprxh until after a match between pr2 (pr4) and tmr2 (tmr4) occurs (i.e., the period is complete). in pwm mode, ccprxh is a read-only register. note: clearing the ccp4con or ccp5con register will force the rg3 or rg4 output latch (depending on device configuration) to the default low level. this is not the portg i/o data latch. ccprxl comparator comparator prx ccpxcon<5:4> q s r ccpx tris output enable ccprxh tmrx 2 lsbs latched from q clocks reset match tmrx = prx latch 0 9 (1) note 1: the two lsbs of the duty cycle register are held by a 2-bit latch that is part of the module?s hardware. it is physically separate from the ccprx registers. duty cycle register set ccpx pin duty cycle pin period duty cycle tmr2 (tmr4) = pr2 (tmr4) tmr2 (tmr4) = duty cycle tmr2 (tmr4) = pr2 (pr4) note: the timer2 and timer 4 postscalers (see section 14.0 ?timer2 module? and section 16.0 ?timer4 module? ) are not used in the determination of the pwm frequency. the postscaler could be used to have a servo update rate at a different frequency than the pwm output. pwm period = [(pr2) + 1] ? 4 ? t osc ? (tmr2 prescale value) pwm duty cycle = (ccpr x l:ccp x con<5:4>) ? t osc ? (tmr2 prescale value)
? 2007 microchip technology inc. preliminary ds39775b-page 213 pic18f87j50 family the ccprxh register and a 2-bit internal latch are used to double-buffer the pwm duty cycle. this double-buffering is essential for glitchless pwm operation. when the ccprxh and 2-bit latch match tmr2 (tmr4), concatenated with an internal 2-bit q clock or 2 bits of the tmr2 (tmr4) prescaler, the ccpx pin is cleared. the maximum pwm resolution (bits) for a given pwm frequency is given by equation 17-3: equation 17-3: 17.4.3 setup for pwm operation the following steps should be taken when configuring the ccp module for pwm operation: 1. set the pwm period by writing to the pr2 (pr4) register. 2. set the pwm duty cycle by writing to the ccprxl register and ccpxcon<5:4> bits. 3. make the ccpx pin an output by clearing the appropriate tris bit. 4. set the tmr2 (tmr4) prescale value, then enable timer2 (timer4) by writing to t2con (t4con). 5. configure the ccpx module for pwm operation. table 17-3: example pwm frequencies and resolutions at 40 mhz note: if the pwm duty cycle value is longer than the pwm period, the ccpx pin will not be cleared. log ( f pwm log(2) f osc ) bits pwm resolution (max) = pwm frequency 2.44 khz 9.77 khz 39.06 khz 156.25 khz 312.50 khz 416.67 khz timer prescaler (1, 4, 16)1641111 pr2 value ffh ffh ffh 3fh 1fh 17h maximum resolution (bits) 10 10 10 8 7 6.58
pic18f87j50 family ds39775b-page 214 preliminary ? 2007 microchip technology inc. table 17-4: registers associated with pwm, timer2 and timer4 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 rcon ipen ? cm ri to pd por bor 60 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 trisg ? ? ? trisg4 trisg3 trisg2 trisg1 trisg0 62 tmr2 (1) timer2 register 60 pr2 (1) timer2 period register 60 t2con ? t2outps3 t2outps2 t2outps1 t2o utps0 tmr2on t2ckps1 t2ckps0 60 tmr4 timer4 register 63 pr4 (1) timer4 period register 63 t4con ? t4outps3 t4outps2 t4outps1 t4o utps0 tmr4on t4ckps1 t4ckps0 63 ccpr4l capture/compare/pwm register 4 low byte 63 ccpr4h capture/compare/pwm register 4 high byte 63 ccpr5l capture/compare/pwm register 5 low byte 63 ccpr5h capture/compare/pwm register 5 high byte 63 ccp4con ? ? dc4b1 dc4b0 ccp4m3 ccp4m2 ccp4m1 ccp4m0 63 ccp5con ? ? dc5b1 dc5b0 ccp5m3 ccp5m2 ccp5m1 ccp5m0 63 odcon1 (2) ? ? ? ccp5od ccp4od eccp3od eccp2od eccp1od 60 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by pwm, timer2 or timer4. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 2: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
? 2007 microchip technology inc. preliminary ds39775b-page 215 pic18f87j50 family 18.0 enhanced capture/ compare/pwm (eccp) module in the pic18f87j50 family of devices, three of the ccp modules are implemented as standard ccp modules with enhanced pwm capabilities. these include the provision for 2 or 4 output channels, user-selectable polarity, dead-band control and automatic shutdown and restart. the enhanced features are discussed in detail in section 18.4 ?enhanced pwm mode? . capture, compare and single-output pwm functions of the eccp module are the same as described for the standard ccp module. the control register for the enhanced ccp module is shown in register 18-1. it differs from the ccp4con/ ccp5con registers in that the two most significant bits are implemented to control pwm functionality. in addition to the expanded range of modes available through the enhanced ccpxcon register, the eccp modules each have two additional registers associated with enhanced pwm operation and auto-shutdown features. they are: ? eccpxdel (eccpx pwm delay) ? eccpxas (eccpx auto-shutdown control) register 18-1: ccpxcon: eccpx contro l register (eccp1/eccp2/eccp3) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pxm1 pxm0 dcxb1 dcxb0 ccpxm3 ccpxm2 ccpxm1 ccpxm0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 pxm1:pxm0: enhanced pwm output configuration bits if ccpxm3:ccpxm2 = 00 , 01 , 10 : xx = pxa assigned as capture/compare input/output; pxb, pxc, pxd assigned as port pins if ccpxm3:ccpxm2 = 11 : 00 = single output: pxa modulated; pxb, pxc, pxd assigned as port pins 01 = full-bridge output forward: p1d modulated; p1a active; p1b, p1c inactive 10 = half-bridge output: p1a, p1b modulated with dead-band control; p1c, p1d assigned as port pins 11 = full-bridge output reverse: p1b modulated; p1c active; p1a, p1d inactive bit 5-4 dcxb1:dcxb0 : pwm duty cycle bit 1 and bit 0 capture mode: unused. compare mode: unused. pwm mode: these bits are the two lsbs of the 10-bit pwm duty cycle. the eight msbs of the duty cycle are found in ccprxl. bit 3-0 ccpxm3:ccpxm0 : eccpx module mode select bits 0000 = capture/compare/pwm off (resets eccpx module) 0001 = reserved 0010 = compare mode: toggle output on match 0011 = capture mode 0100 = capture mode: every falling edge 0101 = capture mode: every rising edge 0110 = capture mode: every 4th rising edge 0111 = capture mode, every 16th rising edge 1000 = compare mode: initialize eccpx pin low; set output on compare match (set ccpxif) 1001 = compare mode: initialize eccpx pin high; clear output on compare match (set ccpxif) 1010 = compare mode: generate software interrupt only; eccpx pin reverts to i/o state 1011 = compare mode: trigger special event (eccpx resets tmr1 or tmr3, sets ccpxif bit, eccp2 trigger also starts a/d conversion if a/d module is enabled) (1) 1100 = pwm mode: pxa, pxc active-high; pxb, pxd active-high 1101 = pwm mode: pxa, pxc active-high; pxb, pxd active-low 1110 = pwm mode: pxa, pxc active-low; pxb, pxd active-high 1111 = pwm mode: pxa, pxc active-low; pxb, pxd active-low note 1: implemented only for eccp1 and eccp2; same as ? 1010 ? for eccp3.
pic18f87j50 family ds39775b-page 216 preliminary ? 2007 microchip technology inc. 18.1 eccp outputs and configuration each of the enhanced ccp modules may have up to four pwm outputs, depending on the selected operat- ing mode. these outputs, designated pxa through pxd, are multiplexed with various i/o pins. some eccp pin assignments are constant, while others change based on device configuration. for those pins that do change, the controlling bits are: ? ccp2mx configuration bit ? eccpmx configuration bit (80-pin devices only) ? program memory operating mode, set by the emb configuration bits (80-pin devices only) the pin assignments for the enhanced ccp modules are summarized in table 18-1, table 18-2 and table 18-3. to configure the i/o pins as pwm outputs, the proper pwm mode must be selected by setting the pxmx and ccpxmx bits (ccpxcon<7:6> and <3:0>, respectively). the appropriate tris direction bits for the corresponding port pins must also be set as outputs. 18.1.1 eccp1/eccp3 outputs and program memory mode in 80-pin devices, the use of extended microcontroller mode has an indirect effect on the use of eccp1 and eccp3 in enhanced pwm modes. by default, pwm outputs, p1b/p1c and p3b/p3c, are multiplexed to porte pins along with the high-order byte of the external memory bus. when the bus is active in extended microcontroller mode, it overrides the enhanced ccp outputs and makes them unavailable. because of this, eccp1 and eccp3 can only be used in compatible (single output) pwm modes when the device is in extended microcontroller mode and default pin configuration. an exception to this configuration is when a 12-bit address width is selected for the external bus (emb1:emb0 configuration bits = 01 ). in this case, the upper pins of porte continue to operate as digital i/o, even when the external bus is active. p1b/p1c and p3b/p3c remain available for use as enhanced pwm outputs. if an application requires the use of additional pwm outputs during enhanced microcontroller operation, the p1b/p1c and p3b/p3c outputs can be reassigned to the upper bits of porth. this is done by clearing the eccpmx configuration bit. 18.1.2 eccp2 outputs and program memory modes for 80-pin devices, the program memory mode of the device ( section 5.1.3 ?pic18f87j50 family program memory modes? ) also impacts pin multiplexing for the module. the eccp2 input/output (eccp2/p2a) can be multiplexed to one of three pins. the default assignment (ccp2mx configuration bit is set) for all devices is rc1. clearing ccp2mx reassigns eccp2/p2a to re7. an additional option exists for 80-pin devices. when these devices are operating in microcontroller mode, the multiplexing options described above still apply. in extended microcontroller mode, clearing ccp2mx reassigns eccp2/p2a to rb3. changing the pin assignment of eccp2 does not auto- matically change any requirements for configuring the port pin. users must always verify that the appropriate tris register is configured correctly for eccp2 operation regardless of where it is located. 18.1.3 use of ccp4 and ccp5 with eccp1 and eccp3 only the eccp2 module has four dedicated output pins that are available for use. assuming that the i/o ports or other multiplexed functions on those pins are not needed, they may be used whenever needed without interfering with any other ccp module. eccp1 and eccp3, on the other hand, only have three dedicated output pins: eccpx/pxa, pxb and pxc. whenever these modules are configured for quad pwm mode, the pin normally used for ccp4 or ccp5 becomes the pxd output pins for eccp3 and eccp1, respectively. the ccp4 and ccp5 modules remain functional but their outputs are overridden. 18.1.4 eccp modules and timer resources like the standard ccp modules, the eccp modules can utilize timers 1, 2, 3 or 4, depending on the mode selected. timer1 and timer3 are available for modules in capture or compare modes, while timer2 and timer4 are available for modules in pwm mode. additional details on timer resources are provided in section 17.1.1 ?ccp modules and timer resources? . 18.1.5 open-drain output option when operating in compare or standard pwm modes, the drivers for the eccpx pins can be optionally config- ured as open-drain outputs. this feature allows the voltage level on the pin to be pulled to a higher level through an external pull-up resistor, and allows the out- put to communicate with external circuits without the need for additional level shifters. for more information, see section 10.1.4 ?open-drain outputs? . the open-drain output option is controlled by the bits in the odcon1 register. setting the appropriate bit con- figures the pin for the corresponding module for open-drain operation. the odcon1 memory shares the same address space as of tmr1h. the odcon1 register can be accessed by setting the adshr bit in the wdtcon register (wdtcon<4>).
? 2007 microchip technology inc. preliminary ds39775b-page 217 pic18f87j50 family table 18-1: pin config urations for eccp1 table 18-2: pin config urations for eccp2 eccp mode ccp1con configuration rc2 re6 re5 rg4 rh7 rh6 all pic18f6xj5x devices: compatible ccp 00xx 11xx eccp1 re6 re5 rg4/ccp5 n/a n/a dual pwm 10xx 11xx p1a p1b re5 rg4/ccp5 n/a n/a quad pwm (1) x1xx 11xx p1a p1b p1c p1d n/a n/a pic18f8xj5x devices, eccpmx = 0 , microcontroller mode: compatible ccp 00xx 11xx eccp1 re6/ad14 re5/ad13 rg4/ccp5 rh7/an15 rh6/an14 dual pwm 10xx 11xx p1a re6/ad14 re5/ad13 rg4/ccp5 p1b rh6/an14 quad pwm (1) x1xx 11xx p1a re6/ad14 re5/ad13 p1d p1b p1c pic18f8xj5x devices, eccpmx = 1 , extended microcontroller mode, 16-bit or 20-bit address width: compatible ccp 00xx 11xx eccp1 re6/ad14 re5/ad13 rg4/ccp5 rh7/an15 rh6/an14 pic18f8xj5x devices, eccpmx = 1 , microcontroller mode or extended microc ontroller mode, 12-bit address width: compatible ccp 00xx 11xx eccp1 re6/ad14 re5/ad13 rg4/ccp5 rh7/an15 rh6/an14 dual pwm 10xx 11xx p1a p1b re5/ad13 rg4/ccp5 rh7/an15 rh6/an14 quad pwm (1) x1xx 11xx p1a p1b p1c p1d rh7/an15 rh6/an14 legend: x = don?t care, n/a = not available. shaded cells indicate pin assignments not used by eccp1 in a given mode. note 1: with eccp1 in quad pwm mode, ccp5?s output is ove rridden by p1d; otherwise, ccp5 is fully operational. eccp mode ccp2con configuration rb3 rc1 re7 re2 re1 re0 all devices, ccp2mx = 1 , either operating mode: compatible ccp 00xx 11xx rb3/int3 eccp2 re7 re2 re1 re0 dual pwm 10xx 11xx rb3/int3 p2a re7 p2b re1 re0 quad pwm x1xx 11xx rb3/int3 p2a re7 p2b p2c p2d all devices, ccp2mx = 0 , microcontroller mode: compatible ccp 00xx 11xx rb3/int3 rc1/t1os1 eccp2 re2 re1 re0 dual pwm 10xx 11xx rb3/int3 rc1/t1os1 p2a p2b re1 re0 quad pwm x1xx 11xx rb3/int3 rc1/t1os1 p2a p2b p2c p2d pic18f8xj5x devices, ccp2mx = 0 , extended microcontroller mode: compatible ccp 00xx 11xx eccp2 rc1/t1os1 re7/ad15 re2/cs re1/wr re0/rd dual pwm 10xx 11xx p2a rc1/t1os1 re7/ad15 p2b re1/wr re0/rd quad pwm x1xx 11xx p2a rc1/t1os1 re7/ad15 p2b p2c p2d legend: x = don?t care. shaded cells indicate pin assignments not used by eccp2 in a given mode.
pic18f87j50 family ds39775b-page 218 preliminary ? 2007 microchip technology inc. table 18-3: pin config urations for eccp3 18.2 capture and compare modes except for the operation of the special event trigger discussed below, the capture and compare modes of the eccp module are identical in operation to that of ccp4. these are discussed in detail in section 17.2 ?capture mode? and section 17.3 ?compare mode? . 18.2.1 special event trigger eccp1 and eccp2 incorporate an internal hardware trigger that is generated in compare mode on a match between the ccprx register pair and the selected timer. this can be used in turn to initiate an action. this mode is selected by setting ccpxcon<3:0> to ? 1011 ?. the special event trigger output of either eccp1 or eccp2 resets the tmr1 or tmr3 register pair, depend- ing on which timer resource is currently selected. this allows the ccprx register pair to effectively be a 16-bit programmable period register for timer1 or timer3. in addition, the eccp2 special event trigger will also start an a/d conversion if the a/d module is enabled. special event triggers are not implemented for eccp3, ccp4 or ccp5. selecting the special event trigger mode for these modules has the same effect as selecting the compare with software interrupt mode (ccpxm3:ccpxm0 = 1010 ). 18.3 standard pwm mode when configured in single output mode, the eccp module functions identically to the standard ccp module in pwm mode, as described in section 17.4 ?pwm mode? . this is also sometimes referred to as ?compatible ccp? mode as in tables 18-1 through 18-3. eccp mode ccp3con configuration rg0 re4 re3 rg3 rh5 rh4 pic18f6xj5x devices: compatible ccp 00xx 11xx eccp3 re4 re3 rg3/ccp4 n/a n/a dual pwm 10xx 11xx p3a p3b re3 rg3/ccp4 n/a n/a quad pwm (1) x1xx 11xx p3a p3b p3c p3d n/a n/a pic18f8xj5x devices, eccpmx = 0 , microcontroller mode: compatible ccp 00xx 11xx eccp3 re6/ad14 re5/ad13 rg3/ccp4 rh7/an15 rh6/an14 dual pwm 10xx 11xx p3a re6/ad14 re5/ad13 rg3/ccp4 p3b rh6/an14 quad pwm (1) x1xx 11xx p3a re6/ad14 re5/ad13 p3d p3b p3c pic18f8xj5x devices, eccpmx = 1 , extended microcontroller mode, 16-bit or 20-bit address width: compatible ccp 00xx 11xx eccp3 re6/ad14 re5/ad13 rg3/ccp4 rh7/an15 rh6/an14 pic18f8xj5x devices, eccpmx = 1 , microcontroller mode or extended microc ontroller mode, 12-bit address width: compatible ccp 00xx 11xx eccp3 re4/ad12 re3/ad11 rg3/ccp4 rh5/an13 rh4/an12 dual pwm 10xx 11xx p3a p3b re3/ad11 rg3/ccp4 rh5/an13 rh4/an12 quad pwm (1) x1xx 11xx p3a p3b p3c p3d rh5/an13 rh4/an12 legend: x = don?t care, n/a = not available. shaded cells indicate pin assignments not used by eccp3 in a given mode. note 1: with eccp3 in quad pwm mode, ccp4?s output is ove rridden by p1d; otherwise, ccp4 is fully operational. note: the special event trigger from eccp2 will not set the timer1 or timer3 interrupt flag bits. note: when setting up single output pwm operations, users are free to use either of the processes described in section 17.4.3 ?setup for pwm operation? or section 18.4.9 ?setup for pwm opera- tion? . the latter is more generic but will work for either single or multi-output pwm.
? 2007 microchip technology inc. preliminary ds39775b-page 219 pic18f87j50 family 18.4 enhanced pwm mode the enhanced pwm mode provides additional pwm output options for a broader range of control applica- tions. the module is a backward compatible version of the standard ccp module and offers up to four outputs, designated pxa through pxd. users are also able to select the polarity of the signal (either active-high or active-low). the module?s output mode and polarity are configured by setting the pxm1:pxm0 and ccpxm3ccpxm0 bits of the ccpxcon register (ccpxcon<7:6> and ccpxcon<3:0>, respectively). for the sake of clarity, enhanced pwm mode operation is described generically throughout this section with respect to the eccp1 and tmr2 modules. control reg- ister names are presented in terms of eccp1. all three enhanced modules, as well as the two timer resources, can be used interchangeably and function identically. tmr2 or tmr4 can be selected for pwm operation by selecting the proper bits in t3con. figure 18-1 shows a simplified block diagram of pwm operation. all control registers are double-buffered and are loaded at the beginning of a new pwm cycle (the period boundary when timer2 resets) in order to prevent glitches on any of the outputs. the exception is the eccpx pwm delay register, eccpxdel, which is loaded at either the duty cycle boundary or the bound- ary period (whichever comes first). because of the buffering, the module waits until the assigned timer resets instead of starting immediately. this means that enhanced pwm waveforms do not exactly match the standard pwm waveforms, but are instead offset by one full instruction cycle (4 t osc ). as before, the user must manually configure the appropriate tris bits for output. 18.4.1 pwm period the pwm period is specified by writing to the pr2 register. the pwm period can be calculated using the equation: equation 18-1: pwm frequency is defined as 1/[pwm period]. when tmr2 is equal to pr2, the following three events occur on the next increment cycle: ?tmr2 is cleared ? the eccp1 pin is set (if pwm duty cycle = 0%, the eccp1 pin will not be set) ? the pwm duty cycle is copied from ccpr1l into ccpr1h figure 18-1: simplified block diagram of the enhanced pwm module note: the timer2 postscaler (see section 14.0 ?timer2 module? ) is not used in the determination of the pwm frequency. the postscaler could be used to have a servo update rate at a different frequency than the pwm output. pwm period = [(pr2) + 1] ? 4 ? t osc ? (tmr2 prescale value) ccpr1l ccpr1h (slave) comparator tmr2 comparator pr2 (note 1) rq s duty cycle registers ccp1con<5:4> clear timer, set eccp1 pin and latch d.c. note: the 8-bit tmr2 register is concatenated with the 2-bit internal q clock, or 2 bits of the prescaler, to create the 10-bit time base. trisx eccp1/p1a trisx p1b trisx trisx p1d output controller p1m1<1:0> 2 ccp1m<3:0> 4 eccp1del eccp1/p1a p1b p1c p1d p1c
pic18f87j50 family ds39775b-page 220 preliminary ? 2007 microchip technology inc. 18.4.2 pwm duty cycle the pwm duty cycle is specified by writing to the ccpr1l register and to the ccp1con<5:4> bits. up to 10-bit resolution is available. the ccpr1l contains the eight msbs and the ccp1con<5:4> contains the two lsbs. this 10-bit value is represented by ccpr1l:ccp1con<5:4>. the pwm duty cycle is calculated by the following equation: equation 18-2: ccpr1l and ccp1con<5:4> can be written to at any time but the duty cycle value is not copied into ccpr1h until a match between pr2 and tmr2 occurs (i.e., the period is complete). in pwm mode, ccpr1h is a read-only register. the ccpr1h register and a 2-bit internal latch are used to double-buffer the pwm duty cycle. this double-buffering is essential for glitchless pwm opera- tion. when the ccpr1h and 2-bit latch match tmr2, concatenated with an internal 2-bit q clock or two bits of the tmr2 prescaler, the eccp1 pin is cleared. the maximum pwm resolution (bits) for a given pwm frequency is given by the equation: equation 18-3: 18.4.3 pwm output configurations the p1m1:p1m0 bits in the ccp1con register allow one of four configurations: ? single output ? half-bridge output ? full-bridge output, forward mode ? full-bridge output, reverse mode the single output mode is the standard pwm mode discussed in section 18.4 ?enhanced pwm mode? . the half-bridge and full-bridge output modes are covered in detail in the sections that follow. the general relationship of the outputs in all configurations is summarized in figure 18-2. table 18-4: example pwm frequencies and resolutions at 40 mhz pwm duty cycle = (ccpr1l:ccp1con<5:4>) ? t osc ? (tmr2 prescale value) ( ) pwm resolution (max) = f osc f pwm log log(2) bits note: if the pwm duty cycle value is longer than the pwm period, the eccp1 pin will not be cleared. pwm frequency 2.44 khz 9.77 khz 39.06 khz 156.25 khz 312.50 khz 416.67 khz timer prescaler (1, 4, 16)1641111 pr2 value ffh ffh ffh 3fh 1fh 17h maximum resolution (bits) 10 10 10 8 7 6.58
? 2007 microchip technology inc. preliminary ds39775b-page 221 pic18f87j50 family figure 18-2: pwm output relationships (active-high state) figure 18-3: pwm output relationships (active-low state) 0 period 00 10 01 11 signal pr2 + 1 ccp1con<7:6> p1a modulated p1a modulated p1b modulated p1a active p1b inactive p1c inactive p1d modulated p1a inactive p1b modulated p1c active p1d inactive duty cycle (single output) (half-bridge) (full-bridge, forward) (full-bridge, reverse) delay (1) delay (1) 0 period 00 10 01 11 signal pr2 + 1 ccp1con<7:6> duty cycle (single output) (half-bridge) (full-bridge, forward) (full-bridge, reverse) delay (1) delay (1) relationships: ? period = 4 * t osc * (pr2 + 1) * (tmr2 prescale value) ? duty cycle = t osc * (ccpr1l<7:0>:ccp1con<5:4>) * (tmr2 prescale value) ? delay = 4 * t osc * (eccp1del<6:0>) note 1: dead-band delay is programmed using the eccp1del register ( section 18.4.6 ?programmable dead-band delay? ). p1a modulated p1a modulated p1b modulated p1a active p1b inactive p1c inactive p1d modulated p1a inactive p1b modulated p1c active p1d inactive
pic18f87j50 family ds39775b-page 222 preliminary ? 2007 microchip technology inc. 18.4.4 half-bridge mode in the half-bridge output mode, two pins are used as outputs to drive push-pull loads. the pwm output signal is output on the p1a pin, while the complemen- tary pwm output signal is output on the p1b pin (figure 18-4). this mode can be used for half-bridge applications, as shown in figure 18-5, or for full-bridge applications, where four power switches are being modulated with two pwm signals. in half-bridge output mode, the programmable dead-band delay can be used to prevent shoot-through current in half-bridge power devices. the value of bits p1dc6:p1dc0 sets the number of instruction cycles before the output is driven active. if the value is greater than the duty cycle, the corresponding output remains inactive during the entire cycle. see section 18.4.6 ?programmable dead-band delay? for more details on dead-band delay operations. since the p1a and p1b outputs are multiplexed with the portc<2> and porte<6> data latches, the trisc<2> and trise<6> bits must be cleared to configure p1a and p1b as outputs. figure 18-4: half-bridge pwm output figure 18-5: examples of half-bri dge output mode applications period duty cycle td td (1) p1a (2) p1b (2) td = dead band delay period (1) (1) note 1: at this time, the tmr2 register is equal to the pr2 register. 2: output signals are shown as active-high. pic18f87j50 p1a p1b fet driver fet driver v+ v- load + v - + v - fet driver fet driver v+ v- load fet driver fet driver pic18f87j50 p1a p1b standard half-bridge circuit (?push-pull?) half-bridge output driving a full-bridge circuit
? 2007 microchip technology inc. preliminary ds39775b-page 223 pic18f87j50 family 18.4.5 full-bridge mode in full-bridge output mode, four pins are used as outputs; however, only two outputs are active at a time. in the forward mode, pin p1a is continuously active and pin p1d is modulated. in the reverse mode, pin p1c is continuously active and pin p1b is modulated. these are illustrated in figure 18-6. p1a, p1b, p1c and p1d outputs are multiplexed with the port pins as described in table 18-1, table 18-2 and table 18-3. the corresponding tris bits must be cleared to make the p1a, p1b, p1c and p1d pins outputs. figure 18-6: full-bridge pwm output period duty cycle p1a (2) p1b (2) p1c (2) p1d (2) forward mode (1) period duty cycle p1a (2) p1c (2) p1d (2) p1b (2) reverse mode (1) (1) (1) note 1: at this time, the tmr2 register is equal to the pr2 register. note 2: output signal is shown as active-high.
pic18f87j50 family ds39775b-page 224 preliminary ? 2007 microchip technology inc. figure 18-7: example of full- bridge output application 18.4.5.1 direction change in full-bridge output mode in the full-bridge output mode, the p1m1 bit in the ccp1con register allows users to control the forward/ reverse direction. when the application firmware changes this direction control bit, the module will assume the new direction on the next pwm cycle. just before the end of the current pwm period, the modulated outputs (p1b and p1d) are placed in their inactive state, while the unmodulated outputs (p1a and p1c) are switched to drive in the opposite direction. this occurs in a time interval of (4 t osc * (timer2 prescale value) before the next pwm period begins. the timer2 prescaler will be either 1, 4 or 16, depend- ing on the value of the t2ckps bits (t2con<1:0>). during the interval from the switch of the unmodulated outputs to the beginning of the next period, the modulated outputs (p1b and p1d) remain inactive. this relationship is shown in figure 18-8. note that in the full-bridge output mode, the eccp1 module does not provide any dead-band delay. in gen- eral, since only one output is modulated at all times, dead-band delay is not required. however, there is a situation where a dead-band delay might be required. this situation occurs when both of the following conditions are true: 1. the direction of the pwm output changes when the duty cycle of the output is at or near 100%. 2. the turn-off time of the power switch, including the power device and driver circuit, is greater than the turn-on time. figure 18-9 shows an example where the pwm direc- tion changes from forward to reverse at a near 100% duty cycle. at time t1, the outputs, p1a and p1d, become inactive, while output, p1c, becomes active. in this example, since the turn-off time of the power devices is longer than the turn-on time, a shoot-through current may flow through power devices, qc and qd (see figure 18-7), for the duration of ?t?. the same phenomenon will occur to power devices, qa and qb, for pwm direction change from reverse to forward. if changing pwm direction at high duty cycle is required for an application, one of the following requirements must be met: 1. reduce pwm for a pwm period before changing directions. 2. use switch drivers that can drive the switches off faster than they can drive them on. other options to prevent shoot-through current may exist. pic18f87j50 p1a p1c fet driver fet driver v+ v- load fet driver fet driver p1b p1d qa qb qd qc
? 2007 microchip technology inc. preliminary ds39775b-page 225 pic18f87j50 family figure 18-8: pwm direction change figure 18-9: pwm direction chang e at near 100% duty cycle dc period (1) signal note 1: the direction bit in the eccp1 control register (ccp1c on<7>) is written at any time during the pwm cycle. 2: when changing directions, the p1a and p1c signals switch before the end of the current pwm cycle at intervals of 4 t osc , 16 t osc or 64 t osc , depending on the timer2 prescaler value. the modulated p1b and p1d signals are inactive at this time. period (note 2) p1a (active-high) p1b (active-high) p1c (active-high) p1d (active-high) dc forward period reverse period p1a (1) t on (2) t off (3) t = t off ? t on (2,3) p1b (1) p1c (1) p1d (1) external switch d (1) potential shoot-through current (1) note 1: all signals are shown as active-high. 2: t on is the turn-on delay of power switch qc and its driver. 3: t off is the turn-off delay of power switch qd and its driver. external switch c (1) t1 dc dc
pic18f87j50 family ds39775b-page 226 preliminary ? 2007 microchip technology inc. 18.4.6 programmable dead-band delay in half-bridge applications, where all power switches are modulated at the pwm frequency at all times, the power switches normally require more time to turn off than to turn on. if both the upper and lower power switches are switched at the same time (one turned on and the other turned off), both switches may be on for a short period of time until one switch completely turns off. during this brief interval, a very high current ( shoot-through current ) may flow through both power switches, shorting the bridge supply. to avoid this potentially destructive shoot-through current from flow- ing during switching, turning on either of the power switches is normally delayed to allow the other switch to completely turn off. in the half-bridge output mode, a digitally program- mable, dead-band delay is available to avoid shoot-through current from destroying the bridge power switches. the delay occurs at the signal transition from the non-active state to the active state (see figure 18-4 for illustration). the lower seven bits of the eccp1del register (register 18-2) set the delay period in terms of microcontroller instruction cycles (t cy or 4 t osc ). 18.4.7 enhanced pwm auto-shutdown when the eccp1 is programmed for any of the enhanced pwm modes, the active output pins may be configured for auto-shutdown. auto-shutdown immedi- ately places the enhanced pwm output pins into a defined shutdown state when a shutdown event occurs. a shutdown event can be caused by either of the two comparator modules or the flt0 pin (or any combina- tion of these three sources). the comparators may be used to monitor a voltage input proportional to a current being monitored in the bridge circuit. if the voltage exceeds a threshold, the comparator switches state and triggers a shutdown. alternatively, a low-level digital sig- nal on the flt0 pin can also trigger a shutdown. the auto-shutdown feature can be disabled by not selecting any auto-shutdown sources. the auto-shutdown sources to be used are selected using the eccp1as2:eccp1as0 bits (eccp1as<6:4>). when a shutdown occurs, the output pins are asynchronously placed in their shutdown states, specified by the pss1ac1:pss1ac0 and pss1bd1:pss1bd0 bits (eccp1as3:eccp1as0). each pin pair (p1a/p1c and p1b/p1d) may be set to drive high, drive low or be tri-stated (not driving). the eccp1ase bit (eccp1as<7>) is also set to hold the enhanced pwm outputs in their shutdown states. the eccp1ase bit is set by hardware when a shutdown event occurs. if automatic restarts are not enabled, the eccp1ase bit is cleared by firmware when the cause of the shutdown clears. if automatic restarts are enabled, the eccp1ase bit is automati- cally cleared when the cause of the auto-shutdown has cleared. if the eccp1ase bit is set when a pwm period begins, the pwm outputs remain in their shutdown state for that entire pwm period. when the eccp1ase bit is cleared, the pwm outputs will return to normal operation at the beginning of the next pwm period. note: writing to the eccp1ase bit is disabled while a shutdown condition is active. register 18-2: eccpxdel: eccpx pwm delay register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pxrsen pxdc6 pxdc5 pxdc4 pxdc3 pxdc2 pxdc1 pxdc0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 pxrsen: pwm restart enable bit 1 = upon auto-shutdown, the eccpxase bit clears automatically once the shutdown event goes away; the pwm restarts automatically 0 = upon auto-shutdown, eccpxase must be cleared in software to restart the pwm bit 6-0 pxdc6:pxdc0: pwm delay count bits delay time, in number of f osc /4 (4 * t osc ) cycles, between the scheduled and actual time for a pwm signal to transition to active.
? 2007 microchip technology inc. preliminary ds39775b-page 227 pic18f87j50 family 18.4.7.1 auto-shutdown and automatic restart the auto-shutdown feature can be configured to allow automatic restarts of the module following a shutdown event. this is enabled by setting the p1rsen bit of the eccp1del register (eccp1del<7>). in shutdown mode with p1rsen = 1 (figure 18-10), the eccp1ase bit will remain set for as long as the cause of the shutdown continues. when the shutdown condition clears, the eccp1ase bit is cleared. if p1rsen = 0 (figure 18-11), once a shutdown condi- tion occurs, the eccp1ase bit will remain set until it is cleared by firmware. once eccp1ase is cleared, the enhanced pwm will resume at the beginning of the next pwm period. independent of the p1rsen bit setting, if the auto-shutdown source is one of the comparators, the shutdown condition is a level. the eccp1ase bit cannot be cleared as long as the cause of the shutdown persists. the auto-shutdown mode can be forced by writing a ? 1 ? to the eccp1ase bit. 18.4.8 start-up considerations when the eccp1 module is used in the pwm mode, the application hardware must use the proper external pull-up and/or pull-down resistors on the pwm output pins. when the microcontroller is released from reset, all of the i/o pins are in the high-impedance state. the external circuits must keep the power switch devices in the off state until the microcontroller drives the i/o pins with the proper signal levels, or activates the pwm output(s). register 18-3: eccpxas: eccpx auto-shutdown control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 eccpxase eccpxas2 eccpxas1 eccpxas0 pssxac1 pssxac0 pssxbd1 pssxbd0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 eccpxase: eccpx auto-shutdown event status bit 0 = eccpx outputs are operating 1 = a shutdown event has occurred; eccpx outputs are in shutdown state bit 6-4 eccpxas2:eccpxas0: eccpx auto-shutdown source select bits 000 = auto-shutdown is disabled 001 = comparator 1 output 010 = comparator 2 output 011 = either comparator 1 or 2 100 =flt0 101 = flt0 or comparator 1 110 = flt0 or comparator 2 111 = flt0 or comparator 1 or comparator 2 bit 3-2 pssxac1:pssxac0: pins a and c shutdown state control bits 00 = drive pins a and c to ? 0 ? 01 = drive pins a and c to ? 1 ? 1x = pins a and c tri-state bit 1-0 pssxbd1:pssxbd0: pins b and d shutdown state control bits 00 = drive pins b and d to ? 0 ? 01 = drive pins b and d to ? 1 ? 1x = pins b and d tri-state note: writing to the eccp1ase bit is disabled while a shutdown condition is active.
pic18f87j50 family ds39775b-page 228 preliminary ? 2007 microchip technology inc. the ccp1m1:ccp1m0 bits (ccp1con<1:0>) allow the user to choose whether the pwm output signals are active-high or active-low for each pair of pwm output pins (p1a/p1c and p1b/p1d). the pwm output polarities must be selected before the pwm pins are configured as outputs. changing the polarity configura- tion while the pwm pins are configured as outputs is not recommended since it may result in damage to the application circuits. the p1a, p1b, p1c and p1d output latches may not be in the proper states when the pwm module is initialized. enabling the pwm pins for output at the same time as the eccp1 module may cause damage to the applica- tion circuit. the eccp1 module must be enabled in the proper output mode and complete a full pwm cycle before configuring the pwm pins as outputs. the completion of a full pwm cycle is indicated by the tmr2if bit being set as the second pwm period begins. figure 18-10: pwm auto-shutdown (p1rsen = 1 , auto-restart enabled) figure 18-11: pwm auto-shutdown (p1rsen = 0 , auto-restart disabled) shutdown pwm eccp1ase bit activity event shutdown event occurs shutdown event clears pwm resumes normal pwm start of pwm period pwm period shutdown pwm eccp1ase bit activity event shutdown event occurs shutdown event clears pwm resumes normal pwm start of pwm period eccp1ase cleared by firmware pwm period
? 2007 microchip technology inc. preliminary ds39775b-page 229 pic18f87j50 family 18.4.9 setup for pwm operation the following steps should be taken when configuring the eccpx module for pwm operation: 1. configure the pwm pins pxa and pxb (and pxc and pxd, if used) as inputs by setting the corresponding tris bits. 2. set the pwm period by loading the pr2 (pr4) register. 3. configure the eccpx module for the desired pwm mode and configuration by loading the ccpxcon register with the appropriate values: ? select one of the available output configurations and direction with the pxm1:pxm0 bits. ? select the polarities of the pwm output signals with the ccpxm3:ccpxm0 bits. 4. set the pwm duty cycle by loading the ccprxl register and the ccpxcon<5:4> bits. 5. for auto-shutdown: ? disable auto-shutdown; eccpxase = 0 ? configure auto-shutdown source ? wait for run condition 6. for half-bridge output mode, set the dead-band delay by loading eccpxdel<6:0> with the appropriate value. 7. if auto-shutdown operation is required, load the eccpxas register: ? select the auto-shutdown sources using the eccpxas2:eccpxas0 bits. ? select the shutdown states of the pwm output pins using the pssxac1:pssxac0 and pssxbd1:pssxbd0 bits. ? set the eccpxase bit (eccpxas<7>). 8. if auto-restart operation is required, set the pxrsen bit (eccpxdel<7>). 9. configure and start tmrn (tmr2 or tmr4): ? clear the tmrn interrupt flag bit by clearing the tmrnif bit (pir1<1> for timer2 or pir3<3> for timer4). ? set the tmrn prescale value by loading the tnckps bits (tncon<1:0>). ? enable timer2 (or timer4) by setting the tmrnon bit (tncon<2>). 10. enable pwm outputs after a new pwm cycle has started: ? wait until tmrn overflows (tmrnif bit is set). ? enable the eccpx/pxa, pxb, pxc and/or pxd pin outputs by clearing the respective tris bits. ? clear the eccpxase bit (eccpxas<7>). 18.4.10 effects of a reset both power-on reset and subsequent resets will force all ports to input mode and the eccp registers to their reset states. this forces the enhanced ccp module to reset to a state compatible with the standard ccp module.
pic18f87j50 family ds39775b-page 230 preliminary ? 2007 microchip technology inc. table 18-5: registers associated with eccp modules and timer1 to timer4 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 rcon ipen ? cm ri to pd por bor 60 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 62 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 62 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 trisb trisb7 trisb6 trisb5 trisb4 trisb3 trisb2 trisb1 trisb0 62 trisc trisc7 trisc6 trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 62 trise trise7 trise6 trise5 trise4 trise3 trise2 trise1 trise0 62 trisg ? ? ? trisg4 trisg3 trisg2 trisg1 trisg0 62 trish (1) trish7 trish6 trish5 trish4 trish3 trish2 trish1 trish0 62 tmr1l (3) timer1 register low byte 60 tmr1h (3) timer1 register high byte 60 t1con (3) rd16 t1run t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 60 tmr2 (3) timer2 register 60 t2con ? t2outps3 t2outps2 t2outps1 t2outps0 tmr2on t2ckps1 t2ckps0 60 pr2 (3) timer2 period register 60 tmr3l timer3 register low byte 63 tmr3h timer3 register high byte 63 t3con rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on 63 tmr4 timer4 register 63 t4con ? t4outps3 t4outps2 t4outps1 t4outps0 tmr4on t4ckps1 t4ckps0 63 pr4 (3) timer4 period register 63 ccprxl (2) capture/compare/pwm register x low byte 61 ccprxh (2) capture/compare/pwm register x high byte 61, ccpxcon (2) pxm1 pxm0 dcxb1 dcxb0 ccpxm3 ccpxm2 ccpxm1 ccpxm0 61 eccpxas (2) eccpxase eccpxas2 eccpxas1 eccpxas0 pssxac1 pssxac0 pssxbd1 pssxbd0 61, 61, 61 eccpxdel (2) pxrsen pxdc6 pxdc5 pxdc4 pxdc3 pxdc2 pxdc1 pxdc0 61, 61, 61 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used during eccp operation. note 1: available on 80-pin devices only. 2: generic term for all of the identical registers of this name for all enhanced ccp modules, where ?x? identifies the individual module (eccp1, eccp2 or eccp3). bit assignments and reset values for all registers of the same generic name are identical. 3: default (legacy) sfr at this address, available when wdtcon<4> = 0 .
? 2007 microchip technology inc. preliminary ds39775b-page 231 pic18f87j50 family 19.0 master synchronous serial port (mssp) module 19.1 master ssp (mssp) module overview the master synchronous serial port (mssp) module is a serial interface, useful for communicating with other peripheral or microcontroller devices. these peripheral devices may be serial eeproms, shift registers, display drivers, a/d converters, etc. the mssp module can operate in one of two modes: ? serial peripheral interface (spi) ? inter-integrated circuit (i 2 c?) - full master mode - slave mode (with general address call) the i 2 c interface supports the following modes in hardware: ?master mode ? multi-master mode ? slave mode with 5-bit and 7-bit address masking (with address masking for both 10-bit and 7-bit addressing) all members of the pic18f87j50 family have two mssp modules, designated as mssp1 and mssp2. each module operates independently of the other. 19.2 control registers each mssp module has three associated control regis- ters. these include a status register (sspxstat) and two control registers (sspxcon1 and sspxcon2). the use of these registers and their individual configuration bits differ significantly depending on whether the mssp module is operated in spi or i 2 c mode. additional details are provided under the individual sections. 19.3 spi mode the spi mode allows 8 bits of data to be synchronously transmitted and received simultaneously. all four modes of spi are supported. to accomplish communication, typically three pins are used: ? serial data out (sdox) ? rc5/sdo1 or rd4/sdo2 ? serial data in (sdix) ? rc4/sdi1/sda1 or rd5/sdi2/sda2 ? serial clock (sckx) ? rc3/sck1/scl1 or rd6/sck2/scl2 additionally, a fourth pin may be used when in a slave mode of operation: ? slave select (ssx ) ? rf7/ss1 or rd7/ss2 figure 19-1 shows the block diagram of the mssp module when operating in spi mode. figure 19-1: msspx block diagram (spi mode) note: throughout this section, generic refer- ences to an mssp module in any of its operating modes may be interpreted as being equally applicable to mssp1 or mssp2. register names and module i/o signals use the generic designator ?x? to indicate the use of a numeral to distinguish a particular module when required. control bit names are not individuated. note: in devices with more than one mssp module, it is very important to pay close attention to sspxcon register names. ssp1con1 and ssp1con2 control different operational aspects of the same module, while ssp1con1 and ssp2con1 control the same features for two different modules. ( ) read write internal data bus sspxsr reg sspm3:sspm0 bit 0 shift clock ss x control enable edge select clock select tmr2 output t osc prescaler 4, 16, 64 2 edge select 2 4 data to txx/rxx in sspxsr tris bit 2 smp:cke sdox sspxbuf reg sdix ssx sckx note: only port i/o names are used in this diagram for the sake of brevity. refer to the text for a full list of multiplexed functions.
pic18f87j50 family ds39775b-page 232 preliminary ? 2007 microchip technology inc. 19.3.1 registers each mssp module has four registers for spi mode operation. these are: ? msspx control register 1 (sspxcon1) ? msspx status register (sspxstat) ? serial receive/transmit buffer register (sspxbuf) ? msspx shift register (sspxsr) ? not directly accessible sspxcon1 and sspxstat are the control and status registers in spi mode operation. the sspxcon1 register is readable and writable. the lower 6 bits of the sspxstat are read-only. the upper two bits of the sspxstat are read/write. sspxsr is the shift register used for shifting data in or out. sspxbuf is the buffer register to which data bytes are written to or read from. in receive operations, sspxsr and sspxbuf together create a double-buffered receiver. when sspxsr receives a complete byte, it is transferred to sspxbuf and the sspxif interrupt is set. during transmission, the sspxbuf is not double-buffered. a write to sspxbuf will write to both sspxbuf and sspxsr. register 19-1: sspxstat: msspx status register (spi mode) r/w-0 r/w-0 r-0 r-0 r-0 r-0 r-0 r-0 smp cke (1) d/a psr/w ua bf bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 smp: sample bit spi master mode: 1 = input data sampled at end of data output time 0 = input data sampled at middle of data output time spi slave mode: smp must be cleared when spi is used in slave mode. bit 6 cke: spi clock select bit (1) 1 = transmit occurs on transition from active to idle clock state 0 = transmit occurs on transition from idle to active clock state bit 5 d/a : data/address bit used in i 2 c mode only. bit 4 p: stop bit used in i 2 c mode only. this bit is cleared when the mssp module is disabled, sspen is cleared. bit 3 s: start bit used in i 2 c mode only. bit 2 r/w : read/write information bit used in i 2 c mode only. bit 1 ua: update address bit used in i 2 c mode only. bit 0 bf: buffer full status bit (receive mode only) 1 = receive complete, sspxbuf is full 0 = receive not complete, sspxbuf is empty note 1: polarity of clock state is set by the ckp bit (sspxcon1<4>).
? 2007 microchip technology inc. preliminary ds39775b-page 233 pic18f87j50 family register 19-2: sspxcon1: msspx co ntrol register 1 (spi mode) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 wcol sspov (1) sspen (2) ckp sspm3 (3) sspm2 (3) sspm1 (3) sspm0 (3) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 wcol: write collision detect bit 1 = the sspxbuf register is written while it is still transmitting the previous word (must be cleared in software) 0 = no collision bit 6 sspov: receive overflow indicator bit (1) spi slave mode: 1 = a new byte is received while the sspxbuf register is still holding the previous data. in case of over- flow, the data in sspxsr is lost. overflow can only occur in slave mode. the user must read the sspxbuf, even if only transmitting data, to avoid setting overflow (must be cleared in software). 0 = no overflow bit 5 sspen: master synchronous serial port enable bit (2) 1 = enables serial port and configures sckx, sdox, sdix and ssx as serial port pins 0 = disables serial port and configures these pins as i/o port pins bit 4 ckp: clock polarity select bit 1 = idle state for clock is a high level 0 = idle state for clock is a low level bit 3-0 sspm3:sspm0: master synchronous serial port mode select bits (3) 0101 = spi slave mode, clock = sckx pin, ssx pin control disabled, ssx can be used as i/o pin 0100 = spi slave mode, clock = sckx pin, ssx pin control enabled 0011 = spi master mode, clock = tmr2 output/2 0010 = spi master mode, clock = f osc /64 0001 = spi master mode, clock = f osc /16 0000 = spi master mode, clock = f osc /4 note 1: in master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the sspxbuf register. 2: when enabled, this pin must be properly configured as input or output. 3: bit combinations not specifically listed here are either reserved or implemented in i 2 c? mode only.
pic18f87j50 family ds39775b-page 234 preliminary ? 2007 microchip technology inc. 19.3.2 operation when initializing the spi, several options need to be specified. this is done by programming the appropriate control bits (sspxcon1<5:0> and sspxstat<7:6>). these control bits allow the following to be specified: ? master mode (sckx is the clock output) ? slave mode (sckx is the clock input) ? clock polarity (idle state of sckx) ? data input sample phase (middle or end of data output time) ? clock edge (output data on rising/falling edge of sckx) ? clock rate (master mode only) ? slave select mode (slave mode only) each mssp module consists of a transmit/receive shift register (sspxsr) and a buffer register (sspxbuf). the sspxsr shifts the data in and out of the device, msb first. the sspxbuf holds the data that was written to the sspxsr until the received data is ready. once the 8 bits of data have been received, that byte is moved to the sspxbuf register. then, the buffer full detect bit, bf (sspxstat<0>) and the interrupt flag bit, sspxif, are set. this double-buffering of the received data (sspxbuf) allows the next byte to start reception before reading the data that was just received. any write to the sspxbuf register during transmission/reception of data will be ignored and the write collision detect bit, wcol (sspxcon1<7>), will be set. user software must clear the wcol bit so that it can be determined if the following write(s) to the sspxbuf register completed successfully. when the application software is expecting to receive valid data, the sspxbuf should be read before the next byte of data to transfer is written to the sspxbuf. the buffer full bit, bf (sspxstat<0>), indicates when sspxbuf has been loaded with the received data (transmission is complete). when the sspxbuf is read, the bf bit is cleared. this data may be irrelevant if the spi is only a transmitter. generally, the mssp interrupt is used to determine when the transmission/reception has completed. if the interrupt method is not going to be used, then software polling can be done to ensure that a write collision does not occur. example 19-1 shows the loading of the sspxbuf (sspxsr) for data transmission. the sspxsr is not directly readable or writable and can only be accessed by addressing the sspxbuf register. additionally, the sspxstat register indicates the various status conditions. 19.3.3 open-drain output option the drivers for the sdox output and sckx clock pins can be optionally configured as open-drain outputs. this feature allows the voltage level on the pin to be pulled to a higher level through an external pull-up resistor, and allows the output to communicate with external circuits without the need for additional level shifters. for more information, see section 10.1.4 ?open-drain outputs? . the open-drain output option is controlled by the spi2od and spi1od bits (odcon3<1:0>. setting an spixod bit configures both sdo and sck pins for the corresponding open-drain operation. the odcon3 register shares the same address as the t1con register. the odcon3 register is accessed by setting the adshr bit in the wdtcon register (wdtcon<4>). example 19-1: loading the ssp1buf (ssp1sr) register loop btfss ssp1stat, bf ;has data been received (transmit complete)? bra loop ;no movf ssp1buf, w ;wreg reg = contents of ssp1buf movwf rxdata ;save in user ram, if data is meaningful movf txdata, w ;w reg = contents of txdata movwf ssp1buf ;new data to xmit
? 2007 microchip technology inc. preliminary ds39775b-page 235 pic18f87j50 family 19.3.4 enabling spi i/o to enable the serial port, mssp enable bit, sspen (sspxcon1<5>), must be set. to reset or reconfigure spi mode, clear the sspen bit, reinitialize the sspxcon registers and then set the sspen bit. this configures the sdix, sdox, sckx and ssx pins as serial port pins. for the pins to behave as the serial port function, some must have their data direction bits (in the tris register) appropriately programmed as follows: ? sdix is automatically controlled by the spi module ? sdox must have the trisc<5> or trisd<4> bit cleared ? sckx (master mode) must have the trisc<3> or trisd<6>bit cleared ? sckx (slave mode) must have the trisc<3> or trisd<6> bit set ? ssx must have the trisf<7> or trisd<7> bit set any serial port function that is not desired may be overridden by programming the corresponding data direction (tris) register to the opposite value. 19.3.5 typical connection figure 19-2 shows a typical connection between two microcontrollers. the master controller (processor 1) initiates the data transfer by sending the sckx signal. data is shifted out of both shift registers on their pro- grammed clock edge and latched on the opposite edge of the clock. both processors should be programmed to the same clock polarity (ckp), then both controllers would send and receive data at the same time. whether the data is meaningful (or dummy data) depends on the application software. this leads to three scenarios for data transmission: ? master sends data ? slave sends dummy data ? master sends data ? slave sends data ? master sends dummy data ? slave sends data figure 19-2: spi master/s lave connection serial input buffer (sspxbuf) shift register (sspxsr) msb lsb sdox sdix processor 1 sckx spi master sspm3:sspm0 = 00xxb serial input buffer (sspxbuf) shift register (sspxsr) lsb msb sdix sdox processor 2 sckx spi slave sspm3:sspm0 = 010xb serial clock
pic18f87j50 family ds39775b-page 236 preliminary ? 2007 microchip technology inc. 19.3.6 master mode the master can initiate the data transfer at any time because it controls the sckx. the master determines when the slave (processor 1, figure 19-2) is to broadcast data by the software protocol. in master mode, the data is transmitted/received as soon as the sspxbuf register is written to. if the spi is only going to receive, the sdox output could be dis- abled (programmed as an input). the sspxsr register will continue to shift in the signal present on the sdix pin at the programmed clock rate. as each byte is received, it will be loaded into the sspxbuf register as if a normal received byte (interrupts and status bits appropriately set). this could be useful in receiver applications as a ?line activity monitor? mode. the clock polarity is selected by appropriately programming the ckp bit (sspxcon1<4>). this then, would give waveforms for spi communication as shown in figure 19-3, figure 19-5 and figure 19-6, where the msb is transmitted first. in master mode, the spi clock rate (bit rate) is user programmable to be one of the following: ?f osc /4 (or t cy ) ?f osc /16 (or 4 ? t cy ) ?f osc /64 (or 16 ? t cy ) ? timer2 output/2 this allows a maximum data rate (at 40 mhz) of 10.00 mbps. figure 19-3 shows the waveforms for master mode. when the cke bit is set, the sdox data is valid before there is a clock edge on sckx. the change of the input sample is shown based on the state of the smp bit. the time when the sspxbuf is loaded with the received data is shown. figure 19-3: spi mode waveform (master mode) sckx (ckp = 0 sckx (ckp = 1 sckx (ckp = 0 sckx (ckp = 1 4 clock modes input sample input sample sdix bit 7 bit 0 sdox bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 bit 7 sdix sspxif (smp = 1 ) (smp = 0 ) (smp = 1 ) cke = 1 ) cke = 0 ) cke = 1 ) cke = 0 ) (smp = 0 ) write to sspxbuf sspxsr to sspxbuf sdox bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 (cke = 0 ) (cke = 1 ) next q4 cycle after q2 bit 0
? 2007 microchip technology inc. preliminary ds39775b-page 237 pic18f87j50 family 19.3.7 slave mode in slave mode, the data is transmitted and received as the external clock pulses appear on sckx. when the last bit is latched, the sspxif interrupt flag bit is set. while in slave mode, the external clock is supplied by the external clock source on the sckx pin. this exter- nal clock must meet the minimum high and low times as specified in the electrical specifications. while in sleep mode, the slave can transmit/receive data. when a byte is received, the device can be configured to wake-up from sleep. 19.3.8 slave select synchronization the ssx pin allows a synchronous slave mode. the spi must be in slave mode with the ssx pin control enabled (sspxcon1<3:0> = 04h). when the ssx pin is low, transmission and reception are enabled and the sdox pin is driven. when the ssx pin goes high, the sdox pin is no longer driven, even if in the middle of a transmitted byte and becomes a floating output. exter- nal pull-up/pull-down resistors may be desirable depending on the application. when the spi module resets, the bit counter is forced to ? 0 ?. this can be done by either forcing the ssx pin to a high level or clearing the sspen bit. to emulate two-wire communication, the sdox pin can be connected to the sdix pin. when the spi needs to operate as a receiver, the sdox pin can be configured as an input. this disables transmissions from the sdox. the sdix can always be left as an input (sdix function) since it cannot create a bus conflict. figure 19-4: slave synchroniza tion waveform note 1: when the spi is in slave mode with ssx pin control enabled (sspxcon1<3:0> = 0100 ), the spi module will reset if the ssx pin is set to v dd . 2: if the spi is used in slave mode with cke set, then the ssx pin control must be enabled. sckx (ckp = 1 sckx (ckp = 0 input sample sdix bit 7 sdox bit 7 bit 6 bit 7 sspxif interrupt (smp = 0 ) cke = 0 ) cke = 0 ) (smp = 0 ) write to sspxbuf sspxsr to sspxbuf ssx flag bit 0 bit 7 bit 0 next q4 cycle after q2
pic18f87j50 family ds39775b-page 238 preliminary ? 2007 microchip technology inc. figure 19-5: spi mode waveform (slave mode with cke = 0 ) figure 19-6: spi mode waveform (slave mode with cke = 1 ) sckx (ckp = 1 sckx (ckp = 0 input sample sdix bit 7 sdox bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 sspxif interrupt (smp = 0 ) cke = 0 ) cke = 0 ) (smp = 0 ) write to sspxbuf sspxsr to sspxbuf ssx flag optional next q4 cycle after q2 bit 0 sckx (ckp = 1 sckx (ckp = 0 input sample sdix bit 7 bit 0 sdox bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 sspxif interrupt (smp = 0 ) cke = 1 ) cke = 1 ) (smp = 0 ) write to sspxbuf sspxsr to sspxbuf ssx flag not optional next q4 cycle after q2
? 2007 microchip technology inc. preliminary ds39775b-page 239 pic18f87j50 family 19.3.9 operation in power-managed modes in spi master mode, module clocks may be operating at a different speed than when in full power mode; in the case of the sleep mode, all clocks are halted. in idle modes, a clock is provided to the peripherals. that clock can be from the primary clock source, the secondary clock (timer1 oscillator) or the intosc source. see section 2.4 ?clock sources and oscillator switching? for additional information. in most cases, the speed that the master clocks spi data is not important; however, this should be evaluated for each system. if mssp interrupts are enabled, they can wake the con- troller from sleep mode, or one of the idle modes, when the master completes sending data. if an exit from sleep or idle mode is not desired, mssp interrupts should be disabled. if the sleep mode is selected, all module clocks are halted and the transmission/reception will remain in that state until the device wakes. after the device returns to run mode, the module will resume transmitting and receiving data. in spi slave mode, the spi transmit/receive shift register operates asynchronously to the device. this allows the device to be placed in any power-managed mode and data to be shifted into the spi trans- mit/receive shift register. when all 8 bits have been received, the mssp interrupt flag bit will be set and if enabled, will wake the device. 19.3.10 effects of a reset a reset disables the mssp module and terminates the current transfer. 19.3.11 bus mode compatibility table 19-1 shows the compatibility between the standard spi modes and the states of the ckp and cke control bits. table 19-1: spi bus modes there is also an smp bit which controls when the data is sampled. 19.3.12 spi clock speed and module interactions because mssp1 and mssp2 are independent modules, they can operate simultaneously at different data rates. setting the sspm3:sspm0 bits of the sspxcon1 register determines the rate for the corresponding module. an exception is when both modules use timer2 as a time base in master mode. in this instance, any changes to the timer2 module?s operation will affect both mssp modules equally. if different bit rates are required for each module, the user should select one of the other three time base options for one of the modules. standard spi mode terminology control bits state ckp cke 0, 0 0 1 0, 1 0 0 1, 0 1 1 1, 1 1 0
pic18f87j50 family ds39775b-page 240 preliminary ? 2007 microchip technology inc. table 19-2: registers associat ed with spi operation name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 trisc trisc7 trisc6 trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 62 trisd trisd7 trisd6 trisd5 trisd4 trisd3 trisd2 trisd1 trisd0 62 trisf trisf7 trisf6 trisf5 trisf4 trisf3 trisf2 ? ?62 ssp1buf mssp1 receive buffer/transmit register 60 sspxcon1 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 60, 63 sspxstat smp cke d/a p s r/w ua bf 60, 63 ssp2buf mssp2 receive buffer/transmit register 63 odcon3 (1) ? ? ? ? ? ?spi2odspi1od60 legend: shaded cells are not used by the mssp module in spi mode. note 1: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
? 2007 microchip technology inc. preliminary ds39775b-page 241 pic18f87j50 family 19.4 i 2 c mode the mssp module in i 2 c mode fully implements all master and slave functions (including general call support), and provides interrupts on start and stop bits in hardware to determine a free bus (multi-master function). the mssp module implements the standard mode specifications, as well as 7-bit and 10-bit addressing. two pins are used for data transfer: ? serial clock (sclx) ? rc3/sck1/scl1 or rd6/sck2/scl2 ? serial data (sdax) ? rc4/sdi1/sda1 or rd5/sdi2/sda2 the user must configure these pins as inputs by setting the associated tris bits. figure 19-7: mssp x block diagram (i 2 c? mode) 19.4.1 registers the mssp module has six registers for i 2 c operation. these are: ? msspx control register 1 (sspxcon1) ? msspx control register 2 (sspxcon2) ? msspx status register (sspxstat) ? serial receive/transmit buffer register (sspxbuf) ? msspx shift register (sspxsr) ? not directly accessible ? msspx address register (sspxadd) ? msspx 7-bit address mask register (sspxmsk) sspxcon1, sspxcon2 and sspxstat are the control and status registers in i 2 c mode operation. the sspxcon1 and sspxcon2 registers are readable and writable. the lower 6 bits of the sspxstat are read-only. the upper two bits of the sspxstat are read/write. sspxsr is the shift register used for shifting data in or out. sspxbuf is the buffer register to which data bytes are written to or read from. sspxadd contains the slave device address when the mssp is configured in i 2 c slave mode. when the mssp is configured in master mode, the lower seven bits of sspxadd act as the baud rate generator reload value. sspxmsk holds the slave address mask value when the module is configured for 7-bit address masking mode. while it is a separate register, it shares the same sfr address as sspxadd; it is only accessible when the sspm3:sspm0 bits are specifically set to permit access. additional details are provided in section 19.4.3.4 ?7-bit address masking mode? . in receive operations, sspxsr and sspxbuf together, create a double-buffered receiver. when sspxsr receives a complete byte, it is transferred to sspxbuf and the sspxif interrupt is set. during transmission, the sspxbuf is not double-buffered. a write to sspxbuf will write to both sspxbuf and sspxsr. read write sspxsr reg match detect sspxadd reg sspxbuf reg internal data bus addr match set, reset s, p bits (sspxstat reg) shift clock msb lsb note: only port i/o names are used in this diagram for the sake of brevity. refer to the text for a full list of multiplexed functions. sclx sdax start and stop bit detect address mask
pic18f87j50 family ds39775b-page 242 preliminary ? 2007 microchip technology inc. register 19-3: sspxstat: msspx status register (i 2 c? mode) r/w-0 r/w-0 r-0 r-0 r-0 r-0 r-0 r-0 smp cke d/a p (1) s (1) r/w (2,3) ua bf bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 smp: slew rate control bit in master or slave mode: 1 = slew rate control disabled for standard speed mode (100 khz and 1 mhz) 0 = slew rate control enabled for high-speed mode (400 khz) bit 6 cke: smbus select bit in master or slave mode: 1 = enable smbus specific inputs 0 = disable smbus specific inputs bit 5 d/a : data/address bit in master mode: reserved. in slave mode: 1 = indicates that the last byte received or transmitted was data 0 = indicates that the last byte received or transmitted was address bit 4 p: stop bit (1) 1 = indicates that a stop bit has been detected last 0 = stop bit was not detected last bit 3 s: start bit (1) 1 = indicates that a start bit has been detected last 0 = start bit was not detected last bit 2 r/w : read/write information bit (2,3) in slave mode: 1 = read 0 = write in master mode: 1 = transmit is in progress 0 = transmit is not in progress bit 1 ua: update address bit (10-bit slave mode only) 1 = indicates that the user needs to update the address in the sspxadd register 0 = address does not need to be updated bit 0 bf: buffer full status bit in transmit mode: 1 = sspxbuf is full 0 = sspxbuf is empty in receive mode: 1 = sspxbuf is full (does not include the ack and stop bits) 0 = sspxbuf is empty (does not include the ack and stop bits) note 1: this bit is cleared on reset and when sspen is cleared. 2: this bit holds the r/w bit information following the last address match. this bit is only valid from the address match to the next start bit, stop bit or not ack bit. 3: oring this bit with sen, rsen, pen, rcen or acken will indicate if the mssp is in active mode.
