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? 2004 microchip technology inc. preliminary ds41202c pic16f684 data sheet 14-pin flash-based, 8-bit cmos microcontrollers with nanowatt technology
ds41202c-page ii preliminary ? 2004 microchip technology inc. information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. it is your responsibility to ensure that your application m eets with your specifications. no representation or warranty is given and no liability is assumed by microchip technol ogy incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. use of mi crochip?s products as critical components in life support syst ems is not authorized except with express written approval by microchip. no licenses are conveyed, implicitly or ot herwise, under any intellectual property rights. trademarks the microchip name and logo, the microchip logo, accuron, dspic, k ee l oq , micro id , mplab, pic, picmicro, picstart, pro mate, powersmart, rfpic, and smartshunt are registered trademarks of micr ochip technology incorporated in the u.s.a. and other countries. amplab, filterlab, mxdev, mxlab, picmaster, seeval, smartsensor and the embedded control solutions company are registered trademarks of microchip technology incorporated in the u.s.a. analog-for-the-digital age, app lication maestro, dspicdem, dspicdem.net, dspicworks, ecan, economonitor, fansense, flexrom, fuzzylab, in-circuit serial programming, icsp, icepic, migratable memory, mpasm, mplib, mplink, mpsim, pickit, picdem, picdem.net, piclab, pictail, powercal, powerinfo, powermate, powertool, rflab, rfpicdem, select mode, smart serial, smarttel and total endurance ar e trademarks of microchip technology incorporated in the u.s.a. and other countries. sqtp is a service mark of mi crochip technology incorporated in the u.s.a. all other trademarks mentioned herein are property of their respective companies. ? 2004, 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 specif ications 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 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona and mountain view, california in october 2003. the company?s quality system processes and procedures are for its picmicro ? 8-bit mcus, 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.
? 2004 microchip technology inc. preliminary ds41202c-page 1 pic16f684 high-performance risc cpu: only 35 instructions to learn: - all single-cycle instructions except branches operating speed: - dc ? 20 mhz oscillator/clock input - dc ? 200 ns instruction cycle interrupt capability 8-level deep hardware stack direct, indirect and relative addressing modes special microcontroller features: precision internal oscillator: - factory calibrated to 1% - software selectable frequency range of 8 mhz to 31 khz - software tunable - two-speed start-up mode - crystal fail detect for critical applications - clock mode switching during operation for power savings power-saving sleep mode wide operating voltage range (2.0v-5.5v) industrial and extended temperature range power-on reset (por) power-up timer (pwrt) and oscillator start-up timer (ost) brown-out detect (bod) with software control option enhanced low-current watchdog timer (wdt) with on-chip oscillator (software selectable nominal 268 seconds with full prescaler) with software enable multiplexed master clear with pull-up/input pin programmable code protection high endurance flash/eeprom cell: - 100,000 write flash endurance - 1,000,000 write eeprom endurance - flash/data eeprom retention: > 40 years low-power features: standby current: - 1 na @ 2.0v, typical operating current: -8.5 a @ 32 khz, 2.0v, typical -100 a @ 1 mhz, 2.0v, typical watchdog timer current: -1 a @ 2.0v, typical peripheral features: 12 i/o pins with individual direction control: - high current source/sink for direct led drive - interrupt-on-pin change - individually programmable weak pull-ups - ultra low-power wake-up (ulpwu) analog comparator module with: - two analog comparators - programmable on-chip voltage reference (cv ref ) module (% of v dd ) - comparator inputs and outputs externally accessible a/d converter: - 10-bit resolution and 8 channels timer0: 8-bit timer/counter with 8-bit programmable prescaler enhanced timer1: - 16-bit timer/counter with prescaler - external gate input mode - option to use osc1 and osc2 in lp mode as timer1 oscillator if intosc mode selected timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler enhanced capture, compare, pwm module: - 16-bit capture, max resolution 12.5 ns - compare, max resolution 200 ns - 10-bit pwm with 1, 2 or 4 output channels, programmable ?dead time?, max frequency 20 khz in-circuit serial programming tm (icsp tm ) via two pins device program memory data memory i/o 10-bit a/d (ch) comparators timers 8/16-bit flash (words) sram (bytes) eeprom (bytes) pic16f684 2048 128 256 12 8 2 2/1 14-pin flash-based, 8-bit cmos microcontrollers with nanowatt technology
pic16f684 ds41202c-page 2 preliminary ? 2004 microchip technology inc. pin diagram 14-pin pdip, soic, tssop v dd ra5/t1cki/osc1/clkin ra4/an3/t1g /osc2/clkout ra3/mclr /v pp rc5/ccp1/p1a rc4/c2out/p1b rc3/an7/p1c v ss ra0/an0/c1in+/icspdat/ulpwu ra1/an1/c1in-/v ref /icspclk ra2/an2/t0cki/int/c1out rc0/an4/c2in+ rc1/an5/c2in- rc2/an6/p1d pic16f684 1 2 3 4 5 6 7 14 13 12 9 11 10 8
? 2004 microchip technology inc. preliminary ds41202c-page 3 pic16f684 table of contents 1.0 device overview ............................................................................................................. ............................................................ 5 2.0 memory organization ......................................................................................................... ......................................................... 7 3.0 clock sources ............................................................................................................... ............................................................ 19 4.0 i/o ports ................................................................................................................... ................................................................. 31 5.0 timer0 module ............................................................................................................... ........................................................... 45 6.0 timer1 module with gate control............................................................................................. ................................................. 49 7.0 timer2 module ............................................................................................................... ........................................................... 53 8.0 comparator module........................................................................................................... ........................................................ 55 9.0 analog-to-digital converter (a/d) module.................................................................................... ............................................. 63 10.0 data eeprom memory ......................................................................................................... ................................................... 71 11.0 enhanced capture/compare/pwm (eccp) module................................................................................. ................................ 75 12.0 special features of the cpu................................................................................................ ..................................................... 91 13.0 instruction set summary .................................................................................................... ..................................................... 111 14.0 development support........................................................................................................ ...................................................... 121 15.0 electrical specifications.................................................................................................. ......................................................... 127 16.0 dc and ac characteristics graphs and tables................................................................................ ...................................... 147 17.0 packaging information...................................................................................................... ....................................................... 149 appendix a: data sheet revision history........................................................................................ ................................................. 153 appendix b: migrating from other picmicro? devices ............................................................................. ........................................ 153 index .......................................................................................................................... ....................................................................... 155 on-line support................................................................................................................ ................................................................ 159 systems information and upgrade hot line ....................................................................................... .............................................. 159 reader response ................................................................................................................ ............................................................. 160 product identification system .................................................................................................. ......................................................... 161 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@mail.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/doc umentation issues become known to us, we will publis h 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 particul ar 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) the microchip corporate literatu re center; u.s. fax: (480) 792-7277 when contacting a sales office or the literature center, please specify which device, revision of silicon and data sheet (inclu de literature number) you are using. customer notification system register on our web site at www.microchip.com/cn to receive the most current information on all of our products.
pic16f684 ds41202c-page 4 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 5 pic16f684 1.0 device overview this document contains device specific information for the pic16f684. additional information may be found in the ? picmicro ? mid-range mcu family reference manual? (ds33023), which may be obtained from your local microchip sales representative or downloaded from the microchip web site. the reference manual should be considered a comple- mentary document to this data sheet and is highly recommended reading for a better understanding of the device architecture and operation of the peripheral modules. the pic16f684 is covered by this data sheet. it is available in 14-pin pdip, soic and tssop packages. figure 1-1 shows a block diagram of the pic16f684 device. table 1-1 shows the pinout description. figure 1-1: pic16f 684 block diagram flash program memory 13 data bus 8 14 program bus instruction reg program counter ram file registers direct addr 7 ram addr 9 addr mux indirect addr fsr reg status reg mux alu w reg instruction decode & control timing generation osc1/clkin osc2/clkout porta 8 8 8 3 8-level stack 128 bytes 2k x 14 (13-bit) power-up timer oscillator start-up timer power-on reset watchdog timer mclr v ss brown-out detect timer0 timer1 data eeprom 256 bytes eedata eeaddr ra0 ra1 ra2 ra3 ra4 ra5 2 analog comparators analog-to-digital converter an0 an1 an2 an3 c1in- c1in+ c1out t0cki int t1cki configuration internal oscillator v ref and reference t1g portc rc0 rc1 rc2 rc3 rc4 rc5 an4 an5 an6 an7 v dd 8 timer2 c2in- c2in+ c2out eccp block ccp1/p1a p1b p1c p1d
pic16f684 ds41202c-page 6 preliminary ? 2004 microchip technology inc. table 1-1: pic16f684 pinout description name function input type output type description ra0/an0/c1in+/icspdat/ulpwu ra0 ttl cmos porta i /o w/programmable pull-up and interrupt-on-change an0 an ? a/d channel 0 input c1in+ an ? comparator 1 input icspdat ttl cmos serial programming data i/o ulpwu an ? ultra low-power wake-up input ra1/an1/c1in-/v ref /icspclk ra1 ttl cmos porta i/o w/program mable pull-up and interrupt-on-change an1 an ? a/d channel 1 input c1in- an ? comparator 1 input v ref an ? external voltage reference for a/d icspclk st ? serial programming clock ra2/an2/t0cki/int/c1out ra2 st cmos porta i/o w/programmable pull-up a nd interrupt-on-change an2 an ? a/d channel 2 input t0cki st ? timer0 clock input int st ? external interrupt c1out ? cmos comparator 1 output ra3/mclr /v pp ra3 ttl ? porta input with interrupt-on-change mclr st ? master clear w/internal pull-up v pp hv ? programming voltage ra4/an3/t1g /osc2/clkout ra4 ttl cmos porta i/o w/progr ammable pull-up and interrupt-on-change an3 an ? a/d channel 3 input t1g st ? timer1 gate osc2 ? xtal crystal/resonator clkout ? cmos f osc /4 output ra5/t1cki/osc1/clkin ra5 ttl cmos porta i/o w/ programmable pull-up a nd interrupt-on-change t1cki st ? timer1 clock osc1 xtal ? crystal/resonator clkin st ? external clock input/rc oscillator connection rc0/an4/c2in+ rc0 ttl cmos portc i/o an4 an ? a/d channel 4 input c2in+ an ? comparator 2 input rc1/an5/c2in- rc1 ttl cmos portc i/o an5 an ? a/d channel 5 input c2in- an ? comparator 2 input rc2/an6/p1d rc2 ttl cmos portc i/o an6 an ? a/d channel 6 input p1d ? cmos pwm output rc3/an7/p1c rc3 ttl cmos portc i/o an7 an ? a/d channel 7 input p1c ? cmos pwm output rc4/c2out/p1b rc4 ttl cmos portc i/o c2out ? cmos comparator 2 output p1b ? cmos pwm output rc5/ccp1/p1a rc5 ttl cmos portc i/o ccp1 st cmos capture input/compare output p1a ? cmos pwm output v ss v ss power ? ground reference v dd v dd power ? positive supply legend: ttl = ttl input buffer, st = schmitt trigger input buffer, an = analog input
? 2004 microchip technology inc. preliminary ds41202c-page 7 pic16f684 2.0 memory organization 2.1 program memory organization the pic16f684 has a 13-bit program counter capable of addressing an 8k x 14 program memory space. only the first 2k x 14 (0000h-07ffh) for the pic16f684 is physically implemented. accessing a location above these boundaries will cause a wrap around within the first 2k x 14 space. the reset vector is at 0000h and the interrupt vector is at 0004h (see figure 2-1). figure 2-1: program memory map and stack for the pic16f684 2.2 data memory organization the data memory (see figure 2-2) is partitioned into two banks, which contain the general purpose regis- ters (gpr) and the special function registers (sfr). the special function registers are located in the first 32 locations of each bank. register locations 20h-7fh in bank 0 and a0h-bfh in bank 1 are general purpose registers, implemented as static ram. register locations f0h-ffh in bank 1 point to addresses 70h-7fh in bank 0. all other ram is unimplemented and returns ? 0 ? when read. rp0 (status<5>) is the bank select bit. rp0 = 0: bank 0 is selected rp0 = 1: bank 1 is selected pc<12:0> 13 000h 0004 0005 07ffh 0800h 1fffh stack level 1 stack level 8 reset vector interrupt vector on-chip program memory call, return retfie, retlw stack level 2 note: the irp and rp1 bits status<7:6> are reserved and should always be maintained as ? 0 ?s.