? 2007 microchip technology inc. preliminary ds39775b-page 243 pic18f87j50 family register 19-4: sspxcon1: msspx control register 1 (i 2 c? mode) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 wcol sspov sspen (1) ckp sspm3 (2) sspm2 (2) sspm1 (2) sspm0 (2) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 wcol: write collision detect bit in master transmit mode: 1 = a write to the sspxbuf register was attempted while the i 2 c conditions were not valid for a transmission to be started (must be cleared in software) 0 = no collision in slave transmit mode: 1 = the sspxbuf register is written while it is still transmitting the previous word (must be cleared in software) 0 = no collision in receive mode (master or slave modes): this is a ?don?t care? bit. bit 6 sspov: receive overflow indicator bit in receive mode: 1 = a byte is received while the sspxbuf register is still holding the previous byte (must be cleared in software) 0 = no overflow in transmit mode: this is a ?don?t care? bit in transmit mode. bit 5 sspen: master synchronous serial port enable bit (1) 1 = enables the serial port and configures the sdax and sclx pins as the serial port pins 0 = disables serial port and configures these pins as i/o port pins bit 4 ckp: sckx release control bit in slave mode: 1 = releases clock 0 = holds clock low (clock stretch), used to ensure data setup time in master mode: unused in this mode. bit 3-0 sspm3:sspm0: master synchronous serial port mode select bits (2) 1111 = i 2 c slave mode, 10-bit address with start and stop bit interrupts enabled 1110 = i 2 c slave mode, 7-bit address with start and stop bit interrupts enabled 1011 = i 2 c firmware controlled master mode (slave idle) 1001 = load sspmsk register at sspadd sfr address (3,4) 1000 = i 2 c master mode, clock = f osc /(4 * (sspxadd + 1)) 0111 = i 2 c slave mode, 10-bit address 0110 = i 2 c slave mode, 7-bit address note 1: when enabled, the sdax and sclx pins must be configured as inputs. 2: bit combinations not specifically listed here are either reserved or implemented in spi mode only. 3: when sspm3:sspm0 = 1001 , any reads or writes to the sspxadd sfr address actually accesses the sspmsk register. 4: this mode is only available when 7-bit address masking mode is selected (msspmsk configuration bit is ? 1 ?).
pic18f87j50 family ds39775b-page 244 preliminary ? 2007 microchip technology inc. register 19-5: sspxcon2: msspx control register 2 (i 2 c? master mode) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 gcen ackstat ackdt (1) acken (2) rcen (2) pen (2) rsen (2) sen (2) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 gcen: general call enable bit (slave mode only) 1 = enable interrupt when a general call address (0000h) is received in the sspxsr 0 = general call address disabled bit 6 ackstat: acknowledge status bit (master transmit mode only) 1 = acknowledge was not received from slave 0 = acknowledge was received from slave bit 5 ackdt: acknowledge data bit (master receive mode only) (1) 1 = not acknowledge 0 = acknowledge bit 4 acken: acknowledge sequence enable bit (2) 1 = initiates acknowledge sequence on sdax and sclx pins and transmit ackdt data bit. automatically cleared by hardware. 0 = acknowledge sequence idle bit 3 rcen: receive enable bit (master receive mode only) (2) 1 = enables receive mode for i 2 c 0 = receive idle bit 2 pen: stop condition enable bit (2) 1 = initiates stop condition on sdax and sclx pins. automatically cleared by hardware. 0 = stop condition idle bit 1 rsen: repeated start condition enable bit (2) 1 = initiates repeated start condition on sdax and sclx pins. automatically cleared by hardware. 0 = repeated start condition idle bit 0 sen: start condition enable bit (2) 1 = initiates start condition on sdax and sclx pins. automatically cleared by hardware. 0 = start condition idle note 1: value that will be transmitted when the user initiates an acknowledge sequence at the end of a receive. 2: if the i 2 c module is active, these bits may not be set (no spooling) and the sspxbuf may not be written (or writes to the sspxbuf are disabled).
? 2007 microchip technology inc. preliminary ds39775b-page 245 pic18f87j50 family register 19-7: sspxmsk: i 2 c? slave address mask register (7-bit masking mode) (1) register 19-6: sspxcon2: msspx control register 2 (i 2 c? slave mode) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 gcen ackstat admsk5 admsk4 admsk3 admsk2 admsk1 sen bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 gcen: general call enable bit (slave mode only) 1 = enables interrupt when a general call address (0000h) is received in the sspxsr 0 = general call address disabled bit 6 ackstat: acknowledge status bit unused in slave mode. bit 5-2 admsk5:admsk2: slave address mask select bits (5-bit address masking) 1 = masking of corresponding bits of sspxadd enabled 0 = masking of corresponding bits of sspxadd disabled bit 1 admsk1: slave address least significant bit(s) mask select bit in 7-bit address ing mode: 1 = masking of sspxadd<1> only enabled 0 = masking of sspxadd<1> only disabled in 10-bit address ing mode: 1 = masking of sspxadd<1:0> enabled 0 = masking of sspxadd<1:0> disabled bit 0 sen: start condition enable/stretch enable bit (1) 1 = clock stretching is enabled for both slave transmit and slave receive (stretch enabled) 0 = clock stretching is disabled note 1: if the i 2 c module is active, these bits may not be set (no spooling) and the sspxbuf may not be written (or writes to the sspxbuf are disabled). r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 msk7 msk6 msk5 msk4 msk3 msk2 msk1 msk0 (2) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-0 msk7:msk0: slave address mask select bit 1 = masking of corresponding bit of sspxadd enabled 0 = masking of corresponding bit of sspxadd disabled note 1: this register shares the same sfr address as sspxadd, and is only addressable in select mssp operating modes. see section 19.4.3.4 ?7-bit address masking mode? for more details. 2: msk0 is not used as a mask bit in 7-bit addressing.
pic18f87j50 family ds39775b-page 246 preliminary ? 2007 microchip technology inc. 19.4.2 operation the mssp module functions are enabled by setting the mssp enable bit, sspen (sspxcon1<5>). the sspxcon1 register allows control of the i 2 c operation. four mode selection bits (sspxcon1<3:0>) allow one of the following i 2 c modes to be selected: ?i 2 c master mode, clock ?i 2 c slave mode (7-bit address) ?i 2 c slave mode (10-bit address) ?i 2 c slave mode (7-bit address) with start and stop bit interrupts enabled ?i 2 c slave mode (10-bit address) with start and stop bit interrupts enabled ?i 2 c firmware controlled master mode, slave is idle selection of any i 2 c mode with the sspen bit set forces the sclx and sdax pins to be open-drain, provided these pins are programmed as inputs by setting the appropriate trisc or trisd bits. to ensure proper operation of the module, pull-up resistors must be provided externally to the sclx and sdax pins. 19.4.3 slave mode in slave mode, the sclx and sdax pins must be configured as inputs (trisc<4:3> set). the mssp module will override the input state with the output data when required (slave-transmitter). the i 2 c slave mode hardware will always generate an interrupt on an address match. address masking will allow the hardware to generate an interrupt for more than one address (up to 31 in 7-bit addressing and up to 63 in 10-bit addressing). through the mode select bits, the user can also choose to interrupt on start and stop bits. when an address is matched, or the data transfer after an address match is received, the hardware auto- matically will generate the acknowledge (ack ) pulse and load the sspxbuf register with the received value currently in the sspxsr register. any combination of the following conditions will cause the mssp module not to give this ack pulse: ? the buffer full bit, bf (sspxstat<0>), was set before the transfer was received. ? the overflow bit, sspov (sspxcon1<6>), was set before the transfer was received. in this case, the sspxsr register value is not loaded into the sspxbuf, but bit sspxif is set. the bf bit is cleared by reading the sspxbuf register, while bit sspov is cleared through software. the sclx clock input must have a minimum high and low for proper operation. the high and low times of the i 2 c specification, as well as the requirement of the mssp module, are shown in timing parameter 100 and parameter 101. 19.4.3.1 addressing once the mssp module has been enabled, it waits for a start condition to occur. following the start condition, the 8 bits are shifted into the sspxsr register. all incoming bits are sampled with the rising edge of the clock (sclx) line. the value of register, sspxsr<7:1>, is compared to the value of the sspxadd register. the address is compared on the falling edge of the eighth clock (sclx) pulse. if the addresses match and the bf and sspov bits are clear, the following events occur: 1. the sspxsr register value is loaded into the sspxbuf register. 2. the buffer full bit, bf, is set. 3. an ack pulse is generated. 4. the mssp interrupt flag bit, sspxif, is set (and interrupt is generated, if enabled) on the falling edge of the ninth sclx pulse. in 10-bit addressing mode, two address bytes need to be received by the slave. the five most significant bits (msbs) of the first address byte specify if this is a 10-bit address. bit r/w (sspxstat<2>) must specify a write so the slave device will receive the second address byte. for a 10-bit address, the first byte would equal ? 11110 a9 a8 0 ?, where ? a9 ? and ? a8 ? are the two msbs of the address. the sequence of events for 10-bit addressing is as follows, with steps 7 through 9 for the slave-transmitter: 1. receive first (high) byte of address (bits sspxif, bf and ua are set on address match). 2. update the sspxadd register with second (low) byte of address (clears bit ua and releases the sclx line). 3. read the sspxbuf register (clears bit, bf) and clear flag bit, sspxif. 4. receive second (low) byte of address (bits sspxif, bf and ua are set). 5. update the sspxadd register with the first (high) byte of address. if match releases sclx line, this will clear bit ua. 6. read the sspxbuf register (clears bit bf) and clear flag bit sspxif. 7. receive repeated start condition. 8. receive first (high) byte of address (bits sspxif and bf are set). 9. read the sspxbuf register (clears bit bf) and clear flag bit, sspxif.
? 2007 microchip technology inc. preliminary ds39775b-page 247 pic18f87j50 family 19.4.3.2 address masking modes masking an address bit causes that bit to become a ?don't care?. when one address bit is masked, two addresses will be acknowledged and cause an interrupt. it is possible to mask more than one address bit at a time, which greatly expands the number of addresses acknowledged. the i 2 c slave behaves the same way whether address masking is used or not. however, when address masking is used, the i 2 c slave can acknowledge multiple addresses and cause interrupts. when this occurs, it is necessary to determine which address caused the interrupt by checking sspxbuf. the pic18f87j50 family of devices is capable of using two different address masking modes in i 2 c slave operation: 5-bit address masking and 7-bit address masking. the masking mode is selected at device configuration using the msspmsk configuration bit. the default device configuration is 7-bit address masking. both masking modes, in turn, support address masking of 7-bit and 10-bit addresses. the combination of masking modes and addresses provide different ranges of acknowledgable addresses for each combination. while both masking modes function in roughly the same manner, the way they use address masks are different. 19.4.3.3 5-bit address masking mode as the name implies, 5-bit address masking mode uses an address mask of up to 5 bits to create a range of addresses to be acknowledged, using bits 5 through 1 of the incoming address. this allows the module to acknowledge up to 31 addresses when using 7-bit addressing, or 63 addresses with 10-bit addressing (see example 19-2). this masking mode is selected when the msspmsk configuration bit is programmed (? 0 ?). the address mask in this mode is stored is stored in the sspxcon2 register, which stops functioning as a control register in i 2 c slave mode (register 19-6). in 7-bit address masking mode, address mask bits, admsk<5:1> (sspxcon2<5:1>), mask the corresponding address bits in the sspxadd register. for any admsk bits that are set (admsk = 1 ), the corresponding address bit is ignored (sspxadd = x ). for the module to issue an address acknowledge, it is sufficient to match only on addresses that do not have an active address mask. in 10-bit address masking mode, bits admsk<5:2> mask the corresponding address bits in the sspxadd register. in addition, admsk1 simultaneously masks the two lsbs of the address (sspxadd<1:0>). for any admsk bits that are active (admsk = 1 ), the cor- responding address bit is ignored (spxadd = x ). also note that although in 10-bit address masking mode, the upper address bits reuse part of the sspxadd register bits. the address mask bits do not interact with those bits; they only affect the lower address bits. example 19-2: address masking examples in 5-bit masking mode note 1: admsk1 masks the two least significant bits of the address. 2: the two most significant bits of the address are not affected by address masking. 7-bit addressing: sspadd<7:1>= a0h ( 1010000 ) (sspadd<0> is assumed to be 0) admsk<5:1> = 00111 addresses acknowledged: a0h, a2h, a4h, a6h, a8h, aah, ach, aeh 10-bit addressing: sspadd<7:0> = a0h ( 10100000 ) (the two msb of the address are ignored in this example, since they are not affected by masking) admsk<5:1> = 00111 addresses acknowledged: a0h, a1h, a2h, a3h, a4h, a5h, a6h, a7h, a8h, a9h, aah, abh, ach, adh, aeh, afh
pic18f87j50 family ds39775b-page 248 preliminary ? 2007 microchip technology inc. 19.4.3.4 7-bit address masking mode unlike 5-bit address masking mode, 7-bit address masking mode uses a mask of up to 8 bits (in 10-bit addressing) to define a range of addresses than can be acknowledged, using the lowest bits of the incoming address. this allows the module to acknowledge up to 127 different addresses with 7-bit addressing, or 255 with 10-bit addressing (see example 19-3). this mode is the default configuration of the module, and is selected when msspmsk is unprogrammed (? 1 ?). the address mask for 7-bit address masking mode is stored in the sspxmsk register, instead of the sspxcon2 register. sspxmsk is a separate hard- ware register within the module, but it is not directly addressable. instead, it shares an address in the sfr space with the sspxadd register. to access the sspxmsk register, it is necessary to select mssp mode, ? 1001 ? (sspcon1<3:0> = 1001 ), and then read or write to the location of sspxadd. to use 7-bit address masking mode, it is necessary to initialize sspxmsk with a value before selecting the i 2 c slave addressing mode. thus, the required sequence of events is: 1. select sspxmsk access mode (sspxcon2<3:0> = 1001 ). 2. write the mask value to the appropriate sspadd register address (fc8h for mssp1, f6eh for mssp2). 3. set the appropriate i 2 c slave mode (sspxcon2<3:0> = 0111 for 10-bit addressing, 0110 for 7-bit addressing). setting or clearing mask bits in sspxmsk behaves in the opposite manner of the admsk bits in 5-bit address masking mode. that is, clearing a bit in sspxmsk causes the corresponding address bit to be masked; setting the bit requires a match in that position. sspxmsk resets to all ? 1 ?s upon any reset condition and, therefore, has no effect on the standard mssp operation until written with a mask value. with 7-bit address masking mode, sspxmsk<7:1> bits mask the corresponding address bits in the sspxadd register. for any sspxmsk bits that are active (sspxmsk = 0 ), the corresponding sspxadd address bit is ignored (sspxadd = x ). for the module to issue an address acknowledge, it is sufficient to match only on addresses that do not have an active address mask. with 10-bit address masking mode, sspxmsk<7:0> bits mask the corresponding address bits in the sspxadd register. for any sspxmsk bits that are active (= 0 ), the corresponding sspxadd address bit is ignored (sspxadd = x ). example 19-3: address masking examples in 7-bit masking mode note: the two most significant bits of the address are not affected by address masking. 7-bit addressing: sspxadd<7:1> = 1010 000 sspxmsk<7:1> = 1111 001 addresses acknowledged = a8h, a6h, a4h, a0h 10-bit addressing: sspxadd<7:0> = 1010 0000 (the two msb are ignored in this example since they are not affected) sspxmsk<5:1> = 1111 0 addresses acknowledged = a8h, a6h, a4h, a0h
? 2007 microchip technology inc. preliminary ds39775b-page 249 pic18f87j50 family 19.4.3.5 reception when the r/w bit of the address byte is clear and an address match occurs, the r/w bit of the sspxstat register is cleared. the received address is loaded into the sspxbuf register and the sdax line is held low (ack ). when the address byte overflow condition exists, then the no acknowledge (ack ) pulse is given. an overflow condition is defined as either bit, bf (sspxstat<0>), is set or bit, sspov (sspxcon1<6>), is set. an mssp interrupt is generated for each data transfer byte. the interrupt flag bit, sspxif, must be cleared in software. the sspxstat register is used to determine the status of the byte. if sen is enabled (sspxcon2<0> = 1 ), sclx will be held low (clock stretch) following each data transfer. the clock must be released by setting bit, ckp (sspxcon1<4>). see section 19.4.4 ?clock stretching? for more details. 19.4.3.6 transmission when the r/w bit of the incoming address byte is set and an address match occurs, the r/w bit of the sspxstat register is set. the received address is loaded into the sspxbuf register. the ack pulse will be sent on the ninth bit and pin sclx is held low regard- less of sen (see section 19.4.4 ?clock stretching? for more details). by stretching the clock, the master will be unable to assert another clock pulse until the slave is done preparing the transmit data. the transmit data must be loaded into the sspxbuf register which also loads the sspxsr register. then, pin sclx should be enabled by setting bit, ckp (sspxcon1<4>). the eight data bits are shifted out on the falling edge of the sclx input. this ensures that the sdax signal is valid during the sclx high time (figure 19-10). the ack pulse from the master-receiver is latched on the rising edge of the ninth sclx input pulse. if the sdax line is high (not ack ), then the data transfer is complete. in this case, when the ack is latched by the slave, the slave logic is reset (resets the sspxstat register) and the slave monitors for another occurrence of the start bit. if the sdax line was low (ack ), the next transmit data must be loaded into the sspxbuf register. again, pin sclx must be enabled by setting bit, ckp. an mssp interrupt is generated for each data transfer byte. the sspxif bit must be cleared in software and the sspxstat register is used to determine the status of the byte. the sspxif bit is set on the falling edge of the ninth clock pulse.
pic18f87j50 family ds39775b-page 250 preliminary ? 2007 microchip technology inc. figure 19-8: i 2 c? slave mode timing with sen = 0 (reception, 7-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) sspov (sspxcon1<6>) s 1 2 34 567 89 1 2 34 5 67 89 1 23 45 7 89 p a7 a6 a5 a4 a3 a2 a1 d7 d6 d5 d4 d3 d2 d1 d0 d7 d6 d5 d4 d3 d1 d0 ack receiving data ack receiving data r/w = 0 ack receiving address cleared in software sspxbuf is read bus master terminates transfer sspov is set because sspxbuf is still full. ack is not sent. d2 6 ckp (sspxcon1<4>) (ckp does not reset to ? 0 ? when sen = 0 )
? 2007 microchip technology inc. preliminary ds39775b-page 251 pic18f87j50 family figure 19-9: i 2 c? slave mode timing with sen = 0 and admsk<5:1> = 01011 (reception, 7-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) sspov (sspxcon1<6>) s 12345678912345678912345 789 p a7 a6 a5 x a3 x x d7d6d5d4d3d2d1 d0 d7d6d5d4d3 d1d0 ack receiving data ack receiving data r/w = 0 ack receiving address cleared in software sspxbuf is read bus master terminates transfer sspov is set because sspxbuf is still full. ack is not sent. d2 6 ckp (sspxcon1<4>) (ckp does not reset to ? 0 ? when sen = 0 ) note 1: x = don?t care (i.e., address bit can either be a ? 1 ? or a ? 0 ?). 2: in this example, an address equal to a7.a6.a5.x.a3.x.x will be acknowledged and cause an interrupt.
pic18f87j50 family ds39775b-page 252 preliminary ? 2007 microchip technology inc. figure 19-10: i 2 c? slave mode timing (transmission, 7-bit address) sdax sclx bf (sspxstat<0>) a6 a5 a4 a3 a2 a1 d6 d5 d4 d3 d2 d1 d0 1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 9 sspxbuf is written in software cleared in software data in sampled s ack transmitting data r/w = 0 ack receiving address a7 d7 9 1 d6 d5 d4 d3 d2 d1 d0 2 3 4 5 6 7 8 9 sspxbuf is written in software cleared in software from sspxif isr transmitting data d7 1 ckp (sspxcon1<4>) p ack ckp is set in software ckp is set in software sclx held low while cpu responds to sspxif sspxif (pir1<3> or pir3<7>) from sspxif isr
? 2007 microchip technology inc. preliminary ds39775b-page 253 pic18f87j50 family figure 19-11: i 2 c? slave mode timing with sen = 0 and admsk<5:1> = 01001 (reception, 10-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) s 123456789 123456789 12345 789 p 1 1 1 1 0 a9 a8 a7 a6 a5 x a3 a2 x x d7 d6 d5 d4 d3 d1 d0 receive data byte ack r/w = 0 ack receive first byte of address cleared in software d2 6 cleared in software receive second byte of address cleared by hardware when sspxadd is updated with low byte of address ua (sspxstat<1>) clock is held low until update of sspxadd has taken place ua is set indicating that the sspxadd needs to be updated ua is set indicating that sspxadd needs to be updated cleared by hardware when sspxadd is updated with high byte of address sspxbuf is written with contents of sspxsr dummy read of sspxbuf to clear bf flag ack ckp (sspxcon1<4>) 12345 789 d7 d6 d5 d4 d3 d1 d0 receive data byte bus master terminates transfer d2 6 ack cleared in software cleared in software sspov (sspxcon1<6>) sspov is set because sspxbuf is still full. ack is not sent. (ckp does not reset to ? 0 ? when sen = 0 ) clock is held low until update of sspxadd has taken place note 1: x = don?t care (i.e., address bit can either be a ? 1 ? or a ? 0 ?). 2: in this example, an address equal to a9.a8.a7.a6.a5 .x.a3.a2.x.x will be acknowl edged and cause an interrupt. 3: note that the most significant bits of the address are not affected by the bit masking.
pic18f87j50 family ds39775b-page 254 preliminary ? 2007 microchip technology inc. figure 19-12: i 2 c? slave mode timing with sen = 0 (reception, 10-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) s 123456789 123456789 12345 789 p 1 1 1 1 0 a9a8 a7 a6a5 a4a3a2a1 a0 d7 d6d5d4d3 d1d0 receive data byte ack r/w = 0 ack receive first byte of address cleared in software d2 6 cleared in software receive second byte of address cleared by hardware when sspxadd is updated with low byte of address ua (sspxstat<1>) clock is held low until update of sspxadd has taken place ua is set indicating that the sspxadd needs to be updated ua is set indicating that sspxadd needs to be updated cleared by hardware when sspxadd is updated with high byte of address sspxbuf is written with contents of sspxsr dummy read of sspxbuf to clear bf flag ack ckp (sspxcon1<4>) 12345 789 d7 d6 d5 d4 d3 d1 d0 receive data byte bus master terminates transfer d2 6 ack cleared in software cleared in software sspov (sspxcon1<6>) sspov is set because sspxbuf is still full. ack is not sent. (ckp does not reset to ? 0 ? when sen = 0 ) clock is held low until update of sspxadd has taken place
? 2007 microchip technology inc. preliminary ds39775b-page 255 pic18f87j50 family figure 19-13: i 2 c? slave mode timing (tra nsmission, 10-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) s 1234 5 6789 1 2345 678 9 12345 7 89 p 1 1 1 1 0 a9a8 a7 a6a5a4a3a2a1 a0 1 1 1 1 0 a8 r/w = 1 ack ack r/w = 0 ack receive first byte of address cleared in software bus master terminates transfer a9 6 receive second byte of address cleared by hardware when sspxadd is updated with low byte of address ua (sspxstat<1>) clock is held low until update of sspxadd has taken place ua is set indicating that the sspxadd needs to be updated ua is set indicating that sspxadd needs to be updated cleared by hardware when sspxadd is updated with high byte of address. sspxbuf is written with contents of sspxsr dummy read of sspxbuf to clear bf flag receive first byte of address 12345 789 d7 d6 d5 d4 d3 d1 ack d2 6 transmitting data byte d0 dummy read of sspxbuf to clear bf flag sr cleared in software write of sspxbuf initiates transmit cleared in software completion of clears bf flag ckp (sspxcon1<4>) ckp is set in software ckp is automatically cleared in hardware, holding sclx low clock is held low until update of sspxadd has taken place data transmission clock is held low until ckp is set to ? 1 ? third address sequence bf flag is clear at the end of the
pic18f87j50 family ds39775b-page 256 preliminary ? 2007 microchip technology inc. 19.4.4 clock stretching both 7-bit and 10-bit slave modes implement automatic clock stretching during a transmit sequence. the sen bit (sspxcon2<0>) allows clock stretching to be enabled during receives. setting sen will cause the sclx pin to be held low at the end of each data receive sequence. 19.4.4.1 clock stretching for 7-bit slave receive mode (sen = 1 ) in 7-bit slave receive mode, on the falling edge of the ninth clock at the end of the ack sequence, if the bf bit is set, the ckp bit in the sspxcon1 register is automatically cleared, forcing the sclx output to be held low. the ckp bit being cleared to ? 0 ? will assert the sclx line low. the ckp bit must be set in the user?s isr before reception is allowed to continue. by holding the sclx line low, the user has time to service the isr and read the contents of the sspxbuf before the master device can initiate another receive sequence. this will prevent buffer overruns from occurring (see figure 19-15). 19.4.4.2 clock stretching for 10-bit slave receive mode (sen = 1 ) in 10-bit slave receive mode during the address sequence, clock stretching automatically takes place but ckp is not cleared. during this time, if the ua bit is set after the ninth clock, clock stretching is initiated. the ua bit is set after receiving the upper byte of the 10-bit address and following the receive of the second byte of the 10-bit address with the r/w bit cleared to ? 0 ?. the release of the clock line occurs upon updating sspxadd. clock stretching will occur on each data receive sequence as described in 7-bit mode. 19.4.4.3 clock stretching for 7-bit slave transmit mode the 7-bit slave transmit mode implements clock stretching by clearing the ckp bit after the falling edge of the ninth clock if the bf bit is clear. this occurs regardless of the state of the sen bit. the user?s isr must set the ckp bit before transmis- sion is allowed to continue. by holding the sclx line low, the user has time to service the isr and load the contents of the sspxbuf before the master device can initiate another transmit sequence (see figure 19-10). 19.4.4.4 clock stretching for 10-bit slave transmit mode in 10-bit slave transmit mode, clock stretching is controlled during the first two address sequences by the state of the ua bit, just as it is in 10-bit slave receive mode. the first two addresses are followed by a third address sequence, which contains the high-order bits of the 10-bit address and the r/w bit set to ? 1 ?. after the third address sequence is performed, the ua bit is not set, the module is now configured in transmit mode and clock stretching is controlled by the bf flag as in 7-bit slave transmit mode (see figure 19-13). note 1: if the user reads the contents of the sspxbuf before the falling edge of the ninth clock, thus clearing the bf bit, the ckp bit will not be cleared and clock stretching will not occur. 2: the ckp bit can be set in software regardless of the state of the bf bit. the user should be careful to clear the bf bit in the isr before the next receive sequence in order to prevent an overflow condition. note: if the user polls the ua bit and clears it by updating the sspxadd register before the falling edge of the ninth clock occurs, and if the user hasn?t cleared the bf bit by reading the sspxbuf register before that time, then the ckp bit will still not be asserted low. clock stretching on the basis of the state of the bf bit only occurs during a data sequence, not an address sequence. note 1: if the user loads the contents of sspxbuf, setting the bf bit before the falling edge of the ninth clock, the ckp bit will not be cleared and clock stretching will not occur. 2: the ckp bit can be set in software regardless of the state of the bf bit.
? 2007 microchip technology inc. preliminary ds39775b-page 257 pic18f87j50 family 19.4.4.5 clock synchronization and the ckp bit when the ckp bit is cleared, the sclx output is forced to ? 0 ?. however, clearing the ckp bit will not assert the sclx output low until the sclx output is already sampled low. therefore, the ckp bit will not assert the sclx line until an external i 2 c master device has already asserted the sclx line. the sclx output will remain low until the ckp bit is set and all other devices on the i 2 c bus have deasserted sclx. this ensures that a write to the ckp bit will not violate the minimum high time requirement for sclx (see figure 19-14). figure 19-14: clock synchronization timing sdax sclx dx ? 1 dx wr q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 sspxcon1 ckp master device deasserts clock master device asserts clock
pic18f87j50 family ds39775b-page 258 preliminary ? 2007 microchip technology inc. figure 19-15: i 2 c? slave mode timing with sen = 1 (reception, 7-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) sspov (sspxcon1<6>) s 1 234 56 7 8 9 1 2345 67 89 1 23 45 7 89 p a7 a6 a5 a4 a3 a2 a1 d7 d6 d5 d4 d3 d2 d1 d0 d7 d6 d5 d4 d3 d1 d0 ack receiving data ack receiving data r/w = 0 ack receiving address cleared in software sspxbuf is read bus master terminates transfer sspov is set because sspxbuf is still full. ack is not sent. d2 6 ckp (sspxcon1<4>) ckp written to ? 1 ? in if bf is cleared prior to the falling edge of the 9th clock, ckp will not be reset to ? 0 ? and no clock stretching will occur software clock is held low until ckp is set to ? 1 ? clock is not held low because buffer full bit is clear prior to falling edge of 9th clock clock is not held low because ack = 1 bf is set after falling edge of the 9th clock, ckp is reset to ? 0 ? and clock stretching occurs
? 2007 microchip technology inc. preliminary ds39775b-page 259 pic18f87j50 family figure 19-16: i 2 c? slave mode timing with sen = 1 (reception, 10-bit address) sdax sclx sspxif (pir1<3> or pir3<7>) bf (sspxstat<0>) s 123456789 123456789 12345 789 p 1 1 1 1 0 a9a8 a7 a6a5a4a3a2a1 a0 d7d6d5d4d3 d1d0 receive data byte ack r/w = 0 ack receive first byte of address cleared in software d2 6 cleared in software receive second byte of address cleared by hardware when sspxadd is updated with low byte of address after falling edge ua (sspxstat<1>) clock is held low until update of sspxadd has taken place ua is set indicating that the sspxadd needs to be updated ua is set indicating that sspxadd needs to be updated cleared by hardware when sspxadd is updated with high byte of address after falling edge sspxbuf is written with contents of sspxsr dummy read of sspxbuf to clear bf flag ack ckp (sspxcon1<4>) 12345 789 d7 d6 d5 d4 d3 d1 d0 receive data byte bus master terminates transfer d2 6 ack cleared in software cleared in software sspov (sspxcon1<6>) ckp written to ? 1 ? note: an update of the sspxadd register before the falling edge of the ninth clock will have no effect on ua and ua will remain set. note: an update of the sspxadd register before the falling edge of the ninth clock will have no effect on ua and ua will remain set. in software clock is held low until update of sspxadd has taken place of ninth clock of ninth clock sspov is set because sspxbuf is still full. ack is not sent. dummy read of sspxbuf to clear bf flag clock is held low until ckp is set to ? 1 ? clock is not held low because ack = 1
pic18f87j50 family ds39775b-page 260 preliminary ? 2007 microchip technology inc. 19.4.5 general call address support the addressing procedure for the i 2 c bus is such that the first byte after the start condition usually determines which device will be the slave addressed by the master. the exception is the general call address which can address all devices. when this address is used, all devices should, in theory, respond with an acknowledge. the general call address is one of eight addresses reserved for specific purposes by the i 2 c protocol. it consists of all ? 0 ?s with r/w = 0 . the general call address is recognized when the general call enable bit, gcen, is enabled (sspxcon2<7> set). following a start bit detect, 8 bits are shifted into the sspxsr and the address is compared against the sspxadd. it is also compared to the general call address and fixed in hardware. if the general call address matches, the sspxsr is transferred to the sspxbuf, the bf flag bit is set (eighth bit), and on the falling edge of the ninth bit (ack bit), the sspxif interrupt flag bit is set. when the interrupt is serviced, the source for the interrupt can be checked by reading the contents of the sspxbuf. the value can be used to determine if the address was device-specific or a general call address. in 10-bit mode, the sspxadd is required to be updated for the second half of the address to match and the ua bit is set (sspxstat<1>). if the general call address is sampled when the gcen bit is set, while the slave is configured in 10-bit addressing mode, then the second half of the address is not necessary, the ua bit will not be set and the slave will begin receiving data after the acknowledge (figure 19-17). figure 19-17: slave mode general call address sequence (7 or 10-bit addressing mode) sdax sclx s sspxif bf (sspxstat<0>) sspov (sspxcon1<6>) cleared in software sspxbuf is read r/w = 0 ack general call address address is compared to general call address gcen (sspxcon2<7>) receiving data ack 123456789123456789 d7 d6 d5 d4 d3 d2 d1 d0 after ack , set interrupt ? 0 ? ? 1 ?
? 2007 microchip technology inc. preliminary ds39775b-page 261 pic18f87j50 family 19.4.6 master mode master mode is enabled by setting and clearing the appropriate sspm bits in sspxcon1 and by setting the sspen bit. in master mode, the sclx and sdax lines are manipulated by the mssp hardware if the tris bits are set. master mode of operation is supported by interrupt generation on the detection of the start and stop con- ditions. the stop (p) and start (s) bits are cleared from a reset or when the mssp module is disabled. control of the i 2 c bus may be taken when the p bit is set, or the bus is idle, with both the s and p bits clear. in firmware controlled master mode, user code conducts all i 2 c bus operations based on start and stop bit conditions. once master mode is enabled, the user has six options. 1. assert a start condition on sdax and sclx. 2. assert a repeated start condition on sdax and sclx. 3. write to the sspxbuf register initiating transmission of data/address. 4. configure the i 2 c port to receive data. 5. generate an acknowledge condition at the end of a received byte of data. 6. generate a stop condition on sdax and sclx. the following events will cause the mssp interrupt flag bit, sspxif, to be set (and mssp interrupt, if enabled): ? start condition ? stop condition ? data transfer byte transmitted/received ? acknowledge transmitted ? repeated start figure 19-18: msspx block diagram (i 2 c? master mode) note: the mssp module, when configured in i 2 c master mode, does not allow queueing of events. for instance, the user is not allowed to initiate a start condition and immediately write the sspxbuf register to initiate transmission before the start condition is complete. in this case, the sspxbuf will not be written to and the wcol bit will be set, indicating that a write to the sspxbuf did not occur. read write sspxsr start bit, stop bit, sspxbuf internal data bus set/reset s, p (sspxstat), wcol (sspxcon1) shift clock msb lsb sdax acknowledge generate stop bit detect write collision detect clock arbitration state counter for end of xmit/rcv sclx sclx in bus collision sdax in receive enable clock cntl clock arbitrate/wcol detect (hold off clock source) sspxadd<6:0> baud set sspxif, bclxif reset ackstat, pen (sspxcon2) rate generator sspm3:sspm0 start bit detect
pic18f87j50 family ds39775b-page 262 preliminary ? 2007 microchip technology inc. 19.4.6.1 i 2 c master mode operation the master device generates all of the serial clock pulses and the start and stop conditions. a transfer is ended with a stop condition or with a repeated start condition. since the repeated start condition is also the beginning of the next serial transfer, the i 2 c bus will not be released. in master transmitter mode, serial data is output through sdax while sclx outputs the serial clock. the first byte transmitted contains the slave address of the receiving device (7 bits) and the read/write (r/w ) bit. in this case, the r/w bit will be logic ? 0 ?. serial data is transmitted 8 bits at a time. after each byte is transmit- ted, an acknowledge bit is received. start and stop conditions are output to indicate the beginning and the end of a serial transfer. in master receive mode, the first byte transmitted contains the slave address of the transmitting device (7 bits) and the r/w bit. in this case, the r/w bit will be logic ? 1 ?. thus, the first byte transmitted is a 7-bit slave address, followed by a ? 1 ? to indicate the receive bit. serial data is received via sdax, while sclx outputs the serial clock. serial data is received 8 bits at a time. after each byte is received, an acknowledge bit is transmitted. start and stop conditions indicate the beginning and end of transmission. the baud rate generator, used for the spi mode operation, is used to set the sclx clock frequency for either 100 khz, 400 khz or 1 mhz i 2 c operation. see section 19.4.7 ?baud rate? for more details. a typical transmit sequence would go as follows: 1. the user generates a start condition by setting the start enable bit, sen (sspxcon2<0>). 2. sspxif is set. the mssp module will wait the required start time before any other operation takes place. 3. the user loads the sspxbuf with the slave address to transmit. 4. address is shifted out the sdax pin until all 8 bits are transmitted. 5. the mssp module shifts in the ack bit from the slave device and writes its value into the sspxcon2 register (sspxcon2<6>). 6. the mssp module generates an interrupt at the end of the ninth clock cycle by setting the sspxif bit. 7. the user loads the sspxbuf with eight bits of data. 8. data is shifted out the sdax pin until all 8 bits are transmitted. 9. the mssp module shifts in the ack bit from the slave device and writes its value into the sspxcon2 register (sspxcon2<6>). 10. the mssp module generates an interrupt at the end of the ninth clock cycle by setting the sspxif bit. 11. the user generates a stop condition by setting the stop enable bit, pen (sspxcon2<2>). 12. interrupt is generated once the stop condition is complete.
? 2007 microchip technology inc. preliminary ds39775b-page 263 pic18f87j50 family 19.4.7 baud rate in i 2 c master mode, the baud rate generator (brg) reload value is placed in the lower 7 bits of the sspxadd register (figure 19-19). when a write occurs to sspxbuf, the baud rate generator will automatically begin counting. the brg counts down to 0 and stops until another reload has taken place. the brg count is decremented twice per instruction cycle (t cy ) on the q2 and q4 clocks. in i 2 c master mode, the brg is reloaded automatically. once the given operation is complete (i.e., transmis- sion of the last data bit is followed by ack ), the internal clock will automatically stop counting and the sclx pin will remain in its last state. table 19-3 demonstrates clock rates based on instruction cycles and the brg value loaded into sspxadd. 19.4.7.1 baud rate and module interdependence because mssp1 and mssp2 are independent, they can operate simultaneously in i 2 c master mode at different baud rates. this is done by using different brg reload values for each module. because this mode derives its basic clock source from the system clock, any changes to the clock will affect both modules in the same proportion. it may be possible to change one or both baud rates back to a previous value by changing the brg reload value. figure 19-19: baud rate generato r block diagram table 19-3: i 2 c? clock rate w/brg sspm3:sspm0 brg down counter clko f osc /4 sspxadd<6:0> sspm3:sspm0 sclx reload control reload f osc f cy f cy * 2 brg value f scl (2 rollovers of brg) 40 mhz 10 mhz 20 mhz 18h 400 khz (1) 40 mhz 10 mhz 20 mhz 1fh 312.5 khz 40 mhz 10 mhz 20 mhz 63h 100 khz 16 mhz 4 mhz 8 mhz 09h 400 khz (1) 16 mhz 4 mhz 8 mhz 0ch 308 khz 16 mhz 4 mhz 8 mhz 27h 100 khz 4 mhz 1 mhz 2 mhz 02h 333 khz (1) 4 mhz 1 mhz 2 mhz 09h 100 khz 4 mhz 1 mhz 2 mhz 00h 1 mhz (1) note 1: the i 2 c interface does not conform to the 400 khz i 2 c specification (which applies to rates greater than 100 khz) in all details, but may be used with care where higher rates are required by the application.
pic18f87j50 family ds39775b-page 264 preliminary ? 2007 microchip technology inc. 19.4.7.2 clock arbitration clock arbitration occurs when the master, during any receive, transmit or repeated start/stop condition, deasserts the sclx pin (sclx allowed to float high). when the sclx pin is allowed to float high, the baud rate generator (brg) is suspended from counting until the sclx pin is actually sampled high. when the sclx pin is sampled high, the baud rate generator is reloaded with the contents of sspxadd<6:0> and begins counting. this ensures that the sclx high time will always be at least one brg rollover count in the event that the clock is held low by an external device (figure 19-20). figure 19-20: baud rate generator timing with clock arbitration sdax sclx sclx deasserted but slave holds dx ? 1 dx brg sclx is sampled high, reload takes place and brg starts its count 03h 02h 01h 00h (hold off) 03h 02h reload brg value sclx low (clock arbitration) sclx allowed to transition high brg decrements on q2 and q4 cycles
? 2007 microchip technology inc. preliminary ds39775b-page 265 pic18f87j50 family 19.4.8 i 2 c master mode start condition timing to initiate a start condition, the user sets the start enable bit, sen (sspxcon2<0>). if the sdax and sclx pins are sampled high, the baud rate generator is reloaded with the contents of sspxadd<6:0> and starts its count. if sclx and sdax are both sampled high when the baud rate generator times out (t brg ), the sdax pin is driven low. the action of the sdax being driven low while sclx is high is the start condi- tion and causes the s bit (sspxstat<3>) to be set. following this, the baud rate generator is reloaded with the contents of sspxadd<6:0> and resumes its count. when the baud rate generator times out (t brg ), the sen bit (sspxcon2<0>) will be automatically cleared by hardware. the baud rate generator is suspended, leaving the sdax line held low and the start condition is complete. 19.4.8.1 wcol status flag if the user writes the sspxbuf when a start sequence is in progress, the wcol bit is set and the contents of the buffer are unchanged (the write doesn?t occur). figure 19-21: first start bit timing note: if, at the beginning of the start condition, the sdax and sclx pins are already sam- pled low or if during the start condition, the sclx line is sampled low before the sdax line is driven low, a bus collision occurs, the bus collision interrupt flag, bclxif, is set, the start condition is aborted and the i 2 c module is reset into its idle state. note: because queueing of events is not allowed, writing to the lower 5 bits of sspxcon2 is disabled until the start condition is complete. sdax sclx s t brg 1st bit 2nd bit t brg sdax = 1 , at completion of start bit, sclx = 1 write to sspxbuf occurs here t brg hardware clears sen bit t brg write to sen bit occurs here set s bit (sspxstat<3>) and sets sspxif bit
pic18f87j50 family ds39775b-page 266 preliminary ? 2007 microchip technology inc. 19.4.9 i 2 c master mode repeated start condition timing a repeated start condition occurs when the rsen bit (sspxcon2<1>) is programmed high and the i 2 c logic module is in the idle state. when the rsen bit is set, the sclx pin is asserted low. when the sclx pin is sampled low, the baud rate generator is loaded with the contents of sspxadd<5:0> and begins counting. the sdax pin is released (brought high) for one baud rate generator count (t brg ). when the baud rate generator times out, and if sdax is sampled high, the sclx pin will be deasserted (brought high). when sclx is sampled high, the baud rate generator is reloaded with the contents of sspxadd<6:0> and begins counting. sdax and sclx must be sampled high for one t brg . this action is then followed by assertion of the sdax pin (sdax = 0 ) for one t brg while sclx is high. following this, the rsen bit (sspxcon2<1>) will be automatically cleared and the baud rate generator will not be reloaded, leaving the sdax pin held low. as soon as a start condition is detected on the sdax and sclx pins, the s bit (sspxstat<3>) will be set. the sspxif bit will not be set until the baud rate generator has timed out. immediately following the sspxif bit getting set, the user may write the sspxbuf with the 7-bit address in 7-bit mode, or the default first address in 10-bit mode. after the first eight bits are transmitted and an ack is received, the user may then transmit an additional eight bits of address (10-bit mode) or eight bits of data (7-bit mode). 19.4.9.1 wcol status flag if the user writes the sspxbuf when a repeated start sequence is in progress, the wcol is set and the contents of the buffer are unchanged (the write doesn?t occur). figure 19-22: repeated start co ndition waveform note 1: if rsen is programmed while any other event is in progress, it will not take effect. 2: a bus collision during the repeated start condition occurs if: ? sdax is sampled low when sclx goes from low-to-high. ? sclx goes low before sdax is asserted low. this may indicate that another master is attempting to transmit a data ? 1 ?. note: because queueing of events is not allowed, writing of the lower 5 bits of sspxcon2 is disabled until the repeated start condition is complete. sdax sclx sr = repeated start write to sspxcon2 write to sspxbuf occurs here on falling edge of ninth clock, end of xmit at completion of start bit, hardware clears rsen bit 1st bit s bit set by hardware t brg sdax = 1 , sdax = 1 , sclx (no change). sclx = 1 occurs here: and sets sspxif rsen bit set by hardware t brg t brg t brg t brg
? 2007 microchip technology inc. preliminary ds39775b-page 267 pic18f87j50 family 19.4.10 i 2 c master mode transmission transmission of a data byte, a 7-bit address or the other half of a 10-bit address, is accomplished by sim- ply writing a value to the sspxbuf register. this action will set the buffer full flag bit, bf, and allow the baud rate generator to begin counting and start the next transmission. each bit of address/data will be shifted out onto the sdax pin after the falling edge of sclx is asserted (see data hold time specification parameter 106). sclx is held low for one baud rate generator rollover count (t brg ). data should be valid before sclx is released high (see data setup time specification parameter 107). when the sclx pin is released high, it is held that way for t brg . the data on the sdax pin must remain stable for that duration and some hold time after the next falling edge of sclx. after the eighth bit is shifted out (the falling edge of the eighth clock), the bf flag is cleared and the master releases sdax. this allows the slave device being addressed to respond with an ack bit during the ninth bit time if an address match occurred, or if data was received properly. the status of ack is written into the ackdt bit on the falling edge of the ninth clock. if the master receives an acknowledge, the acknowledge status bit, ackstat, is cleared; if not, the bit is set. after the ninth clock, the sspxif bit is set and the master clock (baud rate generator) is suspended until the next data byte is loaded into the sspxbuf, leaving sclx low and sdax unchanged (figure 19-23). after the write to the sspxbuf, each bit of the address will be shifted out on the falling edge of sclx until all seven address bits and the r/w bit are completed. on the falling edge of the eighth clock, the master will deassert the sdax pin, allowing the slave to respond with an acknowledge. on the falling edge of the ninth clock, the master will sample the sdax pin to see if the address was recognized by a slave. the status of the ack bit is loaded into the ackstat status bit (sspxcon2<6>). following the falling edge of the ninth clock transmission of the address, the sspxif flag is set, the bf flag is cleared and the baud rate generator is turned off until another write to the sspxbuf takes place, holding sclx low and allowing sdax to float. 19.4.10.1 bf status flag in transmit mode, the bf bit (sspxstat<0>) is set when the cpu writes to sspxbuf and is cleared when all 8 bits are shifted out. 19.4.10.2 wcol status flag if the user writes the sspxbuf when a transmit is already in progress (i.e., sspxsr is still shifting out a data byte), the wcol bit is set and the contents of the buffer are unchanged (the write doesn?t occur) after 2t cy after the sspxbuf write. if sspxbuf is rewritten within 2 t cy , the wcol bit is set and sspxbuf is updated. this may result in a corrupted transfer. the user should verify that the wcol bit is clear after each write to sspxbuf to ensure the transfer is correct. in all cases, wcol must be cleared in software. 19.4.10.3 ackstat status flag in transmit mode, the ackstat bit (sspxcon2<6>) is cleared when the slave has sent an acknowledge (ack = 0 ) and is set when the slave does not acknowl- edge (ack = 1 ). a slave sends an acknowledge when it has recognized its address (including a general call), or when the slave has properly received its data. 19.4.11 i 2 c master mode reception master mode reception is enabled by programming the receive enable bit, rcen (sspxcon2<3>). the baud rate generator begins counting and on each rollover, the state of the sclx pin changes (high-to-low/low-to-high) and data is shifted into the sspxsr. after the falling edge of the eighth clock, the receive enable flag is automatically cleared, the con- tents of the sspxsr are loaded into the sspxbuf, the bf flag bit is set, the sspxif flag bit is set and the baud rate generator is suspended from counting, holding sclx low. the mssp is now in idle state awaiting the next command. when the buffer is read by the cpu, the bf flag bit is automatically cleared. the user can then send an acknowledge bit at the end of reception by setting the acknowledge sequence enable bit, acken (sspxcon2<4>). 19.4.11.1 bf status flag in receive operation, the bf bit is set when an address or data byte is loaded into sspxbuf from sspxsr. it is cleared when the sspxbuf register is read. 19.4.11.2 sspov status flag in receive operation, the sspov bit is set when 8 bits are received into the sspxsr and the bf flag bit is already set from a previous reception. 19.4.11.3 wcol status flag if the user writes the sspxbuf when a receive is already in progress (i.e., sspxsr is still shifting in a data byte), the wcol bit is set and the contents of the buffer are unchanged (the write doesn?t occur). note: the mssp module must be in an inactive state before the rcen bit is set or the rcen bit will be disregarded.
pic18f87j50 family ds39775b-page 268 preliminary ? 2007 microchip technology inc. figure 19-23: i 2 c? master mode waveform (transmission, 7 or 10-bit address) sdax sclx sspxif bf (sspxstat<0>) sen a7 a6 a5 a4 a3 a2 a1 ack = 0 d7 d6 d5 d4 d3 d2 d1 d0 ack transmitting data or second half r/w = 0 transmit address to slave 123456789 123456789 p cleared in software service routine sspxbuf is written in software from mssp interrupt after start condition, sen cleared by hardware s sspxbuf written with 7-bit address and r/w , start transmit sclx held low while cpu responds to sspxif sen = 0 of 10-bit address write sspxcon2<0> (sen = 1 ), start condition begins from slave, clear ackstat bit (sspxcon2<6>) ackstat in sspxcon2 = 1 cleared in software sspxbuf written pen r/w cleared in software
? 2007 microchip technology inc. preliminary ds39775b-page 269 pic18f87j50 family figure 19-24: i 2 c? master mode waveform (reception, 7-bit address) p 9 8 7 6 5 d0 d1 d2 d3 d4 d5 d6 d7 s a7 a6 a5 a4 a3 a2 a1 sdax sclx 12 3 4 5 6 7 8 9 12 3 4 5 678 9 1234 bus master terminates transfer ack receiving data from slave receiving data from slave d0 d1 d2 d3 d4 d5 d6 d7 ack r/w = 0 transmit address to slave sspxif bf ack is not sent write to sspxcon2<0> (sen = 1 ), write to sspxbuf occurs here, ack from slave master configured as a receiver by programming sspxcon2<3> (rcen = 1 ) pen bit = 1 written here data shifted in on falling edge of clk cleared in software start xmit sen = 0 sspov sdax = 0 , sclx = 1 , while cpu (sspxstat<0>) ack cleared in software cleared in software set sspxif interrupt at end of receive set p bit (sspxstat<4>) and sspxif ack from master, set sspxif at end set sspxif interrupt at end of acknowledge sequence set sspxif interrupt at end of acknowledge sequence of receive set acken, start acknowledge sequence, sdax = ackdt = 1 rcen cleared automatically rcen = 1 , start next receive write to sspxcon2<4> to start acknowledge sequence, sdax = ackdt (sspxcon2<5>) = 0 rcen cleared automatically responds to sspxif acken begin start condition cleared in software sdax = ackdt = 0 last bit is shifted into sspxsr and contents are unloaded into sspxbuf cleared in software sspov is set because sspxbuf is still full
pic18f87j50 family ds39775b-page 270 preliminary ? 2007 microchip technology inc. 19.4.12 acknowledge sequence timing an acknowledge sequence is enabled by setting the acknowledge sequence enable bit, acken (sspxcon2<4>). when this bit is set, the sclx pin is pulled low and the contents of the acknowledge data bit are presented on the sdax pin. if the user wishes to generate an acknowledge, then the ackdt bit should be cleared. if not, the user should set the ackdt bit before starting an acknowledge sequence. the baud rate generator then counts for one rollover period (t brg ) and the sclx pin is deasserted (pulled high). when the sclx pin is sampled high (clock arbitration), the baud rate generator counts for t brg ; the sclx pin is then pulled low. following this, the acken bit is auto- matically cleared, the baud rate generator is turned off and the mssp module then goes into an inactive state (figure 19-25). 19.4.12.1 wcol status flag if the user writes the sspxbuf when an acknowledge sequence is in progress, then wcol is set and the contents of the buffer are unchanged (the write doesn?t occur). 19.4.13 stop condition timing a stop bit is asserted on the sdax pin at the end of a receive/transmit by setting the stop sequence enable bit, pen (sspxcon2<2>). at the end of a receive/transmit, the sclx line is held low after the falling edge of the ninth clock. when the pen bit is set, the master will assert the sdax line low. when the sdax line is sampled low, the baud rate generator is reloaded and counts down to 0. when the baud rate generator times out, the sclx pin will be brought high and one t brg (baud rate generator rollover count) later, the sdax pin will be deasserted. when the sdax pin is sampled high while sclx is high, the p bit (sspxstat<4>) is set. a t brg later, the pen bit is cleared and the sspxif bit is set (figure 19-26). 19.4.13.1 wcol status flag if the user writes the sspxbuf when a stop sequence is in progress, then the wcol bit is set and the contents of the buffer are unchanged (the write doesn?t occur). figure 19-25: acknowledge sequen ce waveform figure 19-26: stop cond ition receive or transmit mode note: t brg = one baud rate generator period. sdax sclx sspxif set at acknowledge sequence starts here, write to sspxcon2, acken automatically cleared cleared in t brg t brg the end of receive 8 acken = 1 , ackdt = 0 d0 9 sspxif software sspxif set at the end of acknowledge sequence cleared in software ack sclx sdax sdax asserted low before rising edge of clock write to sspxcon2, set pen falling edge of sclx = 1 for t brg , followed by sdax = 1 for t brg 9th clock sclx brought high after t brg note: t brg = one baud rate generator period. t brg t brg after sdax sampled high. p bit (sspxstat<4>) is set t brg to set up stop condition ack p t brg pen bit (sspxcon2<2>) is cleared by hardware and the sspxif bit is set
? 2007 microchip technology inc. preliminary ds39775b-page 271 pic18f87j50 family 19.4.14 sleep operation while in sleep mode, the i 2 c module can receive addresses or data and when an address match or complete byte transfer occurs, wake the processor from sleep (if the mssp interrupt is enabled). 19.4.15 effects of a reset a reset disables the mssp module and terminates the current transfer. 19.4.16 multi-master mode in multi-master mode, the interrupt generation on the detection of the start and stop conditions allows the determination of when the bus is free. the stop (p) and start (s) bits are cleared from a reset or when the mssp module is disabled. control of the i 2 c bus may be taken when the p bit (sspxstat<4>) is set, or the bus is idle, with both the s and p bits clear. when the bus is busy, enabling the mssp interrupt will generate the interrupt when the stop condition occurs. in multi-master operation, the sdax line must be monitored for arbitration to see if the signal level is the expected output level. this check is performed in hardware with the result placed in the bclxif bit. the states where arbitration can be lost are: ? address transfer ? data transfer ? a start condition ? a repeated start condition ? an acknowledge condition 19.4.17 multi -master communication, bus collision and bus arbitration multi-master mode support is achieved by bus arbitra- tion. when the master outputs address/data bits onto the sdax pin, arbitration takes place when the master outputs a ? 1 ? on sdax, by letting sdax float high and another master asserts a ? 0 ?. when the sclx pin floats high, data should be stable. if the expected data on sdax is a ? 1 ? and the data sampled on the sdax pin = 0 , then a bus collision has taken place. the master will set the bus collision interrupt flag, bclxif and reset the i 2 c port to its idle state (figure 19-27). if a transmit was in progress when the bus collision occurred, the transmission is halted, the bf flag is cleared, the sdax and sclx lines are deasserted and the sspxbuf can be written to. when the user services the bus collision interrupt service routine and if the i 2 c bus is free, the user can resume communication by asserting a start condition. if a start, repeated start, stop or acknowledge condition was in progress when the bus collision occurred, the con- dition is aborted, the sdax and sclx lines are deasserted and the respective control bits in the sspxcon2 register are cleared. when the user services the bus collision interrupt service routine, and if the i 2 c bus is free, the user can resume communication by asserting a start condition. the master will continue to monitor the sdax and sclx pins. if a stop condition occurs, the sspxif bit will be set. a write to the sspxbuf will start the transmission of data at the first data bit regardless of where the transmitter left off when the bus collision occurred. in multi-master mode, the interrupt generation on the detection of start and stop conditions allows the deter- mination of when the bus is free. control of the i 2 c bus can be taken when the p bit is set in the sspxstat register, or the bus is idle and the s and p bits are cleared. figure 19-27: bus collision timing for transmit and acknowledge sdax sclx bclxif sdax released sdax line pulled low by another source sample sdax. while sclx is high, data doesn?t match what is driven bus collision has occurred set bus collision interrupt (bclxif) by the master; by master data changes while sclx = 0
pic18f87j50 family ds39775b-page 272 preliminary ? 2007 microchip technology inc. 19.4.17.1 bus collision during a start condition during a start condition, a bus collision occurs if: a) sdax or sclx is sampled low at the beginning of the start condition (figure 19-28). b) sclx is sampled low before sdax is asserted low (figure 19-29). during a start condition, both the sdax and the sclx pins are monitored. if the sdax pin is already low, or the sclx pin is already low, then all of the following occur: ? the start condition is aborted, ? the bclxif flag is set and ? the mssp module is reset to its inactive state (figure 19-28) the start condition begins with the sdax and sclx pins deasserted. when the sdax pin is sampled high, the baud rate generator is loaded from sspxadd<6:0> and counts down to 0 . if the sclx pin is sampled low while sdax is high, a bus collision occurs because it is assumed that another master is attempting to drive a data ? 1 ? during the start condition. if the sdax pin is sampled low during this count, the brg is reset and the sdax line is asserted early (figure 19-30). if, however, a ? 1 ? is sampled on the sdax pin, the sdax pin is asserted low at the end of the brg count. the baud rate generator is then reloaded and counts down to 0. if the sclx pin is sampled as ? 0 ? during this time, a bus collision does not occur. at the end of the brg count, the sclx pin is asserted low. figure 19-28: bus collision during st art condition (sdax only) note: the reason that bus collision is not a factor during a start condition is that no two bus masters can assert a start condition at the exact same time. therefore, one master will always assert sdax before the other. this condition does not cause a bus colli- sion because the two masters must be allowed to arbitrate the first address following the start condition. if the address is the same, arbitration must be allowed to continue into the data portion, repeated start or stop conditions. sdax sclx sen sdax sampled low before sdax goes low before the sen bit is set. s bit and sspxif set because mssp module reset into idle state. sen cleared automatically because of bus collision. s bit and sspxif set because set sen, enable start condition if sdax = 1 , sclx = 1 sdax = 0 , sclx = 1 . bclxif s sspxif sdax = 0 , sclx = 1 . sspxif and bclxif are cleared in software sspxif and bclxif are cleared in software set bclxif, start condition. set bclxif.
? 2007 microchip technology inc. preliminary ds39775b-page 273 pic18f87j50 family figure 19-29: bus collision d uring start condition (sclx = 0 ) figure 19-30: brg reset due to sdax arbitr ation during start condition sdax sclx sen bus collision occurs. set bclxif. sclx = 0 before sdax = 0 , set sen, enable start sequence if sdax = 1 , sclx = 1 t brg t brg sdax = 0 , sclx = 1 bclxif s sspxif interrupt cleared in software bus collision occurs. set bclxif. sclx = 0 before brg time-out, ? 0 ?? 0 ? ? 0 ? ? 0 ? sdax sclx sen set s less than t brg t brg sdax = 0 , sclx = 1 bclxif s sspxif s interrupts cleared in software set sspxif sdax = 0 , sclx = 1 , sclx pulled low after brg time-out set sspxif ? 0 ? sdax pulled low by other master. reset brg and assert sdax. set sen, enable start sequence if sdax = 1 , sclx = 1
pic18f87j50 family ds39775b-page 274 preliminary ? 2007 microchip technology inc. 19.4.17.2 bus collision during a repeated start condition during a repeated start condition, a bus collision occurs if: a) a low level is sampled on sdax when sclx goes from a low level to a high level. b) sclx goes low before sdax is asserted low, indicating that another master is attempting to transmit a data ? 1 ?. when the user deasserts sdax and the pin is allowed to float high, the brg is loaded with sspxadd<6:0> and counts down to 0. the sclx pin is then deasserted and when sampled high, the sdax pin is sampled. if sdax is low, a bus collision has occurred (i.e., another master is attempting to transmit a data ? 0 ?, see figure 19-31). if sdax is sampled high, the brg is reloaded and begins counting. if sdax goes from high-to-low before the brg times out, no bus collision occurs because no two masters can assert sdax at exactly the same time. if sclx goes from high-to-low before the brg times out and sdax has not already been asserted, a bus collision occurs. in this case, another master is attempting to transmit a data ? 1 ? during the repeated start condition (see figure 19-32). if, at the end of the brg time-out, both sclx and sdax are still high, the sdax pin is driven low and the brg is reloaded and begins counting. at the end of the count, regardless of the status of the sclx pin, the sclx pin is driven low and the repeated start condition is complete. figure 19-31: bus collision during a repeat ed start condition (case 1) figure 19-32: bus collision during repeat ed start condition (case 2) sdax sclx rsen bclxif s sspxif sample sdax when sclx goes high. if sdax = 0 , set bclxif and release sdax and sclx. cleared in software ? 0 ? ? 0 ? sdax sclx bclxif rsen s sspxif interrupt cleared in software sclx goes low before sdax, set bclxif. release sdax and sclx. t brg t brg ? 0 ?