pic16f684 ds41202c-page 8 preliminary ? 2004 microchip technology inc. 2.2.1 general purpose register file the register file is organized as 128 x 8 in the pic16f684. each register is accessed, either directly or indirectly, through the file select register (fsr) (see section 2.4 ?indirect addressing, indf and fsr registers? ). 2.2.2 special function registers the special function registers are registers used by the cpu and peripheral functions for controlling the desired operation of the device (see table 2-1). these registers are static ram. the special registers can be classified into two sets: core and peripheral. the special function registers associated with the ?core? are described in this section. those related to the operation of the peripheral features are described in the section of that peripheral feature. figure 2-2: data memory map of the pic16f684 indirect addr. (1) tmr0 pcl status fsr porta pclath intcon pir1 tmr1l tmr1h t1con 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0ah 0bh 0ch 0dh 0eh 0fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1ah 1bh 1ch 1dh 1eh 1fh 20h 7fh bank 0 unimplemented data memory locations, read as ? 0 ?. note 1: not a physical register. cmcon0 vrcon general purpose registers 96 bytes eedat eeadr eecon2 (1) file address file address wpua ioca indirect addr. (1) option_reg pcl status fsr trisa pclath intcon pie1 pcon 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8ah 8bh 8ch 8dh 8eh 8fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9ah 9bh 9ch 9dh 9eh 9fh a0h ffh bank 1 adresh adcon0 eecon1 adresl adcon1 ansel trisc portc bfh general purpose registers 32 bytes accesses 70h-7fh f0h tmr2 t2con ccpr1l ccpr1h ccp1con pwm1con eccpas wdtcon cmcon1 osccon osctune pr2
? 2004 microchip technology inc. preliminary ds41202c-page 9 pic16f684 table 2-1: pic16f684 special registers summary bank 0 addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod page bank 0 00h indf addressing this location uses contents of fsr to address data memory (not a physical register) xxxx xxxx 17, 99 01h tmr0 timer0 module?s register xxxx xxxx 45, 99 02h pcl program counter?s (pc) least significant byte 0000 0000 17, 99 03h status irp (1) rp1 (1) rp0 to pd z dc c 0001 1xxx 11, 99 04h fsr indirect data memory address pointer xxxx xxxx 17, 99 05h porta ? ? ra5 ra4 ra3 ra2 ra1 ra0 --xx xxxx 31, 99 06h ? unimplemented ? ? 07h portc ? ? rc5 rc4 rc3 rc2 rc1 rc0 --xx xxxx 40, 99 08h ? unimplemented ? ? 09h ? unimplemented ? ? 0ah pclath ? ? ? write buffer for upper 5 bits of program counter ---0 0000 17, 99 0bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 13, 99 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 15, 99 0dh ? unimplemented ? ? 0eh tmr1l holding register for the least significant byte of the 16-bit tmr1 xxxx xxxx 49, 99 0fh tmr1h holding register for the most significant byte of the 16-bit tmr1 xxxx xxxx 49, 99 10h t1con t1ginv tmr1ge t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 0000 0000 51, 99 11h tmr2 timer2 module register 0000 0000 53, 99 12h t2con ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 53, 99 13h ccpr1l capture/compare/pwm register 1 low byte xxxx xxxx 75, 99 14h ccpr1h capture/compare/pwm register 1 high byte xxxx xxxx 75, 99 15h ccp1con p1m1 p1m0 dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 0000 0000 75, 99 16h pwm1con prsen pdc6 pdc5 pdc4 pdc3 pdc2 pdc1 pdc0 0000 0000 85, 99 17h eccpas eccpase eccpas2 eccpas1 eccpas0 pssac1 pssac0 pssbd1 pssbd0 0000 0000 86, 99 18h wdtcon ? ? ? wdtps3 wdtps2 wdtps1 wdtps0 swdten ---0 1000 106, 99 19h cmcon0 c2out c1out c2inv c1inv cis cm2 cm1 cm0 0000 0000 55, 99 1ah cmcon1 ? ? ? ? ? ? t1gss c2sync ---- --10 59, 99 1bh ? unimplemented ? ? 1ch ? unimplemented ? ? 1dh ? unimplemented ? ? 1eh adresh most significant 8 bits of the left shift ed a/d result or 2 bits of right shifted result xxxx xxxx 65, 99 1fh adcon0 adfm vcfg ? chs2 chs1 chs0 go/done adon 00-0 0000 66, 99 legend: ? = unimplemented locations read as ? 0 ?, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented note 1: irp and rp1 bits are reserved, always maintain these bits clear.
pic16f684 ds41202c-page 10 preliminary ? 2004 microchip technology inc. table 2-2: pic16f684 special function registers summary bank 1 addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod page bank 1 80h indf addressing this location uses contents of fsr to address data memory (not a physical register) xxxx xxxx 17, 99 81h option_reg rapu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 12, 99 82h pcl program counter?s (pc) least significant byte 0000 0000 17, 99 83h status irp (1) rp1 (1) rp0 to pd z dc c 0001 1xxx 11, 99 84h fsr indirect data memory address pointer xxxx xxxx 17, 99 85h trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 --11 1111 32, 99 86h ? unimplemented ? ? 87h trisc ? ? trisc5 trisc4 trisc3 t risc2 trisc1 trisc0 --11 1111 43, 99 88h ? unimplemented ? ? 89h ? unimplemented ? ? 8ah pclath ? ? ? write buffer for upper 5 bits of program counter ---0 0000 17, 99 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 13, 99 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 14, 99 8dh ? unimplemented ? ? 8eh pcon ? ? ulpwue sboden ? ?por bod --01 --qq 16, 99 8fh osccon ? ircf2 ircf1 ircf0 osts (2) hts lts scs -110 x000 29, 99 90h osctune ? ? ? tun4 tun3 tun2 tun1 tun0 ---0 0000 23, 99 91h ansel ans7 ans6 ans5 ans4 ans3 ans2 ans1 ans0 1111 1111 65, 99 92h pr2 timer2 module period register 1111 1111 53, 99 93h ? unimplemented ? ? 94h ? unimplemented ? ? 95h wpua (3) ? ? wpua5 wpua4 ? wpua2 wpua1 wpua0 --11 -111 32, 100 96h ioca ? ? ioca5 ioca4 ioca3 ioca2 ioca1 ioca0 --00 0000 33, 100 97h ? unimplemented ? ? 98h ? unimplemented ? ? 99h vrcon vren ?vrr ? vr3 vr2 vr1 vr0 0-0- 0000 62, 100 9ah eedat eedat7 eedat6 eedat5 eedat4 eedat3 eedat2 eedat1 eedat0 0000 0000 71, 100 9bh eeadr eeadr7 eeadr6 eeadr5 eeadr4 eeadr3 eeadr2 eeadr1 eeadr0 0000 0000 71, 100 9ch eecon1 ? ? ? ? wrerr wren wr rd ---- x000 72, 100 9dh eecon2 eeprom control register 2 (not a physical register) ---- ---- 72, 100 9eh adresl least significant 2 bits of the left shifte d result or 8 bits of the right shifted result xxxx xxxx 65, 100 9fh adcon1 ? adcs2 adcs1 adcs0 ? ? ? ? -000 ---- 66, 100 legend: ? = unimplemented locations read as ? 0 ?, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented note 1: irp and rp1 bits are reserved, always maintain these bits clear. 2: osts bit osccon <3> reset to ? 0 ? with dual speed start-up and lp, hs or xt selected as the oscillator. 3: ra3 pull-up is enabled when mclre is ? 1 ? in the configuration word register.