? 2007 microchip technology inc. preliminary ds39775b-page 275 pic18f87j50 family 19.4.17.3 bus collision during a stop condition bus collision occurs during a stop condition if: a) after the sdax pin has been deasserted and allowed to float high, sdax is sampled low after the brg has timed out. b) after the sclx pin is deasserted, sclx is sampled low before sdax goes high. the stop condition begins with sdax asserted low. when sdax is sampled low, the sclx pin is allowed to float. when the pin is sampled high (clock arbitration), the baud rate generator is loaded with sspxadd<6:0> and counts down to 0. after the brg times out, sdax is sampled. if sdax is sampled low, a bus collision has occurred. this is due to another master attempting to drive a data ? 0 ? (figure 19-33). if the sclx pin is sampled low before sdax is allowed to float high, a bus collision occurs. this is another case of another master attempting to drive a data ? 0 ? (figure 19-34). figure 19-33: bus collision during a stop condition (case 1) figure 19-34: bus collision during a stop condition (case 2) sdax sclx bclxif pen p sspxif t brg t brg t brg sdax asserted low sdax sampled low after t brg , set bclxif ? 0 ? ? 0 ? sdax sclx bclxif pen p sspxif t brg t brg t brg assert sdax sclx goes low before sdax goes high, set bclxif ? 0 ? ? 0 ?
pic18f87j50 family ds39775b-page 276 preliminary ? 2007 microchip technology inc. table 19-4: registers associated with i 2 c? operation name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 62 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 62 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 trisc trisc7 trisc6 trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 62 trisd trisd7 trisd6 trisd5 trisd4 trisd3 trisd2 trisd1 trisd0 62 ssp1buf mssp1 receive buffer/transmit register 60 ssp1add mssp1 address register (i 2 c? slave mode), mssp1 baud rate reload register (i 2 c master mode) 63 sspxmsk (1) msk7 msk6 msk5 msk4 msk3 msk2 msk1 msk0 63 sspxcon1 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 60, 63 sspxcon2 gcen ackstat ackdt acken rcen pen rsen sen 60, 63 gcen ackstat admsk5 (2) admsk4 (2) admsk3 (2) admsk2 (2) admsk1 (2) sen sspxstat smp cke d/a psr/w ua bf 60, 63 ssp2buf mssp2 receive buffer/transmit register 60 ssp2add mssp2 address register (i 2 c slave mode), mssp2 baud rate reload register (i 2 c master mode) 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the mssp module in i 2 c? mode. note 1: sspxmsk shares the same address in sfr space as sspxadd, but is only accessible in certain i 2 c? slave operating modes in 7-bit masking mode. see section 19.4.3.4 ?7-bit address masking mode? for more details. 2: alternate bit definitions for use in i 2 c slave mode operations only.
? 2007 microchip technology inc. preliminary ds39775b-page 277 pic18f87j50 family 20.0 enhanced universal synchronous asynchronous receiver transmitter (eusart) the enhanced universal synchronous asynchronous receiver transmitter (eusart) module is one of two serial i/o modules. (generically, the eusart is also known as a serial communications interface or sci.) the eusart can be configured as a full-duplex asynchronous system that can communicate with peripheral devices, such as crt terminals and personal computers. it can also be configured as a half-duplex synchronous system that can communicate with peripheral devices, such as a/d or d/a integrated circuits, serial eeproms, etc. the enhanced usart module implements additional features, including automatic baud rate detection and calibration, automatic wake-up on sync break recep- tion and 12-bit break character transmit. these make it ideally suited for use in local interconnect network bus (lin bus) systems. all members of the pic18f87j50 family are equipped with two independent eusart modules, referred to as eusart1 and eusart2. they can be configured in the following modes: ? asynchronous (full duplex) with: - auto-wake-up on character reception - auto-baud calibration - 12-bit break character transmission ? synchronous ? master (half duplex) with selectable clock polarity ? synchronous ? slave (half duplex) with selectable clock polarity the pins of eusart1 and eusart2 are multiplexed with the functions of portc (rc6/tx1/ck1 and rc7/rx1/dt1) and portg (rg1/tx2/ck2 and rg2/rx2/dt2), respectively. in order to configure these pins as an eusart: ? for eusart1: - bit spen (rcsta1<7>) must be set (= 1 ) - bit trisc<7> must be set (= 1 ) - bit trisc<6> must be cleared (= 0 ) for asynchronous and synchronous master modes - bit trisc<6> must be set (= 1 ) for synchronous slave mode ? for eusart2: - bit spen (rcsta2<7>) must be set (= 1 ) - bit trisg<2> must be set (= 1 ) - bit trisg<1> must be cleared (= 0 ) for asynchronous and synchronous master modes - bit trisc<6> must be set (= 1 ) for synchronous slave mode the txx/ckx i/o pins have an optional open-drain out- put capability. by default, when this pin is used by the eusart as an output, it will function as a standard push-pull cmos output. the txx/ckx i/o pins? open-drain, output feature can be enabled by setting the corresponding uxod bit in the odcon2 register. for more details, see section 10.1.4 ?open-drain outputs? . the operation of each enhanced usart module is controlled through three registers: ? transmit status and control (txstax) ? receive status and control (rcstax) ? baud rate control (baudconx) these are detailed on the following pages in register 20-1, register 20-2 and register 20-3, respectively. note: the eusart control will automatically reconfigure the pin from input to output as needed. note: throughout this section, references to register and bit names that may be associ- ated with a specific eusart module are referred to generically by the use of ?x? in place of the specific module number. thus, ?rcstax? might refer to the receive status register for either eusart1 or eusart2.
pic18f87j50 family ds39775b-page 278 preliminary ? 2007 microchip technology inc. register 20-1: txstax: transmit status and control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r-1 r/w-0 csrc tx9 txen (1) sync sendb brgh trmt tx9d bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 csrc: clock source select bit asynchronous mode: don?t care. synchronous mode: 1 = master mode (clock generated internally from brg) 0 = slave mode (clock from external source) bit 6 tx9: 9-bit transmit enable bit 1 = selects 9-bit transmission 0 = selects 8-bit transmission bit 5 txen: transmit enable bit (1) 1 = transmit enabled 0 = transmit disabled bit 4 sync: eusart mode select bit 1 = synchronous mode 0 = asynchronous mode bit 3 sendb: send break character bit asynchronous mode: 1 = send sync break on next transmission (cleared by hardware upon completion) 0 = sync break transmission completed synchronous mode: don?t care. bit 2 brgh: high baud rate select bit asynchronous mode: 1 = high speed 0 = low speed synchronous mode: unused in this mode. bit 1 trmt: transmit shift register status bit 1 = tsr empty 0 = tsr full bit 0 tx9d: 9th bit of transmit data can be address/data bit or a parity bit. note 1: sren/cren overrides txen in sync mode.
? 2007 microchip technology inc. preliminary ds39775b-page 279 pic18f87j50 family register 20-2: rcstax: receive stat us and control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r-0 r-0 r-x spen rx9 sren cren adden ferr oerr rx9d bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 spen: serial port enable bit 1 = serial port enabled (configures rxx/dtx and txx/ckx pins as serial port pins) 0 = serial port disabled (held in reset) bit 6 rx9: 9-bit receive enable bit 1 = selects 9-bit reception 0 = selects 8-bit reception bit 5 sren: single receive enable bit asynchronous mode : don?t care. synchronous mode ? master: 1 = enables single receive 0 = disables single receive this bit is cleared after reception is complete. synchronous mode ? slave: don?t care. bit 4 cren: continuous receive enable bit asynchronous mode: 1 = enables receiver 0 = disables receiver synchronous mode: 1 = enables continuous receive until enable bit cren is cleared (cren overrides sren) 0 = disables continuous receive bit 3 adden: address detect enable bit asynchronous mode 9- bit (rx9 = 1 ) : 1 = enables address detection, enables interrupt and loads the receive buffer when rsr<8> is set 0 = disables address detection, all bytes are received and ninth bit can be used as parity bit asynchronous mode 9- bit (rx9 = 0 ) : don?t care. bit 2 ferr: framing error bit 1 = framing error (can be updated by reading rcregx register and receiving next valid byte) 0 = no framing error bit 1 oerr: overrun error bit 1 = overrun error (can be cleared by clearing bit cren) 0 = no overrun error bit 0 rx9d: 9th bit of received data this can be address/data bit or a parity bit and must be calculated by user firmware.
pic18f87j50 family ds39775b-page 280 preliminary ? 2007 microchip technology inc. register 20-3: baudconx: baud rate control register r/w-0 r-1 r/w-0 r/w-0 r/w-0 u-0 r/w-0 r/w-0 abdovf rcidl dtrxp sckp brg16 ? wue abden bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 abdovf: auto-baud acquisition rollover status bit 1 = a brg rollover has occurred during auto-baud rate detect mode (must be cleared in software) 0 = no brg rollover has occurred bit 6 rcidl: receive operation idle status bit 1 = receive operation is idle 0 = receive operation is active bit 5 dtrxp: data/receive polarity select bit asynchronous mode: 1 = receive data (rxx) is inverted (active low) 0 = receive data (rxx) is not inverted (active high) synchronous mode: 1 = data (dtx) is inverted (active low) 0 = data (dtx) is not inverted (active high) bit 4 sckp: synchronous clock polarity select bit asynchronous mode: 1 = idle state for transmit (txx) is a low level 0 = idle state for transmit (txx) is a high level synchronous mode: 1 = idle state for clock (ckx) is a high level 0 = idle state for clock (ckx) is a low level bit 3 brg16: 16-bit baud rate register enable bit 1 = 16-bit baud rate generator ? spbrghx and spbrgx 0 = 8-bit baud rate generator ? spbrgx only (compatible mode), spbrghx value ignored bit 2 unimplemented: read as ? 0 ? bit 1 wue: wake-up enable bit asynchronous mode: 1 = eusart will continue to sample the rxx pin ? interrupt generated on falling edge; bit cleared in hardware on following rising edge 0 = rxx pin not monitored or rising edge detected synchronous mode: unused in this mode. bit 0 abden: auto-baud detect enable bit asynchronous mode: 1 = enable baud rate measurement on the next character. requires reception of a sync field (55h); cleared in hardware upon completion. 0 = baud rate measurement disabled or completed synchronous mode: unused in this mode.
? 2007 microchip technology inc. preliminary ds39775b-page 281 pic18f87j50 family 20.1 baud rate generator (brg) the brg is a dedicated, 8-bit or 16-bit generator that supports both the asynchronous and synchronous modes of the eusart. by default, the brg operates in 8-bit mode; setting the brg16 bit (baudconx<3>) selects 16-bit mode. the spbrghx:spbrgx register pair controls the period of a free-running timer. in asynchronous mode, bits brgh (txstax<2>) and brg16 (baudconx<3>) also control the baud rate. in synchronous mode, brgh is ignored. table 20-1 shows the formula for computation of the baud rate for different eusart modes which only apply in master mode (internally generated clock). given the desired baud rate and f osc , the nearest integer value for the spbrghx:spbrgx registers can be calculated using the formulas in table 20-1. from this, the error in baud rate can be determined. an example calculation is shown in example 20-1. typical baud rates and error values for the various asynchronous modes are shown in table 20-2. it may be advantageous to use the high baud rate (brgh = 1 ) or the 16-bit brg to reduce the baud rate error, or achieve a slow baud rate for a fast oscillator frequency. writing a new value to the spbrghx:spbrgx regis- ters causes the brg timer to be reset (or cleared). this ensures the brg does not wait for a timer overflow before outputting the new baud rate. 20.1.1 operation in power-managed modes the device clock is used to generate the desired baud rate. when one of the power-managed modes is entered, the new clock source may be operating at a different frequency. this may require an adjustment to the value in the spbrgx register pair. 20.1.2 sampling the data on the rxx pin (either rc7/rx1/dt1 or rg2/rx2/dt2) is sampled three times by a majority detect circuit to determine if a high or a low level is present at the rxx pin. table 20-1: baud rate formulas configuration bits brg/eusart mode baud rate formula sync brg16 brgh 000 8-bit/asynchronous f osc /[64 (n + 1)] 001 8-bit/asynchronous f osc /[16 (n + 1)] 010 16-bit/asynchronous 011 16-bit/asynchronous f osc /[4 (n + 1)] 10x 8-bit/synchronous 11x 16-bit/synchronous legend: x = don?t care, n = value of spbrghx:spbrgx register pair
pic18f87j50 family ds39775b-page 282 preliminary ? 2007 microchip technology inc. example 20-1: calculat ing baud rate error table 20-2: registers associated with baud rate generator for a device with fosc of 16 mhz, desired baud rate of 9600, asynchronous mode, and 8-bit brg: desired baud rate = f osc /(64 ([spbrghx:spbrgx] + 1)) solving for spbrghx:spbrgx: x=((f osc /desired baud rate)/64) ? 1 = ((16000000/9600)/64) ? 1 = [25.042] = 25 calculated baud rate = 16000000/(64 (25 + 1)) = 9615 error = (calculated baud rate ? desired baud rate)/desired baud rate = (9615 ? 9600)/9600 = 0.16% name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the brg.
? 2007 microchip technology inc. preliminary ds39775b-page 283 pic18f87j50 family table 20-3: baud rates for asynchronous modes baud rate (k) sync = 0 , brgh = 0 , brg16 = 0 f osc = 40.000 mhz f osc = 20.000 mhz f osc = 10.000 mhz f osc = 8.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3???????????? 1.2 ? ? ? 1.221 1.73 255 1.202 0.16 129 1.201 -0.16 103 2.4 2.441 1.73 255 2.404 0.16 129 2.404 0.16 64 2.403 -0.16 51 9.6 9.615 0.16 64 9.766 1.73 31 9.766 1.73 15 9.615 -0.16 12 19.2 19.531 1.73 31 19.531 1.73 15 19.531 1.73 7 ? ? ? 57.6 56.818 -1.36 10 62.500 8.51 4 52.083 -9.58 2 ? ? ? 115.2 125.000 8.51 4 104.167 -9.58 2 78.125 -32.18 1 ? ? ? baud rate (k) sync = 0 , brgh = 0 , brg16 = 0 f osc = 4.000 mhz f osc = 2.000 mhz f osc = 1.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3 0.300 0.16 207 0.300 -0.16 103 0.300 -0.16 51 1.2 1.202 0.16 51 1.201 -0.16 25 1.201 -0.16 12 2.4 2.404 0.16 25 2.403 -0.16 12 ? ? ? 9.6 8.929 -6.99 6 ? ? ? ? ? ? 19.2 20.833 8.51 2 ? ? ? ? ? ? 57.6 62.500 8.51 0 ? ? ? ? ? ? 115.2 62.500 -45.75 0 ? ? ? ? ? ? baud rate (k) sync = 0 , brgh = 1 , brg16 = 0 f osc = 40.000 mhz f osc = 20.000 mhz f osc = 10.000 mhz f osc = 8.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3???????????? 1.2???????????? 2.4 ? ? ? ? ? ? 2.441 1.73 255 2.403 -0.16 207 9.6 9.766 1.73 255 9.615 0.16 129 9.615 0.16 64 9615. -0.16 51 19.2 19.231 0.16 129 19.231 0.16 64 19.531 1.73 31 19.230 -0.16 25 57.6 58.140 0.94 42 56.818 -1.36 21 56.818 -1.36 10 55.555 3.55 8 115.2 113.636 -1.36 21 113.636 -1.36 10 125.000 8.51 4 ? ? ? baud rate (k) sync = 0 , brgh = 1 , brg16 = 0 f osc = 4.000 mhz f osc = 2.000 mhz f osc = 1.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3 ? ? ? ? ? ? 0.300 -0.16 207 1.2 1.202 0.16 207 1.201 -0.16 103 1.201 -0.16 51 2.4 2.404 0.16 103 2.403 -0.16 51 2.403 -0.16 25 9.6 9.615 0.16 25 9.615 -0.16 12 ? ? ? 19.2 19.231 0.16 12 ? ? ? ? ? ? 57.6 62.500 8.51 3 ? ? ? ? ? ? 115.2 125.000 8.51 1 ? ? ? ? ? ?
pic18f87j50 family ds39775b-page 284 preliminary ? 2007 microchip technology inc. baud rate (k) sync = 0 , brgh = 0 , brg16 = 1 f osc = 40.000 mhz f osc = 20.000 mhz f osc = 10.000 mhz f osc = 8.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3 0.300 0.00 8332 0.300 0.02 4165 0.300 0.02 2082 0.300 -0.04 1665 1.2 1.200 0.02 2082 1.200 -0.03 1041 1.200 -0.03 520 1.201 -0.16 415 2.4 2.402 0.06 1040 2.399 -0.03 520 2.404 0.16 259 2.403 -0.16 207 9.6 9.615 0.16 259 9.615 0.16 129 9.615 0.16 64 9.615 -0.16 51 19.2 19.231 0.16 129 19.231 0.16 64 19.531 1.73 31 19.230 -0.16 25 57.6 58.140 0.94 42 56.818 -1.36 21 56.818 -1.36 10 55.555 3.55 8 115.2 113.636 -1.36 21 113.636 -1.36 10 125.000 8.51 4 ? ? ? baud rate (k) sync = 0 , brgh = 0 , brg16 = 1 f osc = 4.000 mhz f osc = 2.000 mhz f osc = 1.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3 0.300 0.04 832 0.300 -0.16 415 0.300 -0.16 207 1.2 1.202 0.16 207 1.201 -0.16 103 1.201 -0.16 51 2.4 2.404 0.16 103 2.403 -0.16 51 2.403 -0.16 25 9.6 9.615 0.16 25 9.615 -0.16 12 ? ? ? 19.2 19.231 0.16 12 ? ? ? ? ? ? 57.6 62.500 8.51 3 ? ? ? ? ? ? 115.2 125.000 8.51 1 ? ? ? ? ? ? baud rate (k) sync = 0 , brgh = 1 , brg16 = 1 or sync = 1 , brg16 = 1 f osc = 40.000 mhz f osc = 20.000 mhz f osc = 10.000 mhz f osc = 8.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3 0.300 0.00 33332 0.300 0.00 16665 0.300 0.00 8332 0.300 -0.01 6665 1.2 1.200 0.00 8332 1.200 0.02 4165 1.200 0.02 2082 1.200 -0.04 1665 2.4 2.400 0.02 4165 2.400 0.02 2082 2.402 0.06 1040 2.400 -0.04 832 9.6 9.606 0.06 1040 9.596 -0.03 520 9.615 0.16 259 9.615 -0.16 207 19.2 19.193 -0.03 520 19.231 0.16 259 19.231 0.16 129 19.230 -0.16 103 57.6 57.803 0.35 172 57.471 -0.22 86 58.140 0.94 42 57.142 0.79 34 115.2 114.943 -0.22 86 116.279 0.94 42 113.636 -1.36 21 117.647 -2.12 16 baud rate (k) sync = 0 , brgh = 1 , brg16 = 1 or sync = 1 , brg16 = 1 f osc = 4.000 mhz f osc = 2.000 mhz f osc = 1.000 mhz actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) actual rate (k) % error spbrg value (decimal) 0.3 0.300 0.01 3332 0.300 -0.04 1665 0.300 -0.04 832 1.2 1.200 0.04 832 1.201 -0.16 415 1.201 -0.16 207 2.4 2.404 0.16 415 2.403 -0.16 207 2.403 -0.16 103 9.6 9.615 0.16 103 9.615 -0.16 51 9.615 -0.16 25 19.2 19.231 0.16 51 19.230 -0.16 25 19.230 -0.16 12 57.6 58.824 2.12 16 55.555 3.55 8 ? ? ? 115.2 111.111 -3.55 8 ? ? ? ? ? ? table 20-3: baud rates for asynchronous modes (continued)
? 2007 microchip technology inc. preliminary ds39775b-page 285 pic18f87j50 family 20.1.3 auto-baud rate detect the enhanced usart module supports the automatic detection and calibration of baud rate. this feature is active only in asynchronous mode and while the wue bit is clear. the automatic baud rate measurement sequence (figure 20-1) begins whenever a start bit is received and the abden bit is set. the calculation is self-averaging. in the auto-baud rate detect (abd) mode, the clock to the brg is reversed. rather than the brg clocking the incoming rxx signal, the rxx signal is timing the brg. in abd mode, the internal baud rate generator is used as a counter to time the bit period of the incoming serial byte stream. once the abden bit is set, the state machine will clear the brg and look for a start bit. the auto-baud rate detect must receive a byte with the value 55h (ascii ?u?, which is also the lin bus sync character) in order to calculate the proper bit rate. the measurement is taken over both a low and a high bit time in order to minimize any effects caused by asymmetry of the incoming signal. after a start bit, the spbrgx begins counting up, using the preselected clock source on the first rising edge of rxx. after eight bits on the rxx pin or the fifth rising edge, an accumulated value totalling the proper brg period is left in the spbrghx:spbrgx register pair. once the 5th edge is seen (this should correspond to the stop bit), the abden bit is automatically cleared. if a rollover of the brg occurs (an overflow from ffffh to 0000h), the event is trapped by the abdovf status bit (baudconx<7>). it is set in hardware by brg roll- overs and can be set or cleared by the user in software. abd mode remains active after rollover events and the abden bit remains set (figure 20-2). while calibrating the baud rate period, the brg regis- ters are clocked at 1/8th the preconfigured clock rate. note that the brg clock will be configured by the brg16 and brgh bits. independent of the brg16 bit setting, both the spbrgx and spbrghx will be used as a 16-bit counter. this allows the user to verify that no carry occurred for 8-bit modes by checking for 00h in the spbrghx register. refer to table 20-4 for counter clock rates to the brg. while the abd sequence takes place, the eusart state machine is held in idle. the rcxif interrupt is set once the fifth rising edge on rxx is detected. the value in the rcregx needs to be read to clear the rcxif interrupt. the contents of rcregx should be discarded. table 20-4: brg counter clock rates 20.1.3.1 abd and eusart transmission since the brg clock is reversed during abd acquisi- tion, the eusart transmitter cannot be used during abd. this means that whenever the abden bit is set, txregx cannot be written to. users should also ensure that abden does not become set during a transmit sequence. failing to do this may result in unpredictable eusart operation. note 1: if the wue bit is set with the abden bit, auto-baud rate detection will occur on the byte following the break character. 2: it is up to the user to determine that the incoming character baud rate is within the range of the selected brg clock source. some combinations of oscillator frequency and eusart baud rates are not possible due to bit error rates. overall system tim- ing and communication baud rates must be taken into consideration when using the auto-baud rate detection feature. brg16 brgh brg counter clock 00 f osc /512 01 f osc /128 10 f osc /128 11 f osc /32 note: during the abd sequence, spbrgx and spbrghx are both used as a 16-bit counter, independent of brg16 setting.
pic18f87j50 family ds39775b-page 286 preliminary ? 2007 microchip technology inc. figure 20-1: automatic baud rate calculation figure 20-2: brg overflow sequence brg value rxx pin abden bit rcxif bit bit 0 bit 1 (interrupt) read rcregx brg clock start auto-cleared set by user xxxxh 0000h edge #1 bit 2 bit 3 edge #2 bit 4 bit 5 edge #3 bit 6 bit 7 edge #4 001ch note: the abd sequence requires the eusart module to be configured in asynchronous mode and wue = 0 . spbrgx xxxxh 1ch spbrghx xxxxh 00h edge #5 stop bit start bit 0 xxxxh 0000h 0000h ffffh brg clock abden bit rxx pin abdovf bit brg value
? 2007 microchip technology inc. preliminary ds39775b-page 287 pic18f87j50 family 20.2 eusart asynchronous mode the asynchronous mode of operation is selected by clearing the sync bit (txstax<4>). in this mode, the eusart uses standard non-return-to-zero (nrz) format (one start bit, eight or nine data bits and one stop bit). the most common data format is 8 bits. an on-chip dedicated 8-bit/16-bit baud rate generator can be used to derive standard baud rate frequencies from the oscillator. the eusart transmits and receives the lsb first. the eusart?s transmitter and receiver are functionally independent but use the same data format and baud rate. the baud rate generator produces a clock, either x16 or x64 of the bit shift rate, depending on the brgh and brg16 bits (txstax<2> and baudconx<3>). parity is not supported by the hardware but can be implemented in software and stored as the 9th data bit. when operating in asynchronous mode, the eusart module consists of the following important elements: ? baud rate generator ? sampling circuit ? asynchronous transmitter ? asynchronous receiver ? auto-wake-up on sync break character ? 12-bit break character transmit ? auto-baud rate detection 20.2.1 eusart asynchronous transmitter the eusart transmitter block diagram is shown in figure 20-3. the heart of the transmitter is the transmit (serial) shift register (tsr). the shift register obtains its data from the read/write transmit buffer register, txregx. the txregx register is loaded with data in software. the tsr register is not loaded until the stop bit has been transmitted from the previous load. as soon as the stop bit is transmitted, the tsr is loaded with new data from the txregx register (if available). once the txregx register transfers the data to the tsr register (occurs in one t cy ), the txregx register is empty and the txxif flag bit is set. this interrupt can be enabled or disabled by setting or clearing the interrupt enable bit, txxie. txxif will be set regardless of the state of txxie; it cannot be cleared in software. txxif is also not cleared immediately upon loading txregx, but becomes valid in the second instruction cycle following the load instruction. polling txxif immediately following a load of txregx will return invalid results. while txxif indicates the status of the txregx regis- ter; another bit, trmt (txstax<1>), shows the status of the tsr register. trmt is a read-only bit which is set when the tsr register is empty. no interrupt logic is tied to this bit so the user has to poll this bit in order to determine if the tsr register is empty. to set up an asynchronous transmission: 1. initialize the spbrghx:spbrgx registers for the appropriate baud rate. set or clear the brgh and brg16 bits, as required, to achieve the desired baud rate. 2. enable the asynchronous serial port by clearing bit sync and setting bit, spen. 3. if interrupts are desired, set enable bit, txxie. 4. if 9-bit transmission is desired, set transmit bit tx9. can be used as address/data bit. 5. enable the transmission by setting bit, txen, which will also set bit, txxif. 6. if 9-bit transmission is selected, the ninth bit should be loaded in bit, tx9d. 7. load data to the txregx register (starts transmission). 8. if using interrupts, ensure that the gie and peie bits in the intcon register (intcon<7:6>) are set. figure 20-3: eusart transmit block diagram note 1: the tsr register is not mapped in data memory, so it is not available to the user. 2: flag bit txxif is set when enable bit, txen, is set. txxif txxie interrupt txen baud rate clk spbrgx baud rate generator tx9d msb lsb data bus txregx register tsr register (8) 0 tx9 trmt spen txx pin pin buffer and control 8 ? ? ? spbrghx brg16
pic18f87j50 family ds39775b-page 288 preliminary ? 2007 microchip technology inc. figure 20-4: asynchronous transmission figure 20-5: asynchronous transmiss ion (back-to-back) table 20-5: registers associated wi th asynchronous transmission word 1 word 1 transmit shift reg start bit bit 0 bit 1 bit 7/8 write to txregx brg output (shift clock) txx (pin) txxif bit (transmit buffer reg. empty flag) trmt bit (transmit shift reg. empty flag) 1 t cy stop bit word 1 transmit shift reg. write to txregx brg output (shift clock) txx (pin) txxif bit (interrupt reg. flag) trmt bit (transmit shift reg. empty flag) word 1 word 2 word 1 word 2 stop bit start bit transmit shift reg. word 1 word 2 bit 0 bit 1 bit 7/8 bit 0 note: this timing diagram shows two consecutive transmissions. 1 t cy 1 t cy start bit name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 txregx eusartx transmit register 61 txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 odcon2 ? ? ? ? u2od u1od 60 legend: ? = unimplemented locations read as ? 0 ?. shaded cells are not used for asynchronous transmission.
? 2007 microchip technology inc. preliminary ds39775b-page 289 pic18f87j50 family 20.2.2 eusart asynchronous receiver the receiver block diagram is shown in figure 20-6. the data is received on the rxx pin and drives the data recovery block. the data recovery block is actually a high-speed shifter operating at x16 times the baud rate, whereas the main receive serial shifter operates at the bit rate or at f osc . this mode would typically be used in rs-232 systems. to set up an asynchronous reception: 1. initialize the spbrghx:spbrgx registers for the appropriate baud rate. set or clear the brgh and brg16 bits, as required, to achieve the desired baud rate. 2. enable the asynchronous serial port by clearing bit, sync, and setting bit, spen. 3. if interrupts are desired, set enable bit, rcxie. 4. if 9-bit reception is desired, set bit, rx9. 5. enable the reception by setting bit, cren. 6. flag bit, rcxif, will be set when reception is complete and an interrupt will be generated if enable bit, rcxie, was set. 7. read the rcstax register to get the 9th bit (if enabled) and determine if any error occurred during reception. 8. read the 8-bit received data by reading the rcregx register. 9. if any error occurred, clear the error by clearing enable bit, cren. 10. if using interrupts, ensure that the gie and peie bits in the intcon register (intcon<7:6>) are set. 20.2.3 setting up 9-bit mode with address detect this mode would typically be used in rs-485 systems. to set up an asynchronous reception with address detect enable: 1. initialize the spbrghx:spbrgx registers for the appropriate baud rate. set or clear the brgh and brg16 bits, as required, to achieve the desired baud rate. 2. enable the asynchronous serial port by clearing the sync bit and setting the spen bit. 3. if interrupts are required, set the rcen bit and select the desired priority level with the rcxip bit. 4. set the rx9 bit to enable 9-bit reception. 5. set the adden bit to enable address detect. 6. enable reception by setting the cren bit. 7. the rcxif bit will be set when reception is complete. the interrupt will be acknowledged if the rcxie and gie bits are set. 8. read the rcstax register to determine if any error occurred during reception, as well as read bit 9 of data (if applicable). 9. read rcregx to determine if the device is being addressed. 10. if any error occurred, clear the cren bit. 11. if the device has been addressed, clear the adden bit to allow all received data into the receive buffer and interrupt the cpu. figure 20-6: eusartx receive block diagram x64 baud rate clk baud rate generator rxx pin buffer and control spen data recovery cren oerr ferr rsr register msb lsb rx9d rcregx register fifo interrupt rcxif rcxie data bus 8 64 16 or stop start (8) 7 1 0 rx9 ? ? ? spbrgx spbrghx brg16 or 4
pic18f87j50 family ds39775b-page 290 preliminary ? 2007 microchip technology inc. figure 20-7: asynchronous reception table 20-6: registers associated with asynchronous reception 20.2.4 auto-wake-up on sync break character during sleep mode, all clocks to the eusart are suspended. because of this, the baud rate generator is inactive and a proper byte reception cannot be per- formed. the auto-wake-up feature allows the controller to wake-up due to activity on the rxx/dtx line while the eusart is operating in asynchronous mode. the auto-wake-up feature is enabled by setting the wue bit (baudconx<1>). once set, the typical receive sequence on rxx/dtx is disabled and the eusart remains in an idle state, monitoring for a wake-up event independent of the cpu mode. a wake-up event consists of a high-to-low transition on the rxx/dtx line. (this coincides with the start of a sync break or a wake-up signal character for the lin protocol.) following a wake-up event, the module generates an rcxif interrupt. the interrupt is generated synchro- nously to the q clocks in normal operating modes (figure 20-8) and asynchronously if the device is in sleep mode (figure 20-9). the interrupt condition is cleared by reading the rcregx register. the wue bit is automatically cleared once a low-to-high transition is observed on the rxx line following the wake-up event. at this point, the eusart module is in idle mode and returns to normal operation. this signals to the user that the sync break event is over. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 rcregx eusartx receive register 61 txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 legend: ? = unimplemented locations read as ? 0 ?. shaded cells are not used for asynchronous reception. start bit bit 7/8 bit 1 bit 0 bit 7/8 bit 0 stop bit start bit start bit bit 7/8 stop bit rxx (pin) rcv buffer reg rcv shift reg read rcv buffer reg rcregx rcxif (interrupt flag) oerr bit cren word 1 rcregx word 2 rcregx stop bit note: this timing diagram shows three words appearing on the rxx input. the rcregx (receive buffer) is read after the third word causing the oerr (overrun) bit to be set.
? 2007 microchip technology inc. preliminary ds39775b-page 291 pic18f87j50 family 20.2.4.1 special considerations using auto-wake-up since auto-wake-up functions by sensing rising edge transitions on rxx/dtx, information with any state changes before the stop bit may signal a false end-of-character (eoc) and cause data or framing errors. to work properly, therefore, the initial character in the transmission must be all ? 0 ?s. this can be 00h (8 bytes) for standard rs-232 devices or 000h (12 bits) for lin bus. oscillator start-up time must also be considered, especially in applications using oscillators with longer start-up intervals (i.e., hs or hspll mode). the sync break (or wake-up signal) character must be of sufficient length and be followed by a sufficient interval to allow enough time for the selected oscillator to start and provide proper initialization of the eusart. 20.2.4.2 special considerations using the wue bit the timing of wue and rcxif events may cause some confusion when it comes to determining the validity of received data. as noted, setting the wue bit places the eusart in an idle mode. the wake-up event causes a receive interrupt by setting the rcxif bit. the wue bit is cleared after this when a rising edge is seen on rxx/dtx. the interrupt condition is then cleared by reading the rcregx register. ordinarily, the data in rcregx will be dummy data and should be discarded. the fact that the wue bit has been cleared (or is still set) and the rcxif flag is set should not be used as an indicator of the integrity of the data in rcregx. users should consider implementing a parallel method in firmware to verify received data integrity. to assure that no actual data is lost, check the rcidl bit to verify that a receive operation is not in process. if a receive operation is not occurring, the wue bit may then be set just prior to entering the sleep mode. figure 20-8: auto-wake-up bit (wue) timings during no rmal operation figure 20-9: auto-wake-up bit (wue) timings during sleep q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 wue bit (1) rxx/dtx line rcxif note 1: the eusart remains in idle while the wue bit is set. bit set by user cleared due to user read of rcregx auto-cleared q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 wue bit (2) rxx/dtx line rcxif cleared due to user read of rcregx sleep command executed note 1: if the wake-up event requires long oscillator warm-up time, the auto-clear of the wue bit can occur before the oscillator is re ady. this sequence should not depend on the presence of q clocks. 2: the eusart remains in idle while the wue bit is set. sleep ends note 1 auto-cleared bit set by user
pic18f87j50 family ds39775b-page 292 preliminary ? 2007 microchip technology inc. 20.2.5 break character sequence the eusart module has the capability of sending the special break character sequences that are required by the lin bus standard. the break character transmit consists of a start bit, followed by twelve ? 0 ? bits and a stop bit. the frame break character is sent whenever the sendb and txen bits (txstax<3> and txstax<5>) are set while the transmit shift register is loaded with data. note that the value of data written to txregx will be ignored and all ? 0 ?s will be transmitted. the sendb bit is automatically reset by hardware after the corresponding stop bit is sent. this allows the user to preload the transmit fifo with the next transmit byte following the break character (typically, the sync character in the lin specification). note that the data value written to the txregx for the break character is ignored. the write simply serves the purpose of initiating the proper sequence. the trmt bit indicates when the transmit operation is active or idle, just as it does during normal transmis- sion. see figure 20-10 for the timing of the break character sequence. 20.2.5.1 break and sync transmit sequence the following sequence will send a message frame header made up of a break, followed by an auto-baud sync byte. this sequence is typical of a lin bus master. 1. configure the eusart for the desired mode. 2. set the txen and sendb bits to set up the break character. 3. load the txregx with a dummy character to initiate transmission (the value is ignored). 4. write ?55h? to txregx to load the sync character into the transmit fifo buffer. 5. after the break has been sent, the sendb bit is reset by hardware. the sync character now transmits in the preconfigured mode. when the txregx becomes empty, as indicated by the txxif, the next data byte can be written to txregx. 20.2.6 receiving a break character the enhanced usart module can receive a break character in two ways. the first method forces configuration of the baud rate at a frequency of 9/13 the typical speed. this allows for the stop bit transition to be at the correct sampling location (13 bits for break versus start bit and 8 data bits for typical data). the second method uses the auto-wake-up feature described in section 20.2.4 ?auto-wake-up on sync break character? . by enabling this feature, the eusart will sample the next two transitions on rxx/dtx, cause an rcxif interrupt and receive the next data byte followed by another interrupt. note that following a break character, the user will typically want to enable the auto-baud rate detect feature. for both methods, the user can set the abden bit once the txxif interrupt is observed. figure 20-10: send break character sequence write to txregx brg output (shift clock) start bit bit 0 bit 1 bit 11 stop bit break txxif bit (transmit buffer reg. empty flag) txx (pin) trmt bit (transmit shift reg. empty flag) sendb bit (transmit shift reg. empty flag) sendb sampled here auto-cleared dummy write
? 2007 microchip technology inc. preliminary ds39775b-page 293 pic18f87j50 family 20.3 eusart synchronous master mode the synchronous master mode is entered by setting the csrc bit (txstax<7>). in this mode, the data is transmitted in a half-duplex manner (i.e., transmission and reception do not occur at the same time). when transmitting data, the reception is inhibited and vice versa. synchronous mode is entered by setting bit, sync (txstax<4>). in addition, enable bit, spen (rcstax<7>), is set in order to configure the txx and rxx pins to ckx (clock) and dtx (data) lines, respectively. the master mode indicates that the processor trans- mits the master clock on the ckx line. clock polarity is selected with the sckp bit (baudconx<4>). setting sckp sets the idle state on ckx as high, while clearing the bit sets the idle state as low. this option is provided to support microwire devices with this module. 20.3.1 eusart synchronous master transmission the eusart transmitter block diagram is shown in figure 20-3. the heart of the transmitter is the transmit (serial) shift register (tsr). the shift register obtains its data from the read/write transmit buffer register, txregx. the txregx register is loaded with data in software. the tsr register is not loaded until the last bit has been transmitted from the previous load. as soon as the last bit is transmitted, the tsr is loaded with new data from the txregx (if available). once the txregx register transfers the data to the tsr register (occurs in one t cy ), the txregx is empty and the txxif flag bit is set. the interrupt can be enabled or disabled by setting or clearing the interrupt enable bit, txxie. txxif is set regardless of the state of enable bit, txxie; it cannot be cleared in software. it will reset only when new data is loaded into the txregx register. while flag bit, txxif, indicates the status of the txregx register, another bit, trmt (txstax<1>), shows the status of the tsr register. trmt is a read-only bit which is set when the tsr is empty. no interrupt logic is tied to this bit, so the user must poll this bit in order to determine if the tsr register is empty. the tsr is not mapped in data memory so it is not available to the user. to set up a synchronous master transmission: 1. initialize the spbrghx:spbrgx registers for the appropriate baud rate. set or clear the brg16 bit, as required, to achieve the desired baud rate. 2. enable the synchronous master serial port by setting bits, sync, spen and csrc. 3. if interrupts are desired, set enable bit, txxie. 4. if 9-bit transmission is desired, set bit, tx9. 5. enable the transmission by setting bit, txen. 6. if 9-bit transmission is selected, the ninth bit should be loaded in bit, tx9d. 7. start transmission by loading data to the txregx register. 8. if using interrupts, ensure that the gie and peie bits in the intcon register (intcon<7:6>) are set. figure 20-11: synchronous transmission bit 0 bit 1 bit 7 word 1 q1 q2 q3q4 q1 q2 q3 q4 q1 q2 q3 q4 q1q2 q3 q4 q1 q2 q3 q4 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 bit 2 bit 0 bit 1 bit 7 rc7/rx1/dt1 rc6/tx1/ck1 pin write to txreg1 reg tx1if bit (interrupt flag) txen bit ? 1 ? ? 1 ? word 2 trmt bit write word 1 write word 2 note: sync master mode, spbrgx = 0 , continuous transmission of two 8-bit words. this example is equally applicable to eusart2 (rg1/tx2/ck2 and rg2/rx2/dt2). rc6/tx1/ck1 pin (sckp = 0 ) (sckp = 1 )
pic18f87j50 family ds39775b-page 294 preliminary ? 2007 microchip technology inc. figure 20-12: synchronous transmis sion (through txen) table 20-7: registers associated with synchronous master transmission rc7/rx1/dt1 pin rc6/tx1/ck1 pin write to txreg1 reg tx1if bit trmt bit bit 0 bit 1 bit 2 bit 6 bit 7 txen bit note: this example is equally applicable to eu sart2 (rg1/tx2/ck2 and rg2/rx2/dt2). name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 txregx eusartx transmit register 61 txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 odcon2 ? ? ? ? u2od u1od 60 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used for synchronous master transmission.
? 2007 microchip technology inc. preliminary ds39775b-page 295 pic18f87j50 family 20.3.2 eusart synchronous master reception once synchronous mode is selected, reception is enabled by setting either the single receive enable bit, sren (rcstax<5>) or the continuous receive enable bit, cren (rcstax<4>). data is sampled on the rxx pin on the falling edge of the clock. if enable bit, sren, is set, only a single word is received. if enable bit, cren, is set, the reception is continuous until cren is cleared. if both bits are set, then cren takes precedence. to set up a synchronous master reception: 1. initialize the spbrghx:spbrgx registers for the appropriate baud rate. set or clear the brg16 bit, as required, to achieve the desired baud rate. 2. enable the synchronous master serial port by setting bits, sync, spen and csrc. 3. ensure bits, cren and sren, are clear. 4. if interrupts are desired, set enable bit, rcxie. 5. if 9-bit reception is desired, set bit, rx9. 6. if a single reception is required, set bit, sren. for continuous reception, set bit, cren. 7. interrupt flag bit, rcxif, will be set when recep- tion is complete and an interrupt will be generated if the enable bit, rcxie, was set. 8. read the rcstax register to get the 9th bit (if enabled) and determine if any error occurred during reception. 9. read the 8-bit received data by reading the rcregx register. 10. if any error occurred, clear the error by clearing bit, cren. 11. if using interrupts, ensure that the gie and peie bits in the intcon register (intcon<7:6>) are set. figure 20-13: synchronous reception (master mode, sren) cren bit rc7/rx1/dt1 rc6/tx1/ck1 pin write to bit sren sren bit rc1if bit (interrupt) read rcreg1 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q2 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 ? 0 ? bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 ? 0 ? q1 q2 q3 q4 note: timing diagram demonstrates sync master mode with bit sren = 1 and bit brgh = 0 . this example is equally applicable to eusart2 (rg1/tx2/ck2 and rg2/rx2/dt2). rc6/tx1/ck1 pin pin (sckp = 0 ) (sckp = 1 )
pic18f87j50 family ds39775b-page 296 preliminary ? 2007 microchip technology inc. table 20-8: registers associated with synchronous master reception 20.4 eusart synchronous slave mode synchronous slave mode is entered by clearing bit, csrc (txstax<7>). this mode differs from the synchronous master mode in that the shift clock is sup- plied externally at the ckx pin (instead of being supplied internally in master mode). this allows the device to transfer or receive data while in any low-power mode. 20.4.1 eusart synchronous slave transmission the operation of the synchronous master and slave modes is identical, except in the case of sleep mode. if two words are written to the txregx and then the sleep instruction is executed, the following will occur: a) the first word will immediately transfer to the tsr register and transmit. b) the second word will remain in the txregx register. c) flag bit, txxif, will not be set. d) when the first word has been shifted out of tsr, the txregx register will transfer the second word to the tsr and flag bit, txxif, will now be set. e) if enable bit, txxie, is set, the interrupt will wake the chip from sleep. if the global interrupt is enabled, the program will branch to the interrupt vector. to set up a synchronous slave transmission: 1. enable the synchronous slave serial port by setting bits, sync and spen, and clearing bit, csrc. 2. clear bits, cren and sren. 3. if interrupts are desired, set enable bit, txxie. 4. if 9-bit transmission is desired, set bit, tx9. 5. enable the transmission by setting enable bit, txen. 6. if 9-bit transmission is selected, the ninth bit should be loaded in bit, tx9d. 7. start transmission by loading data to the txregx register. 8. if using interrupts, ensure that the gie and peie bits in the intcon register (intcon<7:6>) are set. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 rcregx eusartx receive register 61 txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 odcon2 ? ? ? ? u2od u1od 60 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used for synchronous master reception.
? 2007 microchip technology inc. preliminary ds39775b-page 297 pic18f87j50 family table 20-9: registers associated with synchronous slave transmission 20.4.2 eusart synchronous slave reception the operation of the synchronous master and slave modes is identical, except in the case of sleep, or any idle mode and bit, sren, which is a ?don?t care? in slave mode. if receive is enabled by setting the cren bit prior to entering sleep or any idle mode, then a word may be received while in this low-power mode. once the word is received, the rsr register will transfer the data to the rcregx register. if the rcxie enable bit is set, the interrupt generated will wake the chip from the low-power mode. if the global interrupt is enabled, the program will branch to the interrupt vector. to set up a synchronous slave reception: 1. enable the synchronous master serial port by setting bits, sync and spen, and clearing bit, csrc. 2. if interrupts are desired, set enable bit, rcxie. 3. if 9-bit reception is desired, set bit, rx9. 4. to enable reception, set enable bit, cren. 5. flag bit, rcxif, will be set when reception is complete. an interrupt will be generated if enable bit, rcxie, was set. 6. read the rcstax register to get the 9th bit (if enabled) and determine if any error occurred during reception. 7. read the 8-bit received data by reading the rcregx register. 8. if any error occurred, clear the error by clearing bit, cren. 9. if using interrupts, ensure that the gie and peie bits in the intcon register (intcon<7:6>) are set. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 txregx eusartx transmit register 61 txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used for synchronous slave transmission.
pic18f87j50 family ds39775b-page 298 preliminary ? 2007 microchip technology inc. table 20-10: registers associated wi th synchronous slave reception name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir3 ssp2if bcl2if rc2if tx2if tmr4if ccp5if ccp4if ccp3if 62 pie3 ssp2ie bcl2ie rc2ie tx2ie tmr4ie ccp5ie ccp4ie ccp3ie 62 ipr3 ssp2ip bcl2ip rc2ip tx2ip tmr4ip ccp5ip ccp4ip ccp3ip 62 rcstax spen rx9 sren cren adden ferr oerr rx9d 61 rcregx eusartx receive register 61 txstax csrc tx9 txen sync sendb brgh trmt tx9d 61 baudconx abdovf rcidl dtrxp sckp brg16 ? wue abden 63 spbrghx eusartx baud rate generator register high byte 63 spbrgx eusartx baud rate generator register low byte 63 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used for synchronous slave reception.
? 2007 microchip technology inc. preliminary ds39775b-page 299 pic18f87j50 family 21.0 10-bit analog-to-digital converter (a/d) module the analog-to-digital (a/d) converter module has 8 inputs for the 64-pin devices and 12 for the 80-pin devices. this module allows conversion of an analog input signal to a corresponding 10-bit digital number. the module has six registers: ? a/d control register 0 (adcon0) ? a/d control register 1 (adcon1) ? a/d port configuration register 2 (ancon0) ? a/d port configuration register 1 (ancon1) ? a/d result registers (adresh and adresl) the adcon0 register, shown in register 21-1, controls the operation of the a/d module. the adcon1 register, shown in register 21-2, configures the a/d clock source, programmed acquisition time and justification. the ancon0 and ancon1 registers, shown in register 21-4 and register 21-3, configure the functions of the port pins. register 21-1: adcon0: a/ d control register 0 (1) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 vcfg1 vcfg0 chs3 chs2 chs1 chs0 go/done adon bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-6 vcfg1: voltage reference configuration bit (v ref - source) 1 = v ref - (an2) 0 = av ss bit vcfg0: voltage reference configuration bit (v ref + source) 1 = v ref + (an3) 0 = av dd bit 5-2 chs3:chs0: analog channel select bits 0000 = channel 00 (an0) 0001 = channel 01 (an1) 0010 = channel 02 (an2) 0011 = channel 03 (an3) 0100 = channel 04 (an4) 0101 = unused 0110 = unused 0111 = channel 07 (an7) 1000 = unused 1001 = unused 1010 = channel 10 (an10) 1011 = channel 11 (an11) 1100 = channel 12 (an12) (2,3) 1101 = channel 13 (an13) (2,3) 1110 = channel 14 (an14) (2,3) 1111 =channel 15 (an15) (2,3) bit 1 go/done : a/d conversion status bit when adon = 1 : 1 = a/d conversion in progress 0 = a/d idle bit 0 adon: a/d on bit 1 = a/d converter module is enabled 0 = a/d converter module is disabled note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 2: these channels are not implemented on 64-pin devices. 3: performing a conversion on unimplemented channels will return random values.
pic18f87j50 family ds39775b-page 300 preliminary ? 2007 microchip technology inc. register 21-2: adcon1: a/ d control register 1 (1) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 adfm adcal acqt2 acqt1 acqt0 adcs2 adcs1 adcs0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 adfm: a/d result format select bit 1 = right justified 0 = left justified bit 6 adcal: a/d calibration bit 1 = calibration is performed on next a/d conversion 0 = normal a/d converter operation (no conversion is performed) bit 5-3 acqt2:acqt0: a/d acquisition time select bits 111 = 20 t ad 110 = 16 t ad 101 = 12 t ad 100 = 8 t ad 011 = 6 t ad 010 = 4 t ad 001 = 2 t ad 000 = 0 t ad (2) bit 2-0 adcs2:adcs0: a/d conversion clock select bits 111 = f rc (clock derived from a/d rc oscillator) (2) 110 = f osc /64 101 = f osc /16 100 = f osc /4 011 = f rc (clock derived from a/d rc oscillator) (2) 010 = f osc /32 001 = f osc /8 000 = f osc /2 note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 2: if the a/d frc clock source is selected, a delay of one tcy (instruction cycle) is added before the a/d clock starts. this allows the sleep instruction to be executed before starting a conversion.
? 2007 microchip technology inc. preliminary ds39775b-page 301 pic18f87j50 family the ancon0 and ancon1 registers are used to configure the operation of the i/o pin associated with each analog channel. setting any one of the pcfg bits configures the corresponding pin to operate as a digital only i/o. clearing a bit configures the pin to operate as an analog input for either the a/d converter or the com- parator module; all digital peripherals are disabled, and digital inputs read as ? 0 ?. as a rule, i/o pins that are multiplexed with analog inputs default to analog operation on device resets. ancon0 and ancon1 are shared address sfrs, and use the same addresses as the adcon1 and adcon0 registers. the ancon registers are accessed by setting the adshr bit (wdtcon<4>). see section 5.3.5.1 ?shared address sfrs? for more information. register 21-3: ancon0: a/d port configuration register 2 r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 pcfg7: analog port configuration bits (an7) 1 = pin configured as a digital port 0 = pin configured as an analog channel - digital input disabled and reads ? 0 ? bit 6-5 unimplemented: read as ? 0 ? bit 4-0 pcfg4:pcfg0: analog port configuration bits (an4-an0) 1 = pin configured as a digital port 0 = pin configured as an analog channel - digital input disabled and reads ? 0 ? register 21-4: ancon1: a/d port configuration register 1 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 u-0 u-0 pcfg15 pcfg14 pcfg13 pcfg12 pcfg11 pcfg10 ? ? bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-2 pcfg15:pcfg10: analog port configuration bits (an15-an10) (1) 1 = pin configured as a digital port 0 = pin configured as an analog channel - digital input disabled and reads ? 0 ? bit 1-0 unimplemented: read as ? 0 ? note 1: an15 through an12 are available only in 80-pin devices.
pic18f87j50 family ds39775b-page 302 preliminary ? 2007 microchip technology inc. the analog reference voltage is software selectable to either the device?s positive and negative supply voltage (av dd and av ss ), or the voltage level on the ra3/an3/v ref + and ra2/an2/v ref - pins. the a/d converter has a unique feature of being able to operate while the device is in sleep mode. to operate in sleep, the a/d conversion clock must be derived from the a/d?s internal rc oscillator. the output of the sample and hold is the input into the converter, which generates the result via successive approximation. each port pin associated with the a/d converter can be configured as an analog input or as a digital i/o. the adresh and adresl registers contain the result of the a/d conversion. when the a/d conversion is com- plete, the result is loaded into the adresh:adresl register pair, the go/done bit (adcon0<1>) is cleared and a/d interrupt flag bit, adif, is set. a device reset forces all registers to their reset state. this forces the a/d module to be turned off and any conversion in progress is aborted. the value in the adresh:adresl register pair is not modified for a power-on reset. these registers will contain unknown data after a power-on reset. the block diagram of the a/d module is shown in figure 21-1. figure 21-1: a/d block diagram (input voltage) v ain v ref + reference voltage v dd (2) vcfg1:vcfg0 chs3:chs0 an7 an4 an3 an2 an1 an0 0111 0100 0011 0010 0001 0000 10-bit a/d v ref - v ss (2) converter an15 (1) an14 (1) an13 (1) an12 (1) an11 an10 1111 1110 1101 1100 1011 1010 note 1: channels an15 through an12 are not available on 64-pin devices. 2: i/o pins have diode protection to v dd and v ss .
? 2007 microchip technology inc. preliminary ds39775b-page 303 pic18f87j50 family after the a/d module has been configured as desired, the selected channel must be acquired before the conversion is started. the analog input channels must have their corresponding tris bits selected as an input. to determine acquisition time, see section 21.1 ?a/d acquisition requirements? . after this acquisi- tion time has elapsed, the a/d conversion can be started. an acquisition time can be programmed to occur between setting the go/done bit and the actual start of the conversion. the following steps should be followed to do an a/d conversion: 1. configure the a/d module: ? configure the required adc pins as analog pins using ancon0, ancon1 ? set voltage reference using adcon0 ? select a/d input channel (adcon0) ? select a/d acquisition time (adcon1) ? select a/d conversion clock (adcon1) ? turn on a/d module (adcon0) 2. configure a/d interrupt (if desired): ? clear adif bit ? set adie bit ? set gie bit 3. wait the required acquisition time (if required). 4. start conversion: ? set go/done bit (adcon0<1>) 5. wait for a/d conversion to complete, by either: ? polling for the go/done bit to be cleared or ? waiting for the a/d interrupt 6. read a/d result registers (adresh:adresl); clear bit, adif, if required. 7. for next conversion, go to step 1 or step 2, as required. the a/d conversion time per bit is defined as t ad . a minimum wait of 2 t ad is required before next acquisition starts. figure 21-2: analog input model v ain c pin r s anx 5 pf v dd v t = 0.6v v t = 0.6v i leakage r ic 1k sampling switch ss r ss c hold = 25 pf v ss sampling switch 123 4 (k ) v dd 100 na legend: c pin v t i leakage r ic ss c hold = input capacitance = threshold voltage = leakage current at the pin due to = interconnect resistance = sampling switch = sample/hold capacitance (from dac) various junctions = sampling switch resistance r ss
pic18f87j50 family ds39775b-page 304 preliminary ? 2007 microchip technology inc. 21.1 a/d acquisition requirements for the a/d converter to meet its specified accuracy, the charge holding capacitor (c hold ) must be allowed to fully charge to the input channel voltage level. the analog input model is shown in figure 21-2. the source impedance (r s ) and the internal sampling switch (r ss ) impedance directly affect the time required to charge the capacitor c hold . the sampling switch (r ss ) impedance varies over the device voltage (v dd ). the source impedance affects the offset voltage at the analog input (due to pin leakage current). the maximum recommended impedance for analog sources is 2.5 k . after the analog input channel is selected (changed), the channel must be sampled for at least the minimum acquisition time before starting a conversion. to calculate the minimum acquisition time, equation 21-1 may be used. this equation assumes that 1/2 lsb error is used (1024 steps for the a/d). the 1/2 lsb error is the maximum error allowed for the a/d to meet its specified resolution. equation 21-3 shows the calculation of the minimum required acquisition time, t acq . this calculation is based on the following application system assumptions: c hold =25 pf rs = 2.5 k conversion error 1/2 lsb v dd =3v rss = 2 k temperature = 85 c (system max.) equation 21-1: acquisition time equation 21-2: a/d minimum charging time equation 21-3: calculating the minimum required acquisition time note: when the conversion is started, the holding capacitor is disconnected from the input pin. t acq = amplifier settling time + holding capacitor charging time + temperature coefficient =t amp + t c + t coff v hold = (v ref ? (v ref /2048)) ? (1 ? e (-t c /c hold (r ic + r ss + r s )) ) or t c = -(c hold )(r ic + r ss + r s ) ln(1/2048) t acq =t amp + t c + t coff t amp =0.2 s t coff = (temp ? 25 c)(0.02 s/ c) (85 c ? 25 c)(0.02 s/ c) 1.2 s temperature coefficient is only required for temperatures > 25 c. below 25 c, t coff = 0 ms. t c = -(c hold )(r ic + r ss + r s ) ln(1/2048) s -(25 pf) (1 k + 2 k + 2.5 k ) ln(0.0004883) s 1.05 s t acq =0.2 s + 1.05 s + 1.2 s 2.45 s
? 2007 microchip technology inc. preliminary ds39775b-page 305 pic18f87j50 family 21.2 selecting and configuring automatic acquisition time the adcon1 register allows the user to select an acquisition time that occurs each time the go/done bit is set. when the go/done bit is set, sampling is stopped and a conversion begins. the user is responsible for ensur- ing the required acquisition time has passed between selecting the desired input channel and setting the go/done bit. this occurs when the acqt2:acqt0 bits (adcon1<5:3>) remain in their reset state (? 000 ?) and is compatible with devices that do not offer programmable acquisition times. if desired, the acqt bits can be set to select a pro- grammable acquisition time for the a/d module. when the go/done bit is set, the a/d module continues to sample the input for the selected acquisition time, then automatically begins a conversion. since the acquisi- tion time is programmed, there may be no need to wait for an acquisition time between selecting a channel and setting the go/done bit. in either case, when the conversion is completed, the go/done bit is cleared, the adif flag is set and the a/d begins sampling the currently selected channel again. if an acquisition time is programmed, there is nothing to indicate if the acquisition time has ended or if the conversion has begun. 21.3 selecting the a/d conversion clock the a/d conversion time per bit is defined as t ad . the a/d conversion requires 11 t ad per 10-bit conversion. the source of the a/d conversion clock is software selectable. there are seven possible options for t ad : ?2 t osc ?4 t osc ?8 t osc ?16 t osc ?32 t osc ?64 t osc ? internal rc oscillator for correct a/d conversions, the a/d conversion clock (t ad ) must be as short as possible but greater than the minimum t ad (see parameter 130 in table 28-29 for more information). table 21-1 shows the resultant t ad times derived from the device operating frequencies and the a/d clock source selected. table 21-1: t ad vs. device operating frequencies 21.4 configuring analog port pins the ancon0, ancon1, trisa, trisf and trish registers control the operation of the a/d port pins. the port pins needed as analog inputs must have their cor- responding tris bits set (input). if the tris bit is cleared (output), the digital output level (v oh or v ol ) will be converted. the a/d operation is independent of the state of the chs3:chs0 bits and the tris bits. ad clock source (t ad )maximum device frequency operation adcs2:adcs0 2 t osc 000 2.86 mhz 4 t osc 100 5.71 mhz 8 t osc 001 11.43 mhz 16 t osc 101 22.86 mhz 32 t osc 010 45.71 mhz 64 t osc 110 48.0 mhz rc (2) x11 1.00 mhz (1) note 1: the rc source has a typical t ad time of 4 s. 2: for device frequencies above 1 mhz, the device must be in sleep mode for the entire conversion or the a/d accuracy may be out of specification. note 1: when reading the port register, all pins configured as analog input channels will read as cleared (a low level). pins config- ured as digital inputs will convert an analog input. analog levels on a digitally configured input will be accurately converted. 2: analog levels on any pin defined as a digital input may cause the digital input buffer to consume current out of the device?s specification limits.
pic18f87j50 family ds39775b-page 306 preliminary ? 2007 microchip technology inc. 21.5 a/d conversions figure 21-3 shows the operation of the a/d converter after the go/done bit has been set and the acqt2:acqt0 bits are cleared. a conversion is started after the following instruction to allow entry into sleep mode before the conversion begins. figure 21-4 shows the operation of the a/d converter after the go/done bit has been set, the acqt2:acqt0 bits are set to ? 010 ? and selecting a 4t ad acquisition time before the conversion starts. clearing the go/done bit during a conversion will abort the current conversion. the a/d result register pair will not be updated with the partially completed a/d conversion sample. this means the adresh:adresl registers will continue to contain the value of the last completed conversion (or the last value written to the adresh:adresl registers). after the a/d conversion is completed or aborted, a 2t ad wait is required before the next acquisition can be started. after this wait, acquisition on the selected channel is automatically started. 21.6 use of the eccp2 trigger an a/d conversion can be started by the ?special event trigger? of the eccp2 module. this requires that the ccp2m3:ccp2m0 bits (ccp2con<3:0>) be programmed as ? 1011 ? and that the a/d module is enabled (adon bit is set). when the trigger occurs, the go/done bit will be set, starting the a/d acquisition and conversion, and the timer1 (or timer3) counter will be reset to zero. timer1 (or timer3) is reset to auto- matically repeat the a/d acquisition period with minimal software overhead (moving adresh/adresl to the desired location). the appropriate analog input channel must be selected and the minimum acquisition period is either timed by the user, or an appropriate t acq time is selected before the special event trigger sets the go/done bit (starts a conversion). if the a/d module is not enabled (adon is cleared), the special event trigger will be ignored by the a/d module but will still reset the timer1 (or timer3) counter. figure 21-3: a/d conversion t ad cycles (acqt2:acqt0 = 000 , t acq = 0 ) figure 21-4: a/d conversion t ad cycles (acqt2:acqt0 = 010 , t acq = 4 t ad ) note: the go/done bit should not be set in the same instruction that turns on the a/d. t ad 1 t ad 2 t ad 3 t ad 4 t ad 5 t ad 6 t ad 7 t ad 8 t ad 11 set go/done bit holding capacitor is disconnected from analog input (typically 100 ns) t ad 9 t ad 10 t cy - t ad next q4: adresh/adresl is loaded, go/done bit is cleared, adif bit is set, holding capacitor is connected to analog input. conversion starts b0 b9 b6 b5 b4 b3 b2 b1 b8 b7 1 2 3 4 5 6 7 8 11 set go/done bit (holding capacitor is disconnected) 9 10 next q4: adresh:adresl is loaded, go/done bit is cleared, adif bit is set, holding capacitor is reconnected to analog input. conversion starts 1 2 3 4 (holding capacitor continues acquiring input) t acqt cycles t ad cycles automatic acquisition time b0 b9 b6 b5 b4 b3 b2 b1 b8 b7
? 2007 microchip technology inc. preliminary ds39775b-page 307 pic18f87j50 family 21.7 a/d converter calibration the a/d converter in the pic18f87j50 family of devices includes a self-calibration feature which com- pensates for any offset generated within the module. the calibration process is automated and is initiated by setting the adcal bit (adcon1<6>). the next time the go/done bit is set, the module will perform a ?dummy? conversion (that is, with reading none of the input channels) and store the resulting value internally to compensate for the offset. thus, subsequent offsets will be compensated. an example of a calibration routine is shown in example 21-1. the calibration process assumes that the device is in a relatively steady-state operating condition. if a/d calibration is used, it should be performed after each device reset or if there are other major changes in operating conditions. 21.8 operation in power-managed modes the selection of the automatic acquisition time and a/d conversion clock is determined in part by the clock source and frequency while in a power-managed mode. if the a/d is expected to operate while the device is in a power-managed mode, the acqt2:acqt0 and adcs2:adcs0 bits in adcon1 should be updated in accordance with the power-managed mode clock that will be used. after the power-managed mode is entered (either of the power-managed run modes), an a/d acquisition or conversion may be started. once an acquisition or conversion is started, the device should continue to be clocked by the same power-managed mode clock source until the conversion has been com- pleted. if desired, the device may be placed into the corresponding power-managed idle mode during the conversion. if the power-managed mode clock frequency is less than 1 mhz, the a/d rc clock source should be selected. operation in the sleep mode requires the a/d rc clock to be selected. if bits, acqt2:acqt0, are set to ? 000 ? and a conversion is started, the conversion will be delayed one instruction cycle to allow execution of the sleep instruction and entry to sleep mode. the idlen and scs bits in the osccon register must have already been cleared prior to starting the conversion. example 21-1: sample a/d calibration routine bsf wdtcon,adshr ;enable write/read to the shared sfr bcf ancon0,pcfg0 ;make channel 0 analog bcf wdtcon,adshr ;disable write/read to the shared sfr bsf adcon0,adon ;enable a/d module bsf adcon1,adcal ;enable calibration bsf adcon0,go ;start a dummy a/d conversion calibration ; btfsc adcon0,go ;wait for the dummy conversion to finish bra calibration ; bcf adcon1,adcal ;calibration done, turn off calibration enable ;proceed with the actual a/d conversion
pic18f87j50 family ds39775b-page 308 preliminary ? 2007 microchip technology inc. table 21-2: summary of a/d registers name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir1 pmpif adif rc1if tx1if ssp1if ccp1if tmr2if tmr1if 62 pie1 pmpie adie rc1ie tx1ie ssp1ie ccp1ie tmr2ie tmr1ie 62 ipr1 pmpip adip rc1ip tx1ip ssp1ip ccp1ip tmr2ip tmr1ip 62 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 62 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 62 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 62 adresh a/d result register high byte 61 adresl a/d result register low byte 61 adcon0 (1) vcfg1 vcfg0 chs3 chs3 chs1 chs0 go/done adon 61 ancon0 (2) pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 61 adcon1 (1) adfm adcal acqt2 acqt1 acqt0 adcs2 adcs1 adcs0 61 ancon1 (2) pcfg15 pcfg14 pcfg13 pcfg12 pcfg11 pcfg10 ? ?61 ccp2con p2m1 p2m0 dc2b1 dc2b0 ccp2m3 ccp2m2 ccp2m1 ccp2m0 61 porta ? ? ra5 ra4 ra3 ra2 ra1 ra0 63 trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 62 portf rf7 rf6 rf5 rf4 rf3 rf2 ? ?63 trisf trisf5 trisf4 trisf5 trisf4 trisf3 trisf2 ? ?62 porth (3) rh7 rh6 rh5 rh4 rh3 rh2 rh1 rh0 63 trish (3) trish7 trish6 trish5 trish4 trish3 trish2 trish1 trish0 62 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used for a/d conversion. note 1: default (legacy) sfr at this address, available when wdtcon<4> = 0 . 2: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 3: this register is not implemented on 64-pin devices.