? 2004 microchip technology inc. preliminary ds41202c-page 11 pic16f684 2.2.2.1 status register the status register, shown in register 2-1, contains: the arithmetic status of the alu the reset status the bank select bits for data memory (sram) the status register can be the destination for any instruction, like any other register. if the status register is the destination for an instruction that affects the z, dc or c bits, then the write to these three bits is dis- abled. these bits are set or cleared according to the device logic. furthermore, the to and pd bits are not writable. therefore, the result of an instruction with the status register as destination may be different than intended. for example, clrf status , will clear the upper three bits and set the z bit. this leaves the status register as ? 000u u1uu ? (where u = unchanged). it is recommended, therefore, that only bcf, bsf, swapf and movwf instructions are used to alter the status register, because these instructions do not affect any status bits. for other instructions not affecting any status bits, see the ?instruction set summary?. register 2-1: status ? status register (address: 03h or 83h) note 1: bits irp and rp1 (status<7:6>) are not used by the pic16f684 and should be maintained as clear. use of these bits is not recommended, since this may affect upward compatibility with future products. 2: the c and dc bits operate as a borrow and digit borrow out bit, respectively, in subtraction. see the sublw and subwf instructions for examples. reserved reserved r/w-0 r-1 r-1 r/w-x r/w-x r/w-x irp rp1 rp0 to pd z dc c bit 7 bit 0 bit 7 irp: this bit is reserved and should be maintained as ? 0 ? bit 6 rp1: this bit is reserved and should be maintained as ? 0 ? bit 5 rp0: register bank select bit (used for direct addressing) 1 = bank 1 (80h ? ffh) 0 = bank 0 (00h ? 7fh) bit 4 to : time-out bit 1 = after power-up, clrwdt instruction or sleep instruction 0 = a wdt time-out occurred bit 3 pd: power-down bit 1 = after power-up or by the clrwdt instruction 0 = by execution of the sleep instruction 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 ( addwf , addlw,sublw,subwf instructions) for borrow, the polarity is reversed. 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 ( addwf , addlw, sublw, 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 two?s complement of the second operand. for rotate ( rrf , rlf ) instructions, this bit is loaded with either the high-order or low-order bit of the source register. 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
pic16f684 ds41202c-page 12 preliminary ? 2004 microchip technology inc. 2.2.2.2 option register the option register is a readable and writable register, which contains various control bits to configure: tmr0/wdt prescaler external ra2/int interrupt tmr0 weak pull-ups on porta register 2-2: option_reg ? option register (address: 81h) note: to achieve a 1:1 prescaler assignment for tmr0, assign the prescaler to the wdt by setting psa bit to ? 1 ? (option_reg<3>). see section 5.4 ?prescaler? . r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 rapu intedg t0cs t0se psa ps2 ps1 ps0 bit 7 bit 0 bit 7 rapu : porta pull-up enable bit 1 = porta pull-ups are disabled 0 = porta pull-ups are enabled by individual port latch values bit 6 intedg: interrupt edge select bit 1 = interrupt on rising edge of ra2/int pin 0 = interrupt on falling edge of ra2/int pin bit 5 t0cs: tmr0 clock source select bit 1 = transition on ra2/t0cki pin 0 = internal instruction cycle clock (clkout) bit 4 t0se: tmr0 source edge select bit 1 = increment on high-to-low transition on ra2/t0cki pin 0 = increment on low-to-high transition on ra2/t0cki pin bit 3 psa: prescaler assignment bit 1 = prescaler is assigned to the wdt 0 = prescaler is assigned to the timer0 module bit 2-0 ps<2:0>: prescaler rate select bits 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 000 001 010 011 100 101 110 111 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 1 : 1 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 bit value tmr0 rate wdt rate
? 2004 microchip technology inc. preliminary ds41202c-page 13 pic16f684 2.2.2.3 intcon register the intcon register is a readable and writable register, which contains the various enable and flag bits for tmr0 register overflow, porta change and external ra2/int pin interrupts. register 2-3: intcon ? interrupt control register (address: 0bh or 8bh) note: interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit, gie (intcon<7>). user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 gie peie t0ie inte raie t0if intf raif bit 7 bit 0 bit 7 gie: global interrupt enable bit 1 = enables all unmasked interrupts 0 = disables all interrupts bit 6 peie: peripheral interrupt enable bit 1 = enables all unmasked peripheral interrupts 0 = disables all peripheral interrupts bit 5 t0ie: tmr0 overflow interrupt enable bit 1 = enables the tmr0 interrupt 0 = disables the tmr0 interrupt bit 4 inte: ra2/int external interrupt enable bit 1 = enables the ra2/int external interrupt 0 = disables the ra2/int external interrupt bit 3 raie: porta change interrupt enable bit (1) 1 = enables the porta change interrupt 0 = disables the porta change interrupt bit 2 t0if: tmr0 overflow interrupt flag bit (2) 1 = tmr0 register has overflowed (must be cleared in software) 0 = tmr0 register did not overflow bit 1 intf: ra2/int external interrupt flag bit 1 = the ra2/int external interrupt occurred (must be cleared in software) 0 = the ra2/int external interrupt did not occur bit 0 raif: porta change interrupt flag bit 1 = when at least one of the porta <5:0> pins changed state (must be cleared in software) 0 = none of the porta <5:0> pins have changed state note 1: ioca register must also be enabled. 2: t0if bit is set when timer0 rolls over. timer0 is unchanged on reset and should be initialized before clearing t0if bit. 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
pic16f684 ds41202c-page 14 preliminary ? 2004 microchip technology inc. 2.2.2.4 pie1 register the pie1 register contains the interrupt enable bits, as shown in register 2-4. register 2-4: pie1 ? peripheral interrupt enable register 1 (address: 8ch) note: bit peie (intcon<6>) must be set to enable any peripheral interrupt. r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie bit 7 bit 0 bit 7 eeie: ee write complete interrupt enable bit 1 = enables the ee write complete interrupt 0 = disables the ee write complete interrupt bit 6 adie: a/d converter interrupt enable bit 1 = enables the a/d converter interrupt 0 = disables the a/d converter interrupt bit 5 ccp1ie: ccp1 interrupt enable bit 1 = enables the ccp1 interrupt 0 = disables the ccp1 interrupt bit 4 c2ie: comparator 2 interrupt enable bit 1 = enables the comparator 2 interrupt 0 = disables the comparator 2 interrupt bit 3 c1ie: comparator 1 interrupt enable bit 1 = enables the comparator 1 interrupt 0 = disables the comparator 1 interrupt bit 2 osfie: oscillator fail interrupt enable bit 1 = enables the oscillator fail interrupt 0 = disables the oscillator fail interrupt bit 1 tmr2ie: timer2 to pr2 match interrupt enable bit 1 = enables the timer2 to pr2 match interrupt 0 = disables the timer2 to pr2 match interrupt bit 0 tmr1ie: timer1 overflow interrupt enable bit 1 = enables the timer1 overflow interrupt 0 = disables the timer1 overflow interrupt 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
? 2004 microchip technology inc. preliminary ds41202c-page 15 pic16f684 2.2.2.5 pir1 register the pir1 register contains the interrupt flag bits, as shown in register 2-5. register 2-5: pir1 ? peripheral interrupt request register 1 (address: 0ch) note: interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit, gie (intcon<7>). user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if bit 7 bit 0 bit 7 eeif: eeprom write operation interrupt flag bit 1 = the write operation completed (must be cleared in software) 0 = the write operation has not completed or has not been started bit 6 adif: a/d interrupt flag bit 1 = a/d conversion complete 0 = a/d conversion has not completed or has not been started bit 5 ccp1if: ccp1 interrupt flag bit capture mod e: 1 = a tmr1 register capture occurred (must be cleared in software) 0 = no tmr1 register capture occurred compare mode : 1 = a tmr1 register compare match occurred (must be cleared in software) 0 = no tmr1 register compare match occurred pwm mode : unused in this mode bit 4 c2if: comparator 2 interrupt flag bit 1 = comparator 2 output has changed (must be cleared in software) 0 = comparator 2 output has not changed bit 3 c1if: comparator 1 interrupt flag bit 1 = comparator 1 output has changed (must be cleared in software) 0 = comparator 1 output has not changed bit 2 osfif: oscillator fail interrupt flag bit 1 = system oscillator failed, clock input has changed to intosc (must be cleared in software) 0 = system clock operating bit 1 tmr2if: timer2 to pr2 match interrupt flag bit 1 = timer2 to pr2 match occurred (must be cleared in software) 0 = timer2 to pr2 match has not occurred bit 0 tmr1if: timer1 overflow interrupt flag bit 1 = timer1 register overflowed (must be cleared in software) 0 = timer1 has not overflowed 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
pic16f684 ds41202c-page 16 preliminary ? 2004 microchip technology inc. 2.2.2.6 pcon register the power control (pcon) register (see table 12-2) contains flag bits to differentiate between a: power-on reset (por ) brown-out detect (bod ) watchdog timer reset (wdt) external mclr reset the pcon register also controls the ultra low-power wake-up and software enable of the bod . the pcon register bits are shown in register 2-6. register 2-6: pcon ? power control register (address: 8eh) u-0 u-0 r/w-0 r/w-1 u-0 u-0 r/w-0 r/w-x ? ? ulpwue sboden ? ?por bod bit 7 bit 0 bit 7-6 unimplemented: read as ? 0 ? bit 5 ulpwue: ultra low-power wake-up enable bit 1 = ultra low-power wake-up enabled 0 = ultra low-power wake-up disabled bit 4 sboden: software bod enable bit (1) 1 = bod enabled 0 = bod disabled bit 3-2 unimplemented: read as ? 0 ? bit 1 por : power-on reset status bit 1 = no power-on reset occurred 0 = a power-on reset occurred (must be set in software after a power-on reset occurs) bit 0 bod : brown-out detect status bit 1 = no brown-out detect occurred 0 = a brown-out detect occurred (must be set in software after a brown-out detect occurs) note 1: boden<1:0> = 01 in the configuration word register for this bit to control the bod . 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
? 2004 microchip technology inc. preliminary ds41202c-page 17 pic16f684 2.3 pcl and pclath the program counter (pc) is 13 bits wide. the low byte comes from the pcl register, which is a readable and writable register. the high byte (pc<12:8>) is not directly readable or writable and comes from pclath. on any reset, the pc is cleared. figure 2-3 shows the two situations for the loading of the pc. the upper example in figure 2-3 shows how the pc is loaded on a write to pcl (pclath<4:0> pch). the lower exam- ple in figure 2-3 shows how the pc is loaded during a call or goto instruction (pclath<4:3> pch). figure 2-3: loading of pc in different situations 2.3.1 computed goto a computed goto is accomplished by adding an offset to the program counter ( addwf pcl ). when perform- ing a table read using a computed goto method, care should be exercised if the table location crosses a pcl memory boundary (each 256-byte block). refer to the application note an556, ?implementing a table read? (ds00556). 2.3.2 stack the pic16f684 family has an 8-level x 13-bit wide hardware stack (see figure 2-1). the stack space is not part of either program or data space and the stack pointer is not readable or writable. the pc is pushed onto the stack when a call instruction is executed or an interrupt causes a branch. the stack is poped in the event of a return, retlw or a retfie instruction execution. pclath is not affected by a push or pop operation. the stack operates as a circular buffer. this means that after the stack has been pushed eight times, the ninth push overwrites the value that was stored from the first push. the tenth push overwrites the second push (and so on). 2.4 indirect addressing, indf and fsr registers the indf register is not a physical register. addressing the indf register will cause indirect addressing. indirect addressing is possible by using the indf register. any instruction using the indf register actually accesses data pointed to by the file select register (fsr). reading indf itself indirectly will produce 00h. writing to the indf register indirectly results in a no operation (although status bits may be affected). an effective 9-bit address is obtained by concatenating the 8-bit fsr and the irp bit (status<7>), as shown in figure 2-4. a simple program to clear ram location 20h-2fh using indirect addressing is shown in example 2-1. example 2-1: indirect addressing pc 12 8 7 0 5 pclath<4:0> pclath instruction wit h alu result goto, call opcode <10:0 > 8 pc 12 11 10 0 11 pclath<4:3> pch pcl 87 2 pclath pch pcl pcl a s destinatio n note 1: there are no status bits to indicate stack overflow or stack underflow conditions. 2: there are no instructions/mnemonics called push or pop. these are actions that occur from the execution of the call, return, retlw and retfie instructions or the vectoring to an interrupt address. movlw0x20;initialize pointer movwffsr ;to ram next clrfindf ;clear indf register incffsr ;inc pointer btfssfsr,4;all done? gotonext ;no clear next continue ;yes continue
pic16f684 ds41202c-page 18 preliminary ? 2004 microchip technology inc. figure 2-4: direct/indirect addressing pic16f684 for memory map detail, see figure 2-2. note 1: the rp1 and irp bits are reserved; always maintain these bits clear. data memory indirect addressing direct addressing bank select location select rp1 (1) rp0 6 0 from opcode irp (1) file select register 7 0 bank select location select 00 01 10 11 180h 1ffh 00h 7fh bank 0 bank 1 bank 2 bank 3 not used
? 2004 microchip technology inc. preliminary ds41202c-page 19 pic16f684 3.0 clock sources 3.1 overview the pic16f684 has a wide variety of clock sources and selection features to allow it to be used in a wide range of applications while maximizing performance and minimizing power consumption. figure 3-1 illustrates a block diagram of the pic16f684 clock sources. clock sources can be configured from external oscillators, quartz crystal resonators, ceramic resonators and resistor-capacitor (rc) circuits. in addition, the system clock source can be configured from one of two internal oscillators, with a choice of speeds selectable via software. additional clock features include: selectable system clock source between external or internal via software. two-speed clock start-up mode, which mini- mizes latency between external oscillator start-up and code execution. fail-safe clock monitor (fscm) designed to detect a failure of the external clock source (lp, xt, hs, ec or rc modes) and switch to the internal oscillator. the pic16f684 can be configured in one of eight clock modes. 1. ec ? external clock with i/o on ra4. 2. lp ? low gain crystal or ceramic resonator oscillator mode. 3. xt ? medium gain crystal or ceramic resona- tor oscillator mode. 4. hs ? high gain crystal or ceramic resonator mode. 5. rc ? external resistor-capacitor (rc) with f osc /4 output on ra4. 6. rcio ? external resistor-capacitor with i/o on ra4. 7. intrc ? internal oscillator with f osc /4 output on ra4 and i/o on ra5. 8. intrcio ? internal oscillator with i/o on ra4 and ra5. clock source modes are configured by the fosc<2:0> bits in the configuration word register (see section 12.0 ?special features of the cpu? ). the internal clock can be generated by two oscillators. the hfintosc is a high-frequency calibrated oscillator. the lfintosc is a low-frequency uncalibrated oscillator. figure 3-1: pic16f684 cl ock source block diagram (cpu and peripherals) osc1 osc2 sleep external oscillator lp, xt, hs, rc, rcio, ec system clock postscaler mux mux 8 mhz 4 mhz 2 mhz 1 mhz 500 khz 125 khz 250 khz ircf<2:0> 111 110 101 100 011 010 001 000 31 khz power-up timer (pwrt) fosc<2:0> (configuration word) scs (osccon<0>) internal oscillator (osccon<6:4>) watchdog timer (wdt) fail-safe clock monitor (fscm) hfintosc 8 mhz lfintosc 31 khz
pic16f684 ds41202c-page 20 preliminary ? 2004 microchip technology inc. 3.2 clock source modes clock source modes can be classified as external or internal. external clock modes rely on external circuitry for the clock source. examples are oscillator modules (ec mode), quartz crystal resonators or ceramic resonators (lp, xt and hs modes), and resistor-capacitor (rc mode) circuits. internal clock sources are contained internally within the pic16f684. the pic16f684 has two internal oscillators, the 8 mhz high-frequency internal oscillator (hfintosc) and 31 khz low-frequency internal oscillator (lfintosc). the system clock can be selected between external or internal clock sources via the system clock selection (scs) bit (see section 3.5 ?clock switching? ). 3.3 external clock modes 3.3.1 oscillator start-up timer (ost) if the pic16f684 is configured for lp, xt or hs modes, the oscillator start-up timer (ost) counts 1024 oscil- lations from the osc1 pin, following a power-on reset (por) and the power-up timer (pwrt) has expired (if configured), or a wake-up from sleep. during this time, the program counter does not increment and program execution is suspended. the ost ensures that the oscillator circuit, using a quartz crystal resonator or ceramic resonator, has started and is providing a stable system clock to the pic16f684. when switching between clock sources a delay is required to allow the new clock to stabilize. these oscillator delays are shown in table 3-1. in order to minimize latency between external oscillator start-up and code execution, the two-speed clock start-up mode can be selected (see section 3.6 ?two-speed clock start-up mode? ). table 3-1: oscillator delay examples 3.3.2 ec mode the external clock (ec) mode allows an externally generated logic level as the system clock source. when operating in this mode, an external clock source is connected to the osc1 pin and the ra5 pin is available for general purpose i/o. figure 3-2 shows the pin connections for ec mode. the oscillator start-up timer (ost) is disabled when ec mode is selected. therefore, there is no delay in operation after a power-on reset (por) or wake-up from sleep. because the pic16f684 design is fully static, stopping the external clock input will have the effect of halting the device while leaving all data intact. upon restarting the external clock, the device will resume operation as if no time had elapsed. figure 3-2: external clock (ec) mode operation switch from switch to frequency oscillator delay sleep/por lfintosc hfintosc 31 khz 125 khz to 8 mhz 5 s-10 s (approx.) cpu start-up (1) sleep/por ec, rc dc ? 20 mhz lfintosc (31 khz) ec, rc dc ? 20 mhz sleep/por lp, xt, hs 31 khz to 20 mhz 1024 clock cycles (ost) lfintosc (31 khz) hfintosc 125 khz to 8 mhz 1 s (approx.) note 1: the 5 s to 10 s start-up delay is based on a 1 mhz system clock. osc1/clkin i/o (osc2) ra4 clock from ext. system pic16f684
? 2004 microchip technology inc. preliminary ds41202c-page 21 pic16f684 3.3.3 lp, xt, hs modes the lp, xt and hs modes support the use of quartz crystal resonators or ceramic resonators connected to the osc1 and osc2 pins (figure 3-1). the mode selects a low, medium or high gain setting of the internal inverter-amplifier to support various resonator types and speed. lp oscillator mode selects the lowest gain setting of the internal inverter-amplifier. lp mode current con- sumption is the least of the three modes. this mode is best suited to drive resonators with a low drive level specification, for example, tuning fork type crystals. xt oscillator mode selects the intermediate gain setting of the internal inverter-amplifier. xt mode current consumption is the medium of the three modes. this mode is best suited to drive resonators with a medium drive level specification, for example, low-frequency/at-cut quartz crystal resonators. hs oscillator mode selects the highest gain setting of the internal inverter-amplifier. hs mode current consumption is the highest of the three modes. this mode is best suited for resonators that require a high drive setting, for example, high-frequency/at-cut quartz crystal resonators or ceramic resonators. figure 3-3 and figure 3-4 show typical circuits for quartz crystal and ceramic resonators, respectively. figure 3-3: quartz crystal operation (lp, xt or hs mode) figure 3-4: ceramic resonator operation (xt or hs mode) note 1: quartz crystal characteristics vary according to type, package and manufac- turer. the user should consult the manu- facturer data sheets for specifications and recommended application. 2: always verify oscillator performance over the v dd and temperature range that is expected for the application. note 1: a series resistor (r s ) may be required for quartz crystals with low drive level. 2: the value of r f varies with the oscillator mode selected (typically between 2 m ? to 10 m ?) . c1 c2 quartz osc2 r s (1) osc1 r f (2) sleep to internal logic pic16f684 crystal note 1: a series resistor (r s ) may be required fo r ceramic resonators with low drive level. 2: the value of r f varies with the oscillato r mode selected (typically between 2 m ? to 10 m ?) . 3: an additional parallel feedback resistor (r p ) may be required for proper ceramic resonato r operation (typical value 1 m ? ). c1 c2 ceramic osc2 r s (1) osc1 r f (2) sleep to internal logic pic16f684 r p (3) resonator
pic16f684 ds41202c-page 22 preliminary ? 2004 microchip technology inc. 3.3.4 external rc modes the external resistor-capacitor (rc) modes support the use of an external rc circuit. this allows the designer maximum flexibility in frequency choice while keeping costs to a minimum when clock accuracy is not required. there are two modes, rc and rcio. in rc mode, the rc circuit connects to the osc1 pin. the osc2/clkout pin outputs the rc oscillator frequency divided by 4. this signal may be used to provide a clock for external circuitry, synchronization, calibration, test or other application requirements. figure 3-5 shows the rc mode connections. figure 3-5: rc mode in rcio mode, the rc circuit is connected to the osc1 pin. the osc2 pin becomes an additional general purpose i/o pin. the i/o pin becomes bit 4 of porta (ra4). figure 3-6 shows the rcio mode connections. figure 3-6: rcio mode the rc oscillator frequency is a function of the supply voltage, the resistor (r ext ) and capacitor (c ext ) values and the operating temperature. other factors affecting the oscillator frequency are: threshold voltage variation component tolerances packaging variations in capacitance the user also needs to take into account variation due to tolerance of external rc components used. 3.4 internal clock modes the pic16f684 has two independent, internal oscillators that can be configured or selected as the system clock source. 1. the hfintosc (high-frequency internal oscillator) is factory calibrated and operates at 8 mhz. the frequency of the hfintosc can be user adjusted 12% via software using the osctune register (register 3-1). 2. the lfintosc (low-frequency internal oscillator) is uncalibrated and operates at approximately 31 khz. the system clock speed can be selected via software using the internal oscillator frequency select (ircf) bits. the system clock can be selected between external or internal clock sources via the system clock selection (scs) bit (see section 3.5 ?clock switching? ). 3.4.1 intrc and intrcio modes the intrc and intrcio modes configure the internal oscillators as the system clock source when the device is programmed using the oscillator selection (fosc) bits in the configuration word register (register 12-1). in intrc mode, the osc1 pin is available for general purpose i/o. the osc2/clkout pin outputs the selected internal oscillator frequency divided by 4. the clkout signal may be used to provide a clock for external circuitry, synchronization, calibration, test or other application requirements. in intrcio mode, the osc1 and osc2 pins are available for general purpose i/o. 3.4.2 hfintosc the high-frequency internal oscillator (hfintosc) is a factory calibrated 8 mhz internal clock source. the frequency of the hfintosc can be altered approximately 12% via software using the osctune register (register 3-1). the output of the hfintosc connects to a postscaler and multiplexer (see figure 3-1). one of seven frequencies can be selected via software using the ircf bits (see section 3.4.4 ?frequency select bits (ircf)? ). the hfintosc is enabled by selecting any frequency between 8 mhz and 125 khz (ircf 000 ) as the system clock source (scs = 1 ), or when two-speed start-up is enabled (ieso = 1 and ircf 000 ). the hf internal oscillator (hts) bit (osccon<2>) indicates whether the hfintosc is stable or not. osc2/clkout c ext r ext pic16f684 osc1 f osc /4 internal clock v dd v ss recommended values: 3 k ? r ext 100 k ? c ext > 20 pf c ext r ext pic16f684 osc1 internal clock v dd v ss recommended values: 3 k ? r ext 100 k ? c ext > 20 pf i/o (osc2) ra4
? 2004 microchip technology inc. preliminary ds41202c-page 23 pic16f684 3.4.2.1 osctune register the hfintosc is factory calibrated but can be adjusted in software by writing to the osctune register (register 3-1). the osctune register has a tuning range of 12%. the default value of the osctune register is ? 0 ?. the value is a 5-bit two?s complement number. due to process variation, the monotonicity and frequency step cannot be specified. when the osctune register is modified, the hfintosc frequency will begin shifting to the new frequency. the hfintosc clock will stabilize within 1 ms. code execution continues during this shift. there is no indication that the shift has occurred. osctune does not affect the lfintosc frequency. operation of features that depend on the lfintosc clock source frequency, such as the power-up timer (pwrt), watchdog timer (wdt), fail-safe clock monitor (fscm) and peripherals, are not affected by the change in frequency. register 3-1: osctune ? oscillator tuning resistor (address: 90h) u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? ? tun4 tun3 tun2 tun1 tun0 bit 7 bit 0 bit 7-5 unimplemented: read as ? 0 ? bit 4-0 tun<4:0>: frequency tuning bits 01111 = maximum frequency 01110 = 00001 = 00000 = oscillator module is running at the calibrated frequency. 11111 = 10000 = minimum frequency 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
pic16f684 ds41202c-page 24 preliminary ? 2004 microchip technology inc. 3.4.3 lfintosc the low-frequency internal oscillator (lfintosc) is an uncalibrated (approximate) 31 khz internal clock source. the output of the lfintosc connects to a postscaler and multiplexer (see figure 3-1). 31 khz can be selected via software using the ircf bits (see section 3.4.4 ?frequency select bits (ircf)? ). the lfintosc is also the frequency for the power-up timer (pwrt), watchdog timer (wdt) and fail-safe clock monitor (fscm). the lfintosc is enabled by selecting 31 khz (ircf = 000 ) as the system clock source (scs = 1 ), or when any of the following are enabled: two-speed start-up (ieso = 1 and ircf = 000 ) power-up timer (pwrt) watchdog timer (wdt) fail-safe clock monitor (fscm) the lf internal oscillator (lts) bit (osccon<1>) indicates whether the lfintosc is stable or not. 3.4.4 frequency select bits (ircf) the output of the 8 mhz hfintosc and 31 khz lfintosc connects to a postscaler and multiplexer (see figure 3-1). the internal oscillator frequency select bits, ircf<2:0> (osccon<6:4>), select the frequency output of the internal oscillators. one of eight frequencies can be selected via software: 8 mhz 4 mhz (default after reset) 2 mhz 1 mhz 500 khz 250 khz 125 khz 31 khz 3.4.5 hf and lf intosc clock switch timing when switching between the lfintosc and the hfintosc, the new oscillator may already be shut down to save power. if this is the case, there is a 10 s delay after the ircf bits are modified before the frequency selection takes place. the lts/hts bits will reflect the current active status of the lfintosc and the hfintosc oscillators. the timing of a frequency selection is as follows: 1. ircf bits are modified. 2. if the new clock is shut down, a 10 s clock start-up delay is started. 3. clock switch circuitry waits for a falling edge of the current clock. 4. clkout is held low and the clock switch circuitry waits for a rising edge in the new clock. 5. clkout is now connected with the new clock. hts/lts bits are updated as required. 6. clock switch is complete. if the internal oscillator speed selected is between 8 mhz and 125 khz, there is no start-up delay before the new frequency is selected. this is because the old and the new frequencies are derived from the hfintosc via the postscaler and multiplexer. note: following any reset, the ircf bits are set to ? 110 ? and the frequency selection is set to 4 mhz. the user can modify the ircf bits to select a different frequency.