? 2007 microchip technology inc. preliminary ds39775b-page 309 pic18f87j50 family 22.0 universal serial bus (usb) this section describes the details of the usb peripheral. because of the very specific nature of the module, knowledge of usb is expected. some high-level usb information is provided in section 22.9 ?overview of usb? only for application design refer- ence. designers are encouraged to refer to the official specification published by the usb implementers forum (usb-if) for the latest information. usb speci- fication revision 2.0 is the most current specification at the time of publication of this document. 22.1 overview of the usb peripheral pic18f87j50 family devices contain a full-speed and low-speed, compatible usb serial interface engine (sie) that allows fast communication between any usb host and the pic ? microcontroller. the sie can be interfaced directly to the usb, utilizing the internal transceiver. some special hardware features have been included to improve performance. dual access port memory in the device?s data memory space (usb ram) has been supplied to share direct memory access between the microcontroller core and the sie. buffer descriptors are also provided, allowing users to freely program end- point memory usage within the usb ram space. figure 22-1 presents a general overview of the usb peripheral and its features. figure 22-1: usb peripheral and options 3.9 kbyte usb ram usb sie usb control and transceiver p p d+ d- internal pull-ups external 3.3v supply fsen upuen utrdis usb clock from the oscillator module optional external pull-ups (1) (low (full pic18f87j50 family usb bus fs speed) speed) note 1: the internal pull-up resistors should be disabled (upuen = 0 ) if external pull-up resistors are used. configuration v usb
pic18f87j50 family ds39775b-page 310 preliminary ? 2007 microchip technology inc. 22.2 usb status and control the operation of the usb module is configured and managed through three control registers. in addition, a total of 22 registers are used to manage the actual usb transactions. the registers are: ? usb control register (ucon) ? usb configuration register (ucfg) ? usb transfer status register (ustat) ? usb device address register (uaddr) ? frame number registers (ufrmh:ufrml) ? endpoint enable registers 0 through 15 (uepn) 22.2.1 usb control register (ucon) the usb control register (register 22-1) contains bits needed to control the module behavior during transfers. the register contains bits that control the following: ? main usb peripheral enable ? ping-pong buffer pointer reset ? control of the suspend mode ? packet transfer disable in addition, the usb control register contains a status bit, se0 (ucon<5>), which is used to indicate the occurrence of a single-ended zero on the bus. when the usb module is enabled, this bit should be moni- tored to determine whether the differential data lines have come out of a single-ended zero condition. this helps to differentiate the initial power-up state from the usb reset signal. the overall operation of the usb module is controlled by the usben bit (ucon<3>). setting this bit activates the module and resets all of the ppbi bits in the buffer descriptor table to ? 0 ?. this bit also activates the inter- nal pull-up resistors, if they are enabled. thus, this bit can be used as a soft attach/detach to the usb. although all status and control bits are ignored when this bit is clear, the module needs to be fully preconfig- ured prior to setting this bit. this bit cannot be set until the usb module is supplied with an active clock source. if the pll is being used, it should be enabled at least two milliseconds (enough time for the pll to lock) before attempting to set the usben bit. register 22-1: ucon: usb control register u-0 r/w-0 r-x r/c-0 r/w-0 r/w-0 r/w-0 u-0 ? ppbrst se0 pktdis usben (1) resume suspnd ? bit 7 bit 0 legend: c = clearable bit r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 unimplemented: read as ? 0 ? bit 6 ppbrst: ping-pong buffers reset bit 1 = reset all ping-pong buffer pointers to the even buffer descriptor (bd) banks 0 = ping-pong buffer pointers not being reset bit 5 se0: live single-ended zero flag bit 1 = single-ended zero active on the usb bus 0 = no single-ended zero detected bit 4 pktdis: packet transfer disable bit 1 = sie token and packet processing disabled, automatically set when a setup token is received 0 = sie token and packet processing enabled bit 3 usben: usb module enable bit (1) 1 = usb module and supporting circuitry enabled (device attached) 0 = usb module and supporting circuitry disabled (device detached) bit 2 resume: resume signaling enable bit 1 = resume signaling activated 0 = resume signaling disabled bit 1 suspnd: suspend usb bit 1 = usb module and supporting circuitry in power conserve mode, sie clock inactive 0 = usb module and supporting circuitry in normal operation, sie clock clocked at the configured rate bit 0 unimplemented : read as ? 0 ? note 1: this bit cannot be set if the usb module does not have an appropriate clock source.
? 2007 microchip technology inc. preliminary ds39775b-page 311 pic18f87j50 family the ppbrst bit (ucon<6>) controls the reset status when double-buffering mode (ping-pong buffering) is used. when the ppbrst bit is set, all ping-pong buffer pointers are set to the even buffers. ppbrst has to be cleared by firmware. this bit is ignored in buffering modes not using ping-pong buffering. the pktdis bit (ucon<4>) is a flag indicating that the sie has disabled packet transmission and reception. this bit is set by the sie when a setup token is received to allow setup processing. this bit cannot be set by the microcontroller, only cleared; clearing it allows the sie to continue transmission and/or reception. any pending events within the buffer descriptor table will still be available, indicated within the ustat register?s fifo buffer. the resume bit (ucon<2>) allows the peripheral to perform a remote wake-up by executing resume signaling. to generate a valid remote wake-up, firmware must set resume for 10 ms and then clear the bit. for more information on resume signaling, see sections 7.1.7.5, 11.4.4 and 11.9 in the usb 2.0 specification. the suspnd bit (ucon<1>) places the module and supporting circuitry in a low-power mode. the input clock to the sie is also disabled. this bit should be set by the software in response to an idleif interrupt. it should be reset by the microcontroller firmware after an actvif interrupt is observed. when this bit is active, the device remains attached to the bus but the trans- ceiver outputs remain idle. the voltage on the v usb pin may vary depending on the value of this bit. setting this bit before a idleif request will result in unpredictable bus behavior. 22.2.2 usb configuration register (ucfg) prior to communicating over usb, the module?s associated internal and/or external hardware must be configured. most of the configuration is performed with the ucfg register (register 22-2).the ufcg register contains most of the bits that control the system level behavior of the usb module. these include: ? bus speed (full speed versus low speed) ? on-chip pull-up resistor enable ? on-chip transceiver enable ? ping-pong buffer usage the ucfg register also contains two bits which aid in module testing, debugging and usb certifications. these bits control output enable state monitoring and eye pattern generation. 22.2.2.1 internal transceiver the usb peripheral has a built-in, usb 2.0, full-speed and low-speed capable transceiver, internally con- nected to the sie. this feature is useful for low-cost, single chip applications. the utrdis bit (ucfg<3>) controls the transceiver; it is enabled by default (utrdis = 0 ). the fsen bit (ucfg<2>) controls the transceiver speed; setting the bit enables full-speed operation. the on-chip usb pull-up resistors are controlled by the upuen bit (ucfg<4>). they can only be selected when the on-chip transceiver is enabled. the internal usb transceiver obtains power from the v usb pin. in order to meet usb signalling level specifi- cations, v usb must be supplied with a voltage source between 3.0v and 3.6v. the best electrical signal qual- ity is obtained when a 3.3v supply is used and locally bypassed with a high quality ceramic capacitor. the capacitor should be placed as close as possible to the v usb and v ss pins found on the same edge of the package (i.e., route ground of the capacitor to v ss pin 25 on 64-lead tqfp packaged parts, or pin 31 on 80-lead tqfp parts). v usb should be held to within +/-300 mv of v dd . for most applications, v usb and v dd should be connected together and powered from a nominal 3.3v source. when the usb module is not being used, v usb should still be connected to v dd , but v usb /v dd may be connected to a 2.0v to 3.6v source. the d+ and d- signal lines can be routed directly to their respective pins on the usb connector or cable (for hard-wired applications). no additional resistors, capacitors, or magnetic components are required as the d+ and d- drivers have controlled slew rate and output impedance intended to match with the characteristic impedance of the usb cable. in order to meet the usb specifications, the traces should be less than 30 cm long. ideally, these traces should be designed to have a characteristic impedance matching that of the usb cable. note: while in suspend mode, a typical bus-powered usb device is limited to 500 a of current. this is the complete current which may be drawn by the pic device and its supporting circuitry. care should be taken to assure minimum current draw when the device enters suspend mode. note: the usb speed, transceiver and pull-up should only be configured during the mod- ule setup phase. it is not recommended to switch these settings while the module is enabled.
pic18f87j50 family ds39775b-page 312 preliminary ? 2007 microchip technology inc. register 22-2: ucfg: us b configuration register r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 uteye ? ? upuen (1,2) utrdis (1) fsen (1) ppb1 ppb0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 uteye: usb eye pattern test enable bit 1 = eye pattern test enabled 0 = eye pattern test disabled bit 6 unimplemented: always should be programmed to ? 0 ? (3) bit 5 unimplemented: read as ? 0 ? bit 4 upuen: usb on-chip pull-up enable bit (1,2) 1 = on-chip pull-up enabled (pull-up on d+ with fsen = 1 or d- with fsen = 0 ) 0 = on-chip pull-up disabled bit 3 utrdis: on-chip transceiver disable bit (1) 1 = on-chip transceiver disabled 0 = on-chip transceiver active bit 2 fsen: full-speed enable bit (1) 1 = full-speed device: controls transceiver edge rates; requires input clock at 48 mhz 0 = low-speed device: controls transceiver edge rates; requires input clock at 6 mhz bit 1-0 ppb1:ppb0: ping-pong buffers configuration bits 11 = even/odd ping-pong buffers enabled for endpoints 1 to 15 10 = even/odd ping-pong buffers enabled for all endpoints 01 = even/odd ping-pong buffer enabled for out endpoint 0 00 = even/odd ping-pong buffers disabled note 1: the upuen, utrdis and fsen bits should never be changed while the usb module is enabled. these values must be preconfigured prior to enabling the module. 2: this bit is only valid when the on-chip transceiver is active (utrdis = 0 ); otherwise, it is ignored. 3: firmware should never set this bit. doing so may cause unexpected behavior.
? 2007 microchip technology inc. preliminary ds39775b-page 313 pic18f87j50 family 22.2.2.2 internal pull-up resistors the pic18f87j50 family devices have built-in pull-up resistors designed to meet the requirements for low-speed and full-speed usb. the upuen bit (ucfg<4>) enables the internal pull-ups. figure 22-1 shows the pull-ups and their control. 22.2.2.3 external pull-up resistors external pull-up may also be used. the v usb pin may be used to pull up d+ or d-. the pull-up resistor must be 1.5 k (5%) as required by the usb specifications. figure 22-2 shows an example. figure 22-2: external circuitry 22.2.2.4 ping-pong buffer configuration the usage of ping-pong buffers is configured using the ppb1:ppb0 bits. refer to section 22.4.4 ?ping-pong buffering? for a complete explanation of the ping-pong buffers. 22.2.2.5 eye pattern test enable an automatic eye pattern test can be generated by the module when the ucfg<7> bit is set. the eye pattern output will be observable based on module settings, meaning that the user is first responsible for configuring the sie clock settings, pull-up resistor and transceiver mode. in addition, the module has to be enabled. once uteye is set, the module emulates a switch from a receive to transmit state and will start transmitting a j-k-j-k bit sequence (k-j-k-j for full speed). the sequence will be repeated indefinitely while the eye pattern test mode is enabled. note that this bit should never be set while the module is connected to an actual usb system. this test mode is intended for board verification to aid with usb certi- fication tests. it is intended to show a system developer the noise integrity of the usb signals which can be affected by board traces, impedance mismatches and proximity to other system components. it does not properly test the transition from a receive to a transmit state. although the eye pattern is not meant to replace the more complex usb certification test, it should aid during first order system debugging. note: the official usb specifications require that usb devices must never source any cur- rent onto the +5v v bus line of the usb cable. additionally, usb devices must never source any current on the d+ and d- data lines whenever the +5v v bus line is less than 1.17v. in order to meet this requirement, applications which are not purely bus powered should monitor the v bus line and avoid turning on the usb module and the d+ or d- pull-up resistor until v bus is greater than 1.17v. v bus can be connected to and monitored by any 5v tolerant i/o pin for this purpose. pic ? microcontroller host controller/hub v usb d+ d- note: the above setting shows a typical connection for a full-speed configuration using an on-chip regulator and an external pull-up resistor. 1.5 k
pic18f87j50 family ds39775b-page 314 preliminary ? 2007 microchip technology inc. 22.2.3 usb status register (ustat) the usb status register reports the transaction status within the sie. when the sie issues a usb transfer complete interrupt, ustat should be read to determine the status of the transfer. ustat contains the transfer endpoint number, direction and ping-pong buffer pointer value (if used). the ustat register is actually a read window into a four-byte status fifo, maintained by the sie. it allows the microcontroller to process one transfer while the sie processes additional endpoints (figure 22-3). when the sie completes using a buffer for reading or writing data, it updates the ustat register. if another usb transfer is performed before a transaction complete interrupt is serviced, the sie will store the status of the next transfer into the status fifo. clearing the transfer complete flag bit, trnif, causes the sie to advance the fifo. if the next data in the fifo holding register is valid, the sie will reassert the interrupt within 6 t cy of clearing trnif. if no additional data is present, trnif will remain clear; ustat data will no longer be reliable. figure 22-3: ustat fifo note: the data in the usb status register is valid only when the trnif interrupt flag is asserted. note: if an endpoint request is received while the ustat fifo is full, the sie will automatically issue a nak back to the host. data bus ustat from sie 4-byte fifo for ustat clearing trnif advances fifo register 22-3: ustat: usb status register u-0 r-x r-x r-x r-x r-x r-x u-0 ? endp3 endp2 endp1 endp0 dir ppbi (1) ? bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 unimplemented: read as ? 0 ? bit 6-3 endp3:endp0: encoded number of last endpoint activity bits (represents the number of the bdt updated by the last usb transfer) 1111 = endpoint 15 1110 = endpoint 14 .... 0001 = endpoint 1 0000 = endpoint 0 bit 2 dir: last bd direction indicator bit 1 = the last transaction was an in token 0 = the last transaction was an out or setup token bit 1 ppbi: ping-pong bd pointer indicator bit (1) 1 = the last transaction was to the odd bd bank 0 = the last transaction was to the even bd bank bit 0 unimplemented: read as ? 0 ? note 1: this bit is only valid for endpoints with available even and odd bd registers.
? 2007 microchip technology inc. preliminary ds39775b-page 315 pic18f87j50 family 22.2.4 usb endpoint control each of the 16 possible bidirectional endpoints has its own independent control register, uepn (where ?n? rep- resents the endpoint number). each register has an identical complement of control bits. the prototype is shown in register 22-4. the ephshk bit (uepn<4>) controls handshaking for the endpoint; setting this bit enables usb handshaking. typically, this bit is always set except when using isochronous endpoints. the epcondis bit (uepn<3>) is used to enable or disable usb control operations (setup) through the endpoint. clearing this bit enables setup transac- tions. note that the corresponding epinen and epouten bits must be set to enable in and out transactions. for endpoint 0, this bit should always be cleared since the usb specifications identify endpoint 0 as the default control endpoint. the epouten bit (uepn<2>) is used to enable or dis- able usb out transactions from the host. setting this bit enables out transactions. similarly, the epinen bit (uepn<1>) enables or disables usb in transactions from the host. the epstall bit (uepn<0>) is used to indicate a stall condition for the endpoint. if a stall is issued on a particular endpoint, the epstall bit for that end- point pair will be set by the sie. this bit remains set until it is cleared through firmware, or until the sie is reset. register 22-4: uepn: usb endpoint n co ntrol register (uep0 through uep15) u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? ? ephshk epcondis epouten epinen epstall (1) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-5 unimplemented: read as ? 0 ? bit 4 ephshk: endpoint handshake enable bit 1 = endpoint handshake enabled 0 = endpoint handshake disabled (typically used for isochronous endpoints) bit 3 epcondis: bidirectional endpoint control bit if epouten = 1 and epinen = 1 : 1 = disable endpoint n from control transfers; only in and out transfers allowed 0 = enable endpoint n for control (setup) transfers; in and out transfers also allowed bit 2 epouten: endpoint output enable bit 1 = endpoint n output enabled 0 = endpoint n output disabled bit 1 epinen: endpoint input enable bit 1 = endpoint n input enabled 0 = endpoint n input disabled bit 0 epstall: endpoint stall enable bit (1) 1 = endpoint n is stalled 0 = endpoint n is not stalled note 1: valid only if endpoint n is enabled; otherwise, the bit is ignored.
pic18f87j50 family ds39775b-page 316 preliminary ? 2007 microchip technology inc. 22.2.5 usb address register (uaddr) the usb address register contains the unique usb address that the peripheral will decode when active. uaddr is reset to 00h when a usb reset is received, indicated by urstif, or when a reset is received from the microcontroller. the usb address must be written by the microcontroller during the usb setup phase (enumeration) as part of the microchip usb firmware support. 22.2.6 usb frame number registers (ufrmh:ufrml) the frame number registers contain the 11-bit frame number. the low-order byte is contained in ufrml, while the three high-order bits are contained in ufrmh. the register pair is updated with the current frame number whenever a sof token is received. for the microcontroller, these registers are read-only. the frame number registers are primarily used for isochronous transfers. the contents of the ufrmh and ufrml registers are only valid when the 48 mhz sie clock is active (i.e., contents are inaccurate when suspnd (ucon<1>) bit = 1 ). 22.3 usb ram usb data moves between the microcontroller core and the sie through a memory space known as the usb ram. this is a special dual access memory that is mapped into the normal data memory space in banks 0 through 15 (60h to f3fh) for a total of 3.9 kbyte (figure 22-4). bank 4 (400h through 4ffh) is used specifically for endpoint buffer control, while banks 0 through bank3 and banks 5 through bank15 are available for usb data. depending on the type of buffering being used, all but 8 bytes of bank 4 may also be available for use as usb buffer space. although usb ram is available to the microcontroller as data memory, the sections that are being accessed by the sie should not be accessed by the microcontroller. a semaphore mechanism is used to determine the access to a particular buffer at any given time. this is discussed in section 22.4.1.1 ?buffer ownership? . figure 22-4: implementation of usb ram in data memory space 400h 4ffh 500h usb data or buffer descriptors, usb data or user data user data usb data or sfrs 3ffh 000h f60h fffh banks 0 (usb ram) f5fh to 15 access ram 060h 05fh f40h f3fh f00h user data
? 2007 microchip technology inc. preliminary ds39775b-page 317 pic18f87j50 family 22.4 buffer descriptors and the buffer descriptor table the registers in bank 4 are used specifically for end- point buffer control in a structure known as the buffer descriptor table (bdt). this provides a flexible method for users to construct and control endpoint buffers of various lengths and configuration. the bdt is composed of buffer descriptors (bd) which are used to define and control the actual buffers in the usb ram space. each bd, in turn, consists of four reg- isters, where n represents one of the 64 possible bds (range of 0 to 63): ? bdnstat: bd status register ? bdncnt: bd byte count register ? bdnadrl: bd address low register ? bdnadrh: bd address high register bds always occur as a four-byte block in the sequence, bdnstat:bdncnt:bdnadrl:bdnadrh. the address of bdnstat is always an offset of (4n ? 1) (in hexa- decimal) from 400h, with n being the buffer descriptor number. depending on the buffering configuration used ( section 22.4.4 ?ping-pong buffering? ), there are up to 32, 33 or 64 sets of buffer descriptors. at a minimum, the bdt must be at least 8 bytes long. this is because the usb specification mandates that every device must have endpoint 0 with both input and output for initial setup. depending on the endpoint and buffering configuration, the bdt can be as long as 256 bytes. although they can be thought of as special function registers, the buffer descriptor status and address registers are not hardware mapped, as conventional microcontroller sfrs in bank 15 are. if the endpoint cor- responding to a particular bd is not enabled, its registers are not used. instead of appearing as unimplemented addresses, however, they appear as available ram. only when an endpoint is enabled by setting the uepn<1> bit does the memory at those addresses become functional as bd registers. as with any address in the data memory space, the bd registers have an indeterminate value on any device reset. an example of a bd for a 64-byte buffer, starting at 500h, is shown in figure 22-5. a particular set of bd registers is only valid if the corresponding endpoint has been enabled using the uepn register. all bd registers are available in usb ram. the bd for each endpoint should be set up prior to enabling the endpoint. 22.4.1 bd status and configuration buffer descriptors not only define the size of an end- point buffer, but also determine its configuration and control. most of the configuration is done with the bd status register, bdnstat. each bd has its own unique and correspondingly numbered bdnstat register. figure 22-5: example of a buffer descriptor unlike other control registers, the bit configuration for the bdnstat register is context sensitive. there are two distinct configurations, depending on whether the microcontroller or the usb module is modifying the bd and buffer at a particular time. only three bit definitions are shared between the two. 22.4.1.1 buffer ownership because the buffers and their bds are shared between the cpu and the usb module, a simple semaphore mechanism is used to distinguish which is allowed to update the bd and associated buffers in memory. this is done by using the uown bit (bdnstat<7>) as a semaphore to distinguish which is allowed to update the bd and associated buffers in memory. uown is the only bit that is shared between the two configurations of bdnstat. when uown is clear, the bd entry is ?owned? by the microcontroller core. when the uown bit is set, the bd entry and the buffer memory are ?owned? by the usb peripheral. the core should not modify the bd or its corresponding data buffer during this time. note that the microcontroller core can still read bdnstat while the sie owns the buffer and vice versa. the buffer descriptors have a different meaning based on the source of the register update. prior to placing ownership with the usb peripheral, the user can con- figure the basic operation of the peripheral through the bdnstat bits. during this time, the byte count and buffer location registers can also be set. when uown is set, the user can no longer depend on the values that were written to the bds. from this point, the sie updates the bds as necessary, overwriting the original bd values. the bdnstat register is updated by the sie with the token pid and the transfer count, bdncnt, is updated. 400h usb data buffer buffer bd0stat bd0cnt bd0adrl bd0adrh 401h 402h 403h 500h 53fh descriptor note: memory regions not to scale. 40h 00h 05h starting size of block (xxh) registers address contents address
pic18f87j50 family ds39775b-page 318 preliminary ? 2007 microchip technology inc. the bdnstat byte of the bdt should always be the last byte updated when preparing to arm an endpoint. the sie will clear the uown bit when a transaction has completed. no hardware mechanism exists to block access when the uown bit is set. thus, unexpected behavior can occur if the microcontroller attempts to modify memory when the sie owns it. similarly, reading such memory may produce inaccurate data until the usb peripheral returns ownership to the microcontroller. 22.4.1.2 bdnstat register (cpu mode) when uown = 0 , the microcontroller core owns the bd. at this point, the other seven bits of the register take on control functions. the data toggle sync enable bit, dtsen (bdnstat<3>), controls data toggle parity checking. setting dtsen enables data toggle synchronization by the sie. when enabled, it checks the data packet?s par- ity against the value of dts (bdnstat<6>). if a packet arrives with an incorrect synchronization, the data will essentially be ignored. it will not be written to the usb ram and the usb transfer complete interrupt flag will not be set. the sie will send an ack token back to the host to acknowledge receipt, however. the effects of the dtsen bit on the sie are summarized in table 22-1. the buffer stall bit, bstall (bdnstat<2>), provides support for control transfers, usually one-time stalls on endpoint 0. it also provides support for the set_feature/clear_feature commands speci- fied in chapter 9 of the usb specification; typically, continuous stalls to any endpoint other than the default control endpoint. the bstall bit enables buffer stalls. setting bstall causes the sie to return a stall token to the host if a received token would use the bd in that location. the epstall bit in the corresponding uepn control regis- ter is set and a stall interrupt is generated when a stall is issued to the host. the uown bit remains set and the bds are not changed unless a setup token is received. in this case, the stall condition is cleared and the ownership of the bd is returned to the microcontroller core. the bd9:bd8 bits (bdnstat<1:0>) store the two most significant digits of the sie byte count; the lower 8 digits are stored in the corresponding bdncnt register. see section 22.4.2 ?bd byte count? for more information. table 22-1: effect of dtsen bit on odd/even (data0/data1) packet reception out packet from host bdnstat settings device response after receiving packet dtsen dts handshake uown trnif bdnstat and ustat status data0 10 ack 01 updated data1 10 ack 10 not updated data0 11 ack 10 not updated data1 11 ack 01 updated either 0x ack 01 updated either, with error xx nak 10 not updated legend: x = don?t care
? 2007 microchip technology inc. preliminary ds39775b-page 319 pic18f87j50 family register 22-5: bdnstat: buffer descriptor n status register (bd0stat through bd63stat), cpu mode (data is written to the side) r/w-x r/w-x u-0 u-0 r/w-x r/w-x r/w-x r/w-x uown (1) dts (2) ? (3) ? (3) dtsen bstall bc9 bc8 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 uown: usb own bit (1) 0 = the microcontroller core owns the bd and its corresponding buffer bit 6 dts: data toggle synchronization bit (2) 1 = data 1 packet 0 = data 0 packet bit 5-4 unimplemented: these bits should always be programmed to ? 0 ? (3) . bit 3 dtsen: data toggle synchronization enable bit 1 = data toggle synchronization is enabled; data packets with incorrect sync value will be ignored except for a setup transaction, which is accepted even if the data toggle bits do not match 0 = no data toggle synchronization is performed bit 2 bstall: buffer stall enable bit 1 = buffer stall enabled; stall handshake issued if a token is received that would use the bd in the given location (uown bit remains set, bd value is unchanged) 0 = buffer stall disabled bit 1-0 bc9:bc8: byte count 9 and 8 bits the byte count bits represent the number of bytes that will be transmitted for an in token or received during an out token. together with bc<7:0>, the valid byte counts are 0-1023. note 1: this bit must be initialized by the user to the desired value prior to enabling the usb module. 2: this bit is ignored unless dtsen = 1 . 3: if these bits are set, usb communication may not work. hence, these bits should always be maintained as ? 0 ?.
pic18f87j50 family ds39775b-page 320 preliminary ? 2007 microchip technology inc. 22.4.1.3 bdnstat register (sie mode) when the bd and its buffer are owned by the sie, most of the bits in bdnstat take on a different meaning. the configuration is shown in register 22-6. once uown is set, any data or control settings previously written there by the user will be overwritten with data from the sie. the bdnstat register is updated by the sie with the token packet identifier (pid) which is stored in bdnstat<5:3>. the transfer count in the correspond- ing bdncnt register is updated. values that overflow the 8-bit register carry over to the two most significant digits of the count, stored in bdnstat<1:0>. 22.4.2 bd byte count the byte count represents the total number of bytes that will be transmitted during an in transfer. after an in transfer, the sie will return the number of bytes sent to the host. for an out transfer, the byte count represents the maximum number of bytes that can be received and stored in usb ram. after an out transfer, the sie will return the actual number of bytes received. if the number of bytes received exceeds the corresponding byte count, the data packet will be rejected and a nak handshake will be generated. when this happens, the byte count will not be updated. the 10-bit byte count is distributed over two registers. the lower 8 bits of the count reside in the bdncnt register. the upper two bits reside in bdnstat<1:0>. this represents a valid byte range of 0 to 1023. 22.4.3 bd address validation the bd address register pair contains the starting ram address location for the corresponding endpoint buffer. no mechanism is available in hardware to validate the bd address. if the value of the bd address does not point to an address in the usb ram, or if it points to an address within another endpoint?s buffer, data is likely to be lost or overwritten. similarly, overlapping a receive buffer (out endpoint) with a bd location in use can yield unexpected results. when developing usb applications, the user may want to consider the inclusion of software-based address validation in their code. register 22-6: bdnstat: buffer descriptor n status register (bd0stat through bd63stat), sie mode (data returned by the side to the mcu) r/w-x u-x r/w-x r/w-x r/w-x r/w-x r/w-x r/w-x uown ? pid3 pid2 pid1 pid0 bc9 bc8 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 uown: usb own bit 1 = the sie owns the bd and its corresponding buffer bit 6 reserved: not written by the sie bit 5-2 pid3:pid0: packet identifier bits the received token pid value of the last transfer (in, out or setup transactions only). bit 1-0 bc9:bc8: byte count 9 and 8 bits these bits are updated by the sie to reflect the actual number of bytes received on an out transfer and the actual number of bytes transmitted on an in transfer.
? 2007 microchip technology inc. preliminary ds39775b-page 321 pic18f87j50 family 22.4.4 ping-pong buffering an endpoint is defined to have a ping-pong buffer when it has two sets of bd entries: one set for an even transfer and one set for an odd transfer. this allows the cpu to process one bd while the sie is processing the other bd. double-buffering bds in this way allows for maximum throughput to/from the usb. the usb module supports four modes of operation: ? no ping-pong support ? ping-pong buffer support for out endpoint 0 only ? ping-pong buffer support for all endpoints ? ping-pong buffer support for all other endpoints except endpoint 0 the ping-pong buffer settings are configured using the ppb1:ppb0 bits in the ucfg register. the usb module keeps track of the ping-pong pointer individually for each endpoint. all pointers are initially reset to the even bd when the module is enabled. after the completion of a transaction (uown cleared by the sie), the pointer is toggled to the odd bd. after the completion of the next transaction, the pointer is toggled back to the even bd and so on. the even/odd status of the last transaction is stored in the ppbi bit of the ustat register. the user can reset all ping-pong pointers to even using the ppbrst bit. figure 22-6 shows the four different modes of operation and how usb ram is filled with the bds. bds have a fixed relationship to a particular endpoint, depending on the buffering configuration. the mapping of bds to endpoints is detailed in table 22-2. this relationship also means that gaps may occur in the bdt if endpoints are not enabled contiguously. this theoretically means that the bds for disabled endpoints could be used as buffer space. in practice, users should avoid using such spaces in the bdt unless a method of validating bd addresses is implemented. figure 22-6: buffer descriptor t able mapping for buffering modes ep1 in even ep1 out even ep1 out odd ep1 in odd descriptor descriptor descriptor descriptor ep1 in ep15 in ep1 out ep0 out ppb1:ppb0 = 00 ep0 in ep1 in no ping-pong ep15 in ep0 in ep0 out even ppb1:ppb0 = 01 ep0 out odd ep1 out ping-pong buffer ep15 in odd ep0 in even ep0 out even ppb1:ppb0 = 10 ep0 out odd ep0 in odd ping-pong buffers descriptor descriptor descriptor descriptor descriptor descriptor descriptor descriptor descriptor descriptor descriptor descriptor 400h 4ffh 4ffh 4ffh 400h 400h 47fh 483h available as data ram available as data ram maximum memory used: 128 bytes maximum bds: 32 (bd0 to bd31) maximum memory used: 132 bytes maximum bds: 33 (bd0 to bd32) maximum memory used: 256 bytes maximum bds: 6 4 (bd0 to bd63) note: memory area not shown to scale. descriptor descriptor descriptor descriptor buffers on ep0 out on all eps ep1 in even ep1 out even ep1 out odd ep1 in odd descriptor descriptor descriptor descriptor ep15 in odd ep0 out ppb1:ppb0 = 11 ep0 in ping-pong buffers descriptor descriptor descriptor 4ffh 400h maximum memory used: 248 bytes maximum bds: 62 (bd0 to bd61) on all other eps except ep0 available as data ram 4f7h
pic18f87j50 family ds39775b-page 322 preliminary ? 2007 microchip technology inc. table 22-2: assignment of buffer descriptors for the different buffering modes table 22-3: summary of usb buffer descriptor table registers endpoint bds assigned to endpoint mode 0 (no ping-pong) mode 1 (ping-pong on ep0 out) mode 2 (ping-pong on all eps) mode 3 (ping-pong on all other eps, except ep0) out in out in out in out in 0 0 1 0 (e), 1 (o) 2 0 (e), 1 (o) 2 (e), 3 (o) 0 1 1 2 3 3 4 4 (e), 5 (o) 6 (e), 7 (o) 2 (e), 3 (o) 4 (e), 5 (o) 2 4 5 5 6 8 (e), 9 (o) 10 (e), 11 (o) 6 (e), 7 (o) 8 (e), 9 (o) 3 6 7 7 8 12 (e), 13 (o) 14 (e), 15 (o) 10 (e), 11 (o) 12 (e), 13 (o) 4 8 9 9 10 16 (e), 17 (o) 18 (e), 19 (o) 14 (e), 15 (o) 16 (e), 17 (o) 5 10 11 11 12 20 (e), 21 (o) 22 (e), 23 (o) 18 (e), 19 (o) 20 (e), 21 (o) 6 12 13 13 14 24 (e), 25 (o) 26 (e), 27 (o) 22 (e), 23 (o) 24 (e), 25 (o) 7 14 15 15 16 28 (e), 29 (o) 30 (e), 31 (o) 26 (e), 27 (o) 28 (e), 29 (o) 8 16 17 17 18 32 (e), 33 (o) 34 (e), 35 (o) 30 (e), 31 (o) 32 (e), 33 (o) 9 18 19 19 20 36 (e), 37 (o) 38 (e), 39 (o) 34 (e), 35 (o) 36 (e), 37 (o) 10 20 21 21 22 40 (e), 41 (o) 42 (e), 43 (o) 38 (e), 39 (o) 40 (e), 41 (o) 11 22 23 23 24 44 (e), 45 (o) 46 (e), 47 (o) 42 (e), 43 (o) 44 (e), 45 (o) 12 24 25 25 26 48 (e), 49 (o) 50 (e), 51 (o) 46 (e), 47 (o) 48 (e), 49 (o) 13 26 27 27 28 52 (e), 53 (o) 54 (e), 55 (o) 50 (e), 51 (o) 52 (e), 53 (o) 14 28 29 29 30 56 (e), 57 (o) 58 (e), 59 (o) 54 (e), 55 (o) 56 (e), 57 (o) 15 30 31 31 32 60 (e), 61 (o) 62 (e), 63 (o) 58 (e), 59 (o) 60 (e), 61 (o) legend: (e) = even transaction buffer, (o) = odd transaction buffer name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 bdnstat (1) uown dts (4) pid3 (2) pid2 (2) pid1 (2) dtsen (3) pid0 (2) bstall (3) bc9 bc8 bdncnt (1) byte count bdnadrl (1) buffer address low bdnadrh (1) buffer address high note 1: for buffer descriptor registers, n may have a value of 0 to 63. for the sake of brevity, all 64 registers are shown as one generic prototype. all registers have indeterminate reset values ( xxxx xxxx ). 2: bits 5 through 2 of the bdnstat register are used by the sie to return pid3:pid0 values once the register is turned over to the sie (uown bit is set). once the registers have been under sie control, the values written for dtsen and bstall are no longer valid. 3: prior to turning the buffer descriptor over to the sie (uown bit is cleared), bits 5 through 2 of the bdnstat register are used to configure the dtsen and bstall settings. 4: this bit is ignored unless dtsen = 1 .
? 2007 microchip technology inc. preliminary ds39775b-page 323 pic18f87j50 family 22.5 usb interrupts the usb module can generate multiple interrupt con- ditions. to accommodate all of these interrupt sources, the module is provided with its own interrupt logic structure, similar to that of the microcontroller. usb interrupts are enabled with one set of control registers and trapped with a separate set of flag registers. all sources are funneled into a single usb interrupt request, usbif (pir2<4>), in the microcontroller?s interrupt logic. figure 22-7 shows the interrupt logic for the usb module. there are two layers of interrupt registers in the usb module. the top level consists of overall usb status interrupts; these are enabled and flagged in the uie and uir registers, respectively. the second level consists of usb error conditions, which are enabled and flagged in the ueir and ueie registers. an interrupt condition in any of these triggers a usb error interrupt flag (uerrif) in the top level. interrupts may be used to trap routine events in a usb transaction. figure 22-8 shows some common events within a usb frame and their corresponding interrupts. figure 22-7: usb interrupt logic funnel figure 22-8: example of a usb transaction and interrupt events btsef btsee btoef btoee dfn8ef dfn8ee crc16ef crc16ee crc5ef crc5ee pidef pidee sofif sofie trnif trnie idleif idleie stallif stallie actvif actvie urstif urstie uerrif uerrie usbif second level usb interrupts (usb error conditions) ueir (flag) and ueie (enable) registers top level usb interrupts (usb status interrupts) uir (flag) and uie (enable) registers usb reset sof reset setup data status sof setuptoken data ack out token empty data ack start-of-frame (sof) in token data ack sofif urstif 1 ms frame differential data from host from host to h o s t from host to host from host from host from host to h o s t transaction control transfer (1) transaction complete note 1: the control transfer shown here is only an example showing events that can occur for every transaction. typical control transfe rs will spread across multiple frames. set trnif set trnif set trnif
pic18f87j50 family ds39775b-page 324 preliminary ? 2007 microchip technology inc. 22.5.1 usb interrupt status register (uir) the usb interrupt status register (register 22-7) con- tains the flag bits for each of the usb status interrupt sources. each of these sources has a corresponding interrupt enable bit in the uie register. all of the usb status flags are ored together to generate the usbif interrupt flag for the microcontroller?s interrupt funnel. once an interrupt bit has been set by the sie, it must be cleared by software by writing a ? 0 ?. the flag bits can also be set in software which can aid in firmware debugging. register 22-7: uir: usb interrupt status register u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r-0 r/w-0 ? sofif stallif idleif (1) trnif (2) actvif (3) uerrif (4) urstif bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 unimplemented: read as ? 0 ? bit 6 sofif: start-of-frame token interrupt bit 1 = a start-of-frame token received by the sie 0 = no start-of-frame token received by the sie bit 5 stallif: a stall handshake interrupt bit 1 = a stall handshake was sent by the sie 0 = a stall handshake has not been sent bit 4 idleif: idle detect interrupt bit (1) 1 = idle condition detected (constant idle state of 3 ms or more) 0 = no idle condition detected bit 3 trnif: transaction complete interrupt bit (2) 1 = processing of pending transaction is complete; read ustat register for endpoint information 0 = processing of pending transaction is not complete or no transaction is pending bit 2 actvif: bus activity detect interrupt bit (3) 1 = activity on the d+/d- lines was detected 0 = no activity detected on the d+/d- lines bit 1 uerrif: usb error condition interrupt bit (4) 1 = an unmasked error condition has occurred 0 = no unmasked error condition has occurred. bit 0 urstif: usb reset interrupt bit 1 = valid usb reset occurred; 00h is loaded into uaddr register 0 = no usb reset has occurred note 1: once an idle state is detected, the user may want to place the usb module in suspend mode. 2: clearing this bit will cause the ustat fifo to advance (valid only for in, out and setup tokens). 3: this bit is typically unmasked only following the detection of a uidle interrupt event. 4: only error conditions enabled through the ueie register will set this bit. this bit is a status bit only and cannot be set or cleared by the user.
? 2007 microchip technology inc. preliminary ds39775b-page 325 pic18f87j50 family 22.5.1.1 bus activity detect interrupt bit (actvif) the actvif bit cannot be cleared immediately after the usb module wakes up from suspend or while the usb module is suspended. a few clock cycles are required to synchronize the internal hardware state machine before the actvif bit can be cleared by firmware. clearing the actv if bit before the internal hardware is synchronized may not have an effect on the value of actvif. additionally, if the usb module uses the clock from the 96 mhz pll source, then after clearing the suspnd bit, the usb module may not be immediately operational while waiting for the 96 mhz pll to lock. the application code should clear the actvif flag as shown in example 22-1. only one actvif interrupt is generated when resum- ing from the usb bus idle condition. if user firmware clears the actvif bit, the bit will not immediately become set again, even when there is continuous bus traffic. bus traffic must cease long enough to generate another idleif condition before another actvif interrupt can be generated. example 22-1: clearing actvif bit (uir<2>) assembly: bcf ucon, suspnd loop: btfss uir, actvif bra done bcf uir, actvif bra loop done: c: uconbits.suspnd = 0 ; while (uirbits.actvif) { uirbits.actvif = 0 ; }
pic18f87j50 family ds39775b-page 326 preliminary ? 2007 microchip technology inc. 22.5.2 usb interrupt enable register (uie) the usb interrupt enable register (register 22-8) contains the enable bits for the usb status interrupt sources. setting any of these bits will enable the respective interrupt source in the uir register. the values in this register only affect the propagation of an interrupt condition to the microcontroller?s inter- rupt logic. the flag bits are still set by their interrupt conditions, allowing them to be polled and serviced without actually generating an interrupt. register 22-8: uie: usb interrupt enable register u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? sofie stallie idleie trnie actvie uerrie urstie bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 unimplemented: read as ? 0 ? bit 6 sofie: start-of-frame token interrupt enable bit 1 = start-of-frame token interrupt enabled 0 = start-of-frame token interrupt disabled bit 5 stallie: stall handshake interrupt enable bit 1 = stall interrupt enabled 0 = stall interrupt disabled bit 4 idleie: idle detect interrupt enable bit 1 = idle detect interrupt enabled 0 = idle detect interrupt disabled bit 3 trnie: transaction complete interrupt enable bit 1 = transaction interrupt enabled 0 = transaction interrupt disabled bit 2 actvie: bus activity detect interrupt enable bit 1 = bus activity detect interrupt enabled 0 = bus activity detect interrupt disabled bit 1 uerrie: usb error interrupt enable bit 1 = usb error interrupt enabled 0 = usb error interrupt disabled bit 0 urstie: usb reset interrupt enable bit 1 = usb reset interrupt enabled 0 = usb reset interrupt disabled
? 2007 microchip technology inc. preliminary ds39775b-page 327 pic18f87j50 family 22.5.3 usb error interrupt status register (ueir) the usb error interrupt status register (register 22-9) contains the flag bits for each of the error sources within the usb peripheral. each of these sources is controlled by a corresponding interrupt enable bit in the ueie register. all of the usb error flags are ored together to generate the usb error interrupt flag (uerrif) at the top level of the interrupt logic. each error bit is set as soon as the error condition is detected. thus, the interrupt will typically not correspond with the end of a token being processed. once an interrupt bit has been set by the sie, it must be cleared by software by writing a ? 0 ?. register 22-9: ueir: usb erro r interrupt status register r/c-0 u-0 u-0 r/c-0 r/c-0 r/c-0 r/c-0 r/c-0 btsef ? ? btoef dfn8ef crc16ef crc5ef pidef bit 7 bit 0 legend: r = readable bit c = clearable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 btsef: bit stuff error flag bit 1 = a bit stuff error has been detected 0 = no bit stuff error bit 6-5 unimplemented: read as ? 0 ? bit 4 btoef: bus turnaround time-out error flag bit 1 = bus turnaround time-out has occurred (more than 16 bit times of idle from previous eop elapsed) 0 = no bus turnaround time-out bit 3 dfn8ef: data field size error flag bit 1 = the data field was not an integral number of bytes 0 = the data field was an integral number of bytes bit 2 crc16ef: crc16 failure flag bit 1 = the crc16 failed 0 = the crc16 passed bit 1 crc5ef: crc5 host error flag bit 1 = the token packet was rejected due to a crc5 error 0 = the token packet was accepted bit 0 pidef: pid check failure flag bit 1 = pid check failed 0 = pid check passed
pic18f87j50 family ds39775b-page 328 preliminary ? 2007 microchip technology inc. 22.5.4 usb error interrupt enable register (ueie) the usb error interrupt enable register (register 22-10) contains the enable bits for each of the usb error interrupt sources. setting any of these bits will enable the respective error interrupt source in the ueir register to propagate into the uerr bit at the top level of the interrupt logic. as with the uie register, the enable bits only affect the propagation of an interrupt condition to the micro- controller?s interrupt logic. the flag bits are still set by their interrupt conditions, allowing them to be polled and serviced without actually generating an interrupt. register 22-10: ueie: usb error interrupt enable register r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 btsee ? ? btoee dfn8ee crc16ee crc5ee pidee bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 btsee: bit stuff error interrupt enable bit 1 = bit stuff error interrupt enabled 0 = bit stuff error interrupt disabled bit 6-5 unimplemented: read as ? 0 ? bit 4 btoee: bus turnaround time-out error interrupt enable bit 1 = bus turnaround time-out error interrupt enabled 0 = bus turnaround time-out error interrupt disabled bit 3 dfn8ee: data field size error interrupt enable bit 1 = data field size error interrupt enabled 0 = data field size error interrupt disabled bit 2 crc16ee: crc16 failure interrupt enable bit 1 = crc16 failure interrupt enabled 0 = crc16 failure interrupt disabled bit 1 crc5ee: crc5 host error interrupt enable bit 1 = crc5 host error interrupt enabled 0 = crc5 host error interrupt disabled bit 0 pidee: pid check failure interrupt enable bit 1 = pid check failure interrupt enabled 0 = pid check failure interrupt disabled
? 2007 microchip technology inc. preliminary ds39775b-page 329 pic18f87j50 family 22.6 usb power modes many usb applications will likely have several different sets of power requirements and configuration. the most common power modes encountered are bus power only, self-power only and dual power with self-power dominance. the most common cases are presented here. also provided is a means of estimating the current consumption of the usb transceiver. 22.6.1 bus power only in bus power only mode, all power for the application is drawn from the usb (figure 22-9). this is effectively the simplest power method for the device. in order to meet the inrush current requirements of the usb 2.0 specifications, the total effective capacitance appearing across v bus and ground must be no more than 10 f. if not, some kind of inrush liming is required. for more details, see section 7.2.4 of the usb 2.0 specification. according to the usb 2.0 specification, all usb devices must also support a low-power suspend mode. in the usb suspend mode, devices must consume no more than 500 a (or 2.5 ma for high powered devices that are remote wake-up capable) from the 5v v bus line of the usb cable. the host signals the usb device to enter the suspend mode by stopping all usb traffic to that device for more than 3 ms. this condition will cause the idleif bit in the uir register to become set. during the usb suspend mode, the d+ or d- pull-up resistor must remain active, which will consume some of the allowed suspend current: 500 a/2.5 ma budget. figure 22-9: bus power only 22.6.2 self-power only in self-power only mode, the usb application provides its own power, with very little power being pulled from the usb. figure 22-10 shows an example. note that an attach indication is added to indicate when the usb has been connected and the host is actively powering v bus . in order to meet compliance specifications, the usb module (and the d+ or d- pull-up resistor) should not be enabled until the host actively drives v bus high. one of the 5.5v tolerant i/o pins may be used for this purpose. the application should never source any current onto the 5v v bus pin of the usb cable. figure 22-10: self-power only v dd v usb v ss v bus ~5v 3.3v low i q regulator v dd v usb v ss v self ~3.3v attach sense 100 k 100 k v bus ~5v 5.5v tolerant i/o pin
pic18f87j50 family ds39775b-page 330 preliminary ? 2007 microchip technology inc. 22.6.3 dual power with self-power dominance some applications may require a dual power option. this allows the application to use internal power prima- rily, but switch to power from the usb when no internal power is available. figure 22-11 shows a simple dual power with self-power dominance mode example, which automatically switches between self-power only and usb bus power only modes. dual power devices must also meet all of the special requirements for inrush current and suspend mode current and must not enable the usb module until v bus is driven high. see section 22.6.1 ?bus power only? and section 22.6.2 ?self-power only? for descriptions of those requirements. additionally, dual power devices must never source current onto the 5v v bus pin of the usb cable. figure 22-11: dual power example 22.6.4 usb transceiver current consumption the usb transceiver consumes a variable amount of current depending on the characteristic impedance of the usb cable, the length of the cable, the v usb supply voltage and the actual data patterns moving across the usb cable. longer cables have larger capacitances and consume more total energy when switching output states. data patterns that consist of ?in? traffic consume far more current than ?out? traffic. in traffic requires the pic ? device to drive the usb cable, whereas out traffic requires that the host drive the usb cable. the data that is sent across the usb cable is nrzi encoded. in the nrzi encoding scheme, ? 0 ? bits cause a toggling of the output state of the transceiver (either from a ?j? state to a ?k? state, or vise versa). with the exception of the effects of bit-stuffing, nrzi encoded ? 1 ? bits do not cause the output state of the transceiver to change. therefore, in traffic consisting of data bits of value, ? 0 ?, cause the most current consumption, as the transceiver must charge/discharge the usb cable in order to change states. more details about nrzi encoding and bit-stuffing can be found in the usb 2.0 specification?s section 7.1, although knowledge of such details is not required to make usb applications using the pic18f87j50 family of microcontrollers. among other things, the sie han- dles bit-stuffing/unstuffing, nrzi encoding/decoding and crc generation/checking in hardware. the total transceiver current consumption will be application-specific. however, to help estimate how much current actually may be required in full-speed applications, equation 22-1 can be used. example 22-2 shows how this equation can be used for a theoretical application. note: users should keep in mind the limits for devices drawing power from the usb. according to usb specification 2.0, this cannot exceed 100 ma per low-power device or 500 ma per high-power device. v dd v usb i/o pin v ss attach sense v bus v self 100 k ~3.3v ~5v 100 k 3.3v low i q regulator
? 2007 microchip technology inc. preliminary ds39775b-page 331 pic18f87j50 family equation 22-1: estimating usb t ransceiver current consumption example 22-2: calculating usb transceiver current ? for this example, the following assumptions are made about the application: ? 3.3v will be applied to v usb and v dd , with the core voltage regulator enabled. ? this is a full-speed application that uses one interrupt in endpoint that can send one packet of 64 bytes every 1 ms, with no restrictions on the values of the bytes being sent. the application may or may not have additional traffic on out endpoints. ? a regular usb ?b? or ?mini-b? connector will be used on the application circuit board. in this case, p zero = 100% = 1, because there should be no restriction on the value of the data moving through the in endpoint. all 64 kbps of data could potentially be bytes of value, 00h. since ? 0 ? bits cause toggling of the output state of the transceiver, they cause the usb transceiver to consume extra current charging/discharging the cable. in this case, 100% of the data bits sent can be of value ? 0 ?. this should be considered the ?max? value, as normal data will consist of a fair mix of ones and zeros. this application uses 64 kbps for in traffic out of the total bus bandwidth of 1.5 mbps (12 mbps), therefore: since a regular ?b? or ?mini-b? connector is used in this a pplication, the end user may plug in any type of cable up to the maximum allowed 5 m length. therefore, we use the worst-case length: l cable = 5 meters assume i pullup = 2.2 ma. the actual value of i pullup will likely be closer to 218 a, but allow for the worst-case. usb bandwidth is shared between all the devices which are plugged into the root port (via hubs). if the application is plugged into a usb 1.1 hub that has other devices plugged into it, your device may see host to device traffic on the bus, even if it is not addressed to your device. since any traffic, regardless of source, can increase the i pullup current above the base 218 a, it is safest to allow for the worst case of 2.2 ma. therefore: ? the calculated value should be considered an approximation and additional guardband or applica- tion-specific product testing is recommended. the transceiver current is ?in addition to? the rest of the current consumed by the pic18f87j50 family device that is needed to run the core, drive the other i/o lines, power the various modules, etc. i xcvr =+ i pullup (60 ma ? v usb ? p zero ? p in ? l cable ) (3.3v ? 5m) legend: v usb ? voltage applied to the v usb pin in volts. (should be 3.0v to 3.6v.) p zero ? percentage (in decimal) of the in traffic bits sent by the pic ? device that are a value of ? 0 ?. p in ? percentage (in decimal) of total bus bandwidth that is used for in traffic. l cable ? length (in meters) of the usb cable. the usb 2.0 specification requires that full-speed applications use cables no longer than 5m. i pullup ? current which the nominal, 1.5 k pull-up resistor (when enabled) must supply to the usb cable. on the host or hub end of the usb cable, 15 k nominal resistors (14.25 k to 24.8 k ) are present which pull both the d+ and d- lines to ground. during bus idle conditions (such as between packets or during usb suspend mode), this results in up to 218 a of quiescent current drawn at 3.3v. i pullup is also dependant on bus traffic conditions and can be as high as 2.2 ma when the usb bandwidth is fully utilized (either in or out traffic) for data that drives the lines to the ?k? state most of the time. pin = 64 kbps 1.5 mbps = 4.3% = 0.043 i xcvr = + 2.2 ma = 4.8 ma (60 ma ? 3.3v ? 1 ? 0.043 ? 5m) (3.3v ? 5m)
pic18f87j50 family ds39775b-page 332 preliminary ? 2007 microchip technology inc. 22.7 oscillator the usb module has specific clock requirements. for full-speed operation, the clock source must be 48 mhz. even so, the microcontroller core and other peripherals are not required to run at that clock speed. available clocking options are described in detail in section 2.3 ?oscillator settings for usb? . 22.8 usb firmware and drivers microchip provides a number of application-specific resources, such as usb firmware and driver support. refer to www.microchip.com for the latest firmware and driver support. table 22-4: registers associat ed with usb module operation (1) name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 details on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 79 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 83 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 83 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 83 ucon ? ppbrst se0 pktdis usben resume suspnd ?85 ucfg uteye ? ? upuen utrdis fsen ppb1 ppb0 85 ustat ? endp3 endp2 endp1 endp0 dir ppbi ?85 uaddr ? addr6 addr5 addr4 addr3 addr2 addr1 addr0 85 ufrml frm7 frm6 frm5 frm4 frm3 frm2 frm1 frm0 85 ufrmh ? ? ? ? ? frm10 frm9 frm8 85 uir ? sofif stallif idleif trnif actvif uerrif urstif 85 uie ? sofie stallie idleie trnie actvie uerrie urstie 85 ueir btsef ? ? btoef dfn8ef crc16ef crc5ef pidef 85 ueie btsee ? ? btoee dfn8ee crc16ee crc5ee pidee 85 uep0 ? ? ? ephshk epcondis epouten epinen epstall 86 uep1 ? ? ? ephshk epcondis epouten epinen epstall 86 uep2 ? ? ? ephshk epcondis epouten epinen epstall 86 uep3 ? ? ? ephshk epcondis epouten epinen epstall 86 uep4 ? ? ? ephshk epcondis epouten epinen epstall 86 uep5 ? ? ? ephshk epcondis epouten epinen epstall 86 uep6 ? ? ? ephshk epcondis epouten epinen epstall 86 uep7 ? ? ? ephshk epcondis epouten epinen epstall 86 uep8 ? ? ? ephshk epcondis epouten epinen epstall 85 uep9 ? ? ? ephshk epcondis epouten epinen epstall 85 uep10 ? ? ? ephshk epcondis epouten epinen epstall 85 uep11 ? ? ? ephshk epcondis epouten epinen epstall 85 uep12 ? ? ? ephshk epcondis epouten epinen epstall 85 uep13 ? ? ? ephshk epcondis epouten epinen epstall 85 uep14 ? ? ? ephshk epcondis epouten epinen epstall 85 uep15 ? ? ? ephshk epcondis epouten epinen epstall 85 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the usb module. note 1: this table includes only those hardware mapped sfrs locate d in bank 15 of the data memory space. the buffer descriptor registers, which are mapped into bank 4 and ar e not true sfrs, are listed separately in table 22-3.
? 2007 microchip technology inc. preliminary ds39775b-page 333 pic18f87j50 family 22.9 overview of usb this section presents some of the basic usb concepts and useful information necessary to design a usb device. although much information is provided in this section, there is a plethora of information provided within the usb specifications and class specifications. thus, the reader is encouraged to refer to the usb specifications for more information (www.usb.org). if you are very familiar with the details of usb, then this section serves as a basic, high-level refresher of usb. 22.9.1 layered framework usb device functionality is structured into a layered framework graphically shown in figure 22-12. each level is associated with a functional level within the device. the highest layer, other than the device, is the configuration. a device may have multiple configura- tions. for example, a particular device may have multiple power requirements based on self-power only or bus power only modes. for each configuration, there may be multiple interfaces. each interface could support a particular mode of that configuration. below the interface is the endpoint(s). data is directly moved at this level. there can be as many as 16 bidirectional endpoints. endpoint 0 is always a control endpoint and by default, when the device is on the bus, endpoint 0 must be available to configure the device. 22.9.2 frames information communicated on the bus is grouped into 1 ms time slots, referred to as frames. each frame can contain many transactions to various devices and endpoints. figure 22-8 shows an example of a transaction within a frame. 22.9.3 transfers there are four transfer types defined in the usb specification. ? isochronous: this type provides a transfer method for large amounts of data (up to 1023 bytes) with timely delivery ensured; however, the data integrity is not ensured. this is good for streaming applications where small data loss is not critical, such as audio. ? bulk: this type of transfer method allows for large amounts of data to be transferred with ensured data integrity; however, the delivery timeliness is not ensured. ? interrupt: this type of transfer provides for ensured timely delivery for small blocks of data, plus data integrity is ensured. ? control: this type provides for device setup control. while full-speed devices support all transfer types, low-speed devices are limited to interrupt and control transfers only. 22.9.4 power power is available from the universal serial bus. the usb specification defines the bus power requirements. devices may either be self-powered or bus powered. self-powered devices draw power from an external source, while bus powered devices use power supplied from the bus. figure 22-12: usb layers device configuration interface endpoint interface endpoint endpoint endpoint endpoint to other configurations (if any) to other interfaces (if any)
pic18f87j50 family ds39775b-page 334 preliminary ? 2007 microchip technology inc. the usb specification limits the power taken from the bus. each device is ensured 100 ma at approximately 5v (one unit load). additional power may be requested, up to a maximum of 500 ma. note that power above one unit load is a request and the host or hub is not obligated to provide the extra current. thus, a device capable of consuming more than one unit load must be able to maintain a low-power configuration of a one unit load or less, if necessary. the usb specification also defines a suspend mode. in this situation, current must be limited to 500 a, averaged over 1 second. a device must enter a suspend state after 3 ms of inactivity (i.e., no sof tokens for 3 ms). a device entering suspend mode must drop current consumption within 10 ms after suspend. likewise, when signaling a wake-up, the device must signal a wake-up within 10 ms of drawing current above the suspend limit. 22.9.5 enumeration when the device is initially attached to the bus, the host enters an enumeration process in an attempt to identify the device. essentially, the host interrogates the device, gathering information such as power consumption, data rates and sizes, protocol and other descriptive information; descriptors contain this information. a typical enumeration process would be as follows: 1. usb reset: reset the device. thus, the device is not configured and does not have an address (address 0). 2. get device descriptor: the host requests a small portion of the device descriptor. 3. usb reset: reset the device again. 4. set address: the host assigns an address to the device. 5. get device descriptor: the host retrieves the device descriptor, gathering info such as manufacturer, type of device, maximum control packet size. 6. get configuration descriptors. 7. get any other descriptors. 8. set a configuration. the exact enumeration process depends on the host. 22.9.6 descriptors there are eight different standard descriptor types of which five are most important for this device. 22.9.6.1 device descriptor the device descriptor provides general information, such as manufacturer, product number, serial number, the class of the device and the number of configurations. there is only one device descriptor. 22.9.6.2 configuration descriptor the configuration descriptor provides information on the power requirements of the device and how many different interfaces are supported when in this configu- ration. there may be more than one configuration for a device (i.e., low-power and high-power configurations). 22.9.6.3 interface descriptor the interface descriptor details the number of end- points used in this interface, as well as the class of the interface. there may be more than one interface for a configuration. 22.9.6.4 endpoint descriptor the endpoint descriptor identifies the transfer type ( section 22.9.3 ?transfers? ) and direction, as well as some other specifics for the endpoint. there may be many endpoints in a device and endpoints may be shared in different configurations. 22.9.6.5 string descriptor many of the previous descriptors reference one or more string descriptors. string descriptors provide human readable information about the layer ( section 22.9.1 ?layered framework? ) they describe. often these strings show up in the host to help the user identify the device. string descriptors are generally optional to save memory and are encoded in a unicode format. 22.9.7 bus speed each usb device must indicate its bus presence and speed to the host. this is accomplished through a 1.5 k resistor which is connected to the bus at the time of the attachment event. depending on the speed of the device, the resistor either pulls up the d+ or d- line to 3.3v. for a low-speed device, the pull-up resistor is connected to the d- line. for a full-speed device, the pull-up resistor is connected to the d+ line. 22.9.8 class specifications and drivers usb specifications include class specifications which operating system vendors optionally support. examples of classes include audio, mass storage, communications and human interface (hid). in most cases, a driver is required at the host side to ?talk? to the usb device. in custom applications, a driver may need to be developed. fortunately, drivers are available for most common host systems for the most common classes of devices. thus, these drivers can be reused.
? 2007 microchip technology inc. preliminary ds39775b-page 335 pic18f87j50 family 23.0 comparator module the analog comparator module contains two compara- tors that can be independently configured in a variety of ways. the inputs can be selected from the analog inputs and two internal voltage references. the digital outputs are available at the pin level and can also be read through the control register. multiple output and interrupt event generation are also available. a generic single comparator from the module is shown in figure 23-1. key features of the module includes: ? independent comparator control ? programmable input configuration ? output to both pin and register levels ? programmable output polarity ? independent interrupt generation for each comparator with configurable interrupt-on-change 23.1 registers the cmxcon registers (register 23-1) select the input and output configuration for each comparator, as well as the settings for interrupt generation. the cmstat register (register 23-2) provides the out- put results of the comparators. the bits in this register are read-only. figure 23-1: comparator simplified block diagram cx v in - v in + coe cxout 0 1 (1) 2 (1,2) 3 0 1 cch1:cch0 cxinb cxinc cxind v irv cxina cv ref con interrupt logic evpol<4:3> coutx (cmstat<1:0>) cmxif cpol polarity logic cref note 1: available in 80-pin devices only. 2: implemented in comparator 2 only.
pic18f87j50 family ds39775b-page 336 preliminary ? 2007 microchip technology inc. register 23-1: cmxcon: comparator control x register r/w-0 r/w-0 r/w-0 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 con coe cpol evpol1 evpol0 cref cch1 cch0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 con: comparator enable bit 1 = comparator is enabled 0 = comparator is disabled bit 6 coe: comparator output enable bit 1 = comparator output is present on the cxout pin 0 = comparator output is internal only bit 5 cpol: comparator output polarity select bit 1 = comparator output is inverted 0 = comparator output is not inverted bit 4-3 evpol1:evpol0: interrupt polarity select bits 11 = interrupt generation on any change of the output (1) 10 = interrupt generation only on high-to-low transition of the output 01 = interrupt generation only on low-to-high transition of the output 00 = interrupt generation is disabled bit 2 cref: comparator reference select bit (non-inverting input) 1 = non-inverting input connects to internal cv ref voltage 0 = non-inverting input connects to cxina pin bit 1-0 cch1:cch0 : comparator channel select bits 11 = inverting input of comparator connects to v irv 10 = inverting input of comparator connects to cxind pin (2) 01 = inverting input of comparator connects to cxinc pin (2) 00 = inverting input of comparator connects to cxinb pin note 1: the cmxif is automatically set any time this mode is selected and must be cleared by the application after the initial configuration. 2: available in 80-pin devices only.
? 2007 microchip technology inc. preliminary ds39775b-page 337 pic18f87j50 family register 23-2: cmstat: comparator status register u-0 u-0 u-0 u-0 u-0 u-0 r-1 r-1 ? ? ? ? ? ? cout2 cout1 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-2 unimplemented: read as ? 0 ? bit 1-0 cout2:cout1: comparator x status bits if cpol = 0 (non-inverted polarity): 1 = comparator?s v in + > v in - 0 = comparator?s v in + < v in - if cpol = 1 (inverted polarity): 1 = comparator v in + < v in - 0 = comparator v in + > v in -
pic18f87j50 family ds39775b-page 338 preliminary ? 2007 microchip technology inc. 23.2 comparator operation a single comparator is shown in figure 23-2, along with the relationship between the analog input levels and the digital output. when the analog input at v in + is less than the analog input v in -, the output of the comparator is a digital low level. when the analog input at v in + is greater than the analog input v in -, the output of the comparator is a digital high level. the shaded areas of the output of the comparator in figure 23-2 represent the uncertainty due to input offsets and response time. figure 23-2: single comparator 23.3 comparator response time response time is the minimum time, after selecting a new reference voltage or input source, before the com- parator output has a valid level. the response time of the comparator differs from the settling time of the volt- age reference. therefore, both of these times must be considered when determining the total response to a comparator input change. otherwise, the maximum delay of the comparators should be used (see section 28.0 ?electrical characteristics? ). 23.4 analog input connection considerations a simplified circuit for an analog input is shown in figure 23-3. since the analog pins are connected to a digital output, they have reverse biased diodes to v dd and v ss . the analog input, therefore, must be between v ss and v dd . if the input voltage deviates from this range by more than 0.6v in either direction, one of the diodes is forward biased and a latch-up condition may occur. a maximum source impedance of 10 k is recommended for the analog sources. any external component connected to an analog input pin, such as a capacitor or a zener diode, should have very little leakage current. figure 23-3: comparator analog input model output v in - v in + ? + v in + v in - output va r s < 10k a in c pin 5 pf v dd v t = 0.6v v t = 0.6v r ic i leakage 500 na v ss legend: c pin = input capacitance v t = threshold voltage i leakage = leakage current at the pin due to various junctions r ic = interconnect resistance r s = source impedance va = analog voltage comparator input
? 2007 microchip technology inc. preliminary ds39775b-page 339 pic18f87j50 family 23.5 comparator control and configuration each comparator has up to eight possible combina- tions of inputs: up to four external analog inputs, and one of two internal voltage references. both comparators allow a selection of the signal from pin, cxina, or the voltage from the comparator refer- ence (cv ref ) on the non-inverting channel. this is compared to either cxinb, cxinc, cxind or the micro- controller?s fixed internal reference voltage (v irv , 1.2v nominal) on the inverting channel. the comparator inputs and outputs are tied to fixed i/o pins, defined in table 23-1. the available comparator configurations and their corresponding bit settings are shown in figure 23-4. table 23-1: comparator inputs and outputs 23.5.1 comparator enable and input selection setting the con bit of the cmxcon register (cmxcon<7>) enables the comparator for operation. clearing the con bit disables the comparator resulting in minimum current consumption. the cch1:cch0 bits in the cmxcon register (cmxcon<1:0>) direct either one of three analog input pins, or the internal reference voltage (v irv ), to the comparator v in -. depending on the comparator operat- ing mode, either an external or internal voltage reference may be used. the analog signal present at v in - is compared to the signal at v in + and the digital output of the comparator is adjusted accordingly. the external reference is used when cref = 0 (cmxcon<2>) and v in + is connected to the cxina pin. when external voltage references are used, the comparator module can be configured to have the ref- erence sources externally. the reference signal must be between v ss and v dd , and can be applied to either pin of the comparator. the comparator module also allows the selection of an internally generated voltage reference (cv ref ) from the comparator voltage reference module. this module is described in more detail in section 23.0 ?compara- tor module? . the reference from the comparator voltage reference module is only available when cref = 1 . in this mode, the internal voltage reference is applied to the comparator?s v in + pin. 23.5.1.1 comparator configurations in 64-pin and 80-pin devices in pic18f87j50 family devices, the c and d input channels for both comparators are linked to pins in porth and cannot be reassigned to alternate analog inputs. because of this, 64-pin devices offer a total of 4 different configurations for each comparator. in con- trast, 80-pin devices offer a choice of 6 configurations for comparator 1, and 8 configurations for comparator 2. the configurations shown in figure 23-4 are footnoted to indicate where they are not available. 23.5.2 comparator enable and output selection the comparator outputs are read through the cmstat register. the cmstat<0> reads the comparator 1 out- put and cmstat<1> reads the comparator 2 output. these bits are read-only. the comparator outputs may also be directly output to the rf1 and rf2 i/o pins by setting the coe bit (cmxcon<6>). when enabled, multiplexors in the output path of the pins switch to the output of the com- parator. the trisf<1:2> bits still function as the digital output enable for the rf1 and rf2 pins while in this mode. by default, the comparator?s output is at logic high whenever the voltage on v in + is greater than on v in -. the polarity of the comparator outputs can be inverted using the cpol bit (cmxcon<5>). the uncertainty of each of the comparators is related to the input offset voltage and the response time given in the specifications, as discussed in section 23.2 ?comparator operation? . comparator input or output i/o pin 1 c1ina (v in +) rf6 c1inb (v in -) rf5 c1inc (v in -) (1) rh6 (1) c1out rf7 2 c2ina(v in +) rf5 c2inb(v in -) rf2 c2inc(v in -) (1) rh4 (1) c2ind(v in -) (1) rh5 (1) c2out rc5 note 1: available in 80-pin devices only. note: the comparator input pin selected by cch1:ch0 must be configured as an input by setting both the corresponding trisf or trish bit, and the corresponding pcfg bit in the ancon1 register.
pic18f87j50 family ds39775b-page 340 preliminary ? 2007 microchip technology inc. figure 23-4: comparator configurations cx v in - v in + off (read as ? 0 ?) comparator off con = 0 , cref = x , cch<1:0> = xx coe cx v in - v in + coe comparator cxinb > cxina compare con = 1, cref = 0 , cch<1:0> = 00 cxinb cxina cx v in - v in + coe comparator cxinc > cxina compare con = 1, cref = 0 , cch<1:0> = 01 cxinc cxina cx v in - v in + coe comparator cxind > cxina compare con = 1 , cref = 0 , cch<1:0> = 10 cxind cxina cx v in - v in + coe comparator v irv > cxina compare con = 1, cref = 0 , cch<1:0> = 11 v irv cxina cx v in - v in + coe comparator cxinb > cv ref compare con = 1, cref = 1 , cch<1:0> = 00 cxinb cv ref cx v in - v in + coe comparator cxinc > cv ref compare con = 1, cref = 1 , cch<1:0> = 01 cxinc cv ref cx v in - v in + coe comparator cxind > cv ref compare con = 1, cref = 1 , cch<1:0> = 10 cxind cv ref cx v in - v in + coe pin comparator v irv > cv ref compare con = 1, cref = 1 , cch<1:0> = 11 v irv cv ref cxout note: v irv is the internal reference voltage (see table 28-2). pin cxout pin cxout pin cxout pin cxout pin cxout pin cxout pin cxout pin cxout
? 2007 microchip technology inc. preliminary ds39775b-page 341 pic18f87j50 family 23.6 comparator interrupts the comparator interrupt flag is set whenever any of the following occurs: - low-to-high transition of the comparator output - high-to-low transition of the comparator output - any change in the comparator output. the comparator interrupt selection is done by the evpol1:evpol0 bits in the cmxcon register (cmxcon<4:3>). in order to provide maximum flexibility, the output of the comparator may be inverted using the cpol bit in the cmxcon register (cmxcon<5>). this is functionally identical to reversing the inverting and non-inverting inputs of the comparator for a particular mode. an interrupt is generated on the low-to-high or high-to- low transition of the comparator output. this mode of interrupt generation is dependent on evpol<1:0> in the cmxcon register. when evpol<1:0> = 01 or 10 , the interrupt is generated on a low-to-high or high-to- low transition of the comparator output. once the interrupt is generated, it is required to clear the interrupt flag by software. when evpol<1:0> = 11 , the comparator interrupt flag is set whenever there is a change in the output value of either comparator. software will need to maintain infor- mation about the status of the output bits, as read from cmstat<1:0>, to determine the actual change that occurred. the cmxif bits (pir2<6:5>) are the compar- ator interrupt flags. the cmxif bits must be reset by clearing them. since it is also possible to write a ? 1 ? to this register, a simulated interrupt may be initiated. table 23-2 shows the interrupt generation with respect to comparator input voltages and evpol bit settings. both the cmxie bits (pie2<6:5>) and the peie bit (intcon<6>) must be set to enable the interrupt. in addition, the gie bit (intcon<7>) must also be set. if any of these bits are clear, the interrupt is not enabled, though the cmxif bits will still be set if an interrupt condition occurs. a simplified diagram of the interrupt section is shown in figure 23-3. table 23-2: comparator interrupt generation cpol evpol<1:0> comparator input change coutx transition interrupt generated 0 00 v in + > v in - low-to-high no v in + < v in - high-to-low no 01 v in + > v in - low-to-high yes v in + < v in - high-to-low no 10 v in + > v in - low-to-high no v in + < v in - high-to-low yes 11 v in + > v in - low-to-high yes v in + < v in - high-to-low yes 1 00 v in + > v in - high-to-low no v in + < v in - low-to-high no 01 v in + > v in - high-to-low no v in + < v in - low-to-high yes 10 v in + > v in - high-to-low yes v in + < v in - low-to-high no 11 v in + > v in - high-to-low yes v in + < v in - low-to-high yes
pic18f87j50 family ds39775b-page 342 preliminary ? 2007 microchip technology inc. 23.7 comparator operation during sleep when a comparator is active and the device is placed in sleep mode, the comparator remains active and the interrupt is functional, if enabled. this interrupt will wake-up the device from sleep mode, when enabled. each operational comparator will consume additional current. to minimize power consumption while in sleep mode, turn off the comparators (con = 0 ) before entering sleep. if the device wakes up from sleep, the contents of the cmxcon register are not affected. 23.8 effects of a reset a device reset forces the cmxcon registers to their reset state. this forces both comparators and the voltage reference to the off state. table 23-3: registers associated with comparator module name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 59 pir2 oscfif cm2if cm1if usbif bcl1if lvdif tmr3if ccp2if 62 pie2 oscfie cm2ie cm1ie usbie bcl1ie lvdie tmr3ie ccp2ie 62 ipr2 oscfip cm2ip cm1ip usbip bcl1ip lvdip tmr3ip ccp2ip 62 cmxcon con coe cpol evpol1 evpol0 cref cch1 cch0 60 cvrcon (1) cvren cvroe cvrr cvrss cvr3 cvr2 cvr1 cvr0 63 cmstat ? ? ? ? ? ? cout2 cout1 63 ancon1 (1) pcfg15 pcfg14 pcfg13 pcfg12 pcfg11 pcfg10 ? ?61 ancon0 (1) pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 61 porta ? ?ra5 ra4 ra3 ra2 ra1 ?63 trisa ? ?trisa5 trisa4 trisa3 trisa2 trisa1 ?62 lata ? ?lata5 lata4 lata3 lata2 lata1 lata0 62 portc rc7 rc6 rc5 rc4 rc3 rfc2 rfc1 rfc0 63 latc latc7 latc6 latc5 latc4 latc3 latc2 latc1 latc0 62 trisc trisc7 trisc6 trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 62 portf rf7 rf6 rf5 rf4 rf3 rf2 ? ?63 latf latf7 latf6 latf5 latf4 latf3 latf2 ? ?62 trisf trisf7 trisf6 trisf5 trisf4 trisf3 trisf2 ? ?62 porth (2) rh7 rh6 rh5 rh4 rh3 rh2 rh1 rh0 63 trish (2) trish7 trish6 trish5 trish4 trish3 trish2 trish1 trish0 62 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used for a/d conversion. note 1: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 . 2: this register is not implemented on 64-pin devices.
? 2007 microchip technology inc. preliminary ds39775b-page 343 pic18f87j50 family 24.0 comparator voltage reference module the comparator voltage reference is a 16-tap resistor ladder network that provides a selectable reference voltage. although its primary purpose is to provide a reference for the analog comparators, it may also be used independently of them. a block diagram of the module is shown in figure 24-1. the resistor ladder is segmented to provide two ranges of cv ref values and has a power-down function to conserve power when the reference is not being used. the module?s supply reference can be provided from either device v dd /v ss or an external voltage reference. figure 24-1: comparator voltage reference block diagram 16-to-1 mux cvr3:cvr0 8r r cvren cvrss = 0 v dd v ref + cvrss = 1 8r cvrss = 0 v ref - cvrss = 1 r r r r r r 16 steps cvrr cv ref
pic18f87j50 family ds39775b-page 344 preliminary ? 2007 microchip technology inc. 24.1 configuring the comparator voltage reference the comparator voltage reference module is controlled through the cvrcon register (register 24-1). the comparator voltage reference provides two ranges of output voltage, each with 16 distinct levels. the range to be used is selected by the cvrr bit (cvrcon<5>). the primary difference between the ranges is the size of the steps selected by the cv ref selection bits (cvr3:cvr0), with one range offering finer resolution. the equations used to calculate the output of the comparator voltage reference are as follows: if cvrr = 1 : cv ref = ((cvr3:cvr0)/24) x (cv rsrc ) if cvrr = 0 : cv ref =(cv rsrc /4) + ((cvr3:cvr0)/32) x (cv rsrc ) the comparator reference supply voltage can come from either v dd and v ss , or the external v ref + and v ref - that are multiplexed with ra2 and ra3. the voltage source is selected by the cvrss bit (cvrcon<4>). the settling time of the comparator voltage reference must be considered when changing the cv ref output (see table 28-3 in section 28.0 ?electrical characteristics? ). the cvrcon register is a shared address sfr and uses the same address as the pr4 register. the cvrcon register is accessed by setting the adshr bit (wdtcon<4>). register 24-1: cvrcon: comparator vo ltage reference control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 cvren cvroe (1) cvrr cvrss cvr3 cvr2 cvr1 cvr0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 cvren: comparator voltage reference enable bit 1 =cv ref circuit powered on 0 =cv ref circuit powered down bit 6 cvroe: comparator v ref output enable bit (1) 1 =cv ref voltage level is also output on the rf5/an10/c1inb/cv ref pin 0 =cv ref voltage is disconnected from the rf5/an10/c1inb/cv ref pin bit 5 cvrr: comparator v ref range selection bit 1 = 0 to 0.667 cv rsrc , with cv rsrc /24 step size (low range) 0 = 0.25 cv rsrc to 0.75 cv rsrc , with cv rsrc /32 step size (high range) bit 4 cvrss: comparator v ref source selection bit 1 = comparator reference source, cv rsrc = (v ref +) ? (v ref -) 0 = comparator reference source, cv rsrc = av dd ? av ss bit 3-0 cvr3:cvr0: comparator v ref value selection bits (0 (cvr3:cvr0) 15) when cvrr = 1 : cv ref = ((cvr3:cvr0)/24) ? (cv rsrc ) when cvrr = 0 : cv ref = (cv rsrc /4) + ((cvr3:cvr0)/32) ? (cv rsrc ) note 1: cvroe overrides the trisf<5> bit setting.
? 2007 microchip technology inc. preliminary ds39775b-page 345 pic18f87j50 family 24.2 voltage reference accuracy/error the full range of voltage reference cannot be realized due to the construction of the module. the transistors on the top and bottom of the resistor ladder network (figure 24-1) keep cv ref from approaching the refer- ence source rails. the voltage reference is derived from the reference source; therefore, the cv ref output changes with fluctuations in that source. the tested absolute accuracy of the voltage reference can be found in section 28.0 ?electrical characteristics? . 24.3 connection considerations the voltage reference module operates independently of the comparator module. the output of the reference generator may be connected to the rf5 pin if the cvroe bit is set. enabling the voltage reference out- put onto ra2 when it is configured as a digital input will increase current consumption. connecting rf5 as a digital output with cvrss enabled will also increase current consumption. the rf5 pin can be used as a simple d/a output with limited drive capability. due to the limited current drive capability, a buffer must be used on the voltage reference output for external connections to v ref . figure 24-2 shows an example buffering technique. 24.4 operation during sleep when the device wakes up from sleep through an interrupt or a watchdog timer time-out, the contents of the cvrcon register are not affected. to minimize current consumption in sleep mode, the voltage reference should be disabled. 24.5 effects of a reset a device reset disables the voltage reference by clearing bit, cvren (cvrcon<7>). this reset also disconnects the reference from the ra2 pin by clearing bit, cvroe (cvrcon<6>) and selects the high-voltage range by clearing bit, cvrr (cvrcon<5>). the cvr value select bits are also cleared. figure 24-2: comparator voltage refere nce output buffer example table 24-1: registers associated with comparator voltage reference cv ref output + ? cv ref module voltage reference output impedance r (1) rf5 note 1: r is dependent upon the comparator voltage reference configuration bits, cvrcon<5> and cvrcon<3:0>. pic18f87j50 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: cvrcon (1) cvren cvroe cvrr cvrss cvr3 cvr2 cvr1 cvr0 63 cm1con con coe cpol evpol1 evpol0 cref cch1 cch0 60 cm2con con coe cpol evpol1 evpol0 cref cch1 cch0 60 trisa trisa7 trisa6 trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 62 trisf trisf7 trisf6 trisf5 trisf4 trisf3 trisf2 ? ?62 ancon0 (1) pcfg7 ? ? pcfg4 pcfg3 pcfg2 pcfg1 pcfg0 61 ancon1 (1) pcfg15 pcfg14 pcfg13 pcfg12 pcfg11 pcfg10 ? ?61 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used with the comparator voltage reference. note 1: configuration sfr, overlaps with default sfr at this address; available only when wdtcon<4> = 1 .
pic18f87j50 family ds39775b-page 346 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 347 pic18f87j50 family 25.0 special features of the cpu pic18f87j50 family devices include several features intended to maximize reliability and minimize cost through elimination of external components. these are: ? oscillator selection ? resets: - power-on reset (por) - power-up timer (pwrt) - oscillator start-up timer (ost) - brown-out reset (bor) ? interrupts ? watchdog timer (wdt) ? fail-safe clock monitor ? two-speed start-up ? code protection ? in-circuit serial programming the oscillator can be configured for the application depending on frequency, power, accuracy and cost. all of the options are discussed in detail in section 2.0 ?oscillator configurations? . a complete discussion of device resets and interrupts is available in previous sections of this data sheet. in addition to their power-up and oscillator start-up timers provided for resets, the pic18f87j50 family of devices have a configurable watchdog timer which is controlled in software. the inclusion of an internal rc oscillator also provides the additional benefits of a fail-safe clock monitor (fscm) and two-speed start-up. fscm provides for background monitoring of the peripheral clock and automatic switchover in the event of its failure. two-speed start-up enables code to be executed almost immediately on start-up, while the primary clock source completes its start-up delays. all of these features are enabled and configured by setting the appropriate configuration register bits. 25.1 configuration bits the configuration bits can be programmed (read as ? 0 ?) or left unprogrammed (read as ? 1 ?) to select various device configurations. these bits are mapped starting at program memory location 300000h. a complete list is shown in table 25-2. a detailed explanation of the various bit functions is provided in register 25-1 through register 25-6. 25.1.1 considerations for configuring the pic18f87j50 family devices unlike previous pic18 microcontrollers, devices of the pic18f87j50 family do not use persistent memory registers to store configuration information. the config- uration bytes are implemented as volatile memory, which means that configuration data must be programmed each time the device is powered up. configuration data is stored in the four words at the top of the on-chip program memory space, known as the flash configuration words. it is stored in program memory in the same order shown in table 25-2, with config1l at the lowest address and config3h at the highest. the data is automatically loaded in the proper configuration registers during device power-up. when creating applications for these devices, users should always specifically allocate the location of the flash configuration word for configuration data. this is to make certain that program code is not stored in this address when the code is compiled. the volatile memory cells used for the configuration bits always reset to ? 1 ? on power-on resets. for all other type of reset events, the previously programmed values are maintained and used without reloading from program memory. the four most significant bits of config1h, config2h and config3h in program memory should also be ? 1111 ?. this makes these configuration words appear to be nop instructions in the remote event that their locations are ever executed by accident. since configuration bits are not implemented in the corresponding locations, writing ? 1 ?s to these locations has no effect on device operation. to prevent inadvertent configuration changes during code execution, all programmable configuration bits are write-once. after a bit is initially programmed during a power cycle, it cannot be written to again. changing a device configuration requires that power to the device be cycled.
pic18f87j50 family ds39775b-page 348 preliminary ? 2007 microchip technology inc. table 25-1: mapping of the flash co nfiguration words to the configuration registers table 25-2: configuration bits and device ids configuration byte code space address configuration register address config1l xxxf8h 300000h config1h xxxf9h 300001h config2l xxxfah 300002h config2h xxxfbh 300003h config3l xxxfch 300004h config3h xxxfdh 300005h config4l (1) xxxfeh 300006h config4h (1) xxxffh 300007h note 1: unimplemented in pic18f87j50 family devices. file name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 default/ unprogrammed value (1) 300000h config1l debug xinst stvren ? plldiv2 plldiv1 plldiv0 wdten 111- 1111 300001h config1h ? (2) ? (2) ? (2) ? (2) ? cp0 cpdiv1 cpdiv0 1111 -111 300002h config2l ieso fcmen ? ? ? fosc2 fosc1 fosc0 11-- -111 300003h config2h ? (2) ? (2) ? (2) ? (2) wdtps3 wdtps2 wdtps1 wdtps0 1111 1111 300004h config3l wait (3) bw (3) emb1 (3) emb0 (3) eashft (3) ? ? ? 1111 1--- 300005h config3h ? (2) ? (2) ? (2) ? (2) msspmsk pmpmx (3) eccpmx (3) ccp2mx 1111 1111 3ffffeh devid1 dev2 dev1 dev0 rev4 rev3 rev2 rev1 rev0 xxx0 0000 (4) 3fffffh devid2 dev10 dev9 dev8 dev7 dev6 dev5 dev4 dev3 0100 00xx (4) legend: x = unknown, u = unchanged, - = unimplemented. shaded cells are unimplemented, read as ? 0 ?. note 1: values reflect the unprogrammed state as received from t he factory and following power-on resets. in all other reset states, the configuration bytes maintain their previously programmed states. 2: the value of these bits in program memory should always be ? 1 ?. this ensures that the location is executed as a nop if it is accidentally executed. 3: implemented in 80-pin devices only. 4: see register 25-7 and register 25-8 for devid values. t hese registers are read-only and cannot be programmed by the user.
? 2007 microchip technology inc. preliminary ds39775b-page 349 pic18f87j50 family register 25-1: config1l: configuration register 1 low (byte address 300000h) r/wo-1 r/wo-1 r/wo-1 u-0 r/wo-1 r/wo-1 r/wo-1 r/wo-1 debug xinst stvren ? plldiv2 plldiv1 plldiv0 wdten bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 debug : background debugger enable bit 1 = background debugger disabled; rb6 and rb7 configured as general purpose i/o pins 0 = background debugger enabled; rb6 and rb7 are dedicated to in-circuit debug bit 6 xinst: extended instruction set enable bit 1 = instruction set extension and indexed addressing mode enabled 0 = instruction set extension and indexed addressing mode disabled (legacy mode) bit 5 stvren : stack overflow/underflow reset enable bit 1 = reset on stack overflow/underflow enabled 0 = reset on stack overflow/underflow disabled bit 4 unimplemented: read as ? 0 ? bit 3-1 plldiv2:plldiv0: oscillator selection bits divider must be selected to provide a 4 mhz input into the 96 mhz pll 111 = no divide - oscillator used directly (4 mhz input) 110 = oscillator divided by 2 (8 mhz input) 101 = oscillator divided by 3 (12 mhz input) 100 = oscillator divided by 4 (16 mhz input) 011 = oscillator divided by 5 (20 mhz input) 010 = oscillator divided by 6 (24 mhz input) 001 = oscillator divided by 10 (40 mhz input) 000 = oscillator divided by 12 (48 mhz input) bit 0 wdten: watchdog timer enable bit 1 = wdt enabled 0 = wdt disabled (control is placed on swdten bit)
pic18f87j50 family ds39775b-page 350 preliminary ? 2007 microchip technology inc. register 25-2: config1h: co nfiguration register 1 hi gh (byte address 300001h) u-1 u-1 u-1 u-1 u-0 r/wo-1 r/wo-1 r/wo-1 ? ? ? ? ? cp0 cpdiv1 cpdiv0 bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-4 unimplemented: maintain as ? 1 ? bit 3 unimplemented: read as ? 0 ? bit 2 cp0: code protection bit 1 = program memory is not code-protected 0 = program memory is code-protected bit 1-0 cpdiv1:cpdiv0: cpu system clock selection bits 11 = no cpu system clock divide 10 = cpu system clock divided by 2 01 = cpu system clock divided by 3 00 = cpu system clock divided by 6
? 2007 microchip technology inc. preliminary ds39775b-page 351 pic18f87j50 family register 25-3: config2l: configuration re gister 2 low (byte address 300002h) r/wo-1 r/wo-1 u-0 u-0 u-0 r/wo-1 r/wo-1 r/wo-1 ieso fcmen ? ? ? fosc2 fosc1 fosc0 bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 ieso: two-speed start-up (internal/external oscillator switchover) control bit 1 = two-speed start-up enabled 0 = two-speed start-up disabled bit 6 fcmen: fail-safe clock monitor enable bit 1 = fail-safe clock monitor enabled 0 = fail-safe clock monitor disabled bit 5-3 unimplemented: read as ? 0 ? bit 2-0 fosc2:fosc0: oscillator selection bits 111 = ecpll oscillator with pll enabled, clko on ra6, ecpll oscillator used by usb 110 = ec oscillator with clko on ra6 , ec oscillator used by usb 101 = hspll oscillator with pll enabled, hspll oscillator used by usb 100 = hs oscillator, hs oscillator used by usb 011 = intoscpllo, internal oscillator with intoscpll enabled, clko on ra6 and port function ra7 010 = intoscpll, internal oscillator with port function on ra6 and ra7 001 = intosco internal oscillator block (intrc/intosc) with clko on ra6 port function on ra7 000 = intosc internal oscillator block (intrc/intosc) port function on ra6 and ra7
pic18f87j50 family ds39775b-page 352 preliminary ? 2007 microchip technology inc. register 25-4: config2h: co nfiguration register 2 high (byte address 300003h) u-1 u-1 u-1 u-1 r/wo-1 r/wo-1 r/wo-1 r/wo-1 ? ? ? ? wdtps3 wdtps2 wdtps1 wdtps0 bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-4 unimplemented: read as ? 0 ? bit 3-0 wdtps3:wdtps0: watchdog timer postscale select bits 1111 = 1:32,768 1110 = 1:16,384 1101 = 1:8,192 1100 = 1:4,096 1011 = 1:2,048 1010 = 1:1,024 1001 = 1:512 1000 = 1:256 0111 = 1:128 0110 = 1:64 0101 = 1:32 0100 = 1:16 0011 = 1:8 0010 = 1:4 0001 = 1:2 0000 = 1:1
? 2007 microchip technology inc. preliminary ds39775b-page 353 pic18f87j50 family register 25-5: config3l: configuration regi ster 3 low (byte address 300004h) r/wo-1 r/wo-1 r/wo-1 r/wo-1 r/wo-1 u-0 u-0 u-0 wait (1) bw (1) emb1 (1) emb0 (1) eashft (1) ? ? ? bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 wait: external bus wait enable bit (1) 1 = wait states on the external bus are disabled 0 = wait states on the external bus are enabled and selected by memcon<5:4> bit 6 bw: data bus width select bit (1) 1 = 16-bit data width modes 0 = 8-bit data width modes bit 5-4 emb1:emb0: external memory bus configuration bits (1) 11 = microcontroller mode, external bus disabled 10 = extended microcontroller mode, 12-bit address width for external bus 01 = extended microcontroller mode, 16-bit address width for external bus 00 = extended microcontroller mode, 20-bit address width for external bus bit 3 eashft: external address bus shift enable bit (1) 1 = address shifting enabled ? external address bus is shifted to start at 000000h 0 = address shifting disabled ? external address bus reflects the pc value bit 2-0 unimplemented: read as ? 0 ? note 1: implemented only on 80-pin devices.
pic18f87j50 family ds39775b-page 354 preliminary ? 2007 microchip technology inc. register 25-6: config3h: configuration register 3 high (byte address 300005h) u-1 u-1 u-1 u-1 r/wo-1 r/wo-1 r/wo-1 r/wo-1 ? ? ? ? msspmsk pmpmx (1) eccpmx (1) ccp2mx bit 7 bit 0 legend: r = readable bit wo = write-once bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-4 unimplemented: maintain as ? 1 ? bit 3 msspmsk: mssp v3?s 7-bit address masking mode enable bit 1 = 7-bit address masking mode enable 0 = 5-bit address masking mode enable bit 2 pmpmx: pmp pin placement bit for the 80-pin tqfp (1) 1 = pmp pins placed on emb 0 = pmp pins placed else where bit 1 eccpmx: eccpx mux bit (1) 1 = eccp1 outputs (p1b/p1c) are multiplexed with re6 and re5; eccp3 outputs (p3b/p3c) are multiplexed with re4 and re3 0 = eccp1 outputs (p1b/p1c) are multiplexed with rh7 and rh6; eccp3 outputs (p3b/p3c) are multiplexed with rh5 and rh4 bit 0 ccp2mx: eccp2 mux bit 1 = eccp2/p2a is multiplexed with rc1 0 = eccp2/p2a is multiplexed with re7 in microcontroller mode (all devices) or with rb3 in extended microcontroller mode (80-pin devices only) note 1: implemented only on 80-pin devices.
? 2007 microchip technology inc. preliminary ds39775b-page 355 pic18f87j50 family register 25-7: devid1: device id register 1 for pic18f87j50 family devices rrrrrrrr dev2 dev1 dev0 rev4 rev3 rev2 rev1 rev0 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-5 dev2:dev0: device id bits (1) 111 = PIC18F86J50 110 = reserved 101 = pic18f85j50 100 = pic18f67j50 011 = pic18f66j55 010 = pic18f66j50 001 = pic18f87j50 000 = pic18f65j50 and pic18f86j55 bit 4-0 rev4:rev0: revision id bits these bits are used to indicate the device revision. note 1: where values for dev2:dev0 are shared by more than one device number, the specific device is always identified by using the entire dev10:dev0 bit sequence. these bits are used with the dev[10:3] bits in the device id register 2 to identify the part number. register 25-8: devid2: device id register 2 for pic18f87j50 family devices rrrrrrrr dev10 dev9 dev8 dev7 dev6 dev5 dev4 dev3 bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7-0 dev10:dev3: device id bits (1) these bits are used with the dev2:dev0 bits in the device id register 1 to identify the part number. 0100 0001 = pic18f65j50/66j50/66j55/67j50/85j50/86j50 0100 0010 = pic18f87j50/86j55 note 1: the values for dev10:dev3 may be shared with other device families. the specific device is always identified by using the entire dev10:dev0 bit sequence.
pic18f87j50 family ds39775b-page 356 preliminary ? 2007 microchip technology inc. 25.2 watchdog timer (wdt) for pic18f87j50 family devices, the wdt is driven by the intrc oscillator. when the wdt is enabled, the clock source is also enabled. the nominal wdt period is 4 ms and has the same stability as the intrc oscillator. the 4 ms period of the wdt is multiplied by a 16-bit postscaler. any output of the wdt postscaler is selected by a multiplexor, controlled by the wdtps bits in config- uration register 2h. available periods range from about 4 ms to 135 seconds (2.25 minutes depending on voltage, temperature and wdt postscaler). the wdt and postscaler are cleared whenever a sleep or clrwdt instruction is executed, or a clock failure (primary or timer1 oscillator) has occurred. 25.2.1 control register the wdtcon register (register 25-9) is a readable and writable register. the swdten bit enables or dis- ables wdt operation. this allows software to override the wdten configuration bit and enable the wdt only if it has been disabled by the configuration bit. the adshr bit selects which sfrs currently are selected and accessible. for additional details, see section 5.3.5.1 ?shared address sfrs? . lvdstat is a read-only status bit that is continuously updated and provides information about the current level of v ddcore . this bit is only valid when the on-chip voltage regulator is enabled. figure 25-1: wdt block diagram note 1: the clrwdt and sleep instructions clear the wdt and postscaler counts when executed. 2: when a clrwdt instruction is executed, the postscaler count will be cleared. intrc oscillator wdt wake-up from reset wdt wdt counter programmable postscaler 1:1 to 1:32,768 enable wdt wdtps3:wdtps0 swdten clrwdt 4 power-managed reset all device resets sleep intrc control 128 modes
? 2007 microchip technology inc. preliminary ds39775b-page 357 pic18f87j50 family table 25-3: summary of watchdog timer registers register 25-9: wdtcon: wat chdog timer control register r/w-0 r-x u-0 r/w-0 u-0 u-0 u-0 u-0 regslp (2) lvdstat ? adshr ? ? ?swdten (1) bit 7 bit 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit 7 regslp: voltage regulator low-power operation enable bit (2) 1 = on-chip regulator enters low-power operation when device enters sleep mode 0 = on-chip regulator is active even in sleep mode bit 6 lvdstat: low-voltage detect status bit 1 = v ddcore > 2.45v nominal 0 = v ddcore < 2.45v nominal bit 5 unimplemented : read as ? 0 ? bit 4 adshr: shared address sfr select bit for details of bit operation, see register 5-3. bit 3-1 unimplemented : read as ? 0 ? bit 0 swdten: software controlled watchdog timer enable bit (1) 1 = watchdog timer is on 0 = watchdog timer is off note 1: this bit has no effect if the configuration bit, wdten, is enabled. 2: the regslp bit is automatically cleared when a low-voltage detect condition occurs. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset values on page: rcon ipen ? cm ri to pd por bor 60 wdtcon regslp lvdstat ? adshr ? ? ?swdten 61 legend: ? = unimplemented, read as ? 0 ?. shaded cells are not used by the watchdog timer.
pic18f87j50 family ds39775b-page 358 preliminary ? 2007 microchip technology inc. 25.3 on-chip voltage regulator all of the pic18f87j50 family devices power their core digital logic at a nominal 2.5v. for designs that are required to operate at a higher typical voltage, such as 3.3v, all devices in the pic18f87j50 family incorporate an on-chip regulator that allows the device to run its core logic from v dd . the regulator is controlled by the envreg pin. tying v dd to the pin enables the regulator, which in turn, pro- vides power to the core from the other v dd pins. when the regulator is enabled, a low-esr filter capacitor must be connected to the v ddcore /v cap pin (figure 25-2). this helps to maintain the stability of the regulator. the recommended value for the filter capac- itor is provided in section 28.3 ?dc characteristics: pic18f87j50 family (industrial)? . if envreg is tied to v ss , the regulator is disabled. in this case, separate power for the core logic at a nomi- nal 2.5v must be supplied to the device on the v ddcore /v cap pin to run the i/o pins at higher voltage levels, typically 3.3v. alternatively, the v ddcore /v cap and v dd pins can be tied together to operate at a lower nominal voltage. refer to figure 25-2 for possible configurations. 25.3.1 voltage regulator tracking mode and low-voltage detection when it is enabled, the on-chip regulator provides a con- stant voltage of 2.5v nominal to the digital core logic. the regulator can provide th is level from a vdd of about 2.5v, all the way up to the device?s v ddmax . it does not have the capability to boost v dd levels below 2.5v. in order to prevent ?brown-out? conditions, when the volt- age drops too low for the regulator, the regulator enters tracking mode. in tracking mode, the regulator output follows v dd , with a typical voltage drop of 100 mv. the on-chip regulator includes a simple low-voltage detect (lvd) circuit. if v dd drops too low to maintain approximately 2.45v on v ddcore , the circuit sets the low-voltage detect interrupt flag, lvdif (pir2<2>). this can be used to generate an interrupt and put the application into a low-power operational mode, or trig- ger an orderly shutdown. low-voltage detection is only available when the regulator is enabled. the low-voltage detect interrupt is edge-sensitive and will only be set once per falling edge of v ddcore . firm- ware can clear the interrupt flag, but a new interrupt will not be generated until v ddcore rises back above, and then falls below, the 2.45v nominal threshold. device resets will reset the interrupt flag to ? 0 ?, even if v ddcore is less than 2.45v. when the regulator is enabled, the lvdstat bit in the wdtcon register can be polled to determine the current level of v ddcore . figure 25-2: conne ctions for the on-chip regulator v dd envreg v ddcore /v cap v ss pic18f87j50 3.3v (1) 2.5v (1) v dd envreg v ddcore /v cap v ss pic18f87j50 c f 3.3v regulator enabled (envreg tied to v dd ): regulator disabled (envreg tied to ground): v dd envreg v ddcore /v cap v ss pic18f87j50 2.5v (1) regulator disabled (v dd tied to v ddcore ): note 1: these are typical operating voltages. refer to section 28.1 ?dc characteristics: supply voltage? for the full operating ranges of v dd and v ddcore .
? 2007 microchip technology inc. preliminary ds39775b-page 359 pic18f87j50 family 25.3.2 on-chip regulator and bor when the on-chip regulator is enabled, pic18f87j50 family devices also have a simple brown-out capability. if the voltage supplied to the regulator is inadequate to maintain a regulated level, the regulator reset circuitry will generate a brown-out reset. this event is captured by the bor flag bit (rcon<0>). the operation of the brown-out reset is described in more detail in section 4.4 ?brown-out reset (bor)? and section 4.4.1 ?detecting bor? . the brown-out voltage levels are specific in section 28.1 ?dc charac- teristics: supply voltage pic18f87j50 family (industrial)? . 25.3.3 power-up requirements the on-chip regulator is designed to meet the power-up requirements for the device. if the application does not use the regulator, then strict power-up conditions must be adhered to. while powering up, v ddcore must never exceed v dd by 0.3 volts. 25.3.4 operation in sleep mode when enabled, the on-chip regulator always consumes a small incremental amount of current over i dd . this includes when the device is in sleep mode, even though the core digital logic does not require power. to provide additional savings in applications where power resources are critical, the regulator can be configured to automatically disable itself whenever the device goes into sleep mode. this feature is controlled by the regslp bit (wdtcon<7>, register 25-9). setting this bit disables the regulator in sleep mode and reduces its current consumption to a minimum. substantial sleep mode power savings can be obtained by setting the regslp bit, but device wake-up time will increase in order to insure the regu- lator has enough time to stabilize. the regslp bit is automatically cleared by hardware when a low-voltage detect condition occurs. 25.4 two-speed start-up the two-speed start-up feature helps to minimize the latency period, from oscillator start-up to code execu- tion, by allowing the microcontroller to use the intrc oscillator as a clock source until the primary clock source is available. it is enabled by setting the ieso configuration bit. two-speed start-up should be enabled only if the primary oscillator mode is hs or hspll (crystal-based) modes. since the ec and ecpll modes do not require an oscillator start-up timer (ost) delay, two-speed start-up should be disabled. when enabled, resets and wake-ups from sleep mode cause the device to configure itself to run from the inter- nal oscillator block as the clock source, following the time-out of the power-up timer after a power-on reset is enabled. this allows almost immediate code execution while the primary oscillator starts and the ost is running. once the ost times out, the device automatically switches to pri_run mode. in all other power-managed modes, two-speed start-up is not used. the device will be clocked by the currently selected clock source until the primary clock source becomes available. the setting of the ieso bit is ignored. figure 25-3: timing transition for two-speed start-up (intrc to hspll) q1 q3 q4 osc1 peripheral program pc pc + 2 intrc pll clock q1 pc + 6 q2 output q3 q4 q1 cpu clock pc + 4 clock counter q2 q2 q3 note 1: t ost = 1024 t osc ; t pll = 2 ms (approx). these intervals are not shown to scale. wake from interrupt event t pll (1) 12 n-1n clock osts bit set transition t ost (1)
pic18f87j50 family ds39775b-page 360 preliminary ? 2007 microchip technology inc. 25.4.1 special considerations for using two-speed start-up while using the intrc oscillator in two-speed start-up, the device still obeys the normal command sequences for entering power-managed modes, including serial sleep instructions (refer to section 3.1.4 ?multiple sleep commands? ). in prac- tice, this means that user code can change the scs1:scs0 bit settings or issue sleep instructions before the ost times out. this would allow an applica- tion to briefly wake-up, perform routine ?housekeeping? tasks and return to sleep before the device starts to operate from the primary oscillator. user code can also check if the primary clock source is currently providing the device clocking by checking the status of the osts bit (osccon<3>). if the bit is set, the primary oscillator is providing the clock. otherwise, the internal oscillator block is providing the clock during wake-up from reset or sleep mode. 25.5 fail-safe clock monitor the fail-safe clock monitor (fscm) allows the microcontroller to continue operation in the event of an external oscillator failure by automatically switching the device clock to the internal oscillator block. the fscm function is enabled by setting the fcmen configuration bit. when fscm is enabled, the intrc oscillator runs at all times to monitor clocks to peripherals and provide a backup clock in the event of a clock failure. clock monitoring (shown in figure 25-4) is accomplished by creating a sample clock signal which is the intrc out- put divided by 64. this allows ample time between fscm sample clocks for a peripheral clock edge to occur. the peripheral device clock and the sample clock are presented as inputs to the clock monitor latch. the clock monitor is set on the falling edge of the device clock source but cleared on the rising edge of the sample clock. figure 25-4: fscm block diagram clock failure is tested for on the falling edge of the sample clock. if a sample clock falling edge occurs while the clock monitor is still set, a clock failure has been detected (figure 25-5). this causes the following: ? the fscm generates an oscillator fail interrupt by setting bit oscfif (pir2<7>); ? the device clock source is switched to the internal oscillator block (osccon is not updated to show the current clock source ? this is the fail-safe condition); and ? the wdt is reset. during switchover, the postscaler frequency from the internal oscillator block may not be sufficiently stable for timing sensitive applications. in these cases, it may be desirable to select another clock configuration and enter an alternate power-managed mode. this can be done to attempt a partial recovery or execute a controlled shutdown. see section 3.1.4 ?multiple sleep commands? and section 25.4.1 ?special considerations for using two-speed start-up? for more details. the fscm will detect failures of the primary or second- ary clock sources only. if the internal oscillator block fails, no failure would be detected, nor would any action be possible. 25.5.1 fscm and the watchdog timer both the fscm and the wdt are clocked by the intrc oscillator. since the wdt operates with a separate divider and counter, disabling the wdt has no effect on the operation of the intrc oscillator when the fscm is enabled. as already noted, the clock source is switched to the intrc clock when a clock failure is detected; this may mean a substantial change in the speed of code execu- tion. if the wdt is enabled with a small prescale value, a decrease in clock speed allows a wdt time-out to occur and a subsequent device reset. for this reason, fail-safe clock events also reset the wdt and postscaler, allowing it to start timing from when execu- tion speed was changed and decreasing the likelihood of an erroneous time-out. peripheral intrc 64 s c q (32 s) 488 hz (2.048 ms) clock monitor latch (edge-triggered) clock failure detected source clock q
? 2007 microchip technology inc. preliminary ds39775b-page 361 pic18f87j50 family figure 25-5: fscm timing diagram 25.5.2 exiting fail-safe operation the fail-safe condition is terminated by either a device reset or by entering a power-managed mode. on reset, the controller starts the primary clock source specified in configuration register 2h (with any required start-up delays that are required for the oscil- lator mode, such as ost or pll timer). the intrc oscillator provides the device clock until the primary clock source becomes ready (similar to a two-speed start-up). the clock source is then switched to the primary clock (indicated by the osts bit in the osccon register becoming set). the fail-safe clock monitor then resumes monitoring the peripheral clock. the primary clock source may never become ready during start-up. in this case, operation is clocked by the intrc oscillator. the osccon register will remain in its reset state until a power-managed mode is entered. 25.5.3 fscm interrupts in power-managed modes by entering a power-managed mode, the clock multiplexor selects the clock source selected by the osccon register. fail-safe clock monitoring of the power-managed clock source resumes in the power-managed mode. if an oscillator failure occurs during power-managed operation, the subsequent events depend on whether or not the oscillator failure interrupt is enabled. if enabled (oscfif = 1 ), code execution will be clocked by the intrc multiplexor. an automatic transition back to the failed clock source will not occur. if the interrupt is disabled, subsequent interrupts while in idle mode will cause the cpu to begin executing instructions while being clocked by the intrc source. 25.5.4 por or wake-up from sleep the fscm is designed to detect oscillator failure at any point after the device has exited power-on reset (por) or low-power sleep mode. when the primary device clock is either the ec or intrc modes, monitoring can begin immediately following these events. for hs or hspll modes, the situation is somewhat different. since the oscillator may require a start-up time considerably longer than the fscm sample clock time, a false clock failure may be detected. to prevent this, the internal oscillator block is automatically config- ured as the device clock and functions until the primary clock is stable (the ost and pll timers have timed out). this is identical to two-speed start-up mode. once the primary clock is stable, the intrc returns to its role as the fscm source. as noted in section 25.4.1 ?special considerations for using two-speed start-up? , it is also possible to select another clock configuration and enter an alternate power-managed mode while waiting for the primary clock to become stable. when the new power-managed mode is selected, the primary clock is disabled. oscfif clock monitor device clock output sample clock failure detected oscillator failure note: the device clock is normally at a much higher frequen cy than the sample clock. the relative frequencies in this example have been chosen for clarity. output (q ) clock monitor test clock monitor test clock monitor test note: the same logic that prevents false oscilla- tor failure interrupts on por, or wake from sleep, will also prevent the detection of the oscillator?s failure to start at all follow- ing these events. this can be avoided by monitoring the osts bit and using a timing routine to determine if the oscillator is taking too long to start. even so, no oscillator failure interrupt will be flagged.
pic18f87j50 family ds39775b-page 362 preliminary ? 2007 microchip technology inc. 25.6 program verification and code protection for all devices in the pic18f87j50 family of devices, the on-chip program memory space is treated as a single block. code protection for this block is controlled by one configuration bit, cp0. this bit inhibits external reads and writes to the program memory space. it has no direct effect in normal execution mode. 25.6.1 configuration register protection the configuration registers are protected against untoward changes or reads in two ways. the primary protection is the write-once feature of the configuration bits which prevents reconfiguration once the bit has been programmed during a power cycle. to safeguard against unpredictable events, configuration bit changes resulting from individual cell level disruptions (such as esd events) will cause a parity error and trigger a device reset. this is seen by the user as a configuration mismatch (cm) reset. the data for the configuration registers is derived from the flash configuration words in program memory. when the cp0 bit set, the source data for device configuration is also protected as a consequence. 25.7 in-circuit serial programming pic18f87j50 family microcontrollers can be serially programmed while in the end application circuit. this is simply done with two lines for clock and data and three other lines for power, ground and the programming voltage. this allows customers to manufacture boards with unprogrammed devices and then program the microcontroller just before shipping the product. this also allows the most recent firmware or a custom firmware to be programmed. 25.8 in-circuit debugger when the debug configuration bit is programmed to a ? 0 ?, the in-circuit debugger functionality is enabled. this function allows simple debugging functions when used with mplab ? ide. when the microcontroller has this feature enabled, some resources are not available for general use. table 25-4 shows which resources are required by the background debugger. table 25-4: debugger resources i/o pins: rb6, rb7 stack: 2 levels program memory: 512 bytes data memory: 10 bytes
? 2007 microchip technology inc. preliminary ds39775b-page 363 pic18f87j50 family 26.0 instruction set summary the pic18f87j50 family of devices incorporate the standard set of 75 pic18 core instructions, as well as an extended set of 8 new instructions for the optimiza- tion of code that is recursive or that utilizes a software stack. the extended set is discussed later in this section. 26.1 standard instruction set the standard pic18 instruction set adds many enhancements to the previous pic ? instruction sets, while maintaining an easy migration from these pic instruction sets. most instructions are a single program memory word (16 bits), but there are four instructions that require two program memory locations. each single-word instruction is a 16-bit word divided into an opcode, which specifies the instruction type and one or more operands, which further specify the operation of the instruction. the instruction set is highly orthogonal and is grouped into four basic categories: ? byte-oriented operations ? bit-oriented operations ? literal operations ? control operations the pic18 instruction set summary in table 26-2 lists byte-oriented , bit-oriented , literal and control operations. table 26-1 shows the opcode field descriptions. most byte-oriented instructions have three operands: 1. the file register (specified by ?f?) 2. the destination of the result (specified by ?d?) 3. the accessed memory (specified by ?a?) the file register designator, ?f?, specifies which file register is to be used by the instruction. the destination designator, ?d?, specifies where the result of the operation is to be placed. if ?d? is ? 0 ?, the result is placed in the wreg register. if ?d? is ? 1 ?, the result is placed in the file register specified in the instruction. all bit-oriented instructions have three operands: 1. the file register (specified by ?f?) 2. the bit in the file register (specified by ?b?) 3. the accessed memory (specified by ?a?) the bit field designator ?b? selects the number of the bit affected by the operation, while the file register desig- nator, ?f?, represents the number of the file in which the bit is located. the literal instructions may use some of the following operands: ? a literal value to be loaded into a file register (specified by ?k?) ? the desired fsr register to load the literal value into (specified by ?f?) ? no operand required (specified by ???) the control instructions may use some of the following operands: ? a program memory address (specified by ?n?) ? the mode of the call or return instructions (specified by ?s?) ? the mode of the table read and table write instructions (specified by ?m?) ? no operand required (specified by ???) all instructions are a single word, except for four double-word instructions. these instructions were made double-word to contain the required information in 32 bits. in the second word, the 4 msbs are ? 1 ?s. if this second word is executed as an instruction (by itself), it will execute as a nop . all single-word instructions are executed in a single instruction cycle, unless a conditional test is true or the program counter is changed as a result of the instruc- tion. in these cases, the execution takes two instruction cycles with the additional instruction cycle(s) executed as a nop . the double-word instructions execute in two instruction cycles. one instruction cycle consists of four oscillator periods. thus, for an oscillator frequency of 4 mhz, the normal instruction execution time is 1 s. if a conditional test is true, or the program counter is changed as a result of an instruction, the instruction execution time is 2 s. two-word branch instructions (if true) would take 3 s. figure 26-1 shows the general formats that the instruc- tions can have. all examples use the convention ?nnh? to represent a hexadecimal number. the instruction set summary, shown in table 26-2, lists the standard instructions recognized by the microchip mpasm tm assembler. section 26.1.1 ?standard instruction set? provides a description of each instruction.
pic18f87j50 family ds39775b-page 364 preliminary ? 2007 microchip technology inc. table 26-1: opcode field descriptions field description a ram access bit: a = 0 : ram location in access ram (bsr register is ignored) a = 1 : ram bank is specified by bsr register bbb bit address within an 8-bit file register (0 to 7). bsr bank select register. used to select the current ram bank. c, dc, z, ov, n alu status bits: c arry, d igit c arry, z ero, ov erflow, n egative. d destination select bit: d = 0 : store result in wreg d = 1 : store result in file register f dest destination: either the wreg register or the specified register file location. f 8-bit register file address (00h to ff h), or 2-bit fsr designator (0h to 3h). f s 12-bit register file address (000h to fffh). this is the source address. f d 12-bit register file address (000h to ff fh). this is the destination address. gie global interrupt enable bit. k literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value). label label name. mm the mode of the tblptr register for the table read and table write instructions. only used with table read and table write instructions: * no change to register (such as tblptr with table reads and writes) *+ post-increment register (such as tblptr with table reads and writes) *- post-decrement register (such as tblptr with table reads and writes) +* pre-increment register (such as tb lptr with table reads and writes) n the relative address (2?s complement number) for relative branch instructions or the direct address for call/branch and return instructions. pc program counter. pcl program counter low byte. pch program counter high byte. pclath program counter high byte latch. pclatu program counter upper byte latch. pd power-down bit. prodh product of multiply high byte. prodl product of multiply low byte. s fast call/return mode select bit: s = 0 : do not update into/from shadow registers s = 1 : certain registers loaded into/from shadow registers (fast mode) tblptr 21-bit table pointer (points to a program memory location). tablat 8-bit table latch. to time-out bit. tos top-of-stack. u unused or unchanged. wdt watchdog timer. wreg working register (accumulator). x don?t care (? 0 ? or ? 1 ?). the assembler will generate code with x = 0 . it is the recommended form of use for compatibility with all microchip software tools. z s 7-bit offset value for indirect addressing of register files (source). z d 7-bit offset value for indirect addressing of register files (destination). { } optional argument. [text] indicates indexed addressing. (text) the contents of text . [expr] specifies bit n of the register indicated by the pointer, expr . assigned to. < > register bit field. in the set of. italics user-defined term (font is courier new).
? 2007 microchip technology inc. preliminary ds39775b-page 365 pic18f87j50 family figure 26-1: general format for instructions byte-oriented file register operations 15 10 9 8 7 0 d = 0 for result destination to be wreg register opcode d a f (file #) d = 1 for result destination to be file register (f) a = 0 to force access bank bit-oriented file register operations 15 12 11 9 8 7 0 opcode b (bit #) a f (file #) b = 3-bit position of bit in file register (f) literal operations 15 8 7 0 opcode k (literal) k = 8-bit immediate value byte to byte move operations (2-word) 15 12 11 0 opcode f (source file #) call, goto and branch operations 15 8 7 0 opcode n<7:0> (literal) n = 20-bit immediate value a = 1 for bsr to select bank f = 8-bit file register address a = 0 to force access bank a = 1 for bsr to select bank f = 8-bit file register address 15 12 11 0 1111 n<19:8> (literal) 15 12 11 0 1111 f (destination file #) f = 12-bit file register address control operations example instruction addwf myreg, w, b movff myreg1, myreg2 bsf myreg, bit, b movlw 7fh goto label 15 8 7 0 opcode n<7:0> (literal) 15 12 11 0 1111 n<19:8> (literal) call myfunc 15 11 10 0 opcode n<10:0> (literal) s = fast bit bra myfunc 15 8 7 0 opcode n<7:0> (literal) bc myfunc s
pic18f87j50 family ds39775b-page 366 preliminary ? 2007 microchip technology inc. table 26-2: pic18f87j50 family instruction set mnemonic, operands description cycles 16-bit instruction word status affected notes msb lsb byte-oriented operations addwf addwfc andwf clrf comf cpfseq cpfsgt cpfslt decf decfsz dcfsnz incf incfsz infsnz iorwf movf movff movwf mulwf negf rlcf rlncf rrcf rrncf setf subfwb subwf subwfb swapf tstfsz xorwf f, d, a f, d, a f, d, a f, a f, d, a f, a f, a f, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f s , f d f, a f, a f, a f, d, a f, d, a f, d, a f, d, a f, a f, d, a f, d, a f, d, a f, d, a f, a f, d, a add wreg and f add wreg and carry bit to f and wreg with f clear f complement f compare f with wreg, skip = compare f with wreg, skip > compare f with wreg, skip < decrement f decrement f, skip if 0 decrement f, skip if not 0 increment f increment f, skip if 0 increment f, skip if not 0 inclusive or wreg with f move f move f s (source) to 1st word f d (destination) 2nd word move wreg to f multiply wreg with f negate f rotate left f through carry rotate left f (no carry) rotate right f through carry rotate right f (no carry) set f subtract f from wreg with borrow subtract wreg from f subtract wreg from f with borrow swap nibbles in f test f, skip if 0 exclusive or wreg with f 1 1 1 1 1 1 (2 or 3) 1 (2 or 3) 1 (2 or 3) 1 1 (2 or 3) 1 (2 or 3) 1 1 (2 or 3) 1 (2 or 3) 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 (2 or 3) 1 0010 0010 0001 0110 0001 0110 0110 0110 0000 0010 0100 0010 0011 0100 0001 0101 1100 1111 0110 0000 0110 0011 0100 0011 0100 0110 0101 0101 0101 0011 0110 0001 01da 00da 01da 101a 11da 001a 010a 000a 01da 11da 11da 10da 11da 10da 00da 00da ffff ffff 111a 001a 110a 01da 01da 00da 00da 100a 01da 11da 10da 10da 011a 10da ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff c, dc, z, ov, n c, dc, z, ov, n z, n z z, n none none none c, dc, z, ov, n none none c, dc, z, ov, n none none z, n z, n none none none c, dc, z, ov, n c, z, n z, n c, z, n z, n none c, dc, z, ov, n c, dc, z, ov, n c, dc, z, ov, n none none z, n 1, 2 1, 2 1,2 2 1, 2 4 4 1, 2 1, 2, 3, 4 1, 2, 3, 4 1, 2 1, 2, 3, 4 4 1, 2 1, 2 1 1, 2 1, 2 1, 2 1, 2 4 1, 2 note 1: when a port register is modified as a function of itself (e.g., movf portb, 1, 0 ), the value used will be that value present on the pins themselves. for example, if the data latch is ? 1 ? for a pin configured as input and is driven low by an external device, the data will be written back with a ? 0 ?. 2: if this instruction is executed on the tmr0 register (and, where applicable, d = 1 ), the prescaler will be cleared if assigned. 3: if the program counter (pc) is modified or a conditional test is true, the instruction requires two cycles. the second cycle is executed as a nop . 4: some instructions are two-word instructions. the second word of these instructions will be executed as a nop unless the first word of the instruction retrieves the information embedded in these 16 bits. this ensures that all program memory locations have a valid instruction.