? 2004 microchip technology inc. preliminary ds41202c-page 25 pic16f684 3.5 clock switching the system clock source can be switched between external and internal clock sources via software using the system clock select (scs) bit. 3.5.1 system clock select (scs) bit the system clock select (scs) bit (osccon<0>) selects the system clock source that is used for the cpu and peripherals. when scs = 0 , the system clock source is determined by configuration of the fosc<2:0> bits in the configuration word register (config). when scs = 1 , the system clock source is chosen by the internal oscillator frequency selected by the ircf bits. after a reset, scs is always cleared. 3.5.2 oscillator start-up time-out status bit the oscillator start-up time-out status (osts) bit (osccon<3>) indicates whether the system clock is running from the external clock source, as defined by the fosc bits, or from internal clock source. in particular, osts indicates that the oscillator start-up timer (ost) has timed out for lp, xt or hs modes. 3.6 two-speed clock start-up mode two-speed start-up mode provides additional power savings by minimizing the latency between external oscillator start-up and code execution. in applications that make heavy use of the sleep mode, two-speed start-up will remove the external oscillator start-up time from the time spent awake and can reduce the overall power consumption of the device. this mode allows the application to wake-up from sleep, perform a few instructions using the intosc as the clock source and go back to sleep without waiting for the primary oscillator to become stable. when the pic16f684 is configured for lp, xt or hs modes, the oscillator start-up timer (ost) is enabled (see section 3.3.1 ?oscillator start-up timer (ost)? ). the ost timer will suspend program execu- tion until 1024 oscillations are counted. two-speed start-up mode minimizes the delay in code execution by operating from the internal oscillator as the ost is counting. when the ost count reaches 1024 and the osts bit (osccon<3>) is set, program execution switches to the external oscillator. 3.6.1 two-speed start-up mode configuration two-speed start-up mode is configured by the following settings: ieso = 1 (config<10>) internal/external switch over bit. scs = 0 . fosc configured for lp, xt or hs mode. two-speed start-up mode is entered after: power-on reset (por) and, if enabled, after pwrt has expired, or wake-up from sleep. if the external clock oscillator is configured to be any- thing other than lp, xt or hs mode, then two-speed start-up is disabled. this is because the external clock oscillator does not require any stabilization time after por or an exit from sleep. 3.6.2 two-speed start-up sequence 1. wake-up from power-on reset or sleep. 2. instructions begin execution by the internal oscillator at the frequency set in the ircf bits (osccon<6:4>). 3. ost enabled to count 1024 clock cycles. 4. ost timed out, wait for falling edge of the internal oscillator. 5. osts is set. 6. system clock held low until the next falling edge of new clock (lp, xt or hs mode). 7. system clock is switched to external clock source. note: any automatic clock switch, which may occur from two-speed start-up or fail-safe clock monitor, does not update the scs bit. the user can monitor the osts (osccon<3>) to determine the current system clock source. note: executing a sleep instruction will abort the oscillator start-up time and will cause the osts bit (osccon<3>) to remain clear.
pic16f684 ds41202c-page 26 preliminary ? 2004 microchip technology inc. 3.6.3 checking external/internal clock status checking the state of the osts bit (osccon<3>) will confirm if the pic16f684 is running from the external clock source as defined by the fosc bits in the configuration word register (config) or the internal oscillator. figure 3-7: two-speed start-up q1 q2 q3 q4 q1 q2 q3 q4 q1 0 1 1022 1023 pc pc + 1 pc + 2 t ost t intosc osc1 osc2 program counter system clock
? 2004 microchip technology inc. preliminary ds41202c-page 27 pic16f684 3.7 fail-safe clock monitor the fail-safe clock monitor (fscm) is designed to allow the device to continue to operate in the event of an oscillator failure. the fscm can detect oscillator failure at any point after the device has exited a reset or sleep condition and the oscillator start-up timer (ost) has expired. figure 3-8: fscm block diagram the fscm function is enabled by setting the fcmen bit in the configuration word register (config). it is applicable to all external clock options (lp, xt, hs, ec, rc or io modes). in the event of an external clock failure, the fscm will set the osfif bit (pir1<2>) and generate an oscillator fail interrupt if the osfie bit (pie1<2>) is set. the device will then switch the system clock to the internal oscillator. the system clock will continue to come from the internal oscillator unless the external clock recovers and the fail-safe condition is exited. the frequency of the internal oscillator will depend upon the value contained in the ircf bits (osccon<6:4>). upon entering the fail-safe condition, the osts bit (osccon<3>) is automati- cally cleared to reflect that the internal oscillator is active and the wdt is cleared. the scs bit (osccon<0>) is not updated. enabling fscm does not affect the lts bit. the fscm sample clock is generated by dividing the intrc clock by 64. this will allow enough time between fscm sample clocks for a system clock edge to occur. figure 3-8 shows the fscm block diagram. on the rising edge of the sample clock, the monitoring latch (cm = 0 ) will be cleared. on a falling edge of the primary system clock, the monitoring latch will be set (cm = 1 ). in the event that a falling edge of the sample clock occurs, and the monitoring latch is not set, a clock failure has been detected. the assigned internal oscillator is enabled when fscm is enabled, as reflected by the ircf. 3.7.1 fail-safe condition clearing the fail-safe condition is cleared after a reset, the execution of a sleep instruction, or a modification of the scs bit. while in fail-safe condition, the pic16f684 uses the internal oscillator as the system clock source. the ircf bits (osccon<6:4>) can be modified to adjust the internal oscillator frequency without exiting the fail-safe condition. the fail-safe condition must be cleared before the osfif flag can be cleared. primary lfintosc 64 s c q 31 khz (~32 s) 488 hz (~2 ms) clock monitor latch (cm) (edge-triggered) clock failure detected oscillator clock q note: two-speed start-up is automatically enabled when the fail-safe clock monitor mode is enabled. note: primary clocks with a frequency ~488 hz will be considered failed by the fscm. a slow starting oscillator can cause an fscm interrupt.
pic16f684 ds41202c-page 28 preliminary ? 2004 microchip technology inc. figure 3-9: fscm timing diagram 3.7.2 reset or wake-up from sleep the fscm is designed to detect oscillator failure at any point after the device has exited a reset or sleep condition and the oscillator start-up timer (ost) has expired. if the external clock is ec or rc mode, monitoring will begin immediately following these events. for lp, xt or hs mode, the external oscillator may require a start-up time considerably longer than the fscm sample clock time, a false clock failure may be detected (see figure 3-9). to prevent this, the internal oscillator is automatically configured as the system clock and functions until the external clock is stable (the ost has timed out). this is identical to two-speed start-up mode. once the external oscilla- tor is stable, the lfintosc returns to its role as the fscm source. oscfif cm output system clock output sample clock failure detected oscillator failure note: the system clock is normally at a much higher frequency than the sample clock. the relative frequencies in this example have been chosen for clarity. (q ) cm test cm test cm test note: due to the wide range of oscillator start-up times, the fail-safe circuit is not active during oscillator start-up (i.e., after exiting reset or sleep). after an appropriate amount of time, the user should check the osts bit (osccon<3>) to verify the oscillator start-up and system clock switchover has successfully completed.
? 2004 microchip technology inc. preliminary ds41202c-page 29 pic16f684 register 3-2: osccon ? oscillator control register (address: 8fh) table 3-2: summary of registers associated with clock sources u-0 r/w-1 r/w-1 r/w-0 r-1 r-0 r-0 r/w-0 ? ircf2 ircf1 ircf0 osts (1) hts lts scs bit 7 bit 0 bit 7 unimplemented: read as ? 0 ? bit 6-4 ircf<2:0>: internal oscillator frequency select bits 000 =31khz 001 =125khz 010 =250khz 011 =500khz 100 =1mhz 101 =2mhz 110 =4mhz 111 =8mhz bit 3 osts: oscillator start-up time-out status bit 1 = device is running from the external system clock defined by fosc<2:0> 0 = device is running from the internal system clock (hfintosc or lfintosc) bit 2 hts: hfintosc (high frequency ? 8 mhz to 125 khz) status bit 1 =hfintosc is stable 0 = hfintosc is not stable bit 1 lts: lfintosc (low frequency ? 31 khz) stable bit 1 = lfintosc is stable 0 = lfintosc is not stable bit 0 scs: system clock select bit 1 = internal oscillator is used for system clock 0 = clock source defined by fosc<2:0> note 1: bit resets to ? 0 ? with two-speed start-up and lp, xt or hs selected as the oscillator mode or fail-safe mode is enabled. 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 address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on: por, bod value on all other resets 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 8fh osccon ? ircf2 ircf1 ircf0 osts hts lts scs -110 x000 -110 x000 90h osctune ? ? ? tun4 tun3 tun2 tun1 tun0 ---0 0000 ---u uuuu 2007h (1) config cpd cp mclre pwrte wdte fosc2 fosc1 fosc0 ? ? legend: x = unknown, u = unchanged, ? = unimplemented locations read as ? 0 ?. shaded cells are not used by oscillators. note 1: see register 12-1 for operation of all configuration word register bits.