? 2007 microchip technology inc. preliminary ds39775b-page 367 pic18f87j50 family bit-oriented operations bcf bsf btfsc btfss btg f, b, a f, b, a f, b, a f, b, a f, b, a bit clear f bit set f bit test f, skip if clear bit test f, skip if set bit toggle f 1 1 1 (2 or 3) 1 (2 or 3) 1 1001 1000 1011 1010 0111 bbba bbba bbba bbba bbba ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff none none none none none 1, 2 1, 2 3, 4 3, 4 1, 2 control operations bc bn bnc bnn bnov bnz bov bra bz call clrwdt daw goto nop nop pop push rcall reset retfie retlw return sleep n n n n n n n n n n, s ? ? n ? ? ? ? n s k s ? branch if carry branch if negative branch if not carry branch if not negative branch if not overflow branch if not zero branch if overflow branch unconditionally branch if zero call subroutine 1st word 2nd word clear watchdog timer decimal adjust wreg go to address 1st word 2nd word no operation no operation pop top of return stack (tos) push top of return stack (tos) relative call software device reset return from interrupt enable return with literal in wreg return from subroutine go into standby mode 1 (2) 1 (2) 1 (2) 1 (2) 1 (2) 1 (2) 1 (2) 2 1 (2) 2 1 1 2 1 1 1 1 2 1 2 2 2 1 1110 1110 1110 1110 1110 1110 1110 1101 1110 1110 1111 0000 0000 1110 1111 0000 1111 0000 0000 1101 0000 0000 0000 0000 0000 0010 0110 0011 0111 0101 0001 0100 0nnn 0000 110s kkkk 0000 0000 1111 kkkk 0000 xxxx 0000 0000 1nnn 0000 0000 1100 0000 0000 nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn kkkk kkkk 0000 0000 kkkk kkkk 0000 xxxx 0000 0000 nnnn 1111 0001 kkkk 0001 0000 nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn kkkk kkkk 0100 0111 kkkk kkkk 0000 xxxx 0110 0101 nnnn 1111 000s kkkk 001s 0011 none none none none none none none none none none to , pd c none none none none none none all gie/gieh, peie/giel none none to , pd 4 table 26-2: pic18f87j50 family instruction set (continued) mnemonic, operands description cycles 16-bit instruction word status affected notes msb lsb note 1: when a port register is modified as a function of itself (e.g., movf portb, 1, 0 ), the value used will be that value present on the pins themselves. for example, if the data latch is ? 1 ? for a pin configured as input and is driven low by an external device, the data will be written back with a ? 0 ?. 2: if this instruction is executed on the tmr0 register (and, where applicable, d = 1 ), the prescaler will be cleared if assigned. 3: if the program counter (pc) is modified or a conditional test is true, the instruction requires two cycles. the second cycle is executed as a nop . 4: some instructions are two-word instructions. the second word of these instructions will be executed as a nop unless the first word of the instruction retrieves the information embedded in these 16 bits. this ensures that all program memory locations have a valid instruction.
pic18f87j50 family ds39775b-page 368 preliminary ? 2007 microchip technology inc. literal operations addlw andlw iorlw lfsr movlb movlw mullw retlw sublw xorlw k k k f, k k k k k k k add literal and wreg and literal with wreg inclusive or literal with wreg move literal (12-bit) 2nd word to fsr(f) 1st word move literal to bsr<3:0> move literal to wreg multiply literal with wreg return with literal in wreg subtract wreg from literal exclusive or literal with wreg 1 1 1 2 1 1 1 2 1 1 0000 0000 0000 1110 1111 0000 0000 0000 0000 0000 0000 1111 1011 1001 1110 0000 0001 1110 1101 1100 1000 1010 kkkk kkkk kkkk 00ff kkkk 0000 kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk c, dc, z, ov, n z, n z, n none none none none none c, dc, z, ov, n z, n data memory ? program memory operations tblrd* tblrd*+ tblrd*- tblrd+* tblwt* tblwt*+ tblwt*- tblwt+* table read table read with post-increment table read with post-decrement table read with pre-increment table write table write with post-increment table write with post-decrement table write with pre-increment 2 2 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 1000 1001 1010 1011 1100 1101 1110 1111 none none none none none none none none table 26-2: pic18f87j50 family instruction set (continued) mnemonic, operands description cycles 16-bit instruction word status affected notes msb lsb note 1: when a port register is modified as a function of itself (e.g., movf portb, 1, 0 ), the value used will be that value present on the pins themselves. for example, if the data latch is ? 1 ? for a pin configured as input and is driven low by an external device, the data will be written back with a ? 0 ?. 2: if this instruction is executed on the tmr0 register (and, where applicable, d = 1 ), the prescaler will be cleared if assigned. 3: if the program counter (pc) is modified or a conditional test is true, the instruction requires two cycles. the second cycle is executed as a nop . 4: some instructions are two-word instructions. the second word of these instructions will be executed as a nop unless the first word of the instruction retrieves the information embedded in these 16 bits. this ensures that all program memory locations have a valid instruction.
? 2007 microchip technology inc. preliminary ds39775b-page 369 pic18f87j50 family 26.1.1 standard instruction set addlw add literal to w syntax: addlw k operands: 0 k 255 operation: (w) + k w status affected: n, ov, c, dc, z encoding: 0000 1111 kkkk kkkk description: the contents of w are added to the 8-bit literal ?k? and the result is placed in w. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to w example: addlw 15h before instruction w = 10h after instruction w = 25h addwf add w to f syntax: addwf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (w) + (f) dest status affected: n, ov, c, dc, z encoding: 0010 01da ffff ffff description: add w to register ?f?. if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: addwf reg, 0, 0 before instruction w = 17h reg = 0c2h after instruction w = 0d9h reg = 0c2h note: all pic18 instructions may take an optional label argument preceding the instruction mnemonic for use in symbolic addressing. if a label is used, the instruction format then becomes: {label} instruction argument(s).
pic18f87j50 family ds39775b-page 370 preliminary ? 2007 microchip technology inc. addwfc add w and carry bit to f syntax: addwfc f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (w) + (f) + (c) dest status affected: n,ov, c, dc, z encoding: 0010 00da ffff ffff description: add w, the carry flag and data memory location ?f?. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed in data memory location ?f?. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: addwfc reg, 0, 1 before instruction carry bit = 1 reg = 02h w=4dh after instruction carry bit = 0 reg = 02h w = 50h andlw and literal with w syntax: andlw k operands: 0 k 255 operation: (w) .and. k w status affected: n, z encoding: 0000 1011 kkkk kkkk description: the contents of w are anded with the 8-bit literal ?k?. the result is placed in w. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to w example: andlw 05fh before instruction w=a3h after instruction w = 03h
? 2007 microchip technology inc. preliminary ds39775b-page 371 pic18f87j50 family andwf and w with f syntax: andwf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (w) .and. (f) dest status affected: n, z encoding: 0001 01da ffff ffff description: the contents of w are anded with register ?f?. if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: andwf reg, 0, 0 before instruction w = 17h reg = c2h after instruction w = 02h reg = c2h bc branch if carry syntax: bc n operands: -128 n 127 operation: if carry bit is ? 1 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0010 nnnn nnnn description: if the carry bit is ? 1 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bc 5 before instruction pc = address (here) after instruction if carry = 1; pc = address (here + 12) if carry = 0; pc = address (here + 2)
pic18f87j50 family ds39775b-page 372 preliminary ? 2007 microchip technology inc. bcf bit clear f syntax: bcf f, b {,a} operands: 0 f 255 0 b 7 a [0,1] operation: 0 f status affected: none encoding: 1001 bbba ffff ffff description: bit ?b? in register ?f? is cleared. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: bcf flag_reg, 7, 0 before instruction flag_reg = c7h after instruction flag_reg = 47h bn branch if negative syntax: bn n operands: -128 n 127 operation: if negative bit is ? 1 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0110 nnnn nnnn description: if the negative bit is ? 1 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bn jump before instruction pc = address (here) after instruction if negative = 1; pc = address (jump) if negative = 0; pc = address (here + 2)
? 2007 microchip technology inc. preliminary ds39775b-page 373 pic18f87j50 family bnc branch if not carry syntax: bnc n operands: -128 n 127 operation: if carry bit is ? 0 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0011 nnnn nnnn description: if the carry bit is ? 0 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bnc jump before instruction pc = address (here) after instruction if carry = 0; pc = address (jump) if carry = 1; pc = address (here + 2) bnn branch if not negative syntax: bnn n operands: -128 n 127 operation: if negative bit is ? 0 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0111 nnnn nnnn description: if the negative bit is ? 0 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bnn jump before instruction pc = address (here) after instruction if negative = 0; pc = address (jump) if negative = 1; pc = address (here + 2)
pic18f87j50 family ds39775b-page 374 preliminary ? 2007 microchip technology inc. bnov branch if not overflow syntax: bnov n operands: -128 n 127 operation: if overflow bit is ? 0 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0101 nnnn nnnn description: if the overflow bit is ? 0 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bnov jump before instruction pc = address (here) after instruction if overflow = 0; pc = address (jump) if overflow = 1; pc = address (here + 2) bnz branch if not zero syntax: bnz n operands: -128 n 127 operation: if zero bit is ? 0 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0001 nnnn nnnn description: if the zero bit is ? 0 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bnz jump before instruction pc = address (here) after instruction if zero = 0; pc = address (jump) if zero = 1; pc = address (here + 2)
? 2007 microchip technology inc. preliminary ds39775b-page 375 pic18f87j50 family bra unconditional branch syntax: bra n operands: -1024 n 1023 operation: (pc) + 2 + 2n pc status affected: none encoding: 1101 0nnn nnnn nnnn description: add the 2?s complement number ?2n? to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is a two-cycle instruction. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation example: here bra jump before instruction pc = address (here) after instruction pc = address (jump) bsf bit set f syntax: bsf f, b {,a} operands: 0 f 255 0 b 7 a [0,1] operation: 1 f status affected: none encoding: 1000 bbba ffff ffff description: bit ?b? in register ?f? is set. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: bsf flag_reg, 7, 1 before instruction flag_reg = 0ah after instruction flag_reg = 8ah
pic18f87j50 family ds39775b-page 376 preliminary ? 2007 microchip technology inc. btfsc bit test file, skip if clear syntax: btfsc f, b {,a} operands: 0 f 255 0 b 7 a [0,1] operation: skip if (f) = 0 status affected: none encoding: 1011 bbba ffff ffff description: if bit ?b? in register ?f? is ? 0 ?, then the next instruction is skipped. if bit ?b? is ? 0 ?, then the next instruction fetched during the current instruction execution is discarded and a nop is executed instead, making this a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here false true btfsc : : flag, 1, 0 before instruction pc = address (here) after instruction if flag<1> = 0; pc = address (true) if flag<1> = 1; pc = address (false) btfss bit test file, skip if set syntax: btfss f, b {,a} operands: 0 f 255 0 b < 7 a [0,1] operation: skip if (f) = 1 status affected: none encoding: 1010 bbba ffff ffff description: if bit ?b? in register ?f? is ? 1 ?, then the next instruction is skipped. if bit ?b? is ? 1 ?, then the next instruction fetched during the current instruction execution is discarded and a nop is executed instead, making this a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here false true btfss : : flag, 1, 0 before instruction pc = address (here) after instruction if flag<1> = 0; pc = address (false) if flag<1> = 1; pc = address (true)
? 2007 microchip technology inc. preliminary ds39775b-page 377 pic18f87j50 family btg bit toggle f syntax: btg f, b {,a} operands: 0 f 255 0 b < 7 a [0,1] operation: (f ) f status affected: none encoding: 0111 bbba ffff ffff description: bit ?b? in data memory location ?f? is inverted. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: btg portc, 4, 0 before instruction: portc = 0111 0101 [75h] after instruction: portc = 0110 0101 [65h] bov branch if overflow syntax: bov n operands: -128 n 127 operation: if overflow bit is ? 1 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0100 nnnn nnnn description: if the overflow bit is ? 1 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bov jump before instruction pc = address (here) after instruction if overflow = 1; pc = address (jump) if overflow = 0; pc = address (here + 2)
pic18f87j50 family ds39775b-page 378 preliminary ? 2007 microchip technology inc. bz branch if zero syntax: bz n operands: -128 n 127 operation: if zero bit is ? 1 ?, (pc) + 2 + 2n pc status affected: none encoding: 1110 0000 nnnn nnnn description: if the zero bit is ? 1 ?, then the program will branch. the 2?s complement number ?2n? is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal ?n? process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal ?n? process data no operation example: here bz jump before instruction pc = address (here) after instruction if zero = 1; pc = address (jump) if zero = 0; pc = address (here + 2) call subroutine call syntax: call k {,s} operands: 0 k 1048575 s [0,1] operation: (pc) + 4 tos, k pc<20:1>; if s = 1 , (w) ws, (status) statuss, (bsr) bsrs status affected: none encoding: 1st word (k<7:0>) 2nd word(k<19:8>) 1110 1111 110s k 19 kkk k 7 kkk kkkk kkkk 0 kkkk 8 description: subroutine call of entire 2-mbyte memory range. first, return address (pc + 4) is pushed onto the return stack. if ?s? = 1 , the w, status and bsr registers are also pushed into their respective shadow registers, ws, statuss and bsrs. if ?s? = 0 , no update occurs (default). then, the 20-bit value ?k? is loaded into pc<20:1>. call is a two-cycle instruction. words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?k?<7:0>, push pc to stack read literal ?k?<19:8>, write to pc no operation no operation no operation no operation example: here call there,1 before instruction pc = address (here) after instruction pc = address (there) tos = address (here + 4) ws = w bsrs = bsr statuss = status
? 2007 microchip technology inc. preliminary ds39775b-page 379 pic18f87j50 family clrf clear f syntax: clrf f {,a} operands: 0 f 255 a [0,1] operation: 000h f, 1 z status affected: z encoding: 0110 101a ffff ffff description: clears the contents of the specified register. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: clrf flag_reg,1 before instruction flag_reg = 5ah after instruction flag_reg = 00h clrwdt clear watchdog timer syntax: clrwdt operands: none operation: 000h wdt, 000h wdt postscaler, 1 to, 1 pd status affected: to , pd encoding: 0000 0000 0000 0100 description: clrwdt instruction resets the watchdog timer. it also resets the postscaler of the wdt. status bits, to and pd , are set. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation process data no operation example: clrwdt before instruction wdt counter = ? after instruction wdt counter = 00h wdt postscaler = 0 to =1 pd =1
pic18f87j50 family ds39775b-page 380 preliminary ? 2007 microchip technology inc. comf complement f syntax: comf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: f dest status affected: n, z encoding: 0001 11da ffff ffff description: the contents of register ?f? are complemented. if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: comf reg, 0, 0 before instruction reg = 13h after instruction reg = 13h w=ech cpfseq compare f with w, skip if f = w syntax: cpfseq f {,a} operands: 0 f 255 a [0,1] operation: (f) ? (w), skip if (f) = (w) (unsigned comparison) status affected: none encoding: 0110 001a ffff ffff description: compares the contents of data memory location ?f? to the contents of w by performing an unsigned subtraction. if ?f? = w , then the fetched instruction is discarded and a nop is executed instead, making this a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here cpfseq reg, 0 nequal : equal : before instruction pc address = here w=? reg = ? after instruction if reg = w; pc = address (equal) if reg w; pc = address (nequal)
? 2007 microchip technology inc. preliminary ds39775b-page 381 pic18f87j50 family cpfsgt compare f with w, skip if f > w syntax: cpfsgt f {,a} operands: 0 f 255 a [0,1] operation: (f) ? ( w), skip if (f) > (w) (unsigned comparison) status affected: none encoding: 0110 010a ffff ffff description: compares the contents of data memory location ?f? to the contents of the w by performing an unsigned subtraction. if the contents of ?f? are greater than the contents of wreg , then the fetched instruction is discarded and a nop is executed instead, making this a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here cpfsgt reg, 0 ngreater : greater : before instruction pc = address (here) w= ? after instruction if reg > w; pc = address (greater) if reg w; pc = address (ngreater) cpfslt compare f with w, skip if f < w syntax: cpfslt f {,a} operands: 0 f 255 a [0,1] operation: (f) ? ( w), skip if (f) < (w) (unsigned comparison) status affected: none encoding: 0110 000a ffff ffff description: compares the contents of data memory location ?f? to the contents of w by performing an unsigned subtraction. if the contents of ?f? are less than the contents of w, then the fetched instruction is discarded and a nop is executed instead, making this a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here cpfslt reg, 1 nless : less : before instruction pc = address (here) w= ? after instruction if reg < w; pc = address (less) if reg w; pc = address (nless)
pic18f87j50 family ds39775b-page 382 preliminary ? 2007 microchip technology inc. daw decimal adjust w register syntax: daw operands: none operation: if [w<3:0> > 9] or [dc = 1 ] then, (w<3:0>) + 6 w<3:0>; else, (w<3:0>) w<3:0> if [w<7:4> > 9] or [c = 1 ] then, (w<7:4>) + 6 w<7:4>, c = 1 ; else, (w<7:4>) w<7:4> status affected: c encoding: 0000 0000 0000 0111 description: daw adjusts the eight-bit value in w, resulting from the earlier addition of two variables (each in packed bcd format) and produces a correct packed bcd result. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register w process data write w example 1: daw before instruction w=a5h c=0 dc = 0 after instruction w = 05h c=1 dc = 0 example 2: before instruction w=ceh c=0 dc = 0 after instruction w = 34h c=1 dc = 0 decf decrement f syntax: decf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) ? 1 dest status affected: c, dc, n, ov, z encoding: 0000 01da ffff ffff description: decrement register ?f?. if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: decf cnt, 1, 0 before instruction cnt = 01h z=0 after instruction cnt = 00h z=1
? 2007 microchip technology inc. preliminary ds39775b-page 383 pic18f87j50 family decfsz decrement f, skip if 0 syntax: decfsz f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) ? 1 dest, skip if result = 0 status affected: none encoding: 0010 11da ffff ffff description: the contents of register ?f? are decremented. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if the result is ? 0 ?, the next instruction which is already fetched is discarded and a nop is executed instead, making it a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here decfsz cnt, 1, 1 goto loop continue before instruction pc = address (here) after instruction cnt = cnt ? 1 if cnt = 0; pc = address (continue) if cnt 0; pc = address (here + 2) dcfsnz decrement f, skip if not 0 syntax: dcfsnz f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) ? 1 dest, skip if result 0 status affected: none encoding: 0100 11da ffff ffff description: the contents of register ?f? are decremented. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if the result is not ? 0 ?, the next instruction which is already fetched is discarded and a nop is executed instead, making it a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here dcfsnz temp, 1, 0 zero : nzero : before instruction temp = ? after instruction temp = temp ? 1, if temp = 0; pc = address (zero) if temp 0; pc = address (nzero)
pic18f87j50 family ds39775b-page 384 preliminary ? 2007 microchip technology inc. goto unconditional branch syntax: goto k operands: 0 k 1048575 operation: k pc<20:1> status affected: none encoding: 1st word (k<7:0>) 2nd word(k<19:8>) 1110 1111 1111 k 19 kkk k 7 kkk kkkk kkkk 0 kkkk 8 description: goto allows an unconditional branch anywhere within entire 2-mbyte memory range. the 20-bit value ?k? is loaded into pc<20:1>. goto is always a two-cycle instruction. words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?k?<7:0>, no operation read literal ?k?<19:8>, write to pc no operation no operation no operation no operation example: goto there after instruction pc = address (there) incf increment f syntax: incf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) + 1 dest status affected: c, dc, n, ov, z encoding: 0010 10da ffff ffff description: the contents of register ?f? are incremented. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: incf cnt, 1, 0 before instruction cnt = ffh z=0 c=? dc = ? after instruction cnt = 00h z=1 c=1 dc = 1
? 2007 microchip technology inc. preliminary ds39775b-page 385 pic18f87j50 family incfsz increment f, skip if 0 syntax: incfsz f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) + 1 dest, skip if result = 0 status affected: none encoding: 0011 11da ffff ffff description: the contents of register ?f? are incremented. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f?. (default) if the result is ? 0 ?, the next instruction which is already fetched is discarded and a nop is executed instead, making it a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here incfsz cnt, 1, 0 nzero : zero : before instruction pc = address (here) after instruction cnt = cnt + 1 if cnt = 0; pc = address (zero) if cnt 0; pc = address (nzero) infsnz increment f, skip if not 0 syntax: infsnz f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) + 1 dest, skip if result 0 status affected: none encoding: 0100 10da ffff ffff description: the contents of register ?f? are incremented. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if the result is not ? 0 ?, the next instruction which is already fetched is discarded and a nop is executed instead, making it a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here infsnz reg, 1, 0 zero nzero before instruction pc = address (here) after instruction reg = reg + 1 if reg 0; pc = address (nzero) if reg = 0; pc = address (zero)
pic18f87j50 family ds39775b-page 386 preliminary ? 2007 microchip technology inc. iorlw inclusive or literal with w syntax: iorlw k operands: 0 k 255 operation: (w) .or. k w status affected: n, z encoding: 0000 1001 kkkk kkkk description: the contents of w are ored with the eight-bit literal ?k?. the result is placed in w. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to w example: iorlw 35h before instruction w=9ah after instruction w=bfh iorwf inclusive or w with f syntax: iorwf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (w) .or. (f) dest status affected: n, z encoding: 0001 00da ffff ffff description: inclusive or w with register ?f?. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: iorwf result, 0, 1 before instruction result = 13h w = 91h after instruction result = 13h w = 93h
? 2007 microchip technology inc. preliminary ds39775b-page 387 pic18f87j50 family lfsr load fsr syntax: lfsr f, k operands: 0 f 2 0 k 4095 operation: k fsrf status affected: none encoding: 1110 1111 1110 0000 00ff k 7 kkk k 11 kkk kkkk description: the 12-bit literal ?k? is loaded into the file select register pointed to by ?f?. words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?k? msb process data write literal ?k? msb to fsrfh decode read literal ?k? lsb process data write literal ?k? to fsrfl example: lfsr 2, 3abh after instruction fsr2h = 03h fsr2l = abh movf move f syntax: movf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: f dest status affected: n, z encoding: 0101 00da ffff ffff description: the contents of register ?f? are moved to a destination dependent upon the status of ?d?. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). location ?f? can be anywhere in the 256-byte bank. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write w example: movf reg, 0, 0 before instruction reg = 22h w=ffh after instruction reg = 22h w = 22h
pic18f87j50 family ds39775b-page 388 preliminary ? 2007 microchip technology inc. movff move f to f syntax: movff f s ,f d operands: 0 f s 4095 0 f d 4095 operation: (f s ) f d status affected: none encoding: 1st word (source) 2nd word (destin.) 1100 1111 ffff ffff ffff ffff ffff s ffff d description: the contents of source register ?f s ? are moved to destination register ?f d ?. location of source ?f s ? can be anywhere in the 4096-byte data space (000h to fffh) and location of destination ?f d ? can also be anywhere from 000h to fffh. either source or destination can be w (a useful special situation). movff is particularly useful for transferring a data memory location to a peripheral register (such as the transmit buffer or an i/o port). the movff instruction cannot use the pcl, tosu, tosh or tosl as the destination register words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read register ?f? (src) process data no operation decode no operation no dummy read no operation write register ?f? (dest) example: movff reg1, reg2 before instruction reg1 = 33h reg2 = 11h after instruction reg1 = 33h reg2 = 33h movlb move literal to low nibble in bsr syntax: movlw k operands: 0 k 255 operation: k bsr status affected: none encoding: 0000 0001 kkkk kkkk description: the eight-bit literal ?k? is loaded into the bank select register (bsr). the value of bsr<7:4> always remains ? 0 ? regardless of the value of k 7 :k 4 . words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write literal ?k? to bsr example: movlb 5 before instruction bsr register = 02h after instruction bsr register = 05h
? 2007 microchip technology inc. preliminary ds39775b-page 389 pic18f87j50 family movlw move literal to w syntax: movlw k operands: 0 k 255 operation: k w status affected: none encoding: 0000 1110 kkkk kkkk description: the eight-bit literal ?k? is loaded into w. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to w example: movlw 5ah after instruction w=5ah movwf move w to f syntax: movwf f {,a} operands: 0 f 255 a [0,1] operation: (w) f status affected: none encoding: 0110 111a ffff ffff description: move data from w to register ?f?. location ?f? can be anywhere in the 256-byte bank. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: movwf reg, 0 before instruction w=4fh reg = ffh after instruction w=4fh reg = 4fh
pic18f87j50 family ds39775b-page 390 preliminary ? 2007 microchip technology inc. mullw multiply literal with w syntax: mullw k operands: 0 k 255 operation: (w) x k prodh:prodl status affected: none encoding: 0000 1101 kkkk kkkk description: an unsigned multiplication is carried out between the contents of w and the 8-bit literal ?k?. the 16-bit result is placed in prodh:prodl register pair. prodh contains the high byte. w is unchanged. none of the status flags are affected. note that neither overflow nor carry is possible in this operation. a zero result is possible but not detected. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write registers prodh: prodl example: mullw 0c4h before instruction w=e2h prodh = ? prodl = ? after instruction w=e2h prodh = adh prodl = 08h mulwf multiply w with f syntax: mulwf f {,a} operands: 0 f 255 a [0,1] operation: (w) x (f) prodh:prodl status affected: none encoding: 0000 001a ffff ffff description: an unsigned multiplication is carried out between the contents of w and the register file location ?f?. the 16-bit result is stored in the prodh:prodl register pair. prodh contains the high byte. both w and ?f? are unchanged. none of the status flags are affected. note that neither overflow nor carry is possible in this operation. a zero result is possible but not detected. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write registers prodh: prodl example: mulwf reg, 1 before instruction w=c4h reg = b5h prodh = ? prodl = ? after instruction w=c4h reg = b5h prodh = 8ah prodl = 94h
? 2007 microchip technology inc. preliminary ds39775b-page 391 pic18f87j50 family negf negate f syntax: negf f {,a} operands: 0 f 255 a [0,1] operation: (f ) + 1 f status affected: n, ov, c, dc, z encoding: 0110 110a ffff ffff description: location ?f? is negated using two?s complement. the result is placed in the data memory location ?f?. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: negf reg, 1 before instruction reg = 0011 1010 [3ah] after instruction reg = 1100 0110 [c6h] nop no operation syntax: nop operands: none operation: no operation status affected: none encoding: 0000 1111 0000 xxxx 0000 xxxx 0000 xxxx description: no operation. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation no operation no operation example: none.
pic18f87j50 family ds39775b-page 392 preliminary ? 2007 microchip technology inc. pop pop top of return stack syntax: pop operands: none operation: (tos) bit bucket status affected: none encoding: 0000 0000 0000 0110 description: the tos value is pulled off the return stack and is discarded. the tos value then becomes the previous value that was pushed onto the return stack. this instruction is provided to enable the user to properly manage the return stack to incorporate a software stack. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation pop tos value no operation example: pop goto new before instruction tos = 0031a2h stack (1 level down) = 014332h after instruction tos = 014332h pc = new push push top of return stack syntax: push operands: none operation: (pc + 2) tos status affected: none encoding: 0000 0000 0000 0101 description: the pc + 2 is pushed onto the top of the return stack. the previous tos value is pushed down on the stack. this instruction allows implementing a software stack by modifying tos and then pushing it onto the return stack. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode push pc + 2 onto return stack no operation no operation example: push before instruction tos = 345ah pc = 0124h after instruction pc = 0126h tos = 0126h stack (1 level down) = 345ah
? 2007 microchip technology inc. preliminary ds39775b-page 393 pic18f87j50 family rcall relative call syntax: rcall n operands: -1024 n 1023 operation: (pc) + 2 tos, (pc) + 2 + 2n pc status affected: none encoding: 1101 1nnn nnnn nnnn description: subroutine call with a jump up to 1k from the current location. first, return address (pc + 2) is pushed onto the stack. then, add the 2?s complement number ?2n? to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc + 2 + 2n. this instruction is a two-cycle instruction. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?n? push pc to stack process data write to pc no operation no operation no operation no operation example: here rcall jump before instruction pc = address (here) after instruction pc = address (jump) tos = address (here + 2) reset reset syntax: reset operands: none operation: reset all registers and flags that are affected by a mclr reset. status affected: all encoding: 0000 0000 1111 1111 description: this instruction provides a way to execute a mclr reset in software. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode start reset no operation no operation example: reset after instruction registers = reset value flags* = reset value
pic18f87j50 family ds39775b-page 394 preliminary ? 2007 microchip technology inc. retfie return from interrupt syntax: retfie {s} operands: s [0,1] operation: (tos) pc, 1 gie/gieh or peie/giel; if s = 1 , (ws) w, (statuss) status, (bsrs) bsr, pclatu, pclath are unchanged status affected: gie/gieh, peie/giel. encoding: 0000 0000 0001 000s description: return from interrupt. stack is popped and top-of-stack (tos) is loaded into the pc. interrupts are enabled by setting either the high or low-priority global interrupt enable bit. if ?s? = 1 , the contents of the shadow registers ws, statuss and bsrs are loaded into their corresponding registers w, status and bsr. if ?s? = 0 , no update of these registers occurs (default). words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation no operation pop pc from stack set gieh or giel no operation no operation no operation no operation example: retfie 1 after interrupt pc = tos w=ws bsr = bsrs status = statuss gie/gieh, peie/giel = 1 retlw return literal to w syntax: retlw k operands: 0 k 255 operation: k w, (tos) pc, pclatu, pclath are unchanged status affected: none encoding: 0000 1100 kkkk kkkk description: w is loaded with the eight-bit literal ?k?. the program counter is loaded from the top of the stack (the return address). the high address latch (pclath) remains unchanged. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data pop pc from stack, write to w no operation no operation no operation no operation example: call table ; w contains table ; offset value ; w now has ; table value : table addwf pcl ; w = offset retlw k0 ; begin table retlw k1 ; : : retlw kn ; end of table before instruction w = 07h after instruction w = value of kn
? 2007 microchip technology inc. preliminary ds39775b-page 395 pic18f87j50 family return return from subroutine syntax: return {s} operands: s [0,1] operation: (tos) pc; if s = 1 , (ws) w, (statuss) status, (bsrs) bsr, pclatu, pclath are unchanged status affected: none encoding: 0000 0000 0001 001s description: return from subroutine. the stack is popped and the top of the stack (tos) is loaded into the program counter. if ?s?= 1 , the contents of the shadow registers ws, statuss and bsrs are loaded into their corresponding registers w, status and bsr. if ?s? = 0 , no update of these registers occurs (default). words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation process data pop pc from stack no operation no operation no operation no operation example: return after instruction: pc = tos rlcf rotate left f through carry syntax: rlcf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) dest, (f<7>) c, (c) dest<0> status affected: c, n, z encoding: 0011 01da ffff ffff description: the contents of register ?f? are rotated one bit to the left through the carry flag. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: rlcf reg, 0, 0 before instruction reg = 1110 0110 c=0 after instruction reg = 1110 0110 w= 1100 1100 c=1 c register f
pic18f87j50 family ds39775b-page 396 preliminary ? 2007 microchip technology inc. rlncf rotate left f (no carry) syntax: rlncf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) dest, (f<7>) dest<0> status affected: n, z encoding: 0100 01da ffff ffff description: the contents of register ?f? are rotated one bit to the left. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: rlncf reg, 1, 0 before instruction reg = 1010 1011 after instruction reg = 0101 0111 register f rrcf rotate right f through carry syntax: rrcf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) dest, (f<0>) c, (c) dest<7> status affected: c, n, z encoding: 0011 00da ffff ffff description: the contents of register ?f? are rotated one bit to the right through the carry flag. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: rrcf reg, 0, 0 before instruction reg = 1110 0110 c=0 after instruction reg = 1110 0110 w= 0111 0011 c=0 c register f
? 2007 microchip technology inc. preliminary ds39775b-page 397 pic18f87j50 family rrncf rotate right f (no carry) syntax: rrncf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) dest, (f<0>) dest<7> status affected: n, z encoding: 0100 00da ffff ffff description: the contents of register ?f? are rotated one bit to the right. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed back in register ?f? (default). if ?a? is ? 0 ?, the access bank will be selected, overriding the bsr value. if ?a? is ? 1 ?, then the bank will be selected as per the bsr value (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example 1: rrncf reg, 1, 0 before instruction reg = 1101 0111 after instruction reg = 1110 1011 example 2: rrncf reg, 0, 0 before instruction w=? reg = 1101 0111 after instruction w= 1110 1011 reg = 1101 0111 register f setf set f syntax: setf f {,a} operands: 0 f 255 a [0,1] operation: ffh f status affected: none encoding: 0110 100a ffff ffff description: the contents of the specified register are set to ffh. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write register ?f? example: setf reg,1 before instruction reg = 5ah after instruction reg = ffh
pic18f87j50 family ds39775b-page 398 preliminary ? 2007 microchip technology inc. sleep enter sleep mode syntax: sleep operands: none operation: 00h wdt, 0 wdt postscaler, 1 to , 0 pd status affected: to , pd encoding: 0000 0000 0000 0011 description: the power-down status bit (pd ) is cleared. the time-out status bit (to ) is set. the watchdog timer and its postscaler are cleared. the processor is put into sleep mode with the oscillator stopped. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation process data go to sleep example: sleep before instruction to =? pd =? after instruction to =1 ? pd =0 ? if wdt causes wake-up, this bit is cleared. subfwb subtract f from w with borrow syntax: subfwb f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (w) ? (f) ? (c ) dest status affected: n, ov, c, dc, z encoding: 0101 01da ffff ffff description: subtract register ?f? and carry flag (borrow) from w (2?s complement method). if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example 1: subfwb reg, 1, 0 before instruction reg = 3 w=2 c=1 after instruction reg = ff w=2 c=0 z=0 n = 1 ; result is negative example 2: subfwb reg, 0, 0 before instruction reg = 2 w=5 c=1 after instruction reg = 2 w=3 c=1 z=0 n = 0 ; result is positive example 3: subfwb reg, 1, 0 before instruction reg = 1 w=2 c=0 after instruction reg = 0 w=2 c=1 z = 1 ; result is zero n=0
? 2007 microchip technology inc. preliminary ds39775b-page 399 pic18f87j50 family sublw subtract w from literal syntax: sublw k operands: 0 k 255 operation: k ? (w) w status affected: n, ov, c, dc, z encoding: 0000 1000 kkkk kkkk description: w is subtracted from the eight-bit literal ?k?. the result is placed in w. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to w example 1: sublw 02h before instruction w = 01h c=? after instruction w = 01h c = 1 ; result is positive z=0 n=0 example 2: sublw 02h before instruction w = 02h c=? after instruction w = 00h c = 1 ; result is zero z=1 n=0 example 3: sublw 02h before instruction w = 03h c=? after instruction w = ffh ; (2?s complement) c = 0 ; result is negative z=0 n=1 subwf subtract w from f syntax: subwf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) ? (w) dest status affected: n, ov, c, dc, z encoding: 0101 11da ffff ffff description: subtract w from register ?f? (2?s complement method). if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example 1: subwf reg, 1, 0 before instruction reg = 3 w=2 c=? after instruction reg = 1 w=2 c = 1 ; result is positive z=0 n=0 example 2: subwf reg, 0, 0 before instruction reg = 2 w=2 c=? after instruction reg = 2 w=0 c = 1 ; result is zero z=1 n=0 example 3: subwf reg, 1, 0 before instruction reg = 1 w=2 c=? after instruction reg = ffh ;(2?s complement) w=2 c = 0 ; result is negative z=0 n=1
pic18f87j50 family ds39775b-page 400 preliminary ? 2007 microchip technology inc. subwfb subtract w from f with borrow syntax: subwfb f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f) ? (w) ? (c ) dest status affected: n, ov, c, dc, z encoding: 0101 10da ffff ffff description: subtract w and the carry flag (borrow) from register ?f? (2?s complement method). if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addr essing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example 1: subwfb reg, 1, 0 before instruction reg = 19h (0001 1001) w=0dh (0000 1101) c=1 after instruction reg = 0ch (0000 1011) w=0dh (0000 1101) c=1 z=0 n = 0 ; result is positive example 2: subwfb reg, 0, 0 before instruction reg = 1bh (0001 1011) w=1ah (0001 1010) c=0 after instruction reg = 1bh (0001 1011) w = 00h c=1 z = 1 ; result is zero n=0 example 3: subwfb reg, 1, 0 before instruction reg = 03h (0000 0011) w=0eh (0000 1101) c=1 after instruction reg = f5h (1111 0100) ; [2?s comp] w=0eh (0000 1101) c=0 z=0 n = 1 ; result is negative swapf swap f syntax: swapf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (f<3:0>) dest<7:4>, (f<7:4>) dest<3:0> status affected: none encoding: 0011 10da ffff ffff description: the upper and lower nibbles of register ?f? are exchanged. if ?d? is ? 0 ?, the result is placed in w. if ?d? is ? 1 ?, the result is placed in register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset a ddressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: swapf reg, 1, 0 before instruction reg = 53h after instruction reg = 35h
? 2007 microchip technology inc. preliminary ds39775b-page 401 pic18f87j50 family tblrd table read syntax: tblrd ( *; *+; *-; +*) operands: none operation: if tblrd *, (prog mem (tblptr)) tablat, tblptr ? no change; if tblrd *+, (prog mem (tblptr)) tablat, (tblptr) + 1 tblptr; if tblrd *-, (prog mem (tblptr)) tablat, (tblptr) ? 1 tblptr; if tblrd +*, (tblptr) + 1 tblptr, (prog mem (tblptr)) tablat status affected: none encoding: 0000 0000 0000 10nn nn=0 * =1 *+ =2 *- =3 +* description: this instruction is used to read the contents of program memory (p.m.). to address the program memory, a pointer called table pointer (tblptr) is used. the tblptr (a 21-bit pointer) points to each byte in the program memory. tblptr has a 2-mbyte address range. tblptr<0> = 0 : least significant byte of program memory word tblptr<0> = 1 : most significant byte of program memory word the tblrd instruction can modify the value of tblptr as follows: ? no change ? post-increment ? post-decrement ? pre-increment words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation no operation no operation no operation no operation (read program memory) no operation no operation (write tablat) tblrd table read (continued) example 1: tblrd *+ ; before instruction tablat = 55h tblptr = 00a356h memory(00a356h) = 34h after instruction tablat = 34h tblptr = 00a357h example 2: tblrd +* ; before instruction tablat = aah tblptr = 01a357h memory(01a357h) = 12h memory(01a358h) = 34h after instruction tablat = 34h tblptr = 01a358h
pic18f87j50 family ds39775b-page 402 preliminary ? 2007 microchip technology inc. tblwt table write syntax: tblwt ( *; *+; *-; +*) operands: none operation: if tblwt*, (tablat) holding register, tblptr ? no change; if tblwt*+, (tablat) holding register, (tblptr) + 1 tblptr; if tblwt*-, (tablat) holding register, (tblptr) ? 1 tblptr; if tblwt+*, (tblptr) + 1 tblptr, (tablat) holding register status affected: none encoding: 0000 0000 0000 11nn nn=0 * =1 *+ =2 *- =3 +* description: this instruction uses the 3 lsbs of tblptr to determine which of the 8 holding registers the tablat is written to. the holding registers are used to program the contents of program memory (p.m.). (refer to section 5.0 ?memory organization? for additional details on programming flash memory.) the tblptr (a 21-bit pointer) points to each byte in the program memory. tblptr has a 2-mbyte address range. the lsb of the tblptr selects which byte of the program memory location to access. tblptr<0> = 0 : least significant byte of program memory word tblptr<0> = 1 : most significant byte of program memory word the tblwt instruction can modify the value of tblptr as follows: ? no change ? post-increment ? post-decrement ? pre-increment words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation no operation no operation no operation no operation (read tablat) no operation no operation (write to holding register) tblwt table write (continued) example 1: tblwt *+; before instruction tablat = 55h tblptr = 00a356h holding register (00a356h) = ffh after instructions (table write completion) tablat = 55h tblptr = 00a357h holding register (00a356h) = 55h example 2: tblwt +*; before instruction tablat = 34h tblptr = 01389ah holding register (01389ah) = ffh holding register (01389bh) = ffh after instruction (table write completion) tablat = 34h tblptr = 01389bh holding register (01389ah) = ffh holding register (01389bh) = 34h
? 2007 microchip technology inc. preliminary ds39775b-page 403 pic18f87j50 family tstfsz test f, skip if 0 syntax: tstfsz f {,a} operands: 0 f 255 a [0,1] operation: skip if f = 0 status affected: none encoding: 0110 011a ffff ffff description: if ?f? = 0 , the next instruction fetched during the current instruction execution is discarded and a nop is executed, making this a two-cycle instruction. if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction. q cycle activity: q1 q2 q3 q4 decode read register ?f? process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example: here tstfsz cnt, 1 nzero : zero : before instruction pc = address (here) after instruction if cnt = 00h, pc = address (zero) if cnt 00h, pc = address (nzero) xorlw exclusive or literal with w syntax: xorlw k operands: 0 k 255 operation: (w) .xor. k w status affected: n, z encoding: 0000 1010 kkkk kkkk description: the contents of w are xored with the 8-bit literal ?k?. the result is placed in w. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to w example: xorlw 0afh before instruction w=b5h after instruction w=1ah
pic18f87j50 family ds39775b-page 404 preliminary ? 2007 microchip technology inc. xorwf exclusive or w with f syntax: xorwf f {,d {,a}} operands: 0 f 255 d [0,1] a [0,1] operation: (w) .xor. (f) dest status affected: n, z encoding: 0001 10da ffff ffff description: exclusive or the contents of w with register ?f?. if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in the register ?f? (default). if ?a? is ? 0 ?, the access bank is selected. if ?a? is ? 1 ?, the bsr is used to select the gpr bank (default). if ?a? is ? 0 ? and the extended instruction set is enabled, this instruction operates in indexed literal offset addressing mode whenever f 95 (5fh). see section 26.2.3 ?byte-oriented and bit-oriented instructions in indexed literal offset mode? for details. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: xorwf reg, 1, 0 before instruction reg = afh w=b5h after instruction reg = 1ah w=b5h
? 2007 microchip technology inc. preliminary ds39775b-page 405 pic18f87j50 family 26.2 extended instruction set in addition to the standard 75 instructions of the pic18 instruction set, the pic18f87j50 family of devices also provide an optional extension to the core cpu function- ality. the added features include eight additional instructions that augment indirect and indexed addressing operations and the implementation of indexed literal offset addressing for many of the standard pic18 instructions. the additional features of the extended instruction set are enabled by default on unprogrammed devices. users must properly set or clear the xinst configura- tion bit during programming to enable or disable these features. the instructions in the extended set can all be classified as literal operations, which either manipulate the file select registers, or use them for indexed addressing. two of the instructions, addfsr and subfsr , each have an additional special instantiation for using fsr2. these versions ( addulnk and subulnk ) allow for automatic return after execution. the extended instructions are specifically implemented to optimize re-entrant program code (that is, code that is recursive or that uses a software stack) written in high-level languages, particularly c. among other things, they allow users working in high-level languages to perform certain operations on data structures more efficiently. these include: ? dynamic allocation and deallocation of software stack space when entering and leaving subroutines ? function pointer invocation ? software stack pointer manipulation ? manipulation of variables located in a software stack a summary of the instructions in the extended instruc- tion set is provided in table 26-3. detailed descriptions are provided in section 26.2.2 ?extended instruction set? . the opcode field descriptions in table 26-1 (page 364) apply to both the standard and extended pic18 instruction sets. 26.2.1 extended instruction syntax most of the extended instructions use indexed argu- ments, using one of the file select registers and some offset to specify a source or destination register. when an argument for an instruction serves as part of indexed addressing, it is enclosed in square brackets (?[ ]?). this is done to indicate that the argument is used as an index or offset. the mpasm? assembler will flag an error if it determines that an index or offset value is not bracketed. when the extended instruction set is enabled, brackets are also used to indicate index arguments in byte-oriented and bit-oriented instructions. this is in addition to other changes in their syntax. for more details, see section 26.2.3.1 ?extended instruction syntax with standard pic18 commands? . table 26-3: extensions to the pic18 instruction set note: the instruction set extension and the indexed literal offset addressing mode were designed for optimizing applications written in c; the user may likely never use these instructions directly in assembler. the syntax for these commands is provided as a reference for users who may be reviewing code that has been generated by a compiler. note: in the past, square brackets have been used to denote optional arguments in the pic18 and earlier instruction sets. in this text and going forward, optional arguments are denoted by braces (?{ }?). mnemonic, operands description cycles 16-bit instruction word status affected msb lsb addfsr addulnk callw movsf movss pushl subfsr subulnk f, k k z s , f d z s , z d k f, k k add literal to fsr add literal to fsr2 and return call subroutine using wreg move z s (source) to 1st word f d (destination) 2nd word move z s (source) to 1st word z d (destination) 2nd word store literal at fsr2, decrement fsr2 subtract literal from fsr subtract literal from fsr2 and return 1 2 2 2 2 1 1 2 1110 1110 0000 1110 1111 1110 1111 1110 1110 1110 1000 1000 0000 1011 ffff 1011 xxxx 1010 1001 1001 ffkk 11kk 0001 0zzz ffff 1zzz xzzz kkkk ffkk 11kk kkkk kkkk 0100 zzzz ffff zzzz zzzz kkkk kkkk kkkk none none none none none none none none
pic18f87j50 family ds39775b-page 406 preliminary ? 2007 microchip technology inc. 26.2.2 extended instruction set addfsr add literal to fsr syntax: addfsr f, k operands: 0 k 63 f [ 0, 1, 2 ] operation: fsr(f) + k fsr(f) status affected: none encoding: 1110 1000 ffkk kkkk description: the 6-bit literal ?k? is added to the contents of the fsr specified by ?f?. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to fsr example: addfsr 2, 23h before instruction fsr2 = 03ffh after instruction fsr2 = 0422h addulnk add literal to fsr2 and return syntax: addulnk k operands: 0 k 63 operation: fsr2 + k fsr2, (tos) pc status affected: none encoding: 1110 1000 11kk kkkk description: the 6-bit literal ?k? is added to the contents of fsr2. a return is then executed by loading the pc with the tos. the instruction takes two cycles to execute; a nop is performed during the second cycle. this may be thought of as a special case of the addfsr instruction, where f = 3 (binary ? 11 ?); it operates only on fsr2. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal ?k? process data write to fsr no operation no operation no operation no operation example: addulnk 23h before instruction fsr2 = 03ffh pc = 0100h after instruction fsr2 = 0422h pc = (tos) note: all pic18 instructions may take an optional label argument preceding the instruction mnemonic for use in symbolic addressing. if a label is used, the instruction format then becomes: {label} instruction argument(s).
? 2007 microchip technology inc. preliminary ds39775b-page 407 pic18f87j50 family callw subroutine call using wreg syntax: callw operands: none operation: (pc + 2) tos, (w) pcl, (pclath) pch, (pclatu) pcu status affected: none encoding: 0000 0000 0001 0100 description first, the return address (pc + 2) is pushed onto the return stack. next, the contents of w are written to pcl; the existing value is discarded. then, the contents of pclath and pclatu are latched into pch and pcu, respectively. the second cycle is executed as a nop instruction while the new next instruction is fetched. unlike call , there is no option to update w, status or bsr. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read wreg push pc to stack no operation no operation no operation no operation no operation example: here callw before instruction pc = address (here) pclath = 10h pclatu = 00h w = 06h after instruction pc = 001006h tos = address (here + 2) pclath = 10h pclatu = 00h w = 06h movsf move indexed to f syntax: movsf [z s ], f d operands: 0 z s 127 0 f d 4095 operation: ((fsr2) + z s ) f d status affected: none encoding: 1st word (source) 2nd word (destin.) 1110 1111 1011 ffff 0zzz ffff zzzz s ffff d description: the contents of the source register are moved to destination register ?f d ?. the actual address of the source register is determined by adding the 7-bit literal offset ?z s ?, in the first word, to the value of fsr2. the address of the destination register is specified by the 12-bit literal ?f d ? in the second word. both addresses can be anywhere in the 4096-byte data space (000h to fffh). the movsf instruction cannot use the pcl, tosu, tosh or tosl as the destination register. if the resultant source address points to an indirect addressing register, the value returned will be 00h. words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode determine source addr determine source addr read source reg decode no operation no dummy read no operation write register ?f? (dest) example: movsf [05h], reg2 before instruction fsr2 = 80h contents of 85h = 33h reg2 = 11h after instruction fsr2 = 80h contents of 85h = 33h reg2 = 33h
pic18f87j50 family ds39775b-page 408 preliminary ? 2007 microchip technology inc. movss move indexed to indexed syntax: movss [z s ], [z d ] operands: 0 z s 127 0 z d 127 operation: ((fsr2) + z s ) ((fsr2) + z d ) status affected: none encoding: 1st word (source) 2nd word (dest.) 1110 1111 1011 xxxx 1zzz xzzz zzzz s zzzz d description the contents of the source register are moved to the destination register. the addresses of the source and destination registers are determined by adding the 7-bit literal offsets ?z s ? or ?z d ?, respectively, to the value of fsr2. both registers can be located anywhere in the 4096-byte data memory space (000h to fffh). the movss instruction cannot use the pcl, tosu, tosh or tosl as the destination register. if the resultant source address points to an indirect addressing register, the value returned will be 00h. if the resultant destination address points to an indirect addressing register, the instruction will execute as a nop . words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode determine source addr determine source addr read source reg decode determine dest addr determine dest addr write to dest reg example: movss [05h], [06h] before instruction fsr2 = 80h contents of 85h = 33h contents of 86h = 11h after instruction fsr2 = 80h contents of 85h = 33h contents of 86h = 33h pushl store literal at fsr2, decrement fsr2 syntax: pushl k operands: 0 k 255 operation: k (fsr2), fsr2 ? 1 fsr2 status affected: none encoding: 1111 1010 kkkk kkkk description: the 8-bit literal ?k? is written to the data memory address specified by fsr2. fsr2 is decremented by 1 after the operation. this instruction allows users to push values onto a software stack. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read ?k? process data write to destination example: pushl 08h before instruction fsr2h:fsr2l = 01ech memory (01ech) = 00h after instruction fsr2h:fsr2l = 01ebh memory (01ech) = 08h
? 2007 microchip technology inc. preliminary ds39775b-page 409 pic18f87j50 family subfsr subtract literal from fsr syntax: subfsr f, k operands: 0 k 63 f [ 0, 1, 2 ] operation: fsrf ? k fsrf status affected: none encoding: 1110 1001 ffkk kkkk description: the 6-bit literal ?k? is subtracted from the contents of the fsr specified by ?f?. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: subfsr 2, 23h before instruction fsr2 = 03ffh after instruction fsr2 = 03dch subulnk subtract literal from fsr2 and return syntax: subulnk k operands: 0 k 63 operation: fsr2 ? k fsr2, (tos) pc status affected: none encoding: 1110 1001 11kk kkkk description: the 6-bit literal ?k? is subtracted from the contents of the fsr2. a return is then executed by loading the pc with the tos. the instruction takes two cycles to execute; a nop is performed during the second cycle. this may be thought of as a special case of the subfsr instruction, where f = 3 (binary ? 11 ?); it operates only on fsr2. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination no operation no operation no operation no operation example: subulnk 23h before instruction fsr2 = 03ffh pc = 0100h after instruction fsr2 = 03dch pc = (tos)
pic18f87j50 family ds39775b-page 410 preliminary ? 2007 microchip technology inc. 26.2.3 byte-oriented and bit-oriented instructions in indexed literal offset mode in addition to eight new commands in the extended set, enabling the extended instruction set also enables indexed literal offset addressing ( section 5.6.1 ?indexed addressing with literal offset? ). this has a significant impact on the way that many commands of the standard pic18 instruction set are interpreted. when the extended set is disabled, addresses embed- ded in opcodes are treated as literal memory locations: either as a location in the access bank (a = 0 ) or in a gpr bank designated by the bsr (a = 1 ). when the extended instruction set is enabled and a = 0 , however, a file register argument of 5fh or less is interpreted as an offset from the pointer value in fsr2 and not as a literal address. for practical purposes, this means that all instructions that use the access ram bit as an argument ? that is, all byte-oriented and bit-oriented instructions, or almost half of the core pic18 instruc- tions ? may behave differently when the extended instruction set is enabled. when the content of fsr2 is 00h, the boundaries of the access ram are essentially remapped to their original values. this may be useful in creating backward-compatible code. if this technique is used, it may be necessary to save the value of fsr2 and restore it when moving back and forth between c and assembly routines in order to preserve the stack pointer. users must also keep in mind the syntax requirements of the extended instruction set (see section 26.2.3.1 ?extended instruction syntax with standard pic18 commands? ). although the indexed literal offset mode can be very useful for dynamic stack and pointer manipulation, it can also be very annoying if a simple arithmetic opera- tion is carried out on the wrong register. users who are accustomed to the pic18 programming must keep in mind that, when the extended instruction set is enabled, register addresses of 5fh or less are used for indexed literal offset addressing. representative examples of typical byte-oriented and bit-oriented instructions in the indexed literal offset mode are provided on the following page to show how execution is affected. the operand conditions shown in the examples are applicable to all instructions of these types. 26.2.3.1 extended instruction syntax with standard pic18 commands when the extended instruction set is enabled, the file register argument ?f? in the standard byte-oriented and bit-oriented commands is replaced with the literal offset value ?k?. as already noted, this occurs only when ?f? is less than or equal to 5fh. when an offset value is used, it must be indicated by square brackets (?[ ]?). as with the extended instructions, the use of brackets indicates to the compiler that the value is to be interpreted as an index or an offset. omitting the brackets, or using a value greater than 5fh within the brackets, will generate an error in the mpasm assembler. if the index argument is properly bracketed for indexed literal offset addressing, the access ram argument is never specified; it will automatically be assumed to be ? 0 ?. this is in contrast to standard operation (extended instruction set disabled), when ?a? is set on the basis of the target address. declaring the access ram bit in this mode will also generate an error in the mpasm assembler. the destination argument ?d? functions as before. in the latest versions of the mpasm assembler, language support for the extended instruction set must be explicitly invoked. this is done with either the command line option, /y , or the pe directive in the source listing. 26.2.4 considerations when enabling the extended instruction set it is important to note that the extensions to the instruc- tion set may not be beneficial to all users. in particular, users who are not writing code that uses a software stack may not benefit from using the extensions to the instruction set. additionally, the indexed literal offset addressing mode may create issues with legacy applications written to the pic18 assembler. this is because instructions in the legacy code may attempt to address registers in the access bank below 5fh. since these addresses are interpreted as literal offsets to fsr2 when the instruction set extension is enabled, the application may read or write to the wrong data addresses. when porting an application to the pic18f87j50 fam- ily, it is very important to consider the type of code. a large, re-entrant application that is written in c and would benefit from efficient compilation will do well when using the instruction set extensions. legacy applications that heavily use the access bank will most likely not benefit from using the extended instruction set. note: enabling the pic18 instruction set exten- sion may cause legacy applications to behave erratically or fail entirely.
? 2007 microchip technology inc. preliminary ds39775b-page 411 pic18f87j50 family addwf add w to indexed (indexed literal offset mode) syntax: addwf [k] {,d} operands: 0 k 95 d [0,1] operation: (w) + ((fsr2) + k) dest status affected: n, ov, c, dc, z encoding: 0010 01d0 kkkk kkkk description: the contents of w are added to the contents of the register indicated by fsr2, offset by the value ?k?. if ?d? is ? 0 ?, the result is stored in w. if ?d? is ? 1 ?, the result is stored back in register ?f? (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read ?k? process data write to destination example: addwf [ofst] ,0 before instruction w = 17h ofst = 2ch fsr2 = 0a00h contents of 0a2ch = 20h after instruction w = 37h contents of 0a2ch = 20h bsf bit set indexed (indexed literal offset mode) syntax: bsf [k], b operands: 0 f 95 0 b 7 operation: 1 ((fsr2) + k) status affected: none encoding: 1000 bbb0 kkkk kkkk description: bit ?b? of the register indicated by fsr2, offset by the value ?k?, is set. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register ?f? process data write to destination example: bsf [flag_ofst], 7 before instruction flag_ofst = 0ah fsr2 = 0a00h contents of 0a0ah = 55h after instruction contents of 0a0ah = d5h setf set indexed (indexed literal offset mode) syntax: setf [k] operands: 0 k 95 operation: ffh ((fsr2) + k) status affected: none encoding: 0110 1000 kkkk kkkk description: the contents of the register indicated by fsr2, offset by ?k?, are set to ffh. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read ?k? process data write register example: setf [ofst] before instruction ofst = 2ch fsr2 = 0a00h contents of 0a2ch = 00h after instruction contents of 0a2ch = ffh
pic18f87j50 family ds39775b-page 412 preliminary ? 2007 microchip technology inc. 26.2.5 special considerations with microchip mplab ? ide tools the latest versions of microchip?s software tools have been designed to fully support the extended instruction set for the pic18f87j50 family. this includes the mplab c18 c compiler, mpasm assembly language and mplab integrated development environment (ide). when selecting a target device for software development, mplab ide will automatically set default configuration bits for that device. the default setting for the xinst configuration bit is ? 0 ?, disabling the extended instruction set and indexed literal offset addressing. for proper execution of applications developed to take advantage of the extended instruction set, xinst must be set during programming. to develop software for the extended instruction set, the user must enable support for the instructions and the indexed addressing mode in their language tool(s). depending on the environment being used, this may be done in several ways: ? a menu option or dialog box within the environment that allows the user to configure the language tool and its settings for the project ? a command line option ? a directive in the source code these options vary between different compilers, assemblers and development environments. users are encouraged to review the documentation accompany- ing their development systems for the appropriate information.
? 2007 microchip technology inc. preliminary ds39775b-page 413 pic18f87j50 family 27.0 development support the pic ? microcontrollers are supported with a full range of hardware and software development tools: ? integrated development environment - mplab ? ide software ? assemblers/compilers/linkers - mpasm tm assembler - mplab c18 and mplab c30 c compilers -mplink tm object linker/ mplib tm object librarian - mplab asm30 assembler/linker/library ? simulators - mplab sim software simulator ?emulators - mplab ice 2000 in-circuit emulator - mplab real ice? in-circuit emulator ? in-circuit debugger - mplab icd 2 ? device programmers - picstart ? plus development programmer - mplab pm3 device programmer - pickit? 2 development programmer ? low-cost demonstration and development boards and evaluation kits 27.1 mplab integrated development environment software the mplab ide software brings an ease of software development previously unseen in the 8/16-bit micro- controller market. the mplab ide is a windows ? operating system-based application that contains: ? a single graphical interface to all debugging tools - simulator - programmer (sold separately) - emulator (sold separately) - in-circuit debugger (sold separately) ? a full-featured editor with color-coded context ? a multiple project manager ? customizable data windows with direct edit of contents ? high-level source code debugging ? visual device initializer for easy register initialization ? mouse over variable inspection ? drag and drop variables from source to watch windows ? extensive on-line help ? integration of select third party tools, such as hi-tech software c compilers and iar c compilers the mplab ide allows you to: ? edit your source files (either assembly or c) ? one touch assemble (or compile) and download to pic mcu emulator and simulator tools (automatically updates all project information) ? debug using: - source files (assembly or c) - mixed assembly and c - machine code mplab ide supports multiple debugging tools in a single development paradigm, from the cost-effective simulators, through low-cost in-circuit debuggers, to full-featured emulators. this eliminates the learning curve when upgrading to tools with increased flexibility and power.
pic18f87j50 family ds39775b-page 414 preliminary ? 2007 microchip technology inc. 27.2 mpasm assembler the mpasm assembler is a full-featured, universal macro assembler for all pic mcus. the mpasm assembler generates relocatable object files for the mplink object linker, intel ? standard hex files, map files to detail memory usage and symbol reference, absolute lst files that contain source lines and generated machine code and coff files for debugging. the mpasm assembler features include: ? integration into mplab ide projects ? user-defined macros to streamline assembly code ? conditional assembly for multi-purpose source files ? directives that allow complete control over the assembly process 27.3 mplab c18 and mplab c30 c compilers the mplab c18 and mplab c30 code development systems are complete ansi c compilers for microchip?s pic18 and pic24 families of microcontrol- lers and the dspic30 and dspic33 family of digital sig- nal controllers. these compilers provide powerful integration capabilities, superior code optimization and ease of use not found with other compilers. for easy source level debugging, the compilers provide symbol information that is optimized to the mplab ide debugger. 27.4 mplink object linker/ mplib object librarian the mplink object linker combines relocatable objects created by the mpasm assembler and the mplab c18 c compiler. it can link relocatable objects from precompiled libraries, using directives from a linker script. the mplib object librarian manages the creation and modification of library files of precompiled code. when a routine from a library is called from a source file, only the modules that contain that routine will be linked in with the application. this allows large libraries to be used efficiently in many different applications. the object linker/library features include: ? efficient linking of single libraries instead of many smaller files ? enhanced code maintainability by grouping related modules together ? flexible creation of libraries with easy module listing, replacement, deletion and extraction 27.5 mplab asm30 assembler, linker and librarian mplab asm30 assembler produces relocatable machine code from symbolic assembly language for dspic30f devices. mplab c30 c compiler uses the assembler to produce its object file. the assembler generates relocatable object files that can then be archived or linked with other relocatable object files and archives to create an executable file. notable features of the assembler include: ? support for the entire dspic30f instruction set ? support for fixed-point and floating-point data ? command line interface ? rich directive set ? flexible macro language ? mplab ide compatibility 27.6 mplab sim software simulator the mplab sim software simulator allows code development in a pc-hosted environment by simulat- ing the pic mcus and dspic ? dscs on an instruction level. on any given instruction, the data areas can be examined or modified and stimuli can be applied from a comprehensive stimulus controller. registers can be logged to files for further run-time analysis. the trace buffer and logic analyzer display extend the power of the simulator to record and track program execution, actions on i/o, most peripherals and internal registers. the mplab sim software simulator fully supports symbolic debugging using the mplab c18 and mplab c30 c compilers, and the mpasm and mplab asm30 assemblers. the software simulator offers the flexibility to develop and debug code outside of the hardware laboratory environment, making it an excellent, economical software development tool.