pic16f684 ds41202c-page 30 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 31 pic16f684 4.0 i/o ports there are as many as twelve general purpose i/o pins available. depending on which peripherals are enabled, some or all of the pins may not be available as general purpose i/o. in general, when a peripheral is enabled, the associated pin may not be used as a general purpose i/o pin. 4.1 porta and the trisa registers porta is a 6-bit wide, bidirectional port. the corresponding data direction register is trisa (register 4-2). setting a trisa bit (= 1 ) will make the corresponding porta pin an input (i.e., put the corresponding output driver in a high-impedance mode). clearing a trisa bit (= 0 ) will make the corresponding porta pin an output (i.e., put the contents of the output latch on the selected pin). the exception is ra3, which is input only and its tris bit will always read as ? 1 ?. example 4-1 shows how to initialize porta. reading the porta register (register 4-1) reads the status of the pins, whereas writing to it will write to the port latch. all write operations are read-modify-write operations. therefore, a write to a port implies that the port pins are read, this value is modified and then written to the port data latch. ra3 reads ? 0 ? when mclre = 1 . 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. i/o pins configured as analog input always read ? 0 ?. example 4-1: initializing porta 4.2 additional pin functions every porta pin on the pic16f684 has an interrupt- on-change option and a weak pull-up option. ra0 has an ultra low-power wake-up option. the next three sections describe these functions. 4.2.1 weak pull-ups each of the porta pins, except ra3, has an individu- ally configurable internal weak pull-up. control bits wpuax enable or disable each pull-up. refer to register 4-3. each 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 by the rapu bit (option_reg<7>). a weak pull-up is auto- matically enabled for ra3 when configured as mclr and disabled when ra3 is an i/o. there is no software control of the mclr pull-up. register 4-1: porta ? porta register (address: 05h) note: additional information on i/o ports may be found in the ? picmicro ? mid-range mcu family reference manual? (ds33023). note: the ansel (91h) and cmcon0 (19h) registers must be initialized to configure an analog channel as a digital input. pins configured as analog inputs will read ? 0 ?. bcf status,rp0 ;bank 0 clrf porta ;init porta movlw 07h ;set ra<2:0> to movwf cmcon0 ;digital i/o bsf status,rp0 ;bank 1 clrf ansel ;digital i/o movlw 0ch ;set ra<3:2> as inputs movwf trisa ;and set ra<5:4,1:0> ;as outputs bcf status,rp0 ;bank 0 u-0 u-0 r/w-x r/w-x r/w-x r/w-x r/w-0 r/w-0 ? ? ra5 ra4 ra3 ra2 ra1 ra0 bit 7 bit 0 bit 7-6: unimplemented : read as ? 0 ? bit 5-0: ra<5:0> : porta i/o pin bit 1 = port pin is > v ih 0 = port pin is < v il 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
pic16f684 ds41202c-page 32 preliminary ? 2004 microchip technology inc. register 4-2: trisa ? porta tri-state register (address: 85h) register 4-3: wpua ? weak pull-up register (address: 95h) u-0 u-0 r/w-1 r/w-1 r-1 r/w-1 r/w-1 r/w-1 ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 bit 7 bit 0 bit 7-6: unimplemented: read as ? 0 ? bit 5-0: trisa<5:0>: porta tri-state control bit 1 = porta pin configured as an input (tri-stated) 0 = porta pin configured as an output note 1: trisa<3> always reads ? 1 ?. 2: trisa<5:4> always reads ? 1 ? in xt, hs and lp osc modes. 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 u-0 u-0 r/w-1 r/w-1 u-0 r/w-1 r/w-1 r/w-1 ? ? wpua5 wpua4 ? wpua2 wpua1 wpua0 bit 7 bit 0 bit 7-6 unimplemented: read as ? 0 ? bit 5-4 wpua<5:4>: weak pull-up register bit 1 = pull-up enabled 0 = pull-up disabled bit 3 unimplemented: read as ? 0 ? bit 2-0 wpua<2:0>: weak pull-up register bit 1 = pull-up enabled 0 = pull-up disabled note 1: global rapu must be enabled for individual pull-ups to be enabled. 2: the weak pull-up device is automatically disabled if the pin is in output mode (trisa = 0 ). 3: the ra3 pull-up is enabled when configured as mclr and disabled as an i/o in the configuration word. 4: wpua<5:4> always reads ? 1 ? in xt, hs and lp osc modes. 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
? 2004 microchip technology inc. preliminary ds41202c-page 33 pic16f684 4.2.2 interrupt-on-change each of the porta pins is individually configurable as an interrupt-on-change pin. control bits iocax enable or disable the interrupt function for each pin. refer to register 4-4. the interrupt-on-change is disabled on a power-on reset. for enabled interrupt-on-change pins, the values are compared with the old value latched on the last read of porta. the ?mismatch? outputs of the last read are or?d together to set the porta change interrupt flag bit (raif) in the intcon register (register 2-3). this interrupt can wake the device from sleep. the user, in the interrupt service routine, clears the interrupt by: a) any read or write of porta. this will end the mismatch condition, then, b) clear the flag bit raif. a mismatch condition will continue to set flag bit raif. reading porta will end the mismatch condition and allow flag bit raif to be cleared. the latch holding the last read value is not affected by a mclr nor bod reset. after these resets, the raif flag will continue to be set if a mismatch is present. register 4-4: ioca ? interrupt-on-change porta regi ster (address: 96h) note: if a change on the i/o pin should occur when the read operation is being executed (start of the q2 cycle), then the raif interrupt flag may not get set. u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? ioca5 ioca4 ioca3 ioca2 ioca1 ioca0 bit 7 bit 0 bit 7-6 unimplemented: read as ? 0 ? bit 5-0 ioca<5:0>: interrupt-on-change porta control bit 1 = interrupt-on-change enabled 0 = interrupt-on-change disabled note 1: global interrupt enable (gie) must be enabled for individual interrupts to be recognized. 2: ioca<5:4> always reads ? 1 ? in xt, hs and lp osc modes. 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
pic16f684 ds41202c-page 34 preliminary ? 2004 microchip technology inc. 4.2.3 ultra low-power wake-up the ultra low-power wake-up (ulpwu) on ra0 allows a slow falling voltage to generate an interrupt- on-change on ra0 without excess current consump- tion. the mode is selected by setting the ulpwue bit (pcon<5>). this enables a small current sink which can be used to discharge a capacitor on ra0. to use this feature, the ra0 pin is configured to output ? 1 ? to charge the capacitor, interrupt-on-change for ra0 is enabled, and ra0 is configured as an input. the ulpwue bit is set to begin the discharge and a sleep instruction is performed. when the voltage on ra0 drops below v il , an interrupt will be generated which will cause the device to wake-up. depending on the state of the gie bit (intcon<7>), the device will either jump to the interrupt vector (0004h) or execute the next instruction when the interrupt event occurs. see section 4.2.2 ?interrupt-on-change? and section 12.4.3 ?porta interrupt? for more information. this feature provides a low-power technique for periodically waking up the device from sleep. the time-out is dependent on the discharge time of the rc circuit on ra0. see example 4-2 for initializing the ultra low-power wake-up module. the series resistor provides overcurrent protection for the ra0 pin and can allow for software calibration of the time-out (see figure 4-1). a timer can be used to measure the charge time and discharge time of the capacitor. the charge time can then be adjusted to pro- vide the desired interrupt delay. this technique will compensate for the affects of temperature, voltage and component accuracy. the ultra low-power wake-up peripheral can also be configured as a simple programmable low voltage detect or temperature sensor. example 4-2: ultra low-power wake-up initialization note: for more information, refer to an879, ? using the microchip ultra low-power wake-up module ? application note (ds00879). bcf status,rp0 ;bank 0 bsf porta,0 ;set ra0 data latch movlw h?7? ;turn off movwf cmcon0 ;comparators bsf status,rp0 ;bank 1 bcf ansel,0 ;ra0 to digital i/o bcf trisa,0 ;output high to call capdelay ; charge capacitor bsf pcon,ulpwue ;enable ulp wake-up bsf ioca,0 ;select ra0 ioc bsf trisa,0 ;ra0 to input movlw b?10001000? ;enable interrupt movwf intcon ; and clear flag sleep ;wait for ioc
? 2004 microchip technology inc. preliminary ds41202c-page 35 pic16f684 figure 4-1: block diagram of rao i/o pin v dd v ss d q ck q d q ck q d q ck q d q ck q v dd d en q d en q weak rd porta rd wr wr rd wr ioca rd ioca interrupt-on- to comparator analog (1) input mode rapu analog (1) input mode change q3 wr rd 01 i ulp wpuda data bus wpuda porta trisa trisa porta note 1: comparator mode and ansel determines analog input mode. - +v t ulpwue to a/d converter v ss
pic16f684 ds41202c-page 36 preliminary ? 2004 microchip technology inc. 4.2.4 pin descriptions and diagrams each porta pin is multiplexed with other functions. the pins and their combined functions are briefly described here. for specific information about individ- ual functions such as the comparator or the a/d, refer to the appropriate section in this data sheet. 4.2.4.1 ra0/an0/c1in+/icspdat/ulpwu figure 4-2 shows the diagram for this pin. the ra0 pin is configurable to function as one of the following: a general purpose i/o an analog input for the a/d an analog input to the comparator in-circuit serial programming data an analog input for the ultra low-power wake-up 4.2.4.2 ra1/an1/c1in-/v ref /icspclk figure 4-2 shows the diagram for this pin. the ra1 pin is configurable to function as one of the following: a general purpose i/o an analog input for the a/d an analog input to the comparator a voltage reference input for the a/d in-circuit serial programming clock figure 4-2: block diagram of ra1 i/o pin v dd v ss d q ck q d q ck q d q ck q d q ck q v dd d en q d en q weak data bus wr wpua rd wpua rd porta rd porta wr porta wr trisa rd trisa wr ioca rd ioca interrupt-on- to comparator analog (1) input mode rapu analog (1) input mode change q3 note 1: comparator mode and ansel determines analog input mode. to a/d converter
? 2004 microchip technology inc. preliminary ds41202c-page 37 pic16f684 4.2.4.3 ra2/an2/t0cki/int/c1out figure 4-3 shows the diagram for this pin. the ra2 pin is configurable to function as one of the following: a general purpose i/o an analog input for the a/d the clock input for tmr0 an external edge triggered interrupt a digital output from comparator 1 figure 4-3: block diagram of ra2 4.2.4.4 ra3/mclr /v pp figure 4-4 shows the diagram for this pin. the ra3 pin is configurable to function as one of the following: a general purpose input as master clear reset with weak pull-up figure 4-4: block diagram of ra3 i/o pin v dd v ss d q ck q d q ck q d q ck q d q ck q v dd d en q d en q weak analog (1) input mode data bus wr wpua rd wpua rd porta wr porta wr trisa rd trisa wr ioca rd ioca to a/d converter 0 1 cout cout 1 enable to int to t m r 0 analog (1) input mode rapu rd porta interrupt-on- change q3 note 1: analog input mode is generated by ansel. input v ss d q ck q d en q data bus rd porta rd porta wr ioca rd ioca reset mclre rd trisa v ss d en q mclre v dd weak mclre interrupt-on- change pin q3
pic16f684 ds41202c-page 38 preliminary ? 2004 microchip technology inc. 4.2.4.5 ra4/an3/t1g /osc2/clkout figure 4-5 shows the diagram for this pin. the ra4 pin is configurable to function as one of the following: a general purpose i/o an analog input for the a/d a tmr1 gate input a crystal/resonator connection a clock output figure 4-5: block diagram of ra4 4.2.4.6 ra5/t1cki/osc1/clkin figure 4-6 shows the diagram for this pin. the ra5 pin is configurable to function as one of the following: a general purpose i/o a tmr1 clock input a crystal/resonator connection a clock input figure 4-6: block diagram of ra5 i/o pin v dd v ss d q ck q d q ck q d q ck q d q ck q v dd d en q d en q weak analog input mode data bus wr wpua rd wpua rd porta wr porta wr trisa rd trisa wr ioca rd ioca f osc /4 to a/d converter oscillator circuit osc1 clkout 0 1 clkout enable enable analog (3) input mode rapu rd porta to t 1 g intosc/ rc/ec (2) clk (1) modes clkout enable note 1: clk modes are xt, hs, lp, lptmr1 and clkout enable. 2: with clkout option. 3: analog input mode comes from ansel. interrupt-on- change q3 i/o pin v dd v ss d q ck q d q ck q d q ck q d q ck q v dd d en q d en q weak data bus wr wpua rd wpua rd porta wr porta wr trisa rd trisa wr ioca rd ioca to tmr1 or clkgen intosc mode rd porta intosc mode rapu osc2 (2) note 1: timer1 lp oscillator enabled. 2: when using timer1 with lp oscillator, the schmitt trigger is bypassed. tmr1lpen (1) interrupt-on- change oscillator circuit q3
? 2004 microchip technology inc. preliminary ds41202c-page 39 pic16f684 table 4-1: summary of registers associated with porta addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on: por, bod value on all other resets 05h porta ? ? ra5 ra4 ra3 ra2 ra1 ra0 --xx xx00 --uu uu00 0bh/8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 19h cmcon0 c2out c1out c2inv c1inv cis cm2 cm1 cm0 0000 0000 0000 0000 81h option_reg rapu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 1111 1111 85h trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 --11 1111 --11 1111 91h ansel ans7 ans6 ans5 ans4 ans3 ans2 ans1 ans0 1111 1111 1111 1111 95h wpua ? ?wpua5wpua4 ? wpua2 wpua1 wpua0 --11 -111 --11 -111 96h ioca ? ? ioca5 ioca4 ioca3 ioca2 ioca1 ioca0 --00 0000 --00 0000 legend: x = unknown, u = unchanged, ? = unimplem ented locations read as ? 0 ?. shaded cells are not used by porta.
pic16f684 ds41202c-page 40 preliminary ? 2004 microchip technology inc. 4.3 portc portc is a general purpose i/o port consisting of 6 bidirectional pins. the pins can be configured for either digital i/o or analog input to a/d converter or compara- tor. for specific information about individual functions such as the enhanced ccp or the a/d, refer to the appropriate section in this data sheet. example 4-3: initializing portc 4.3.1 rc0/an4/c2in+ the rc0 is configurable to function as one of the following: a general purpose i/o an analog input for the a/d converter an analog input to the comparator 4.3.2 rc1/an5/c2in- the rc1 is configurable to function as one of the following: a general purpose i/o an analog input for the a/d converter an analog input to the comparator figure 4-7: block diagram of rc0 and rc1 note: the ansel (91h) and cmcon0 (19h) registers must be initialized to configure an analog channel as a digital input. pins configured as analog inputs will read ? 0 ?. bcf status,rp0 ;bank 0 clrf portc ;init portc movlw 07h ;set rc<4,1:0> to movwf cmcon0 ;digital i/o bsf status,rp0 ;bank 1 clrf ansel ;digital i/o movlw 0ch ;set rc<3:2> as inputs movwf trisc ;and set rc<5:4,1:0> ;as outputs bcf status,rp0 ;bank 0 i/o pin v dd v ss d q ck q d q ck q data bus wr portc wr trisc rd trisc to a/d converter rd portc analog input mode (1) to comparators note 1: analog input mode comes from ansel or comparator mode.
? 2004 microchip technology inc. preliminary ds41202c-page 41 pic16f684 4.3.3 rc2/an6/p1d the rc2 is configurable to function as one of the following: a general purpose i/o an analog input for the a/d converter a digital output from the enhanced ccp 4.3.4 rc3/an7/p1c the rc3 is configurable to function as one of the following: a general purpose i/o an analog input for the a/d converter a digital output from the enhanced ccp figure 4-8: block diagram of rc2 and rc3 4.3.5 rc4/c2out/p1b the rc4 is configurable to function as one of the following: a general purpose i/o a digital output from the comparator a digital output from the enhanced ccp figure 4-9: block diagram of rc4 i/o pin v dd v ss d q ck q d q ck q data bus wr portc wr trisc rd trisc to a/d converter rd portc analog input mode (1) 0 1 ccpout ccpout enable note 1: analog input mode comes from ansel. note: enabling both c2out and p1b will cause a conflict on rc4 and create unpredictable results. therefore, if c2out is enabled, the eccp can not be used in half-bridge or full-bridge mode and vise-versa. i/o pin v dd v ss d q ck q d q ck q data bus wr portc wr trisc rd trisc rd portc 0 1 note 1: port/peripheral select signals selects between port data and peripheral output. c2out en ccpout en c2out en c2out ccpout en ccpout
pic16f684 ds41202c-page 42 preliminary ? 2004 microchip technology inc. 4.3.6 rc5/ccp1/p1a the rc5 is configurable to function as one of the following: a general purpose i/o a digital input/output for the enhanced ccp figure 4-10: block diagram of rc5 pin i/o pin v dd v ss d q ck q d q ck q data bus wr portc wr trisc rd trisc to enhanced ccp rd portc 0 1 ccp1out ccp1out enable
? 2004 microchip technology inc. preliminary ds41202c-page 43 pic16f684 register 4-5: portc ? portc register (address: 07h) register 4-6: trisc ? portc tri-state register (address: 87h) table 4-2: summary of registers associated with portc u-0 u-0 r/w-x r/w-x r/w-x r/w-x r/w-0 r/w-0 ? ? rc5 rc4 rc3 rc2 rc1 rc0 bit 7 bit 0 bit 7-6: unimplemented: read as ? 0 ? bit 5-0: rc<5:0>: portc general purpose i/o pin bits 1 = port pin is >v ih 0 = port pin is : portc tri-state control bit 1 = portc pin configured as an input (tri-stated) 0 = portc pin configured as an output 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 address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on: por, bod value on all other resets 07h portc ? ? rc5 rc4 rc3 rc2 rc1 rc0 --xx xx00 --uu uu00 19h cmcon0 c2out c1out c2inv c1inv cis cm2 cm1 cm0 0000 0000 0000 0000 87h trisc ? ? trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 --11 1111 --11 1111 91h ansel ans7 ans6 ans5 ans4 ans3 ans2 ans1 ans0 1111 1111 1111 1111 legend: x = unknown, u = unchanged, ? = unimplemented locations read as ? 0 ?. shaded cells are not used by portc.
pic16f684 ds41202c-page 44 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 45 pic16f684 5.0 timer0 module the timer0 module timer/counter has the following features: 8-bit timer/counter readable and writable 8-bit software programmable prescaler internal or external clock select interrupt on overflow from ffh to 00h edge select for external clock figure 5-1 is a block diagram of the timer0 module and the prescaler shared with the wdt. 5.1 timer0 operation timer mode is selected by clearing the t0cs bit (option_reg<5>). in timer mode, the timer0 module will increment every instruction cycle (without prescaler). if tmr0 is written, 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. counter mode is selected by setting the t0cs bit (option_reg<5>). in this mode, the timer0 module will increment either on every rising or falling edge of pin ra2/t0cki. the incrementing edge is determined by the source edge (t0se) control bit (option_reg<4>). clearing the t0se bit selects the rising edge. 5.2 timer0 interrupt a timer0 interrupt is generated when the tmr0 register timer/counter overflows from ffh to 00h. this overflow sets the t0if bit (intcon<2>). the interrupt can be masked by clearing the t0ie bit (intcon<5>). the t0if bit must be cleared in software by the timer0 module interrupt service routine before re-enabling this interrupt. the timer0 interrupt cannot wake the processor from sleep since the timer is shut off during sleep. figure 5-1: block diagram of the timer0/wdt prescaler note: additional information on the timer0 module is available in the ? picmicro ? mid-range mcu family reference manual? (ds33023). note: counter mode has specific external clock requirements. additional information on these requirements is available in the ?picmicro ? mid-range mcu family reference manual? (ds33023). t0cki t0se pin clkout tmr0 watchdog timer wdt time-out ps<2:0> wdte data bus set flag bit t0if on overflow t0cs note 1: t0se, t0cs, psa, ps<2:0> are bits in the option register, wdtps<3:0> are bits in the wdtcon register. 0 1 0 1 0 1 sync 2 cycles 8 8 8-bit prescaler 0 1 (= f osc /4) psa psa psa 16-bit prescaler 16 wdtps<3:0> 31 khz intrc swdten
pic16f684 ds41202c-page 46 preliminary ? 2004 microchip technology inc. 5.3 using timer0 with an external clock when no prescaler is used, the external clock input is the same as the prescaler output. the synchronization of t0cki, with the internal phase clocks, is accom- plished by sampling the prescaler output on the q2 and q4 cycles of the internal phase clocks. therefore, it is necessary for t0cki to be high for at least 2 t osc (and a small rc delay of 20 ns) and low for at least 2 t osc (and a small rc delay of 20 ns). refer to the electrical specification of the desired device. register 5-1: option_reg ? option register (address: 81h) note: the ansel (91h) and cmcon0 (19h) registers must be initialized to configure an analog channel as a digital input. pins configured as analog inputs will read ? 0 ?. r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 rapu intedg t0cs t0se psa ps2 ps1 ps0 bit 7 bit 0 bit 7 rapu : porta pull-up enable bit 1 = porta pull-ups are disabled 0 = porta pull-ups are enabled by individual port latch values in wpua register bit 6 intedg: interrupt edge select bit 1 = interrupt on rising edge of ra2/int pin 0 = interrupt on falling edge of ra2/int pin bit 5 t0cs: tmr0 clock source select bit 1 = transition on ra2/t0cki pin 0 = internal instruction cycle clock (clkout) bit 4 t0se: tmr0 source edge select bit 1 = increment on high-to-low transition on ra2/t0cki pin 0 = increment on low-to-high transition on ra2/t0cki pin bit 3 psa: prescaler assignment bit 1 = prescaler is assigned to the wdt 0 = prescaler is assigned to the timer0 module bit 2-0 ps<2:0>: prescaler rate select bits note 1: a dedicated 16-bit wdt postscaler is available for the pic16f684. see section 12.6 ?watchdog timer (wdt)? for more information. 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 000 001 010 011 100 101 110 111 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 1 : 1 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 bit value tmr0 rate wdt rate (1)
? 2004 microchip technology inc. preliminary ds41202c-page 47 pic16f684 5.4 prescaler an 8-bit counter is available as a prescaler for the timer0 module, or as a postscaler for the watchdog timer. for simplicity, this counter will be referred to as ?prescaler? throughout this data sheet. the prescaler assignment is controlled in software by the control bit psa (option_reg<3>). clearing the psa bit will assign the prescaler to timer0. prescale values are selectable via the ps<2:0> bits (option_reg<2:0>). the prescaler is not readable or writable. when assigned to the timer0 module, all instructions writing to the tmr0 register (e.g., clrf 1, movwf 1, bsf 1, x....etc. ) will clear the prescaler. when assigned to wdt, a clrwdt instruction will clear the prescaler along with the watchdog timer. 5.4.1 switching prescaler assignment the prescaler assignment is fully under software control (i.e., it can be changed ?on the fly? during program execution). to avoid an unintended device reset, the following instruction sequence (example 5-1 and example 5-2) must be executed when changing the prescaler assignment from timer0 to wdt. example 5-1: changing prescaler (timer0 wdt) to change prescaler from the wdt to the tmr0 module, use the sequence shown in example 5-2. this precaution must be taken even if the wdt is disabled. example 5-2: changing prescaler (wdt timer0) table 5-1: registers associated with timer0 bcf status,rp0 ;bank 0 clrwdt ;clear wdt clrf tmr0 ;clear tmr0 and ; prescaler bsf status,rp0 ;bank 1 movlw b?00101111? ;required if desired movwf option_reg ; ps2:ps0 is clrwdt ; 000 or 001 ; movlw b?00101xxx? ;set postscaler to movwf option_reg ; desired wdt rate bcf status,rp0 ;bank 0 clrwdt ;clear wdt and ; prescaler bsf status,rp0 ;bank 1 movlw b?xxxx0xxx? ;select tmr0, ; prescale, and ; clock source movwf option_reg ; bcf status,rp0 ;bank 0 address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets 01h tmr0 timer0 module register xxxx xxxx uuuu uuuu 0bh/8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 81h option_reg rapu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 1111 1111 85h trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 --11 1111 --11 1111 legend: ? = unimplemented locations, read as ? 0 ?, u = unchanged, x = unknown. shaded cells are not used by the timer0 module.