? 2007 microchip technology inc. preliminary ds39775b-page 415 pic18f87j50 family 27.7 mplab ice 2000 high-performance in-circuit emulator the mplab ice 2000 in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for pic microcontrollers. software control of the mplab ice 2000 in-circuit emulator is advanced by the mplab integrated development environment, which allows editing, building, downloading and source debugging from a single environment. the mplab ice 2000 is a full-featured emulator system with enhanced trace, trigger and data monitor- ing features. interchangeable processor modules allow the system to be easily reconfigured for emulation of different processors. the architecture of the mplab ice 2000 in-circuit emulator allows expansion to support new pic microcontrollers. the mplab ice 2000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. the pc platform and microsoft ? windows ? 32-bit operating system were chosen to best make these features available in a simple, unified application. 27.8 mplab real ice in-circuit emulator system mplab real ice in-circuit emulator system is microchip?s next generation high-speed emulator for microchip flash dsc ? and mcu devices. it debugs and programs pic ? and dspic ? flash microcontrollers with the easy-to-use, powerful graphical user interface of the mplab integrated development environment (ide), included with each kit. the mplab real ice probe is connected to the design engineer?s pc using a high-speed usb 2.0 interface and is connected to the target with either a connector compatible with the popular mplab icd 2 system (rj11) or with the new high speed, noise tolerant, low- voltage differential signal (lvds) interconnection (cat5). mplab real ice is field upgradeable through future firmware downloads in mplab ide. in upcoming releases of mplab ide, new devices will be supported, and new features will be added, such as software break- points and assembly code trace. mplab real ice offers significant advantages over competitive emulators including low-cost, full-speed emulation, real-time variable watches, trace analysis, complex breakpoints, a ruggedized probe interface and long (up to three meters) interconnection cables. 27.9 mplab icd 2 in-circuit debugger microchip?s in-circuit debugger, mplab icd 2, is a powerful, low-cost, run-time development tool, connecting to the host pc via an rs-232 or high-speed usb interface. this tool is based on the flash pic mcus and can be used to develop for these and other pic mcus and dspic dscs. the mplab icd 2 utilizes the in-circuit debugging capability built into the flash devices. this feature, along with microchip?s in-circuit serial programming tm (icsp tm ) protocol, offers cost- effective, in-circuit flash debugging from the graphical user interface of the mplab integrated development environment. this enables a designer to develop and debug source code by setting breakpoints, single step- ping and watching variables, and cpu status and peripheral registers. running at full speed enables testing hardware and applications in real time. mplab icd 2 also serves as a development programmer for selected pic devices. 27.10 mplab pm3 device programmer the mplab pm3 device programmer is a universal, ce compliant device programmer with programmable voltage verification at v ddmin and v ddmax for maximum reliability. it features a large lcd display (128 x 64) for menus and error messages and a modu- lar, detachable socket assembly to support various package types. the icsp? cable assembly is included as a standard item. in stand-alone mode, the mplab pm3 device programmer can read, verify and program pic devices without a pc connection. it can also set code protection in this mode. the mplab pm3 connects to the host pc via an rs-232 or usb cable. the mplab pm3 has high-speed communications and optimized algorithms for quick programming of large memory devices and incorporates an sd/mmc card for file storage and secure data applications.
pic18f87j50 family ds39775b-page 416 preliminary ? 2007 microchip technology inc. 27.11 picstart plus development programmer the picstart plus development programmer is an easy-to-use, low-cost, prototype programmer. it connects to the pc via a com (rs-232) port. mplab integrated development environment software makes using the programmer simple and efficient. the picstart plus development programmer supports most pic devices in dip packages up to 40 pins. larger pin count devices, such as the pic16c92x and pic17c76x, may be supported with an adapter socket. the picstart plus development programmer is ce compliant. 27.12 pickit 2 development programmer the pickit? 2 development programmer is a low-cost programmer and selected flash device debugger with an easy-to-use interface for programming many of microchip?s baseline, mid-range and pic18f families of flash memory microcontrollers. the pickit 2 starter kit includes a prototyping development board, twelve sequential lessons, software and hi-tech?s picc? lite c compiler, and is designed to help get up to speed quickly using pic ? microcontrollers. the kit provides everything needed to program, evaluate and develop applications using microchip?s powerful, mid-range flash memory family of microcontrollers. 27.13 demonstration, development and evaluation boards a wide variety of demonstration, development and evaluation boards for various pic mcus and dspic dscs allows quick application development on fully func- tional systems. most boards include prototyping areas for adding custom circuitry and provide application firmware and source code for examination and modification. the boards support a variety of features, including leds, temperature sensors, switches, speakers, rs-232 interfaces, lcd displays, potentiometers and additional eeprom memory. the demonstration and development boards can be used in teaching environments, for prototyping custom circuits and for learning about various microcontroller applications. in addition to the picdem? and dspicdem? demon- stration/development board series of circuits, microchip has a line of evaluation kits and demonstration software for analog filter design, k ee l oq ? security ics, can, irda ? , powersmart ? battery management, seeval ? evaluation system, sigma-delta adc, flow rate sensing, plus many more. check the microchip web page (www.microchip.com) and the latest ?product selector guide? (ds00148) for the complete list of demonstration, development and evaluation kits.
? 2007 microchip technology inc. preliminary ds39775b-page 417 pic18f87j50 family 28.0 electrical characteristics absolute maximum ratings (?) ambient temperature under bias................................................................................................. ............-40c to +100c storage temperature ............................................................................................................ .................. -65c to +150c voltage on any digital only i/o pin or mclr with respect to v ss (except v dd ) ........................................... -0.3v to 6.0v voltage on any combined digital and analog pin with respect to v ss (except v dd )........................ -0.3v to (v dd + 0.3v) voltage on v ddcore with respect to v ss ................................................................................................... -0.3v to 2.75v voltage on v dd with respect to v ss ........................................................................................................... -0.3v to 4.0v voltage on v usb with respect to v ss ................................................................................... (v dd ? 0.3v) to (v dd + 0.3v) total power dissipation (note 1) ............................................................................................................................... 1.0w maximum current out of v ss pin ........................................................................................................................... 300 ma maximum current into v dd pin ........................................................................................................................... ...250 ma maximum output current sunk by any portb and portc i/o pin..................................................................... ...25 ma maximum output current sunk by any portd, porte and portj i/o pin ............................................................8 m a maximum output current sunk by any porta, portf, portg and porth i/o pin .............................................2 ma maximum output current sourced by any portb and portc i/o pin .................................................................. 25 ma maximum output current sourced by any portd, porte and portj i/o pin.......................................................8 ma maximum output current sourced by any porta, portf, portg and porth i/o pin ........................................2 ma maximum current sunk by all ports ...................................................................................................................... .200 ma maximum current sourced by all ports ........................................................................................... .......................200 ma note 1: power dissipation is calculated as follows: pdis = v dd x {i dd ? i oh } + {(v dd ? v oh ) x i oh } + (v ol x i ol ) ? notice: stresses above those listed under ?absolute maximum ratings? may cause permanent damage to the device. this is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. exposure to maximum rating conditions for extended periods may affect device reliability.
pic18f87j50 family ds39775b-page 418 preliminary ? 2007 microchip technology inc. figure 28-1: pic18f87j50 family v dd frequency graph (industrial) figure 28-2: pic18f87j50 family v ddcore frequency graph (industrial) (1) 0 note 1: when the usb module is enabled, v usb and v dd should be connected together and provided 3.0v-3.6v while v ddcore must be 2.45v. when the core regulator is enabled and v dd is 3.0v, it will always regulate to 2.45v. when the usb module is not enabled, v usb and v dd should still be connected together, but the wider limits shaded in gray apply. frequency voltage (v dd ) 4.0v 2.0v 48 mhz 3.5v 3.0v 2.5v 3.6v 8 mhz pic18f87j50 family 2.35v (note 1) frequency voltage (v ddcore ) 3.00v 2.00v 48 mhz 2.75v 2.50v 2.25v 2.75v 8 mhz 2.35v note 1: v dd and v ddcore must be maintained so that v ddcore v dd . 2: when the usb module is enabled, v usb and v dd should be connected together and provided 3.0v-3.6v while v ddcore must be 2.45v. when the core regulator is enabled and v dd is 3.0v, it will always regulate to 2.45v. when the usb module is not enabled, v usb and v dd should still be connected together, but the wider limits shaded in gray apply. 0 2.45v (2) pic18f87j50 family
? 2007 microchip technology inc. preliminary ds39775b-page 419 pic18f87j50 family 28.1 dc characteristics: supply voltage pic18f87j50 family (industrial) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. symbol characteristic min typ max units conditions d001 v dd supply voltage v ddcore 2.0 ? ? 3.6 3.6 v v envreg = 0 envreg = 1 d001b v ddcore external supply for microcontroller core 2.0 ? 2.75 v envreg = 0 d001c av dd analog supply voltage v dd ? 0.3 ? v dd + 0.3 v d001d av ss analog ground potential v ss ? 0.3 ? v ss + 0.3 v d001e v usb usb supply voltage 3.0 3.3 3.6 v usb module enabled (2) d002 v dr ram data retention voltage (1) 1.5 ? ? v d003 v por v dd start voltage to ensure internal power-on reset signal ? ? 0.7 v see section 4.3 ?power-on reset (por)? for details d004 s vdd v dd rise rate to ensure internal power-on reset signal 0.05 ? ? v/ms see section 4.3 ?power-on reset (por)? for details d005 v bor brown-out reset voltage ?1.8? v note 1: this is the limit to which v dd can be lowered in sleep mode, or during a device reset, without losing ram data. 2: v usb should be connected to v dd . when the usb module is disabled, the limits of figure 28-1 apply.
pic18f87j50 family ds39775b-page 420 preliminary ? 2007 microchip technology inc. 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions power-down current (i pd ) (1) all devices 0.5 1.4 a -40c v dd = 2.0v (4) , v ddcore = 2.0v ( sleep mode) 0.5 1.4 a +25c 5.5 10.2 a +85c all devices 0.6 1.5 a -40c v dd = 2.5v (4) , v ddcore = 2.5v ( sleep mode) 0.6 1.5 a +25c 6.8 12.6 a +85c all devices 2.9 7 a -40c v dd = 3.3v (5) ( sleep mode) 3.6 7 a +25c 9.6 19 a +85c note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage , frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add de lta current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to +7 0c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb m odule is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? ac cording to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
? 2007 microchip technology inc. preliminary ds39775b-page 421 pic18f87j50 family supply current (i dd ) (2) all devices 5 14.2 a-40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 31 khz ( rc_run mode, internal oscillator source) 5.5 14.2 a +25c 10 19.0 a +85c all devices 6.8 16.5 a-40c v dd = 2.5v, v ddcore = 2.5v (4) 7.6 16.5 a +25c 14 22.4 a +85c all devices 37 84 a-40c 51 84 a +25c v dd = 3.3v (5) 72 108 a +85c all devices 0.43 0.82 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 1 mhz ( rc_run mode, internal oscillator source) 0.47 0.82 ma +25c 0.52 0.95 ma +85c all devices 0.52 0.98 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 0.57 0.98 ma +25c 0.63 1.10 ma +85c all devices 0.59 0.96 ma -40c 0.65 0.96 ma +25c v dd = 3.3v (5) 0.72 1.18 ma +85c all devices 0.88 1.45 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 4 mhz ( rc_run mode, internal oscillator source) 1.0 1.45 ma +25c 1.1 1.58 ma +85c all devices 1.2 1.72 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 1.3 1.72 ma +25c 1.4 1.85 ma +85c all devices 1.3 2.87 ma -40c 1.4 2.87 ma +25c v dd = 3.3v (5) 1.5 2.96 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating volt age, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add delt a current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to + 70c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb modul e is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? acco rding to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
pic18f87j50 family ds39775b-page 422 preliminary ? 2007 microchip technology inc. supply current (i dd ) cont. (2) all devices 3 9.4 a-40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 31 khz ( rc_idle mode, internal oscillator source) 3.3 9.4 a +25c 8.5 17.2 a +85c all devices 4 10.5 a-40c v dd = 2.5v, v ddcore = 2.5v (4) 4.3 10.5 a +25c 10.3 19.5 a +85c all devices 34 82 a-40c 48 82 a +25c v dd = 3.3v (5) 69 105 a +85c all devices 0.33 0.75 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 1 mhz ( rc_idle mode, internal oscillator source) 0.37 0.75 ma +25c 0.41 0.84 ma +85c all devices 0.39 0.78 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 0.42 0.78 ma +25c 0.47 0.91 ma +85c all devices 0.43 0.82 ma -40c 0.48 0.82 ma +25c v dd = 3.3v (5) 0.54 0.95 ma +85c all devices 0.53 0.98 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 4 mhz ( rc_idle mode, internal oscillator source) 0.57 0.98 ma +25c 0.61 1.12 ma +85c all devices 0.63 1.14 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 0.67 1.14 ma +25c 0.72 1.25 ma +85c all devices 0.70 1.27 ma -40c 0.76 1.27 ma +25c v dd = 3.3v (5) 0.82 1.45 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage , frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add de lta current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to +7 0c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb m odule is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? ac cording to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
? 2007 microchip technology inc. preliminary ds39775b-page 423 pic18f87j50 family supply current (i dd ) cont. (2) all devices 0.17 0.35 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 1 mh z ( pri_run mode, ec oscillator) 0.18 0.35 ma +25c 0.20 0.42 ma +85c all devices 0.29 0.52 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 0.31 0.52 ma +25c 0.34 0.61 ma +85c all devices 0.59 1.1 ma -40c 0.44 0.85 ma +25c v dd = 3.3v (5) 0.42 0.85 ma +85c all devices 0.70 1.25 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 4 mhz ( pri_run mode, ec oscillator) 0.75 1.25 ma +25c 0.79 1.36 ma +85c all devices 1.10 1.7 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 1.10 1.7 ma +25c 1.12 1.82 ma +85c all devices 1.55 1.95 ma -40c 1.47 1.89 ma +25c v dd = 3.3v (5) 1.54 1.92 ma +85c all devices 9.9 14.8 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) f osc = 48 mh z ( pri_run mode, ec oscillator) 9.5 14.8 ma +25c 10.1 15.2 ma +85c all devices 13.3 23.2 ma -40c 12.2 22.7 ma +25c v dd = 3.3v (5) 12.1 22.7 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating volt age, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add delt a current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to + 70c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb modul e is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? acco rding to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
pic18f87j50 family ds39775b-page 424 preliminary ? 2007 microchip technology inc. supply current (i dd ) cont. (2) all devices 4.5 5.2 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) f osc = 4 mh z . 16 mhz internal ( pri_run hspll mode) 4.4 5.2 ma +25c 4.5 5.2 ma +85c all devices 5.7 6.7 ma -40c v dd = 3.3v (5) 5.5 6.3 ma +25c 5.3 6.3 ma +85c all devices 10.8 13.5 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) f osc = 12 mh z , 48 mhz internal ( pri_run hspll mode) 10.8 13.5 ma +25c 9.9 13.0 ma +85c all devices 13.4 24.1 ma -40c v dd = 3.3v (5) 12.3 20.2 ma +25c 11.2 19.5 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage , frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add de lta current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to +7 0c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb m odule is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? ac cording to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
? 2007 microchip technology inc. preliminary ds39775b-page 425 pic18f87j50 family supply current (i dd ) cont. (2) all devices 0.10 0.26 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 1 mhz ( pri_idle mode, ec oscillator) 0.07 0.18 ma +25c 0.09 0.22 ma +85c all devices 0.25 0.48 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 0.13 0.30 ma +25c 0.10 0.26 ma +85c all devices 0.45 0.68 ma -40c 0.26 0.45 ma +25c v dd = 3.3v (5) 0.30 0.54 ma +85c all devices 0.36 0.60 ma -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 4 mhz ( pri_idle mode, ec oscillator) 0.33 0.56 ma +25c 0.35 0.56 ma +85c all devices 0.52 0.81 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) 0.45 0.70 ma +25c 0.46 0.70 ma +85c all devices 0.80 1.15 ma -40c 0.66 0.98 ma +25c v dd = 3.3v (5) 0.65 0.98 ma +85c all devices 5.2 6.5 ma -40c v dd = 2.5v, v ddcore = 2.5v (4) f osc = 48 mhz ( pri_idle mode, ec oscillator) 4.9 5.9 ma +25c 3.4 4.5 ma +85c all devices 6.2 12.4 ma -40c 5.9 11.5 ma +25c v dd = 3.3v (5) 5.8 11.5 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating volt age, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add delt a current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to + 70c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb modul e is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? acco rding to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
pic18f87j50 family ds39775b-page 426 preliminary ? 2007 microchip technology inc. supply current (i dd ) cont. (2) all devices 18 35 a -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 32 khz (3) ( sec_run mode, timer1 as clock) 19 35 a +25c 28 49 a +85c all devices 20 45 a -40c v dd = 2.5v, v ddcore = 2.5v (4) 21 45 a +25c 32 61 a +85c all devices 0.06 0.11 ma -40c 0.07 0.11 ma +25c v dd = 3.3v (5) 0.09 0.15 ma +85c all devices 14 28 a -40c v dd = 2.0v, v ddcore = 2.0v (4) f osc = 32 khz (3) ( sec_idle mode, timer1 as clock) 15 28 a +25c 24 43 a +85c all devices 15 31 a -40c v dd = 2.5v, v ddcore = 2.5v (4) 16 31 a +25c 27 50 a +85c all devices 0.05 0.10 ma -40c 0.06 0.10 ma +25c v dd = 3.3v (5) 0.08 0.14 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage , frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add de lta current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to +7 0c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb m odule is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? ac cording to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
? 2007 microchip technology inc. preliminary ds39775b-page 427 pic18f87j50 family d022 ( i wdt ) module differential currents ( i wdt , i oscb , i ad , i usb ) watchdog timer 2.1 7.0 a-40c v dd = 2.0v, v ddcore = 2.0v (4) 2.2 7.0 a +25c 4.3 9.5 a +85c 3.0 8.0 a-40c v dd = 2.5v, v ddcore = 2.5v (4) 3.1 8.0 a +25c 5.5 10.4 a +85c 5.9 12.1 a-40c v dd = 3.3v 6.2 12.1 a +25c 6.9 13.6 a +85c d025 ( i oscb ) timer1 oscillator 14 24 a-40c v dd = 2.0v, v ddcore = 2.0v (4) 32 khz on timer1 (3) 15 24 a +25c 23 36 a +85c 17 26 a-40c v dd = 2.5v, v ddcore = 2.5v (4) 32 khz on timer1 (3) 18 26 a +25c 25 38 a +85c 19 35 a-40c v dd = 3.3v 32 khz on timer1 (3) 21 35 a +25c 28 44 a +85c d026 ( i ad ) a/d converter 3.0 10.0 a -40c to +85c v dd = 2.0v, v ddcore = 2.0v (4) a/d on, not converting 3.0 10.0 a -40c to +85c v dd = 2.5v, v ddcore = 2.5v (4) 3.2 11.0 a -40c to +85c v dd = 3.3v d027 ( i usb ) usb module 1.5 3.2 ma -40c v usb = 3.3v v dd = 3.3v (5) usb enabled (6) , no cable connected traffic makes a large difference (see section 22.6.4 ). 1.5 3.2 ma +25c 1.5 3.2 ma +85c 28.2 dc characteristics: power-down and supply current pic18f87j50 family (industrial) (continued) pic18f87j50 family (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating volt age, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code ex ecution pattern and temperature, also have an impact on the current consumption. all features that add delt a current are disabled (usb module, wdt, etc.). the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled unless otherwise specified. 3: standard, low-cost 32 khz crystals have an operating temper ature range of -10c to + 70c. extended temperature crystals are available at a much higher cost. 4: voltage regulator disabled (envreg = 0 , tied to v ss ). 5: voltage regulator enabled (envreg = 1 , tied to v dd ), regslp = 1 . 6: this is the module differential current when the usb modul e is enabled and clocked at 48 mhz, but with no usb cable attached. when the usb cable is attac hed or data is being transmitted, the current consumption may be much higher (see section 22.6.4 ?usb transceiver current consumption? ). during usb suspend mode (usben = 1 , suspnd = 1 , bus in idle state), the usb module current will be dominated by the d+ or d- pull-up resistor. the integrated pull-up resistors use ?resistor switching? acco rding to the resistor_ecn supplement to the usb 2.0 specifications, and therefore, may be as low as 900 during idle conditions.
pic18f87j50 family ds39775b-page 428 preliminary ? 2007 microchip technology inc. 28.3 dc characteristics:pic18f87j50 family (industrial) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. symbol characteristic min max units conditions v il input low voltage all i/o ports: d030 with ttl buffer v ss 0.15 v dd v d031 with schmitt trigger buffer v ss 0.2 v dd v d032 mclr v ss 0.2 v dd v d033 osc1 v ss 0.3 v dd v hs, hspll modes d033a d034 osc1 t13cki v ss v ss 0.2 v dd 0.3 v v ec, ecpll modes v ih input high voltage i/o ports with analog functions: d040 with ttl buffer 0.25 v dd + 0.8v v dd vv dd < 3.3v d041 with schmitt trigger buffer 0.8 v dd v dd v digital-only i/o ports: dxxx with ttl buffer 0.25 v dd + 0.8v 5.5 v v dd < 3.3v dxxxa 2.0 5.5 v 3.3v v dd 3.6v dxxx with schmitt trigger buffer 0.8 v dd 5.5 v d042 mclr 0.8 v dd v dd v d043 osc1 0.7 v dd v dd v hs, hspll modes d043a d044 osc1 t13cki 0.8 v dd 1.6 v dd v dd v v ec, ecpll modes i il input leakage current (1,2) d060 i/o ports ? 1 av ss v pin v dd , pin at high-impedance d061 mclr ? 1 avss v pin v dd d063 osc1 ? 5 avss v pin v dd i pu weak pull-up current d070 i purb portb, portd, porte, and portj (3) weak pull-up current 80 400 av dd = 3.3v, v pin = v ss note 1: the leakage current on the mclr pin is strongly dependent on the applied voltage level. the specified levels represent normal operating conditions. higher leakage current may be measured at different input voltages. 2: negative current is defined as current sourced by the pin. 3: only available in 80-pin devices.
? 2007 microchip technology inc. preliminary ds39775b-page 429 pic18f87j50 family v ol output low voltage d080 i/o ports: porta, portf, portg, porth (3) ?0.4vi ol = 2 ma, v dd = 3.3v, -40 c to +85 c portd, porte, portj (3) ?0.4vi ol = 3.4 ma, v dd = 3.3v, -40 c to +85 c portb, portc ? 0.4 v i ol = 3.4 ma, v dd = 3.3v, -40 c to +85 c d083 osc2/clko (ec, ecpll modes) ?0.4vi ol = 1.6 ma, v dd = 3.3v, -40 c to +85 c v oh output high voltage d090 i/o ports: v porta, portf, portg, porth (3) 2.4 ? v i oh = -2 ma, v dd = 3.3v, -40 c to +85 c portd, porte, portj (3) 2.4 ? v i oh = -2 ma, v dd = 3.3v, -40 c to +85 c portb, portc 2.4 ? v i oh = -2 ma, v dd = 3.3v, -40 c to +85 c d092 osc2/clko (intosc, ec, ecpll modes) 2.4 ? v i oh = -1 ma, v dd = 3.3v, -40 c to +85 c capacitive loading specs on output pins d100 (3) cosc2 osc2 pin ? 15 pf in hs mode when external clock is used to drive osc1 d101 c io all i/o pins and osc2 ? 50 pf to meet the ac timing specifications d102 c b sclx, sdax ? 400 pf i 2 c? specification 28.3 dc characteristics:pic18f87j50 family (industrial) (continued) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. symbol characteristic min max units conditions note 1: the leakage current on the mclr pin is strongly dependent on the applied voltage level. the specified levels represent normal operating conditions. higher leakage current may be measured at different input voltages. 2: negative current is defined as current sourced by the pin. 3: only available in 80-pin devices.
pic18f87j50 family ds39775b-page 430 preliminary ? 2007 microchip technology inc. table 28-1: memory programming requirements dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. sym characteristic min typ? max units conditions program flash memory d130 e p cell endurance 10k ? ? e/w -40 c to +85 c d131 v pr v dd for read v min ?3.6vv min = minimum operating voltage d132b v pew v dd for self-timed write v min ?3.6vv min = minimum operating voltage d133a t iw self-timed write cycle time ? 2.8 ? ms d134 t retd characteristic retention 20 ? ? year provided no other specifications are violated d135 i ddp supply current during programming ?314ma d1xxx t we writes per erase cycle ? ? 1 per one physical-word address ? data in ?typ? column is at 3.3v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested.
? 2007 microchip technology inc. preliminary ds39775b-page 431 pic18f87j50 family table 28-2: comparator specifications table 28-3: voltage reference specifications table 28-4: internal voltag e regulator specifications operating conditions: 3.0v < vdd < 3.6v, -40c < ta < +85c (unless otherwise stated) param no. sym characteristics min typ max units comments d300 v ioff input offset voltage ? 5.0 10 mv d301 v icm input common mode voltage 0 ? av dd ? 1.5 v v irv internal reference voltage ? 1.2 (2) ?v1.2% d302 cmrr common mode rejection ratio 55 ? ? db 300 t resp response time (1) ?150400 ns 301 t mc 2 ov comparator mode change to output valid ?? 10 s note 1: response time measured with one comparator input at (v dd ? 1.5)/2, while the other input transitions from v ss to v dd . 2: tolerance is 1.2%. operating conditions: 3.0v < v dd < 3.6v, -40c < t a < +85c (unless otherwise stated) param no. sym characteristics min typ max units comments d310 v res resolution v dd /24 ? v dd /32 lsb d311 vr aa absolute accuracy ? ? 1/2 lsb d312 vr ur unit resistor value (r) ? 2k ? 310 t set settling time (1) ? ? 10 s note 1: settling time measured while cvrr = 1 and cvr3:cvr0 bits transition from ? 0000 ? to ? 1111 ?. operating conditions: -40c < t a < +85c (unless otherwise stated) param no. sym characteristics min typ max units comments v rgout regulator output voltage 2.45 2.5 ? v v dd , envreg = 3.0v c efc external filter capacitor value 4.7 10 ? f capacitor must be low-esr
pic18f87j50 family ds39775b-page 432 preliminary ? 2007 microchip technology inc. table 28-5: usb module specifications operating conditions: -40c < ta < +85c (unless otherwise stated) param no. sym characteristics min typ max units comments d313 v usb usb voltage 3.0 ? 3.6 v voltage on v usb pin must be in this range for proper usb operation d314 i il input leakage on pin ? ? 1 av ss < v pin < v dd pin at high impedance d315 v ilusb input low voltage for usb buffer ??0.8 vfor v usb range d316 v ihusb input high voltage for usb buffer 2.0 ? ? v for v usb range d318 v difs differential input sensitivity ? ? 0.2 v the difference between d+ and d- must exceed this value while v cm is met d319 v cm differential common mode range 0.8 ? 2.5 v d320 z out driver output impedance (1) 28 ? 44 d321 v ol voltage output low 0.0 ? 0.3 v 1.5 k load connected to 3.6v d322 v oh voltage output high 2.8 ? 3.6 v 1.5 k load connected to ground note 1: the d+ and d- signal lines have built-in impedance matching resistors. no external resistors, capacitors or magnetic components are necessary on the d+/d- signal paths between the pic18f87j50 family device and usb cable.
? 2007 microchip technology inc. preliminary ds39775b-page 433 pic18f87j50 family 28.4 ac (timing) characteristics 28.4.1 timing parameter symbology the timing parameter symbols have been created following one of the following formats: 1. tpps2pps 3. t cc : st (i 2 c specifications only) 2. tpps 4. ts (i 2 c specifications only) t f frequency t time lowercase letters (pp) and their meanings: pp cc ccp1 osc osc1 ck clko rd rd cs cs rw rd or wr di sdi sc sck do sdo ss ss dt data in t0 t0cki io i/o port t1 t13cki mc mclr wr wr uppercase letters and their meanings: s f fall p period hhigh rrise i invalid (high-impedance) v valid l low z high-impedance i 2 c only aa output access high high buf bus free low low t cc : st (i 2 c specifications only) cc hd hold su setup st dat data input hold sto stop condition sta start condition
pic18f87j50 family ds39775b-page 434 preliminary ? 2007 microchip technology inc. 28.4.2 timing conditions the temperature and voltages specified in table 28-6 apply to all timing specifications unless otherwise noted. figure 28-3 specifies the load conditions for the timing specifications. table 28-6: temperature and voltage specifications ? ac figure 28-3: load conditions for devi ce timing specifications ac characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial operating voltage v dd range as described in section 28.1 and section 28.3 . v dd /2 c l r l pin pin v ss v ss c l r l =464 c l = 50 pf for all pins except osc2/clko/ra6 and including d and e outputs as ports c l = 15 pf for osc2/clko/ra6 load condition 1 load condition 2
? 2007 microchip technology inc. preliminary ds39775b-page 435 pic18f87j50 family 28.4.3 timing diagrams and specifications figure 28-4: external clock timing table 28-7: external clock timing requirements osc1 clko q4 q1 q2 q3 q4 q1 1 2 3 3 4 4 param. no. symbol characteristic min max units conditions 1a f osc external clki frequency (1) dc 48 mhz ec oscillator mode dc 48 ecpll oscillator mode (2) oscillator frequency (1) 4 25 mhz hs oscillator mode 4 25 hspll oscillator mode (3) 1t osc external clki period (1) 20.8 ? ns ec oscillator mode 20.8 ? ecpll oscillator mode (2) oscillator period (1) 40.0 250 ns hs oscillator mode 40.0 250 hspll oscillator mode (3) 2t cy instruction cycle time (1) 83.3 ? ns t cy = 4/f osc , industrial 3t os l, t os h external clock in (osc1) high or low time 10 ? ns ec oscillator mode 4t os r, t os f external clock in (osc1) rise or fall time ? 7.5 ns ec oscillator mode note 1: instruction cycle period (t cy ) equals four times the input oscillator time base period for all configurations except pll. all specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. all devices are tested to operate at ?min.? values with an external clock applied to the osc1/clki pin. when an external clock input is used, the ?max.? cycle time limit is ?dc? (no clock) for all devices. 2: in order to use the pll, the external clock frequency must be either 4, 8, 12, 16, 20, 24, 40 or 48 mhz. 3: in order to use the pll, the crystal/resonator must produce a frequency of either 4, 8, 12, 16, 20 or 24 mhz.
pic18f87j50 family ds39775b-page 436 preliminary ? 2007 microchip technology inc. table 28-8: pll clock timi ng specifications (v dd = 2.15v to 3.6v) table 28-9: internal rc accuracy (intosc and intrc sources) param no. sym characteristic min typ? max units conditions f10 f osc oscillator frequency range 4 ? 48 mhz f11 f sys on-chip vco system frequency ? 96 ? mhz f12 t rc pll start-up time (lock time) ? ? 2 ms f13 clk clko stability (jitter) -0.25 ? +0.25 % ? data in ?typ? column is at 3.3v, 25 c, unless otherwise stated. these parameters are for design guidance only and are not tested. param no. device min typ max units conditions intosc accuracy @ freq = 8 mhz, 4 mhz, 2 mhz, 1 mhz, 500 khz, 250 khz, 125 khz, 31 khz (1) all devices -2 +/-1 2 % +25c v dd = 2.7-3.3v -5 ? 5 % -10c to +85c v dd = 2.0-3.3v -10 +/-1 10 % -40c to +85c v dd = 2.0-3.3v intrc accuracy @ freq = 31 khz (1) all devices 26.56 ? 35.94 khz -40c to +85c v dd = 2.0-3.3v note 1: the accuracy specification of the 31 khz clock is determined by which source is providing it at a given time. when intsrc (osctune<7>) is ? 1 ?, use the intosc accuracy specification. when intsrc is ? 0 ?, use the intrc accuracy specification.
? 2007 microchip technology inc. preliminary ds39775b-page 437 pic18f87j50 family figure 28-5: clko and i/o timing table 28-10: clko and i/o timing requirements note: refer to figure 28-3 for load conditions. osc1 clko i/o pin (input) i/o pin (output) q4 q1 q2 q3 10 13 14 17 20, 21 19 18 15 11 12 16 old value new value param no. symbol characteristic min typ max units conditions 10 t os h2 ck losc1 to clko ? 75 200 ns (note 1) 11 t os h2 ck hosc1 to clko ? 75 200 ns (note 1) 12 t ck rclko rise time ? 15 30 ns (note 1) 13 t ck fclko fall time ? 15 30 ns (note 1) 14 t ck l2 io vclko to port out valid ? ? 0.5 t cy + 20 ns 15 t io v2 ck h port in valid before clko 0.25 t cy + 25 ? ? ns 16 t ck h2 io i port in hold after clko 0??ns 17 t os h2 io vosc1 (q1 cycle) to port out valid ? 50 150 ns 18 t os h2 io iosc1 (q2 cycle) to port input invalid (i/o in hold time) 100 ? ? ns 19 t io v2 os h port input valid to osc1 (i/o in setup time) 0??ns 20 t io r port output rise time ? ? 6 ns 21 t io f port output fall time ? ? 5 ns 22? t inp intx pin high or low time t cy ??ns 23? t rbp rb7:rb4 change intx high or low time t cy ??ns ? these parameters are asynchronous events not related to any internal clock edges. note 1: measurements are taken in ec mode, where clko output is 4 x t osc .
pic18f87j50 family ds39775b-page 438 preliminary ? 2007 microchip technology inc. figure 28-6: program memo ry read timing diagram table 28-11: program memory read timing requirements param. no symbol characteristics min typ max units 150 tadv2all address out valid to ale (address setup time) 0.25 t cy ? 10 ? ? ns 151 tall2adl ale to address out invalid (address hold time) 5??ns 155 tall2oel ale to oe 10 0.125 t cy ?ns 160 tadz2oel ad high-z to oe (bus release to oe )0??ns 161 toeh2add oe to ad driven 0.125 t cy ? 5 ? ? ns 162 tadv2oeh least significant data valid before oe (data setup time) 20 ? ? ns 163 toeh2adl oe to data in invalid (data hold time) 0 ? ? ns 164 talh2all ale pulse width ? 0.25 t cy ?ns 165 toel2oeh oe pulse width 0.5 t cy ? 5 0.5 t cy ?ns 166 talh2alh ale to ale (cycle time) ? t cy ?ns 167 tacc address valid to data valid 0.75 t cy ? 25 ? ? ns 168 toe oe to data valid ? 0.5 t cy ? 25 ns 169 tall2oeh ale to oe 0.625 t cy ? 10 ? 0.625 t cy + 10 ns 171 talh2csl chip enable active to ale 0.25 t cy ? 20 ? ? ns 171a tubl2oeh ad valid to chip enable active ? ? 10 ns q1 q2 q3 q4 q1 q2 osc1 ale oe address data from external 164 166 160 165 161 151 162 163 ad<15:0> 167 168 155 address address 150 a<19:16> address 169 ba0 ce 171 171a operating conditions: 2.0v < v dd < 3.6v, -40c < t a < +85c unless otherwise stated.
? 2007 microchip technology inc. preliminary ds39775b-page 439 pic18f87j50 family figure 28-7: program memory write timing diagram table 28-12: program memory write timing requirements param. no symbol characteristics min typ max units 150 tadv2all address out valid to ale (address setup time) 0.25 t cy ? 10 ? ? ns 151 tall2adl ale to address out invalid (address hold time) 5 ? ? ns 153 twrh2adl wrn to data out invalid (data hold time) 5 ? ? ns 154 twrl wrn pulse width 0.5 t cy ? 5 0.5 t cy ?ns 156 tadv2wrh data valid before wrn (data setup time) 0.5 t cy ? 10 ? ? ns 157 tbsv2wrl byte select valid before wrn (byte select setup time) 0.25 t cy ??ns 157a twrh2bsi wrn to byte select invalid (byte select hold time) 0.125 t cy ? 5 ? ? ns 166 talh2alh ale to ale (cycle time) ? t cy ?ns 171 talh2csl chip enable active to ale 0.25 t cy ? 20 ? ? ns 171a tubl2oeh ad valid to chip enable active ? ? 10 ns q1 q2 q3 q4 q1 q2 osc1 ale address data 156 150 151 153 ad<15:0> address wrh or wrl ub or lb 157 154 157a address a<19:16> address ba0 166 ce 171 171a operating conditions: 2.0v < v cc < 3.6v, -40c < t a < +125c unless otherwise stated.
pic18f87j50 family ds39775b-page 440 preliminary ? 2007 microchip technology inc. figure 28-8: reset, watchdog timer, oscillator start-up timer and power-up timer timing table 28-13: reset, watchdog timer, oscill ator start-up timer, power-up timer and brown-out reset requirements param. no. symbol characteristic min typ max units conditions 30 t mc lmclr pulse width (low) 2 ? ? s 31 t wdt watchdog timer time-out period (no postscaler) 3.4 4.0 4.6 ms 32 t ost oscillator start-up timer period 1024 t osc ? 1024 t osc ?t osc = osc1 period 33 t pwrt power-up timer period ? 65.5 93 ms 34 t ioz i/o high-impedance from mclr low or watchdog timer reset ??3 t cy + 2 s (note 1) 38 t csd cpu start-up time ? 200 ? s (note 2) note 1: the maximum t ioz is the lesser of (3 t cy + 2 s) or 400 s. 2: mclr rising edge to code execution, assuming t pwrt (and t ost if applicable) has already expired. v dd mclr internal por pwrt time-out oscillator time-out internal reset watchdog timer reset 33 32 30 31 34 i/o pins 34 note: refer to figure 28-3 for load conditions.
? 2007 microchip technology inc. preliminary ds39775b-page 441 pic18f87j50 family figure 28-9: timer0 and timer1 external clock timings table 28-14: timer0 and timer1 external clock requirements note: refer to figure 28-3 for load conditions. 46 47 45 48 41 42 40 t0cki t1oso/t13cki tmr0 or tmr1 param no. symbol characteristic min max units conditions 40 t t 0h t0cki high pulse width no prescaler 0.5 t cy + 20 ? ns with prescaler 10 ? ns 41 t t 0l t0cki low pulse width no prescaler 0.5 t cy + 20 ? ns with prescaler 10 ? ns 42 t t 0p t0cki period no prescaler t cy + 10 ? ns with prescaler greater of: 20 ns or (t cy + 40)/n ?nsn = prescale value (1, 2, 4,..., 256) 45 t t 1h t13cki high time synchronous, no prescaler 0.5 t cy + 20 ? ns synchronous, with prescaler 10 ? ns asynchronous 30 ? ns 46 t t 1l t13cki low time synchronous, no prescaler 0.5 t cy + 5 ? ns synchronous, with prescaler 10 ? ns asynchronous 30 ? ns 47 t t 1p t13cki input period synchronous greater of: 20 ns or (t cy + 40)/n ?nsn = prescale value (1, 2, 4, 8) asynchronous 60 ? ns f t 1 t13cki oscillator input frequency range dc 50 khz 48 t cke 2 tmr i delay from external t13cki clock edge to timer increment 2 t osc 7 t osc ?
pic18f87j50 family ds39775b-page 442 preliminary ? 2007 microchip technology inc. figure 28-10: capture/compare/pwm timing s (including eccp modules) table 28-15: capture/compare/pwm requ irements (including eccp modules) note: refer to figure 28-3 for load conditions. ccpx (capture mode) 50 51 52 ccpx 53 54 (compare or pwm mode) param no. symbol characteristic min max units conditions 50 t cc l ccpx input low time no prescaler 0.5 t cy + 20 ? ns with prescaler 10 ? ns 51 t cc h ccpx input high time no prescaler 0.5 t cy + 20 ? ns with prescaler 10 ? ns 52 t cc p ccpx input period 3 t cy + 40 n ? ns n = prescale value (1, 4 or 16) 53 t cc r ccpx output fall time ? 25 ns 54 t cc f ccpx output fall time ? 25 ns
? 2007 microchip technology inc. preliminary ds39775b-page 443 pic18f87j50 family figure 28-11: parallel master port read timing diagram table 28-16: parallel master port read timing requirements param. no symbol characteristics min typ max units pm1 pmall/pmalh pulse width ? 0.5 t cy ?ns pm2 address out valid to pmall/pmalh invalid (address setup time) ?0.75 t cy ?ns pm3 pmall/pmalh invalid to address out invalid (address hold time) ? 0.25 t cy ?ns pm5 pmrd pulse width ? 0.5 t cy ?ns pm6 pmrd or pmenb active to data in valid (data setup time) ???ns pm7 pmrd or pmenb inactive to data in invalid (data hold time) ???ns q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 system pmall/pmalh pmd<7:0> address pma<13:18> operating conditions: 2.0v < v dd < 3.6v, -40c < t a < +85c unless otherwise stated. pmwr pmcs<2:1> pmrd clock pm2 pm3 pm6 pm7 pm5 pm1 data address<7:0>
pic18f87j50 family ds39775b-page 444 preliminary ? 2007 microchip technology inc. figure 28-12: parallel master port write timing diagram table 28-17: parallel master port write timing requirements q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 system pmall/ pmd<7:0> address pma<13:18> operating conditions: 2.0v < v dd < 3.6v, -40c < t a < +85c unless otherwise stated. pmwr pmcs<2:1> pmrd clock pm12 pm13 pm11 pm16 data address<7:0> pmalh param. no symbol characteristics min typ max units pm11 pmwr pulse width ? 0.5 t cy ?ns pm12 data out valid before pmwr or pmenb goes inactive (data setup time) ???ns pm13 pmwr or pmemb invalid to data out invalid (data hold time) ???ns pm16 pmcs pulse width t cy ? 5 ? ? ns
? 2007 microchip technology inc. preliminary ds39775b-page 445 pic18f87j50 family figure 28-13: example spi ma ster mode timing (cke = 0 ) table 28-18: example spi mode requirements (master mode, cke = 0 ) ss x sckx (ckp = 0 ) sckx (ckp = 1 ) sdox sdix 70 71 72 73 74 75, 76 78 79 80 79 78 msb lsb bit 6 - - - - - - 1 msb in lsb in bit 6 - - - - 1 note: refer to figure 28-3 for load conditions. param no. symbol characteristic min max units conditions 73 t di v2 sc h, t di v2 sc l setup time of sdix data input to sckx edge 100 ? ns 73a t b 2 b last clock edge of byte 1 to the 1st clock edge of byte 2 1.5 t cy + 40 ? ns 74 t sc h2 di l, t sc l2 di l hold time of sdix data input to sckx edge 100 ? ns 75 t do r sdox data output rise time ? 25 ns 76 t do f sdox data output fall time ? 25 ns 78 t sc r sckx output rise time (master mode) ? 25 ns 79 t sc f sckx output fall time (master mode) ? 25 ns 80 t sc h2 do v, t sc l2 do v sdox data output valid after sckx edge ? 50 ns
pic18f87j50 family ds39775b-page 446 preliminary ? 2007 microchip technology inc. figure 28-14: example spi ma ster mode timing (cke = 1 ) table 28-19: example spi mode requirements (master mode, cke = 1 ) ss x sckx (ckp = 0 ) sckx (ckp = 1 ) sdox sdix 81 71 72 74 75, 76 78 80 msb 79 73 msb in bit 6 - - - - - - 1 lsb in bit 6 - - - - 1 lsb note: refer to figure 28-3 for load conditions. param. no. symbol characteristic min max units conditions 73 t di v2 sc h, t di v2 sc l setup time of sdix data input to sckx edge 100 ? ns 73a t b 2 b last clock edge of byte 1 to the 1st clock edge of byte 2 1.5 t cy + 40 ? ns 74 t sc h2 di l, t sc l2 di l hold time of sdix data input to sckx edge 100 ? ns 75 t do r sdox data output rise time ? 25 ns 76 t do f sdox data output fall time ? 25 ns 78 t sc r sckx output rise time (master mode) ? 25 ns 79 t sc f sckx output fall time (master mode) ? 25 ns 80 t sc h2 do v, t sc l2 do v sdox data output valid after sckx edge ? 50 ns 81 t do v2 sc h, t do v2 sc l sdox data output setup to sckx edge t cy ?ns
? 2007 microchip technology inc. preliminary ds39775b-page 447 pic18f87j50 family figure 28-15: example spi slave mode timing (cke = 0 ) table 28-20: example spi mode requirements (slave mode timing, cke = 0 ) param no. symbol characteristic min max units conditions 70 t ss l2 sc h, t ss l2 sc l ssx to sckx or sckx input 3 t cy ?ns 70a t ss l2wb ssx to write to sspxbuf 3 t cy ?ns 71 t sc h sckx input high time (slave mode) continuous 1.25 t cy + 30 ? ns 71a single byte 40 ? ns (note 1) 72 t sc l sckx input low time (slave mode) continuous 1.25 t cy + 30 ? ns 72a single byte 40 ? ns (note 1) 73 t di v2 sc h, t di v2 sc l setup time of sdix data input to sckx edge 100 ? ns 73a t b 2 b last clock edge of byte 1 to the first clock edge of byte 2 1.5 t cy + 40 ? ns (note 2) 74 t sc h2 di l, t sc l2 di l hold time of sdix data input to sckx edge 100 ? ns 75 t do r sdox data output rise time ? 25 ns 76 t do f sdox data output fall time ? 25 ns 77 t ss h2 do z ssx to sdox output high-impedance 10 50 ns 78 t sc r sckx output rise time (master mode) ? 25 ns 79 t sc f sckx output fall time (master mode) ? 25 ns 80 t sc h2 do v, t sc l2 do v sdox data output valid after sckx edge ? 50 ns 83 t sc h2 ss h, t sc l2 ss h ssx after sckx edge 1.5 t cy + 40 ? ns note 1: requires the use of parameter #73a. 2: only if parameter #71a and #72a are used. ss x sckx (ckp = 0 ) sckx (ckp = 1 ) sdox sdi 70 71 72 73 74 75, 76 77 78 79 80 79 78 sdix msb lsb bit 6 - - - - - - 1 bit 6 - - - - 1 lsb in 83 note: refer to figure 28-3 for load conditions. msb in
pic18f87j50 family ds39775b-page 448 preliminary ? 2007 microchip technology inc. figure 28-16: example spi slave mode timing (cke = 1 ) table 28-21: example spi slave mode requirements (cke = 1 ) param no. symbol characteristic min max units conditions 70 t ss l2 sc h, t ss l2 sc l ssx to sckx or sckx input 3 t cy ?ns 70a t ss l2wb ssx to write to sspxbuf 3 t cy ?ns 71 t sc h sckx input high time (slave mode) continuous 1.25 t cy + 30 ? ns 71a single byte 40 ? ns (note 1) 72 t sc l sckx input low time (slave mode) continuous 1.25 t cy + 30 ? ns 72a single byte 40 ? ns (note 1) 73 t di v2 sc h, t di v2 sc l setup time of sdix data input to sckx edge 100 ? ns 73a t b 2 b last clock edge of byte 1 to the first clock edge of byte 2 1.5 t cy + 40 ? ns (note 2) 74 t sc h2 di l, t sc l2 di l hold time of sdix data input to sckx edge 100 ? ns 75 t do r sdox data output rise time ? 25 ns 76 t do f sdox data output fall time ? 25 ns 77 t ss h2 do z ssx to sdox output high-impedance 10 50 ns 78 t sc r sckx output rise time (master mode) ? 25 ns 79 t sc f sckx output fall time (master mode) ? 25 ns 80 t sc h2 do v, t sc l2 do v sdox data output valid after sckx edge ? 50 ns 81 t do v2 sc h, t do v2 sc l sdox data output setup to sckx edge t cy ?ns 82 t ss l2 do v sdox data output valid after ssx edge ? 50 ns 83 t sc h2 ss h, t sc l2 ss h ssx after sckx edge 1.5 t cy + 40 ? ns note 1: requires the use of parameter #73a. 2: only if parameter #71a and #72a are used. ss x sckx (ckp = 0 ) sckx (ckp = 1 ) sdox sdi 70 71 72 82 sdix 74 75, 76 msb bit 6 - - - - - - 1 lsb 77 bit 6 - - - - 1 lsb in 80 83 note: refer to figure 28-3 for load conditions. 73 msb in
? 2007 microchip technology inc. preliminary ds39775b-page 449 pic18f87j50 family figure 28-17: i 2 c? bus start/stop bits timing table 28-22: i 2 c? bus start/stop bits requirements (slave mode) figure 28-18: i 2 c? bus data timing note: refer to figure 28-3 for load conditions. 91 92 93 sclx sdax start condition stop condition 90 param. no. symbol characteristic min max units conditions 90 t su : sta start condition 100 khz mode 4700 ? ns only relevant for repeated start condition setup time 400 khz mode 600 ? 91 t hd : sta start condition 100 khz mode 4000 ? ns after this period, the first clock pulse is generated hold time 400 khz mode 600 ? 92 t su : sto stop condition 100 khz mode 4700 ? ns setup time 400 khz mode 600 ? 93 t hd : sto stop condition 100 khz mode 4000 ? ns hold time 400 khz mode 600 ? note: refer to figure 28-3 for load conditions. 90 91 92 100 101 103 106 107 109 109 110 102 sclx sdax in sdax out
pic18f87j50 family ds39775b-page 450 preliminary ? 2007 microchip technology inc. table 28-23: i 2 c? bus data requirements (slave mode) param. no. symbol characteristic min max units conditions 100 t high clock high time 100 khz mode 4.0 ? s 400 khz mode 0.6 ? s mssp modules 1.5 t cy ? 101 t low clock low time 100 khz mode 4.7 ? s 400 khz mode 1.3 ? s mssp modules 1.5 t cy ? 102 t r sdax and sclx rise time 100 khz mode ? 1000 ns 400 khz mode 20 + 0.1 c b 300 ns c b is specified to be from 10 to 400 pf 103 t f sdax and sclx fall time 100 khz mode ? 300 ns 400 khz mode 20 + 0.1 c b 300 ns c b is specified to be from 10 to 400 pf 90 t su : sta start condition setup time 100 khz mode 4.7 ? s only relevant for repeated start condition 400 khz mode 0.6 ? s 91 t hd : sta start condition hold time 100 khz mode 4.0 ? s after this period, the first clock pulse is generated 400 khz mode 0.6 ? s 106 t hd : dat data input hold time 100 khz mode 0 ? ns 400 khz mode 0 0.9 s 107 t su : dat data input setup time 100 khz mode 250 ? ns (note 2) 400 khz mode 100 ? ns 92 t su : sto stop condition setup time 100 khz mode 4.7 ? s 400 khz mode 0.6 ? s 109 t aa output valid from clock 100 khz mode ? 3500 ns (note 1) 400 khz mode ? ? ns 110 t buf bus free time 100 khz mode 4.7 ? s time the bus must be free before a new transmission can start 400 khz mode 1.3 ? s d102 c b bus capacitive loading ? 400 pf note 1: as a transmitter, the device must provi de this internal minimum delay time to bridge the undefined region (min. 300 ns) of the falling edge of sclx to avoid unint ended generation of start or stop conditions. 2: a fast mode i 2 c? bus device can be us ed in a standard mode i 2 c bus system, but the requirement, t su : dat 250 ns, must then be met. this will automatically be the case if the device does not stretch the low period of the sclx signal. if such a device does stretch the low period of the sclx si gnal, it must output the next data bit to the sdax line, t r max. + t su : dat = 1000 + 250 = 1250 ns (according to the standard mode i 2 c bus specification), before the sclx line is released.
? 2007 microchip technology inc. preliminary ds39775b-page 451 pic18f87j50 family figure 28-19: msspx i 2 c? bus start/stop bits timing waveforms table 28-24: msspx i 2 c? bus start/stop bits requirements figure 28-20: msspx i 2 c? bus data timing note: refer to figure 28-3 for load conditions. 91 93 sclx sdax start condition stop condition 90 92 param. no. symbol characteristic min max units conditions 90 t su : sta start condition 100 khz mode 2(t osc )(brg + 1) ? ns only relevant for repeated start condition setup time 400 khz mode 2(t osc )(brg + 1) ? 1 mhz mode (1) 2(t osc )(brg + 1) ? 91 t hd : sta start condition 100 khz mode 2(t osc )(brg + 1) ? ns after this period, the first clock pulse is generated hold time 400 khz mode 2(t osc )(brg + 1) ? 1 mhz mode (1) 2(t osc )(brg + 1) ? 92 t su : sto stop condition 100 khz mode 2(t osc )(brg + 1) ? ns setup time 400 khz mode 2(t osc )(brg + 1) ? 1 mhz mode (1) 2(t osc )(brg + 1) ? 93 t hd : sto stop condition 100 khz mode 2(t osc )(brg + 1) ? ns hold time 400 khz mode 2(t osc )(brg + 1) ? 1 mhz mode (1) 2(t osc )(brg + 1) ? note 1: maximum pin capacitance = 10 pf for all i 2 c? pins. note: refer to figure 28-3 for load conditions. 90 91 92 100 101 103 106 107 109 109 110 102 sclx sdax in sdax out
pic18f87j50 family ds39775b-page 452 preliminary ? 2007 microchip technology inc. table 28-25: msspx i 2 c? bus data requirements param. no. symbol characteristic min max units conditions 100 t high clock high time 100 khz mode 2(t osc )(brg + 1) ? ms 400 khz mode 2(t osc )(brg + 1) ? ms 1 mhz mode (1) 2(t osc )(brg + 1) ? ms 101 t low clock low time 100 khz mode 2(t osc )(brg + 1) ? ms 400 khz mode 2(t osc )(brg + 1) ? ms 1 mhz mode (1) 2(t osc )(brg + 1) ? ms 102 t r sdax and sclx rise time 100 khz mode ? 1000 ns c b is specified to be from 10 to 400 pf 400 khz mode 20 + 0.1 c b 300 ns 1 mhz mode (1) ? 300 ns 103 t f sdax and sclx fall time 100 khz mode ? 300 ns c b is specified to be from 10 to 400 pf 400 khz mode 20 + 0.1 c b 300 ns 1 mhz mode (1) ? 100 ns 90 t su : sta start condition setup time 100 khz mode 2(t osc )(brg + 1) ? ms only relevant for repeated start condition 400 khz mode 2(t osc )(brg + 1) ? ms 1 mhz mode (1) 2(t osc )(brg + 1) ? ms 91 t hd : sta start condition hold time 100 khz mode 2(t osc )(brg + 1) ? ms after this period, the first clock pulse is generated 400 khz mode 2(t osc )(brg + 1) ? ms 1 mhz mode (1) 2(t osc )(brg + 1) ? ms 106 t hd : dat data input hold time 100 khz mode 0 ? ns 400 khz mode 0 0.9 ms 1 mhz mode (1) tbd ? ns 107 t su : dat data input setup time 100 khz mode 250 ? ns (note 2) 400 khz mode 100 ? ns 1 mhz mode (1) tbd ? ns 92 t su : sto stop condition setup time 100 khz mode 2(t osc )(brg + 1) ? ms 400 khz mode 2(t osc )(brg + 1) ? ms 1 mhz mode (1) 2(t osc )(brg + 1) ? ms 109 t aa output valid from clock 100 khz mode ? 3500 ns 400 khz mode ? 1000 ns 1 mhz mode (1) ??ns 110 t buf bus free time 100 khz mode 4.7 ? ms time the bus must be free before a new transmission can start 400 khz mode 1.3 ? ms 1 mhz mode (1) tbd ? ms d102 c b bus capacitive loading ? 400 pf legend: tbd = to be determined note 1: maximum pin capacitance = 10 pf for all i 2 c? pins. 2: a fast mode i 2 c bus device can be used in a standard mode i 2 c bus system, but parameter #107 250 ns must then be met. this will automatically be the case if the device does not stretch the low period of the sclx signal. if such a device does stretch the low period of the sclx signal, it must output the next data bit to the sdax line, parameter #102 + parameter #107 = 1000 + 250 = 1250 ns (for 100 khz mode), before the sclx line is released.
? 2007 microchip technology inc. preliminary ds39775b-page 453 pic18f87j50 family figure 28-21: eusartx synchronous transmission (maste r/slave) timing table 28-26: eusartx sy nchronous transmission requirements figure 28-22: eusartx synchrono us receive (master/slave) timing table 28-27: eusartx sy nchronous receive requirements 121 121 120 122 txx/ckx rxx/dtx pin pin note: refer to figure 28-3 for load conditions. param no. symbol characteristic min max units conditions 120 t ck h2 dt v sync xmit (master and slave) clock high to data out valid ? 40 ns 121 t ckrf clock out rise time and fall time (master mode) ? 20 ns 122 t dtrf data out rise time and fall time ? 20 ns 125 126 txx/ckx rxx/dtx pin pin note: refer to figure 28-3 for load conditions. param. no. symbol characteristic min max units conditions 125 t dt v2 ckl sync rcv (master and slave) data hold before ckx (dtx hold time) 10 ? ns 126 t ck l2 dtl data hold after ckx (dtx hold time) 15 ? ns
pic18f87j50 family ds39775b-page 454 preliminary ? 2007 microchip technology inc. table 28-28: a/d converter characteristics: pic18f87j50 family (industrial) figure 28-23: a/d conversion timing param no. symbol characteristic min typ max units conditions a01 n r resolution ? ? 10 bit v ref 3.0v a03 e il integral linearity error ? ? <1 lsb v ref 3.0v a04 e dl differential linearity error ? ? <1 lsb v ref 3.0v a06 e off offset error ? ? <3 lsb v ref 3.0v a07 e gn gain error ? ? <3 lsb v ref 3.0v a10 ? monotonicity guaranteed (1) ?v ss v ain v ref a20 v ref reference voltage range (v refh ? v refl ) 2.0 3 ? ? ? ? v v v dd < 3.0v v dd 3.0v a21 v refh reference voltage high v ss ?v refh v a22 v refl reference voltage low v ss ? 0.3v ? v dd ? 3.0v v a25 v ain analog input voltage v refl ?v refh v a30 z ain recommended impedance of analog voltage source ??2.5k a50 i ref v ref input current (2) ? ? ? ? 5 150 a a during v ain acquisition. during a/d conversion cycle. note 1: the a/d conversion result never decreases with an increase in the input voltage and has no missing codes. 2: v refh current is from ra3/an3/v ref + pin or v dd , whichever is selected as the v refh source. v refl current is from ra2/an2/v ref - pin or v ss , whichever is selected as the v refl source. 131 130 132 bsf adcon0, go q4 a/d clk a/d data adres adif go sample old_data sampling stopped done new_data (note 2) 987 21 0 note 1: if the a/d clock source is selected as rc, a time of t cy is added before the a/d clock starts. this allows the sleep instruction to be executed. 2: this is a minimal rc delay (typically 100 ns), which also disconnects the holding capacitor from the analog input. . . . . . . t cy (note 1)
? 2007 microchip technology inc. preliminary ds39775b-page 455 pic18f87j50 family table 28-29: a/d conversion requirements param no. symbol characteristic min max units conditions 130 t ad a/d clock period 0.7 25.0 (1) st osc based, v ref 3.0v ?1 s a/d rc mode 131 t cnv conversion time (not including acquisition time) (2) 11 12 t ad 132 t acq acquisition time (3) 1.4 ? s-40 c to +85 c 135 t swc switching time from convert sample ? (note 4) 137 t dis discharge time 0.2 ? s note 1: the time of the a/d clock period is dependent on the device frequency and the t ad clock divider. 2: adres registers may be read on the following t cy cycle. 3: the time for the holding capacitor to acquire the ?new? input voltage when the voltage changes full scale after the conversion (v dd to v ss or v ss to v dd ). the source impedance (r s ) on the input channels is 50 . 4: on the following cycle of the device clock.
pic18f87j50 family ds39775b-page 456 preliminary ? 2007 microchip technology inc. figure 28-24: usb signal timing table 28-30: usb low-speed timing requirements table 28-31: usb full-speed requirements v crs usb data differential lines 90% 10% t lr , t fr t lf , t ff param no. symbol characteristic min typ max units conditions t lr transition rise time 75 ? 300 ns c l = 200 to 600 pf t lf transition fall time 75 ? 300 ns c l = 200 to 600 pf t lrfm rise/fall time matching 80 ? 125 % param no. symbol characteristic min typ max units conditions t fr transition rise time 4 ? 20 ns c l = 50 pf t ff transition fall time 4 ? 20 ns c l = 50 pf t frfm rise/fall time matching 90 ? 111.1 %
? 2007 microchip technology inc. preliminary ds39775b-page 457 pic18f87j50 family 29.0 packaging information 29.1 package marking information 64-lead tqfp xxxxxxxxxx xxxxxxxxxx xxxxxxxxxx yywwnnn example 18f67j50 -i/pt 0710017 80-lead tqfp xxxxxxxxxxxx xxxxxxxxxxxx yywwnnn example pic18f87j50 -i/pt 0710017 legend: xx...x customer-specific information y year code (last digit of calendar year) yy year code (last 2 digits of calendar year) ww week code (week of january 1 is week ?01?) nnn alphanumeric traceability code pb-free jedec designator for matte tin (sn) * this package is pb-free. the pb-free jedec designator ( ) can be found on the outer packaging for this package. note : in the event the full microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. 3 e 3 e 3 e 3 e
pic18f87j50 family ds39775b-page 458 preliminary ? 2007 microchip technology inc. 29.2 package details the following sections give the technical details of the packages. 64-lead plastic thin quad flatpack (pt) ? 10x10x1 mm body, 2.00 mm footprint [tqfp] notes: 1. pin 1 visual index feature may vary, but must be located within the hatched area. 2. chamfers at corners are optional; size may vary. 3. dimensions d1 and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.25 mm per side. 4. dimensioning and tolerancing per asme y14.5m. bsc: basic dimension. theoretically exact value shown without tolerances. ref: reference dimension, usually without tolerance, for information purposes only. note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging units millimeters dimension limits min nom max number of leads n 64 lead pitch e 0.50 bsc overall height a ? ? 1.20 molded package thickness a2 0.95 1.00 1.05 standoff a1 0.05 ? 0.15 foot length l 0.45 0.60 0.75 footprint l1 1.00 ref foot angle 0 3.5 7 overall width e 12.00 bsc overall length d 12.00 bsc molded package width e1 10.00 bsc molded package length d1 10.00 bsc lead thickness c 0.09 ? 0.20 lead width b 0.17 0.22 0.27 mold draft angle top 11 12 13 mold draft angle bottom 11 12 13 d d1 e e1 e b n note 1 12 3 note 2 c l a1 l1 a2 a microchip technology drawing c04-085b
? 2007 microchip technology inc. preliminary ds39775b-page 459 pic18f87j50 family 80-lead plastic thin quad flatpack (pt) ? 12x12x1 mm body, 2.00 mm footprint [tqfp] notes: 1. pin 1 visual index feature may vary, but must be located within the hatched area. 2. chamfers at corners are optional; size may vary. 3. dimensions d1 and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.25 mm per side. 4. dimensioning and tolerancing per asme y14.5m. bsc: basic dimension. theoretically exact value shown without tolerances. ref: reference dimension, usually without tolerance, for information purposes only. note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging units millimeters dimension limits min nom max number of leads n 80 lead pitch e 0.50 bsc overall height a ? ? 1.20 molded package thickness a2 0.95 1.00 1.05 standoff a1 0.05 ? 0.15 foot length l 0.45 0.60 0.75 footprint l1 1.00 ref foot angle 0 3.5 7 overall width e 14.00 bsc overall length d 14.00 bsc molded package width e1 12.00 bsc molded package length d1 12.00 bsc lead thickness c 0.09 ? 0.20 lead width b 0.17 0.22 0.27 mold draft angle top 11 12 13 mold draft angle bottom 11 12 13 d d1 e e1 e b n note 1 12 3 note 2 a a2 l1 a1 l c microchip technology drawing c04-092b
pic18f87j50 family ds39775b-page 460 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 461 pic18f87j50 family appendix a: revision history revision a (february 2007) original data sheet for the pic18f87j50 family of devices. revision b (may 2007) updated electrical specification data. appendix b: device differences the differences between the devices listed in this data sheet are shown in table b-1, table b-1: device differences between pic18f87j50 family members features pic18f65j50 pic18f66j50 pic18f66j55 pic18f67j50 pic18f85j50 PIC18F86J50 pic18f86j55 pic18f87j50 program memory 32k 64k 96k 128k 32k 64k 96k 128k program memory (instructions) 16380 32764 49148 65532 16380 32764 49148 65532 i/o ports (pins) ports a, b, c, d, e, f, g ports a, b, c, d, e, f, g, h, j emb no yes 10-bit adc module 8 input channels 12 input channels packages 64-pin tqfp 80-pin tqfp
pic18f87j50 family ds39775b-page 462 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 463 pic18f87j50 family index a a/d ................................................................................... 299 a/d converter interrupt, configuring ....................... 303 acquisition requirements ........................................ 304 adcal bit ................................................................ 307 adresh register .................................................... 302 analog port pins, configuring .................................. 305 associated registers ............................................... 308 automatic acquisition time ...................................... 305 calibration ................................................................ 307 configuring the module ............................................ 303 conversion clock (t ad ) ........................................... 305 conversion requirements ....................................... 455 conversion status (go/done bit) .......................... 302 conversions ............................................................. 306 converter characteristics ........................................ 454 operation in power-managed modes ...................... 307 special event trigger (eccp) ......................... 218, 306 use of the eccp2 trigger ....................................... 306 absolute maximum ratings ............................................. 417 ac (timing) characteristics ............................................. 433 load conditions for device timing specifications ................................................... 434 parameter symbology ............................................. 433 temperature and voltage specific ations ................. 434 timing conditions .................................................... 434 ackstat ........................................................................ 267 ackstat status flag ..................................................... 267 adcal bit ........................................................................ 307 adcon0 register go/done bit ........................................................... 302 addfsr .......................................................................... 406 addlw ............................................................................ 369 addulnk ........................................................................ 406 addwf ............................................................................ 369 addwfc ......................................................................... 370 adresl register ............................................................ 302 analog-to-digital converter. see a/d. andlw ............................................................................ 370 andwf ............................................................................ 371 assembler mpasm assembler .................................................. 414 auto-wake-up on sync break character ......................... 290 b baud rate generator ....................................................... 263 bc .................................................................................... 371 bcf .................................................................................. 372 bf .................................................................................... 267 bf status flag ................................................................. 267 block diagrams 16-bit byte select mode .......................................... 111 16-bit byte write mode ............................................ 109 16-bit word write mode ........................................... 110 8-bit multiplexed address and data application ...... 186 8-bit multiplexed modes ........................................... 113 a/d ........................................................................... 302 analog input model .................................................. 303 baud rate generator ............................................... 263 capture mode operation ......................................... 209 comparator analog input model .............................. 338 comparator configurations ...................................... 340 comparator output .................................................. 335 comparator voltage reference ............................... 343 comparator voltage reference output buffer example .................................... 345 compare mode operation ....................................... 210 connections for on-chip voltage regulator ........... 358 demultiplexed addressing mode ............................. 179 device clock .............................................................. 34 enhanced pwm ....................................................... 219 eusart transmit ................................................... 287 eusartx receive .................................................. 289 external power-on reset circuit (slow v dd power-up) ........................................ 55 fail-safe clock monitor ........................................... 360 fully multiplexed addressing mode ......................... 179 generic i/o port operation ...................................... 135 interrupt logic .......................................................... 120 lcd control ............................................................. 187 legacy parallel slave port ...................................... 173 mssp (i 2 c mode) .................................................... 241 mssp (spi mode) ................................................... 231 msspx (i 2 c master mode) ...................................... 261 multiplexed addressing application ......................... 186 on-chip reset circuit ................................................ 53 parallel eeprom (up to 15-bit address, 16-bit data) ..................................................... 187 parallel eeprom (up to 15-bit address, 8-bit data) ....................................................... 187 parallel master/slave connection addressed buffer ............................................. 176 parallel master/slave connection buffered ............. 175 partially multiplexed addressing application ........... 186 partially multiplexed addressing mode .................... 179 pic18f6xj5x (64-pin) .............................................. 10 pic18f8xj5x (80-pin) .............................................. 11 pmp module ............................................................ 165 pwm operation (simplified) .................................... 212 reads from flash program memory ........................ 99 single comparator ................................................... 338 table read operation ............................................... 95 table write operation ............................................... 96 table writes to flash program memory .................. 101 timer0 in 16-bit mode ............................................. 190 timer0 in 8-bit mode ............................................... 190 timer1 ..................................................................... 194 timer1 (16-bit read/write mode) ............................ 194 timer2 ..................................................................... 200 timer3 ..................................................................... 202 timer3 (16-bit read/write mode) ............................ 202 timer4 ..................................................................... 206 usb interrupt logic ................................................. 323 usb peripheral and options ................................... 309 using the open-drain output .................................. 136 watchdog timer ...................................................... 356 bn .................................................................................... 372 bnc ................................................................................. 373 bnn ................................................................................. 373 bnov .............................................................................. 374 bnz ................................................................................. 374 bor. see brown-out reset. bov ................................................................................. 377 bra ................................................................................. 375 break character (12-bit) transmit and receive .............. 292 brg. see baud rate generator.
pic18f87j50 family ds39775b-page 464 preliminary ? 2007 microchip technology inc. brown-out reset (bor) ..................................................... 55 and on-chip voltage regulator ............................... 359 detecting .................................................................... 55 disabling in sleep mode ............................................ 55 bsf .................................................................................. 375 btfsc ............................................................................. 376 btfss .............................................................................. 376 btg .................................................................................. 377 bz ..................................................................................... 378 c c compilers mplab c18 ............................................................. 414 mplab c30 ............................................................. 414 calibration (a/d converter) .............................................. 307 call ................................................................................ 378 callw ............................................................................. 407 capture (ccp module) ..................................................... 209 associated registers ............................................... 211 ccprxh:ccprxl registers ................................... 209 ccpx pin configuration ........................................... 209 prescaler .................................................................. 209 software interrupt .................................................... 209 timer1/timer3 mode selection ................................ 209 capture (eccp module) .................................................. 218 capture/compare/pwm (ccp) ........................................ 207 capture mode. see capture. ccp mode and timer resources ............................ 208 ccprxh register .................................................... 208 ccprxl register ..................................................... 208 compare mode. see compare. eccp/ccp timer interconnect configurations .................................................. 208 module configuration ............................................... 208 clock sources .................................................................... 40 effects of power-managed modes ............................. 44 selecting the 31 khz source ...................................... 40 selection using osccon register ........................... 40 clrf ................................................................................ 379 clrwdt .......................................................................... 379 code examples 16 x 16 signed multiply routine .............................. 118 16 x 16 unsigned multiply routine .......................... 118 8 x 8 signed multiply routine .................................. 117 8 x 8 unsigned multiply routine .............................. 117 a/d calibration routine ........................................... 307 changing between capture prescalers ................... 209 computed goto using an offset value ................... 73 erasing a flash program memory row ................... 100 fast register stack .................................................... 73 how to clear ram (bank 1) using indirect addressing ............................................ 88 implementing a real-time clock using a timer1 interrupt service ............................... 197 initializing porta .................................................... 138 initializing portb .................................................... 141 initializing portc .................................................... 144 initializing portd .................................................... 147 initializing porte .................................................... 150 initializing portf .................................................... 153 initializing portg ................................................... 156 initializing porth .................................................... 159 initializing portj .................................................... 162 loading the ssp1buf (ssp1sr) register ............. 234 reading a flash program memory word .................. 99 saving status, wreg and bsr registers in ram ............................................. 134 writing to flash program memory ........................... 102 code protection ............................................................... 347 comf .............................................................................. 380 comparator ...................................................................... 335 analog input connection considerations ................ 338 associated registers ............................................... 342 configuration ........................................................... 339 control ..................................................................... 339 effects of a reset .................................................... 342 enable and input selection ...................................... 339 enable and output selection ................................... 339 interrupts ................................................................. 341 operation ................................................................. 338 operation during sleep ........................................... 342 response time ........................................................ 338 comparator specifications ............................................... 431 comparator voltage reference ....................................... 343 accuracy and error .................................................. 345 associated registers ............................................... 345 configuring .............................................................. 344 connection considerations ...................................... 345 effects of a reset .................................................... 345 operation during sleep ........................................... 345 compare (ccp module) .................................................. 210 associated registers ............................................... 211 ccprx register ...................................................... 210 pin configuration ..................................................... 210 software interrupt .................................................... 210 timer1/timer3 mode selection ................................ 210 compare (eccp module) ................................................ 218 special event trigger .............................. 203, 218, 306 computed goto ............................................................... 73 configuration bits ............................................................ 347 configuration mismatch (cm) reset .................................. 55 configuration register protection .................................... 362 core features easy migration ............................................................. 8 expanded memory ....................................................... 7 extended instruction set ............................................. 8 external memory bus .................................................. 8 nanowatt technology .................................................. 7 oscillator options and features .................................. 7 universal serial bus (usb) .......................................... 7 cpfseq .......................................................................... 380 cpfsgt .......................................................................... 381 cpfslt ........................................................................... 381 crystal oscillator/ceramic resonator ................................ 35 customer change notification service ............................ 474 customer notification service ......................................... 474 customer support ............................................................ 474 d data addressing modes .................................................... 88 comparing addressing modes with the extended instruction set enabled ..................... 92 direct ......................................................................... 88 indexed literal offset ................................................ 91 bsr ................................................................... 93 instructions affected .......................................... 91 mapping access bank ....................................... 93 indirect ....................................................................... 88 inherent and literal .................................................... 88
? 2007 microchip technology inc. preliminary ds39775b-page 465 pic18f87j50 family data memory ..................................................................... 76 access bank .............................................................. 78 bank select register (bsr) ....................................... 76 extended instruction set ............................................ 91 general purpose registers ........................................ 78 memory maps pic18f87j50 family devices ........................... 77 shared address registers ................................. 80 special function registers ................................ 79 special function registers ........................................ 79 context defined sfrs ....................................... 80 usb ram ................................................................... 76 daw ................................................................................. 382 dc characteristics ........................................................... 428 power-down and supply current ............................ 420 supply voltage ......................................................... 419 dcfsnz .......................................................................... 383 decf ............................................................................... 382 decfsz ........................................................................... 383 development support ...................................................... 413 device differences ........................................................... 461 device overview .................................................................. 7 details on individual family members ......................... 8 features (64-pin devices) ........................................... 9 features (80-pin devices) ........................................... 9 direct addressing ............................................................... 89 e eccp associated registers ............................................... 230 capture and compare modes .................................. 218 enhanced pwm mode ............................................. 219 standard pwm mode ............................................... 218 effect on standard pic instructions ................................. 410 electrical characteristics .................................................. 417 enhanced capture/compare/pwm (eccp) .................... 215 capture mode. see capture (eccp module). eccp1/eccp3 outputs and program memory mode .................................................. 216 eccp2 outputs and program memory modes ................................................ 216 outputs and configuration ....................................... 216 pin configurations for eccp1 ................................. 217 pin configurations for eccp2 ................................. 217 pin configurations for eccp3 ................................. 218 pwm mode. see pwm (eccp module). timer resources ...................................................... 216 use of ccp4/ccp5 with eccp1/eccp3 ................ 216 enhanced universal synchronous asynchronous receiver transmitter (eusart). see eusart. envreg pin .................................................................... 358 equations a/d acquisition time ................................................ 304 a/d minimum charging time ................................... 304 calculating the minimum required acquisition time .............................................. 304 estimating usb transceiver current consumption ....................................... 331 errata ................................................................................... 5 eusart asynchronous mode ................................................ 287 12-bit break transmit and receive ................. 292 associated registers, receive ........................ 290 associated registers, transmit ....................... 288 auto-wake-up on sync break ......................... 290 receiver .......................................................... 289 setting up 9-bit mode with address detect ........................................ 289 transmitter ...................................................... 287 baud rate generator operation in power-managed mode ................ 281 baud rate generator (brg) ................................... 281 associated registers ....................................... 282 auto-baud rate detect .................................... 285 baud rate error, calculating ........................... 282 baud rates, asynchronous modes ................. 283 high baud rate select (brgh bit) ................. 281 sampling ......................................................... 281 synchronous master mode ...................................... 293 associated registers, receive ........................ 296 associated registers, transmit ....................... 294 reception ........................................................ 295 transmission ................................................... 293 synchronous slave mode ........................................ 296 associated registers, receive ........................ 298 associated registers, transmit ....................... 297 reception ........................................................ 297 transmission ................................................... 296 extended instruction set addfsr .................................................................. 406 addulnk ............................................................... 406 callw .................................................................... 407 movsf .................................................................... 407 movss .................................................................... 408 pushl ..................................................................... 408 subfsr .................................................................. 409 subulnk ................................................................ 409 external clock input ........................................................... 36 external memory bus ...................................................... 105 16-bit byte select mode .......................................... 111 16-bit byte write mode ............................................ 109 16-bit data width modes ......................................... 108 16-bit mode timing ................................................. 112 16-bit word write mode .......................................... 110 8-bit data width mode ............................................ 113 8-bit mode timing ................................................... 114 address and data line usage (table) ..................... 107 address and data width .......................................... 107 address shifting ...................................................... 107 control ..................................................................... 106 i/o port functions .................................................... 105 operation in power-managed modes ...................... 115 program memory modes ......................................... 108 extended microcontroller ................................. 108 microcontroller ................................................. 108 wait states .............................................................. 108 weak pull-ups on port pins ..................................... 108
pic18f87j50 family ds39775b-page 466 preliminary ? 2007 microchip technology inc. f fail-safe clock monitor ............................................ 347, 360 interrupts in power-managed modes ....................... 361 por or wake-up from sleep .................................. 361 wdt during oscillator failure ................................. 360 fast register stack ............................................................ 73 firmware instructions ....................................................... 363 flash configuration words ............................................... 347 flash program memory ...................................................... 95 associated registers ............................................... 104 control registers ....................................................... 96 eecon1 and eecon2 ..................................... 96 tablat (table latch) register ......................... 98 tblptr (table pointer) register ...................... 98 erase sequence ...................................................... 100 erasing ..................................................................... 100 operation during code-protect ............................... 104 reading ...................................................................... 99 table pointer boundaries based on operation ........................ 98 table pointer boundaries .......................................... 98 table reads and table writes .................................. 95 write sequence ....................................................... 101 writing ...................................................................... 101 unexpected termination .................................. 104 write verify ...................................................... 104 fscm. see fail-safe clock monitor. g goto ............................................................................... 384 h hardware multiplier .......................................................... 117 8 x 8 multiplication algorithms ................................. 117 operation ................................................................. 117 performance comparison (table) ............................. 117 i i/o ports ........................................................................... 135 input pull-up configuration ...................................... 136 open-drain outputs ................................................. 136 pin capabilities ........................................................ 135 ttl input buffer option ........................................... 136 i 2 c mode (mssp) acknowledge sequence timing ............................... 270 associated registers ............................................... 276 baud rate generator ............................................... 263 bus collision during a repeated start condition .................. 274 during a stop condition ................................... 275 clock arbitration ....................................................... 264 clock stretching ....................................................... 256 10-bit slave receive mode (sen = 1) ............. 256 10-bit slave transmit mode ............................. 256 7-bit slave receive mode (sen = 1) ............... 256 7-bit slave transmit mode ............................... 256 clock synchronization and the ckp bit ................... 257 effects of a reset ..................................................... 271 general call address support ................................. 260 i 2 c clock rate w/brg ............................................. 263 master mode ............................................................ 261 operation ......................................................... 262 reception ......................................................... 267 repeated start condition timing ..................... 266 start condition timing ..................................... 265 transmission .................................................... 267 multi-master communication, bus collision and arbitration ................................................. 271 multi-master mode ................................................... 271 operation ................................................................. 246 read/write bit information (r/w bit) ............... 246, 249 registers ................................................................. 241 serial clock (rc3/sckx/sclx) ............................... 249 slave mode .............................................................. 246 addressing ....................................................... 246 addressing masking modes 5-bit ......................................................... 247 7-bit ......................................................... 248 reception ........................................................ 249 transmission ................................................... 249 sleep operation ....................................................... 271 stop condition timing ............................................. 270 incf ................................................................................ 384 incfsz ............................................................................ 385 in-circuit debugger .......................................................... 362 in-circuit serial programming (icsp) ...................... 347, 362 indexed literal offset addressing and standard pic18 instructions ............................. 410 indexed literal offset mode ............................................. 410 indirect addressing ............................................................ 89 infsnz ............................................................................ 385 initialization conditions for all registers ...................... 59?65 instruction cycle ................................................................ 74 clocking scheme ....................................................... 74 flow/pipelining ........................................................... 74 instruction set .................................................................. 363 addlw .................................................................... 369 addwf .................................................................... 369 addwf (indexed literal offset mode) .................... 411 addwfc ................................................................. 370 andlw .................................................................... 370 andwf .................................................................... 371 bc ............................................................................ 371 bcf ......................................................................... 372 bn ............................................................................ 372 bnc ......................................................................... 373 bnn ......................................................................... 373 bnov ...................................................................... 374 bnz ......................................................................... 374 bov ......................................................................... 377 bra ......................................................................... 375 bsf .......................................................................... 375 bsf (indexed literal offset mode) .......................... 411 btfsc ..................................................................... 376 btfss ..................................................................... 376 btg ......................................................................... 377 bz ............................................................................ 378 call ........................................................................ 378 clrf ....................................................................... 379 clrwdt ................................................................. 379 comf ...................................................................... 380 cpfseq .................................................................. 380 cpfsgt .................................................................. 381 cpfslt ................................................................... 381 daw ........................................................................ 382 dcfsnz .................................................................. 383 decf ....................................................................... 382 decfsz .................................................................. 383 extended instructions .............................................. 405 considerations when enabling ........................ 410 syntax .............................................................. 405 use with mplab ide tools ............................. 412
? 2007 microchip technology inc. preliminary ds39775b-page 467 pic18f87j50 family general format ........................................................ 365 goto ...................................................................... 384 incf ......................................................................... 384 incfsz .................................................................... 385 infsnz .................................................................... 385 iorlw ..................................................................... 386 iorwf ..................................................................... 386 lfsr ........................................................................ 387 movf ....................................................................... 387 movff .................................................................... 388 movlb .................................................................... 388 movlw ................................................................... 389 movwf ................................................................... 389 mullw .................................................................... 390 mulwf .................................................................... 390 negf ....................................................................... 391 nop ......................................................................... 391 opcode field descriptions ....................................... 364 pop ......................................................................... 392 push ....................................................................... 392 rcall ..................................................................... 393 reset ..................................................................... 393 retfie .................................................................... 394 retlw .................................................................... 394 return .................................................................. 395 rlcf ........................................................................ 395 rlncf ..................................................................... 396 rrcf ....................................................................... 396 rrncf ................................ .................................... 397 setf ........................................................................ 397 setf (indexed literal offset mode) ........................ 411 sleep ..................................................................... 398 standard instructions ............................................... 363 subfwb .................................................................. 398 sublw .................................................................... 399 subwf .................................................................... 399 subwfb .................................................................. 400 swapf .................................................................... 400 tblrd ..................................................................... 401 tblwt ..................................................................... 402 tstfsz ................................................................... 403 xorlw .................................................................... 403 xorwf .................................................................... 404 intcon register rbif bit .................................................................... 141 intcon registers ........................................................... 121 inter-integrated circuit. see i 2 c. internal oscillator block ..................................................... 36 adjustment ................................................................. 37 osctune register ................................................... 37 internal rc oscillator use with wdt .......................................................... 356 internal voltage reference specific ations ....................... 431 internet address ............................................................... 474 interrupt sources ............................................................. 347 a/d conversion complete ....................................... 303 capture complete (ccp) ......................................... 209 compare complete (ccp) ....................................... 210 interrupt-on-change (rb7:rb4) .............................. 141 tmr0 overflow ........................................................ 191 tmr1 overflow ........................................................ 193 tmr2 to pr2 match (pwm) .................................... 219 tmr3 overflow ................................................ 201, 203 tmr4 to pr4 match ................................................ 206 tmr4 to pr4 match (pwm) .................................... 205 interrupts ......................................................................... 119 during, context saving ............................................ 134 intx pin ................................................................... 134 portb, interrupt-on-change .................................. 134 tmr0 ....................................................................... 134 interrupts, flag bits interrupt-on-change (rb7:rb4) flag (rbif bit) ................................................. 141 intosc frequency drift .................................................... 37 intosc, intrc. see internal oscillator block. iorlw ............................................................................. 386 iorwf ............................................................................. 386 ipr registers ................................................................... 130 l lfsr ............................................................................... 387 m master clear (mclr ) ......................................................... 55 master synchronous serial port (mssp). see mssp. memory organization ........................................................ 67 data memory ............................................................. 76 program memory ....................................................... 67 memory programming requirements .............................. 430 microchip internet web site ............................................. 474 movf .............................................................................. 387 movff ............................................................................ 388 movlb ............................................................................ 388 movlw ........................................................................... 389 movsf ............................................................................ 407 movss ............................................................................ 408 movwf ........................................................................... 389 mplab asm30 assembler, linker, librarian .................. 414 mplab icd 2 in-circuit debugger .................................. 415 mplab ice 2000 high-performance universal in-circuit emulator ................................................... 415 mplab integrated development environment software ............................................. 413 mplab pm3 device programmer ................................... 415 mplab real ice in-circuit emulator system ............... 415 mplink object linker/mplib object librarian ............... 414 mssp ack pulse ....................................................... 246, 249 i 2 c mode. see i 2 c mode. module overview ..................................................... 231 spi master/slave connection .................................. 235 tmr4 output for clock shift .................................... 206 mullw ............................................................................ 390 mulwf ............................................................................ 390 n negf ............................................................................... 391 nop ................................................................................. 391 o oscillator configuration ..................................................... 33 internal oscillator block ............................................. 36 oscillator control ....................................................... 33 oscillator modes and usb operation ........................ 34 oscillator selection .......................................................... 347 oscillator settings for usb ................................................ 38 oscillator start-up timer (ost) ......................................... 44 oscillator switching ........................................................... 40 oscillator transitions ......................................................... 41 oscillator, timer1 ..................................................... 193, 203 oscillator, timer3 ............................................................. 201
pic18f87j50 family ds39775b-page 468 preliminary ? 2007 microchip technology inc. p packaging ........................................................................ 457 details ...................................................................... 458 marking .................................................................... 457 parallel master port (pmp) .............................................. 165 application examples ............................................... 186 associated registers ............................................... 188 master port modes ................................................... 178 module registers ..................................................... 166 slave port modes ..................................................... 173 picstart plus development programmer .................... 416 pie registers ................................................................... 127 pin functions av dd .......................................................................... 32 av dd .......................................................................... 19 av ss .......................................................................... 32 av ss .......................................................................... 19 envreg .............................................................. 19, 32 mclr ................................................................... 12, 20 osc1/clki/ra7 .................................................. 12, 20 osc2/clko/ra6 ................................................ 12, 20 ra0/an0 .............................................................. 13, 21 ra1/an1 .............................................................. 13, 21 ra2/an2/v ref - .................................................... 13, 21 ra3/an3/v ref + ................................................... 13, 21 ra4/pmd5/t0cki ...................................................... 21 ra4/t0cki ................................................................. 13 ra5/an4/c2ina ........................................................ 13 ra5/pmd4/an4/c2ina ............................................. 21 ra6 ...................................................................... 13, 21 ra7 ...................................................................... 13, 21 rb0/flt0/int0 .................................................... 14, 22 rb1/int1/pma4 .................................................. 14, 22 rb2/int2/pma3 .................................................. 14, 22 rb3/int3/eccp2/p2a/pma2 .................................... 22 rb3/int3/pma2 ........................................................ 14 rb4/kbi0/pma1 .................................................. 14, 22 rb5/kbi1/pma0 .................................................. 14, 22 rb6/kbi2/pgc .................................................... 14, 22 rb7/kbi3/pgd .................................................... 14, 22 rc0/t1oso/t13cki ........................................... 15, 23 rc1/t1osi/eccp2/p2a ...................................... 15, 23 rc2/eccp1/p1a ................................................. 15, 23 rc3/sck1/scl1 ................................................. 15, 23 rc4/sdi1/sda1 .................................................. 15, 23 rc5/sdo1/c2out .............................................. 15, 23 rc6/tx1/ck1 ...................................................... 15, 23 rc7/rx1/dt1 ...................................................... 15, 23 rd0/ad0/pmd0 ......................................................... 24 rd0/pmd0 ................................................................. 16 rd1/ad1/pmd1 ......................................................... 24 rd1/pmd1 ................................................................. 16 rd2/ad2/pmd2 ......................................................... 24 rd2/pmd2 ................................................................. 16 rd3/ad3/pmd3 ......................................................... 24 rd3/pmd3 ................................................................. 16 rd4/ad4/pmd4/sdo2 .............................................. 24 rd4/pmd4/sdo2 ...................................................... 16 rd5/ad5/pmd5/sdi2/sda2 ..................................... 24 rd5/pmd5/sdi2/sda2 ............................................. 16 rd6/ad6/pmd6/sck2/scl2 .................................... 25 rd6/pmd6/sck2/scl2 ............................................ 16 rd7/ad7/pmd7/ss2 ................................................. 25 rd7/pmd7/ss2 ......................................................... 16 re0/ad8/pmrd/p2d ................................................ 26 re0/pmrd/p2d ........................................................ 17 re1/ad9/pmwr/p2c ............................................... 26 re1/pmwr/p2c ....................................................... 17 re2/ad10/pmbe/p2b ............................................... 26 re2/pmbe/p2b ......................................................... 17 re3/ad11/pma13/p3c/refo .................................. 26 re3/pma13/p3c/refo ............................................ 17 re4/ad12/pma12/p3b ............................................. 26 re4/pma12/p3b ....................................................... 17 re5/ad13/pma11/p1c ............................................. 26 re5/pma11/p1c ....................................................... 17 re6/ad14/pma10/p1b ............................................. 27 re6/pma10/p1b ....................................................... 17 re7/ad15/pma9/eccp2/p2a .................................. 27 re7/pma9/eccp2/p2a ............................................ 17 rf2/pma5/an7/c2inb ........................................ 18, 28 rf3/d- ................................................................. 18, 28 rf4/d+ ................................................................ 18, 28 rf5/an10/c1inb/cv ref ........................................... 18 rf5/pmd2/an10/c1inb/cv ref ................................ 28 rf6/an11/c1ina ...................................................... 18 rf6/pmd1/an11/c1ina ........................................... 28 rf7/pmd0/ss1 /c1out ............................................ 28 rf7/ss1 /c1out ....................................................... 18 rg0/pma8/eccp3/p3a ...................................... 19, 29 rg1/pma7/tx2/ck2 ........................................... 19, 29 rg2/pma6/rx2/dt2 ........................................... 19, 29 rg3/pmcs1/ccp4/p3d ..................................... 19, 29 rg4/pmcs2/ccp5/p1d ..................................... 19, 29 rh0/a16 .................................................................... 30 rh1/a17 .................................................................... 30 rh2/a18/pmd7 ......................................................... 30 rh3/a19/pmd6 ......................................................... 30 rh4/pmd3/an12/p3c/c2inc ................................... 30 rh5/pmbe/an13/p3b/c2ind ................................... 30 rh6/pmrd/an14/p1c/c1inc .................................. 30 rh7/pmwr/an15/p1b ............................................. 31 rj0/ale .................................................................... 32 rj1/oe ...................................................................... 32 rj2/wrl ................................................................... 32 rj3/wrh ................................................................... 32 rj4/ba0 .................................................................... 32 rj5/ce ...................................................................... 32 rj6/lb ....................................................................... 32 rj7/ub ...................................................................... 32 v dd ............................................................................ 32 v dd ............................................................................ 19 v ddcore /v cap ..................................................... 19, 32 v ss ............................................................................ 32 v ss ............................................................................ 19 v usb .................................................................... 19, 32 pinout i/o descriptions pic18f6xj5x (64-pin tqfp) .................................... 12 pic18f8xj5x (80-pin tqfp) .................................... 20 pir registers ................................................................... 124 pll frequency multiplier ................................................... 36 pop ................................................................................. 392 por. see power-on reset. porta associated registers ............................................... 140 lata register ......................................................... 138 porta register ...................................................... 138 trisa register ........................................................ 138
? 2007 microchip technology inc. preliminary ds39775b-page 469 pic18f87j50 family portb associated registers ............................................... 143 latb register .......................................................... 141 portb register ...................................................... 141 rb7:rb4 interrupt-on-change flag (rbif bit) ......................................................... 141 trisb register ........................................................ 141 portc associated registers ............................................... 146 latc register ......................................................... 144 portc register ...................................................... 144 rc3/sckx/sclx pin ................................................ 249 trisc register ........................................................ 144 portd associated registers ............................................... 149 latd register ......................................................... 147 portd register ...................................................... 147 trisd register ........................................................ 147 porte associated registers ............................................... 152 late register .......................................................... 150 porte register ...................................................... 150 trise register ........................................................ 150 portf associated registers ............................................... 155 latf register .......................................................... 153 portf register ...................................................... 153 trisf register ........................................................ 153 portg associated registers ............................................... 158 latg register ......................................................... 156 portg register ...................................................... 156 trisg register ........................................................ 156 porth associated registers ............................................... 161 lath register ......................................................... 159 porth register ...................................................... 159 trish register ........................................................ 159 portj associated registers ............................................... 163 latj register .......................................................... 162 portj register ....................................................... 162 trisj register ......................................................... 162 power-managed modes ..................................................... 45 and eusart operation ........................................... 281 and spi operation ................................................... 239 clock transitions and status indicators ..................... 46 entering ...................................................................... 45 exiting idle and sleep modes .................................... 51 by interrupt ........................................................ 51 by reset ............................................................ 51 by wdt time-out .............................................. 51 without an oscillator start-up delay .................. 51 idle modes ................................................................. 49 pri_idle ........................................................... 50 rc_idle ............................................................ 51 sec_idle ......................................................... 50 multiple sleep commands ......................................... 46 run modes ................................................................. 46 pri_run ........................................................... 46 rc_run ............................................................ 48 sec_run .......................................................... 46 selecting .................................................................... 45 sleep mode ................................................................ 49 summary (table) ........................................................ 45 power-on reset (por) ...................................................... 55 power-up delays ............................................................... 44 power-up timer (pwrt) ............................................. 44, 56 time-out sequence ................................................... 56 prescaler timer2 ..................................................................... 220 prescaler, timer0 ............................................................ 191 prescaler, timer2 (timer4) .............................................. 213 pri_idle mode ................................................................. 50 pri_run mode ................................................................. 46 program counter ............................................................... 71 pcl, pch and pcu registers .................................. 71 pclath and pclatu registers .............................. 71 program memory alu status ................................................................ 87 extended instruction set ........................................... 90 flash configuration words ........................................ 68 hard memory vectors ................................................ 68 instructions ................................................................ 75 two-word .......................................................... 75 interrupt vector .......................................................... 68 look-up tables .......................................................... 73 memory maps ............................................................ 67 hard vectors and configuration words ............. 68 modes ................................................................ 70 modes ........................................................................ 69 extended microcontroller ................................... 69 extended microcontroller (address shifting) ...................................... 70 memory access (table) ...................................... 70 microcontroller ................................................... 69 reset vector .............................................................. 68 program verification and code protection ...................... 362 programming, device instructions ................................... 363 pulse-width modulation. see pwm (ccp module) and pwm (eccp module). push ............................................................................... 392 push and pop instructions .............................................. 72 pushl ............................................................................. 408 pwm (ccp module) associated registers ............................................... 214 duty cycle ............................................................... 212 example frequencies/resolutions .......................... 213 operation setup ...................................................... 213 period ...................................................................... 212 pr2/pr4 registers ................................................. 212 tmr2 (tmr4) to pr2 (pr4) match ........................ 212 tmr2 to pr2 match ................................................ 219 tmr4 to pr4 match ................................................ 205 pwm (eccp module) ...................................................... 219 ccpr1h:ccpr1l registers .................................. 219 direction change in full-bridge output mode .................................................... 224 duty cycle ............................................................... 220 effects of a reset .................................................... 229 enhanced pwm auto-shutdown ............................. 226 example frequencies/resolutions .......................... 220 full-bridge mode ..................................................... 223 full-bridge output application example .................. 224 half-bridge mode ..................................................... 222 half-bridge output mode applications example ...................................... 222 output configurations .............................................. 220 output relationships (active-high) ......................... 221
pic18f87j50 family ds39775b-page 470 preliminary ? 2007 microchip technology inc. output relationships (active-low) ........................... 221 period ....................................................................... 219 programmable dead-band delay ............................ 226 setup for pwm operation ........................................ 229 start-up considerations ........................................... 227 q q clock .................................................................... 213, 220 r ram. see data memory. rc_idle mode .................................................................. 51 rc_run mode .................................................................. 48 rcall .............................................................................. 393 rcon register bit status during initialization .................................... 58 reader response ............................................................ 475 register file ....................................................................... 78 register file summary ................................................. 81?86 registers adcon0 (a/d control 0) ......................................... 299 adcon1 (a/d control 1) ......................................... 300 ancon0 (a/d port configuration 2) ........................ 301 ancon1 (a/d port configuration 1) ........................ 301 baudconx (baud rate control) ............................ 280 bdnstat (buffer descriptor n status, cpu mode) ...................................................... 319 bdnstat (buffer descriptor n status, sie mode) ........................................................ 320 ccpxcon (ccpx control) ...................................... 207 ccpxcon (eccpx control) .................................... 215 cmstat (comparator status) ................................. 337 cmxcon (comparator control x) ............................ 336 config1h (configuration 1 high) .......................... 350 config1l (configuration 1 low) ............................ 349 config2h (configuration 2 high) .......................... 352 config3h (configuration 3 high) .......................... 354 config3l (configuration 3 low) ...................... 69, 353 cvrcon (comparator voltage reference control) ........................................... 344 devid1 (device id 1) .............................................. 355 devid2 (device id 2) .............................................. 355 eccpxas (eccpx auto-shutdown control) ........... 227 eccpxdel (eccpx pwm delay) ........................... 226 eecon1 (eeprom control 1) .................................. 97 intcon (interrupt control) ...................................... 121 intcon2 (interrupt control 2) ................................. 122 intcon3 (interrupt control 3) ................................. 123 ipr1 (peripheral interrupt priority 1) ........................ 130 ipr2 (peripheral interrupt priority 2) ........................ 131 ipr3 (peripheral interrupt priority 3) ........................ 132 memcon (external memory bus control) .............. 106 odcon1 (peripheral open-drain control 1) ........... 137 odcon2 (peripheral open-drain control 2) ........... 137 odcon3 (peripheral open-drain control 3) ........... 137 osccon (oscillator control) .................................... 42 osctune (oscillator tuning) ................................... 38 padcfg1 (pad configuration control 1) ................ 138 pie1 (peripheral interrupt enable 1) ........................ 127 pie2 (peripheral interrupt enable 2) ........................ 128 pie3 (peripheral interrupt enable 3) ........................ 129 pir1 (peripheral interrupt request (flag) 1) ........... 124 pir2 (peripheral interrupt request (flag) 2) ........... 125 pir3 (peripheral interrupt request (flag) 3) ........... 126 pmaddrh (parallel port address high byte) ......... 172 pmconh (parallel port control high byte) ............. 166 pmconl (parallel port control low byte) .............. 167 pmeh (parallel port enable high byte) ................... 169 pmel (parallel port enable low byte) .................... 170 pmmodeh (parallel port mode high byte) ............ 168 pmmodel (parallel port mode low byte) .............. 169 pmstath (parallel port status high byte) ............. 170 pmstatl (parallel port status low byte) .............. 171 rcon (reset control) ....................................... 54, 133 rcstax (receive status and control) .................... 279 sspxcon1 (msspx control 1, i 2 c mode) .............. 243 sspxcon1 (msspx control 1, spi mode) ............. 233 sspxmsk (i 2 c slave address mask) ...................... 245 sspxstat (msspx status, i 2 c mode) ................... 242 sspxstat (msspx status, spi mode) .................. 232 status .................................................................... 87 stkptr (stack pointer) ............................................ 72 t0con (timer0 control) ......................................... 189 t1con (timer1 control) ......................................... 193 t2con (timer2 control) ......................................... 199 t3con (timer3 control) ......................................... 201 t4con (timer4 control) ......................................... 205 txstax (transmit status and control) ................... 278 ucfg (usb configuration) ..................................... 312 ucon (usb control) ............................................... 310 ueie (usb error interrupt enable) .......................... 328 ueir (usb error interrupt status) ........................... 327 uepn (usb endpoint n control) .............................. 315 uie (usb interrupt enable) ..................................... 326 uir (usb interrupt status) ...................................... 324 ustat (usb status) ............................................... 314 wdtcon (watchdog timer control) ...................... 357 reset ............................................................................. 393 reset ................................................................................. 53 brown-out reset (bor) ............................................. 53 mclr reset, during power-managed modes .......... 53 mclr reset, normal operation ................................ 53 power-on reset (por) .............................................. 53 reset instruction ..................................................... 53 stack full reset ......................................................... 53 stack underflow reset .............................................. 53 watchdog timer (wdt) reset .................................. 53 resets .............................................................................. 347 brown-out reset (bor) ........................................... 347 oscillator start-up timer (ost) ............................... 347 power-on reset (por) ............................................ 347 power-up timer (pwrt) ......................................... 347 retfie ............................................................................ 394 retlw ............................................................................ 394 return .......................................................................... 395 revision history ............................................................... 461 rlcf ............................................................................... 395 rlncf ............................................................................. 396 rrcf ............................................................................... 396 rrncf ................... ......................................................... 397 s sckx ................................................................................ 231 sdix ................................................................................. 231 sdox ............................................................................... 231 sec_idle mode ............................................................... 50 sec_run mode ................................................................ 46 serial clock, sckx .......................................................... 231 serial data in (sdix) ........................................................ 231 serial data out (sdox) ................................................... 231 serial peripheral interface. see spi mode. setf ................................................................................ 397
? 2007 microchip technology inc. preliminary ds39775b-page 471 pic18f87j50 family slave select (ssx ) ........................................................... 231 sleep ............................................................................. 398 software simulator (mplab sim) .................................... 414 special event trigger. see compare (eccp module). special features of the cpu ........................................... 347 special function registers shared registers ....................................................... 80 spi mode (mssp) ............................................................ 231 associated registers ............................................... 240 bus mode compatibility ........................................... 239 clock speed, interactions ........................................ 239 effects of a reset ..................................................... 239 enabling spi i/o ...................................................... 235 master mode ............................................................ 236 master/slave connection ......................................... 235 operation ................................................................. 234 operation in power-managed modes ...................... 239 serial clock .............................................................. 231 serial data in ........................................................... 231 serial data out ........................................................ 231 slave mode .............................................................. 237 slave select ............................................................. 231 slave select synchronization .................................. 237 spi clock ................................................................. 236 sspxbuf register .................................................. 236 sspxsr register ..................................................... 236 typical connection .................................................. 235 sspov ............................................................................. 267 sspov status flag ......................................................... 267 sspxstat register r/w bit ............................................................. 246, 249 ssx .................................................................................. 231 stack full/underflow resets .............................................. 73 subfsr .......................................................................... 409 subfwb .......................................................................... 398 sublw ............................................................................ 399 subulnk ........................................................................ 409 subwf ............................................................................ 399 subwfb .......................................................................... 400 swapf ............................................................................ 400 t table pointer operations (table) ........................................ 98 table reads/table writes ................................................. 73 tblrd ............................................................................. 401 tblwt ............................................................................. 402 timer0 .............................................................................. 189 associated registers ............................................... 191 operation ................................................................. 190 overflow interrupt .................................................... 191 prescaler .................................................................. 191 switching assignment ...................................... 191 prescaler assignment (psa bit) .............................. 191 prescaler select (t0ps2:t0ps0 bits) ..................... 191 prescaler. see prescaler, timer0. reads and writes in 16-bit mode ............................ 190 source edge select (t0se bit) ................................ 190 source select (t0cs bit) ......................................... 190 timer1 .............................................................................. 193 16-bit read/write mode ........................................... 195 associated registers ............................................... 198 interrupt .................................................................... 196 operation ................................................................. 194 oscillator .......................................................... 193, 195 layout considerations ..................................... 195 overflow interrupt .................................................... 193 resetting, using the eccp special event trigger ...................................... 196 special event trigger (eccp) ................................. 218 tmr1h register ...................................................... 193 tmr1l register ...................................................... 193 use as a clock source ............................................ 195 use as a real-time clock ....................................... 196 timer2 ............................................................................. 199 associated registers ............................................... 200 interrupt ................................................................... 200 operation ................................................................. 199 output ...................................................................... 200 pr2 register ........................................................... 219 tmr2 to pr2 match interrupt .................................. 219 timer3 ............................................................................. 201 16-bit read/write mode .......................................... 203 associated registers ............................................... 203 operation ................................................................. 202 oscillator .......................................................... 201, 203 overflow interrupt ............................................ 201, 203 special event trigger (eccp) ................................. 203 tmr3h register ...................................................... 201 tmr3l register ...................................................... 201 timer4 ............................................................................. 205 associated registers ............................................... 206 mssp clock shift .................................................... 206 operation ................................................................. 205 postscaler. see postscaler, timer4. pr4 register ........................................................... 205 prescaler. see prescaler, timer4. tmr4 register ........................................................ 205 tmr4 to pr4 match interrupt .......................... 205, 206 timing diagrams a/d conversion ....................................................... 454 asynchronous reception ......................................... 290 asynchronous transmission ................................... 288 asynchronous transmission (back-to-back) ........... 288 automatic baud rate calculation ............................ 286 auto-wake-up bit (wue) during normal operation ............................................ 291 auto-wake-up bit (wue) during sleep ................... 291 baud rate generator with clock arbitration ............ 264 brg overflow sequence ........................................ 286 brg reset due to sdax arbitration during start condition ................................................. 273 bus collision during a repeated start condition (case 1) ........................................... 274 bus collision during a repeated start condition (case 2) ........................................... 274 bus collision during a start condition (sclx = 0) ....................................... 273 bus collision during a stop condition (case 1) ........................................... 275 bus collision during a stop condition (case 2) ........................................... 275 bus collision during start condition (sdax only) .................................... 272 bus collision for transmit and acknowledge .......... 271 capture/compare/pwm (including eccp modules) .............................. 442 clko and i/o .......................................................... 437 clock synchronization ............................................. 257 clock/instruction cycle .............................................. 74 eusartx synchronous receive (master/slave) ................................................. 453
pic18f87j50 family ds39775b-page 472 preliminary ? 2007 microchip technology inc. eusartx synchronous transmission (master/slave) .................................................. 453 example spi master mode (cke = 0) ..................... 445 example spi master mode (cke = 1) ..................... 446 example spi slave mode (cke = 0) ....................... 447 example spi slave mode (cke = 1) ....................... 448 external clock .......................................................... 435 external memory bus for sleep (extended microcontroller mode) ............. 112, 114 external memory bus for tblrd (extended microcontroller mode) ............. 112, 114 fail-safe clock monitor ............................................ 361 first start bit timing ................................................ 265 full-bridge pwm output .......................................... 223 half-bridge pwm output ......................................... 222 i 2 c acknowledge sequence .................................... 270 i 2 c bus data ............................................................ 449 i 2 c bus start/stop bits ............................................. 449 i 2 c master mode (7 or 10-bit transmission) ........... 268 i 2 c master mode (7-bit reception) .......................... 269 i 2 c slave mode (10-bit recepti on, sen = 0) .......... 254 i 2 c slave mode (10-bit reception, sen = 0, admsk = 01001) ............................................. 253 i 2 c slave mode (10-bit recepti on, sen = 1) .......... 259 i 2 c slave mode (10-bit transmission) ..................... 255 i 2 c slave mode (7-bit reception, sen = 0) ............ 250 i 2 c slave mode (7-bit reception, sen = 0, admsk = 01011) ............................................. 251 i 2 c slave mode (7-bit reception, sen = 1) ............ 258 i 2 c slave mode (7-bit transmission) ....................... 252 i 2 c slave mode general call address sequence (7 or 10-bit address mode) ............. 260 i 2 c stop condition receive or transmit mode ........ 270 msspx i 2 c bus data ............................................... 451 msspx i 2 c bus start/stop bits ................................ 451 parallel master port read ........................................ 443 parallel master port write ........................................ 444 parallel slave port read .................................. 174, 177 parallel slave port write .................................. 174, 177 program memory read ............................................ 438 program memory write ............................................ 439 pwm auto-shutdown (p1rsen = 0, auto-restart disabled) ..................................... 228 pwm auto-shutdown (p1rsen = 1, auto-restart enabled) ..................................... 228 pwm direction change ........................................... 225 pwm direction change at near 100% duty cycle ............................................. 225 pwm output ............................................................ 212 read and write, 8-bit data, demultiplexed address .................................... 181 read, 16-bit data, demultiplexed address ............. 184 read, 16-bit multiplexed data, fully multiplexed 16-bit address .............................. 185 read, 16-bit multiplexed data, partially multiplexed address ......................................... 184 read, 8-bit data, fully multiplexed 16-bit address ................................................. 183 read, 8-bit data, partially multiplexed address ...... 181 read, 8-bit data, partially multiplexed address, enable strobe .................................................. 182 read, 8-bit data, wait states enabled, partially multiplexed address ........................... 181 repeated start condition ......................................... 266 reset, watchdog timer (wdt), oscillator start-up timer (ost) and power-up timer (pwrt) ..... 440 send break character sequence ............................ 292 slave synchronization ............................................. 237 slow rise time (mclr tied to v dd , v dd rise > t pwrt ) ............................................ 57 spi mode (master mode) ......................................... 236 spi mode (slave mode, cke = 0) ........................... 238 spi mode (slave mode, cke = 1) ........................... 238 synchronous reception (master mode, sren) ...... 295 synchronous transmission ..................................... 293 synchronous transmission (through txen) .......... 294 time-out sequence on power-up (mclr not tied to v dd ), case 1 ...................... 56 time-out sequence on power-up (mclr not tied to v dd ), case 2 ...................... 57 time-out sequence on power-up (mclr tied to v dd , v dd rise < t pwrt ) ........... 56 timer0 and timer1 external clock .......................... 441 transition for entry to idle mode ................................ 50 transition for entry to sec_run mode .................... 47 transition for entry to sleep mode ............................ 49 transition for two-speed start-up (intrc to hspll) ........................................... 359 transition for wake from idle to run mode .............. 50 transition for wake from sleep (hspll) ................. 49 transition from rc_run mode to pri_run mode ................................................. 48 transition from sec_run mode to pri_run mode (hspll) .................................. 47 transition to rc_run mode ..................................... 48 usb signal .............................................................. 456 write, 16-bit data, demultiplexed address ............. 184 write, 16-bit multiplexed data, fully multiplexed 16-bit address .............................. 185 write, 16-bit multiplexed data, partially multiplexed address ........................................ 185 write, 8-bit data, fully multiplexed 16-bit address ................................................. 183 write, 8-bit data, partially multiplexed address ...... 182 write, 8-bit data, partially multiplexed address, enable strobe ................................... 183 write, 8-bit data, wait states enabled, partially multiplexed address .......................... 182 timing diagrams and specifications ac characteristics internal rc accuracy ....................................... 436 capture/compare/pwm requirements (including eccp modules) .............................. 442 clko and i/o requirements ................................... 437 eusartx synchronous receive requirements .................................................. 453 eusartx synchronous transmission requirements .................................................. 453 example spi mode requirements (master mode, cke = 0) .................................. 445 example spi mode requirements (master mode, cke = 1) .................................. 446 example spi mode requirements (slave mode, cke = 0) .................................... 447 example spi slave mode requirements (cke = 1) ................................. 448 external clock requirements .................................. 435 i 2 c bus data requirements (slave mode) .............. 450
? 2007 microchip technology inc. preliminary ds39775b-page 473 pic18f87j50 family i 2 c bus start/stop bits requirements (slave mode) ................................................... 449 msspx i 2 c bus data requirements ........................ 452 msspx i 2 c bus start/stop bits requirements ........ 451 parallel master port read requirements ................ 443 parallel master port write requirements ................. 444 pll clock ................................................................. 436 program memory read requirements .................... 438 program memory write requirements .................... 439 reset, watchdog timer, oscillator start-up timer, power-up timer and brown-out reset requirements ........................................ 440 timer0 and timer1 external clock requirements .................................................. 441 usb full-speed requirements ................................ 456 usb low-speed requirements ............................... 456 tstfsz ........................................................................... 403 two-speed start-up ................................................. 347, 359 two-word instructions example cases .......................................................... 75 txstax register brgh bit ................................................................. 281 u universal serial bus address register (uaddr) ..................................... 316 associated registers ............................................... 332 buffer descriptor table ............................................ 317 buffer descriptors .................................................... 317 address validation ........................................... 320 assignment in different buffering modes ........ 322 bdnstat register (cpu mode) ..................... 318 bdnstat register (sie mode) ....................... 320 byte count ....................................................... 320 example ........................................................... 317 memory map .................................................... 321 ownership ........................................................ 317 ping-pong buffering ......................................... 321 register summary ........................................... 322 status and configuration ................................. 317 class specifications and drivers ............................. 334 descriptors ............................................................... 334 endpoint control ...................................................... 315 enumeration ............................................................. 334 external pull-up resistors ........................................ 313 eye pattern test enable .......................................... 313 firmware and drivers ............................................... 332 frame number registers ........................................ 316 frames .................................................................... 333 internal pull-up resistors ........................................ 313 internal transceiver ................................................. 311 interrupts ................................................................. 323 and usb transactions ..................................... 323 layered framework ................................................. 333 oscillator requirements .......................................... 332 overview .......................................................... 309, 333 ping-pong buffer configuration ............................... 313 power ...................................................................... 333 power modes ........................................................... 329 bus power only ............................................... 329 dual power with self-power dominance ......... 330 self-power only ............................................... 329 ram ......................................................................... 316 memory map .................................................... 316 speed ...................................................................... 334 status and control ................................................... 310 transfer types ........................................................ 333 ufrmh:ufrml registers ...................................... 316 usb ram serial interface engine (sie) ..................................... 76 usb specifications .......................................................... 432 usb. see universal serial bus. v v ddcore /v cap pin .......................................................... 358 voltage reference specifications .................................... 431 voltage regulator (on-chip) ........................................... 358 operation in sleep mode ......................................... 359 w watchdog timer (wdt) ........................................... 347, 356 associated registers ............................................... 357 control register ....................................................... 356 during oscillator failure .......................................... 360 programming considerations .................................. 356 wcol ...................................................... 265, 266, 267, 270 wcol status flag ................................... 265, 266, 267, 270 www address ................................................................ 474 www, on-line support .................... .................................. 5 x xorlw ........................................................................... 403 xorwf ........................................................................... 404
pic18f87j50 family ds39775b-page 474 preliminary ? 2007 microchip technology inc. notes:
? 2007 microchip technology inc. preliminary ds39775b-page 475 pic18f87j50 family the microchip web site microchip provides online support via our www site at www.microchip.com. this web site is used as a means to make files and information easily available to customers. accessible by using your favorite internet browser, the web site contains the following information: ? product support ? data sheets and errata, application notes and sample programs, design resources, user?s guides and hardware support documents, latest software releases and archived software ? general technical support ? frequently asked questions (faq), technical support requests, online discussion groups, microchip consultant program member listing ? business of microchip ? product selector and ordering guides, latest microchip press releases, listing of seminars and events, listings of microchip sales offices, distributors and factory representatives customer change notification service microchip?s customer notification service helps keep customers current on microchip products. subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest. to register, access the microchip web site at www.microchip.com, click on customer change notification and follow the registration instructions. customer support users of microchip products can receive assistance through several channels: ? distributor or representative ? local sales office ? field application engineer (fae) ? technical support ? development systems information line customers should contact their distributor, representative or field application engineer (fae) for support. local sales offices are also available to help customers. a listing of sales offices and locations is included in the back of this document. technical support is available through the web site at: http://support.microchip.com
pic18f87j50 family ds39775b-page 476 preliminary ? 2007 microchip technology inc. reader response it is our intention to provide you with the best documentation possible to ensure successful use of your microchip prod- uct. if you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please fax your comments to the technical publications manager at (480) 792-4150. please list the following information, and use this outline to provide us with your comments about this document. to : technical publications manager re: reader response total pages sent ________ from: name company address city / state / zip / country telephone: (_______) _________ - _________ application (optional): would you like a reply? y n device: literature number: questions: fax: (______) _________ - _________ ds39775b pic18f87j50 family 1. what are the best features of this document? 2. how does this document meet your hardware and software development needs? 3. do you find the organization of this document easy to follow? if not, why? 4. what additions to the document do you think would enhance the structure and subject? 5. what deletions from the document could be made without affecting the overall usefulness? 6. is there any incorrect or misleading information (what and where)? 7. how would you improve this document?
? 2007 microchip technology inc. preliminary ds39775b-page 477 pic18f87j50 family product identification system to order or obtain information, e. g., on pricing or delivery, refer to the factory or the listed sales office . part no. x /xx xxx pattern package temperature range device device pic18f65j50/66j50/66j55/67j50 (1) , pic18f85j50/86j50/86j55/87j50 (1) , pic18f65j50/66j50/66j55/67j50t (2) , pic18f85j50/86j50/86j55/87j50t (2) ; temperature range i = -40 c to +85 c (industrial) package pt = tqfp (thin quad flatpack) pattern qtp, sqtp, code or special requirements (blank otherwise) examples: a) PIC18F86J50-i/pt 301 = industrial temp., tqfp package, qtp pattern #301. b) pic18f66j55t-i/pt = tape and reel, industrial temp., tqfp package. note 1: f = standard voltage range 2: t = in tape and reel
ds39775b-page 478 preliminary ? 2007 microchip technology inc. americas corporate office 2355 west chandler blvd. chandler, az 85224-6199 tel: 480-792-7200 fax: 480-792-7277 technical support: http://support.microchip.com web address: www.microchip.com atlanta duluth, ga tel: 678-957-9614 fax: 678-957-1455 boston westborough, ma tel: 774-760-0087 fax: 774-760-0088 chicago itasca, il tel: 630-285-0071 fax: 630-285-0075 dallas addison, tx tel: 972-818-7423 fax: 972-818-2924 detroit farmington hills, mi tel: 248-538-2250 fax: 248-538-2260 kokomo kokomo, in tel: 765-864-8360 fax: 765-864-8387 los angeles mission viejo, ca tel: 949-462-9523 fax: 949-462-9608 santa clara santa clara, ca tel: 408-961-6444 fax: 408-961-6445 toronto mississauga, ontario, canada tel: 905-673-0699 fax: 905-673-6509 asia/pacific asia pacific office suites 3707-14, 37th floor tower 6, the gateway habour city, kowloon hong kong tel: 852-2401-1200 fax: 852-2401-3431 australia - sydney tel: 61-2-9868-6733 fax: 61-2-9868-6755 china - beijing tel: 86-10-8528-2100 fax: 86-10-8528-2104 china - chengdu tel: 86-28-8665-5511 fax: 86-28-8665-7889 china - fuzhou tel: 86-591-8750-3506 fax: 86-591-8750-3521 china - hong kong sar tel: 852-2401-1200 fax: 852-2401-3431 china - qingdao tel: 86-532-8502-7355 fax: 86-532-8502-7205 china - shanghai tel: 86-21-5407-5533 fax: 86-21-5407-5066 china - shenyang tel: 86-24-2334-2829 fax: 86-24-2334-2393 china - shenzhen tel: 86-755-8203-2660 fax: 86-755-8203-1760 china - shunde tel: 86-757-2839-5507 fax: 86-757-2839-5571 china - wuhan tel: 86-27-5980-5300 fax: 86-27-5980-5118 china - xian tel: 86-29-8833-7250 fax: 86-29-8833-7256 asia/pacific india - bangalore tel: 91-80-4182-8400 fax: 91-80-4182-8422 india - new delhi tel: 91-11-4160-8631 fax: 91-11-4160-8632 india - pune tel: 91-20-2566-1512 fax: 91-20-2566-1513 japan - yokohama tel: 81-45-471- 6166 fax: 81-45-471-6122 korea - gumi tel: 82-54-473-4301 fax: 82-54-473-4302 korea - seoul tel: 82-2-554-7200 fax: 82-2-558-5932 or 82-2-558-5934 malaysia - penang tel: 60-4-646-8870 fax: 60-4-646-5086 philippines - manila tel: 63-2-634-9065 fax: 63-2-634-9069 singapore tel: 65-6334-8870 fax: 65-6334-8850 taiwan - hsin chu tel: 886-3-572-9526 fax: 886-3-572-6459 taiwan - kaohsiung tel: 886-7-536-4818 fax: 886-7-536-4803 taiwan - taipei tel: 886-2-2500-6610 fax: 886-2-2508-0102 thailand - bangkok tel: 66-2-694-1351 fax: 66-2-694-1350 europe austria - wels tel: 43-7242-2244-39 fax: 43-7242-2244-393 denmark - copenhagen tel: 45-4450-2828 fax: 45-4485-2829 france - paris tel: 33-1-69-53-63-20 fax: 33-1-69-30-90-79 germany - munich tel: 49-89-627-144-0 fax: 49-89-627-144-44 italy - milan tel: 39-0331-742611 fax: 39-0331-466781 netherlands - drunen tel: 31-416-690399 fax: 31-416-690340 spain - madrid tel: 34-91-708-08-90 fax: 34-91-708-08-91 uk - wokingham tel: 44-118-921-5869 fax: 44-118-921-5820 w orldwide s ales and s ervice 12/08/06

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