pic16f684 ds41202c-page 48 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 49 pic16f684 6.0 timer1 module with gate control the pic16f684 has a 16-bit timer. figure 6-1 shows the basic block diagram of the timer1 module. timer1 has the following features: 16-bit timer/counter (tmr1h:tmr1l) readable and writable internal or external clock selection synchronous or asynchronous operation interrupt on overflow from ffffh to 0000h wake-up upon overflow (asynchronous mode) optional external enable input - selectable gate source: t1g or c2 output (t1gss) - selectable gate polarity (t1ginv) optional lp oscillator the timer1 control register (t1con), shown in register 6-1, is used to enable/disable timer1 and select the various features of the timer1 module. figure 6-1: timer1 on the pi c16f684 block diagram note: additional information on timer modules is available in the ? picmicro ? mid-range mcu family reference manual? (ds33023). tmr1h tmr1l oscillator t1sync tmr1cs t1ckps<1:0> sleep input f osc /4 internal clock prescaler 1, 2, 4, 8 synchronize det 1 0 0 1 synchronized clock input 2 osc1/t1cki osc2/t1g set flag bit tmr1if on overflow tmr1 (1) tmr1on tmr1ge tmr1on tmr1ge intosc t1oscen without clkout (2 ) 1 0 c2out t1gss t1ginv to c2 comparator module tmr1 clock note 1: timer1 increments on the rising edge. 2: st buffer is low power type when using lp oscillator or high speed type when using t1cki.
pic16f684 ds41202c-page 50 preliminary ? 2004 microchip technology inc. 6.1 timer1 modes of operation timer1 can operate in one of three modes: 16-bit timer with prescaler 16-bit synchronous counter 16-bit asynchronous counter in timer mode, timer1 is incremented on every instruc- tion cycle. in counter mode, timer1 is incremented on the rising edge of the external clock input t1cki. in addition, the counter mode clock can be synchronized to the microcontroller system clock or run asynchronously. in counter and timer modules, the counter/timer clock can be gated by the timer1 gate, which can be selected as either the t1g pin or comparator 2 output. if an external clock oscillator is needed (and the microcontroller is using the intosc without clkout), timer1 can use the lp oscillator as a clock source. 6.2 timer1 interrupt the timer1 register pair (tmr1h:tmr1l) increments to ffffh and rolls over to 0000h. when timer1 rolls over, the timer1 interrupt flag bit (pir1<0>) is set. to enable the interrupt on rollover, you must set these bits: timer1 interrupt enable bit (pie1<0>) peie bit (intcon<6>) gie bit (intcon<7>) the interrupt is cleared by clearing the tmr1if bit in the interrupt service routine. 6.3 timer1 prescaler timer1 has four prescaler options allowing 1, 2, 4 or 8 divisions of the clock input. the t1ckps bits (t1con<5:4>) control the prescale counter. the prescale counter is not directly readable or writable; however, the prescaler counter is cleared upon a write to tmr1h or tmr1l. 6.4 timer1 gate timer1 gate source is software configurable to be the t1g pin or the output of comparator 2. this allows the device to directly time external events using t1g or analog events using comparator 2. see cmcon1 (register 8-2) for selecting the timer1 gate source. this feature can simplify the software for a delta-sigma a/d converter and many other applications. for more information on delta-sigma a/d converters, see the microchip web site (www.microchip.com). timer1 gate can be inverted using the t1ginv bit (t1con<7>), whether it originates from the t1g pin or comparator 2 output. this configures timer1 to measure either the active-high or active-low time between events. figure 6-2: timer1 incrementing edge note: in counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge. note: the tmr1h:ttmr1l register pair and the tmr1if bit should be cleared before enabling interrupts. note: tmr1ge bit (t1con<6>) must be set to use either t1g or c2out as the timer1 gate source. see register 8-2 for more information on selecting the timer1 gate source. t1cki = 1 when tmr1 enabled t1cki = 0 when tmr1 enabled note 1: arrows indicate counter increments. 2: in counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock.
? 2004 microchip technology inc. preliminary ds41202c-page 51 pic16f684 register 6-1: t1con ? timer1 control re gister (address: 10h) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 t1ginv tmr1ge t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on bit 7 bit 0 bit 7 t1ginv: timer1 gate invert bit (1) 1 = timer1 gate is inverted 0 = timer1 gate is not inverted bit 6 tmr1ge: timer1 gate enable bit (2) if tmr1on = 0 : this bit is ignored if tmr1on = 1 : 1 = timer1 is on if timer1 gate is not active 0 = timer1 is on bit 5-4 t1ckps<1:0>: 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: lp oscillator enable control bit if intosc without clkout oscillator is active: 1 = lp oscillator is enabled for timer1 clock 0 = lp oscillator is off else: this bit is ignored bit 2 t1sync : timer1 external clock input synchronization control bit tmr1cs = 1 : 1 = do not synchronize external clock input 0 = synchronize external clock input tmr1cs = 0 : this bit is ignored. timer1 uses the internal clock. bit 1 tmr1cs: timer1 clock source select bit 1 = external clock from t1cki pin (on the rising edge) 0 = internal clock (f osc /4) bit 0 tmr1on: timer1 on bit 1 = enables timer1 0 = stops timer1 note 1: t1ginv bit inverts the timer1 gate logic, regardless of source. 2: tmr1ge bit must be set to use either t1g pin or c2out, as selected by the t1gss bit (cmcon1<1>), as a timer1 gate source. 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
pic16f684 ds41202c-page 52 preliminary ? 2004 microchip technology inc. 6.5 timer1 operation in asynchronous counter mode if control bit t1sync (t1con<2>) is set, the external clock input is not synchronized. the timer continues to increment asynchronous to the internal phase clocks. the timer will continue to run during sleep and can generate an interrupt on overflow, which will wake-up the processor. however, special precautions in software are needed to read/write the timer (see section 6.5.1 ?reading and writing timer1 in asynchronous counter mode? ). 6.5.1 reading and writing timer1 in asynchronous counter mode reading tmr1h or tmr1l while the timer is running from an external asynchronous clock will ensure a valid read (taken care of in hardware). however, the user should keep in mind that reading the 16-bit timer in two 8-bit values itself, poses certain problems, since the timer may overflow between the reads. for writes, it is recommended that the user simply stop the timer and write the desired values. a write conten- tion may occur by writing to the timer registers, while the register is incrementing. this may produce an unpredictable value in the timer register. reading the 16-bit value requires some care. examples in the ? picmicro ? mid-range mcu family reference manual? (ds33023) show how to read and write timer1 when it is running in asynchronous mode. 6.6 timer1 oscillator a crystal oscillator circuit is built-in between pins osc1 (input) and osc2 (amplifier output). it is enabled by setting control bit, t1oscen (t1con<3>). the oscillator is a low-power oscillator rated up to 32 khz. it will continue to run during sleep. it is primarily intended for a 32 khz crystal. table 3-1 shows the capacitor selection for the timer1 oscillator. the timer1 oscillator is shared with the system lp oscillator. thus, timer1 can use this mode only when the primary system clock is derived from the internal oscillator. as with the system lp oscillator, the user must provide a software time delay to ensure proper oscillator start-up. trisa5 and trisa4 bits are set when the timer1 oscillator is enabled. ra5 and ra4 read as ? 0 ? and trisa5 and trisa4 bits read as ? 1 ?. 6.7 timer1 operation during sleep timer1 can only operate during sleep when setup in asynchronous counter mode. in this mode, an external crystal or clock source can be used to increment the counter. to set up the timer to wake the device: timer1 must be on (t1con<0>) tmr1ie bit (pie1<0>) must be set peie bit (intcon<6>) must be set the device will wake-up on an overflow. if the gie bit (intcon<7>) is set, the device will wake-up and jump to the interrupt service routine (0004h) on an overflow. if the gie bit is clear, execution will continue with the next instruction. table 6-1: registers associated with timer1 note: the ansel (91h) and cmcon0 (19h) registers must be initialized to configure an analog channel as a digital input. pins configured as analog inputs will read ? 0 ?. note: the oscillator requires a start-up and stabilization time before use. thus, t1oscen should be set and a suitable delay observed prior to enabling timer 1. addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets 0bh/ 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 0eh tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 0fh tmr1h holding register for the most significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 10h t1con t1ginv tmr1ge t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 0000 0000 uuuu uuuu 1ah cmcon1 ? ? ? ? ? ?t1gss c2sync ---- --10 ---- --10 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 legend: x = unknown, u = unchanged, ? = unimplemented, read as ? 0 ?. shaded cells are not used by the timer1 module.
? 2004 microchip technology inc. preliminary ds41202c-page 53 pic16f684 7.0 timer2 module the timer2 module timer has the following features: 8-bit timer (tmr2 register) 8-bit period register (pr2) readable and writable (both registers) software programmable prescaler (1:1, 1:4, 1:16) software programmable postscaler (1:1 to 1:16) interrupt on tmr2 match with pr2 timer2 has a control register shown in register 7-1. tmr2 can be shut-off by clearing control bit, tmr2on (t2con<2>), to minimize power consumption. figure 7-1 is a simplified block diagram of the timer2 module. the prescaler and postscaler selection of timer2 are controlled by this register. 7.1 timer2 operation timer2 can be used as the pwm time base for the pwm mode of the eccp module. the tmr2 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 t2ckps<1:0> (t2con<1:0>). the match output of tmr2 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a tmr2 interrupt (latched in flag bit, tmr2if (pir1<1>)). the prescaler and postscaler counters are cleared when any of the following occurs: 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 7-1: t2con ? timer2 control register (address: 12 h ) u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 bit 7 bit 0 bit 7 unimplemented: read as ? 0 ? bit 6-3 toutps<3:0>: 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 t2ckps<1:0>: timer2 clock prescale select bits 00 = prescaler is 1 01 = prescaler is 4 1x = prescaler is 16 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
pic16f684 ds41202c-page 54 preliminary ? 2004 microchip technology inc. 7.2 timer2 interrupt the timer2 module has an 8-bit period register, pr2. timer2 increments from 00h until it matches pr2 and then resets to 00h on the next increment cycle. pr2 is a readable and writable register. the pr2 register is initialized to ffh upon reset. figure 7-1: timer2 block diagram table 7-1: registers associated with timer2 addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets 0bh/ 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 11h tmr2 holding register for the 8-bit tmr2 register 0000 0000 0000 0000 12h t2con ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 92h pr2 timer2 module period register 1111 1111 1111 1111 legend: x = unknown, u = unchanged, ? = unimplemented, read as ? 0 ?. shaded cells are not used by the timer2 module. comparator tmr2 sets flag tmr2 output reset postscaler prescaler pr2 2 f osc /4 1:1 to 1:16 1:1, 1:4, 1:16 eq 4 bit tmr2if toutps<3:0> t2ckps<1:0>
? 2004 microchip technology inc. preliminary ds41202c-page 55 pic16f684 8.0 comparator module the comparator module contains two analog comparators. the inputs to the comparators are multiplexed with i/o port pins ra0, ra1, rc0 and rc1, while the outputs are multiplexed to pins ra2 and rc4. an on-chip comparator voltage reference (cv ref ) can also be applied to the inputs of the comparators. the cmcon0 register (register 8-1) controls the comparator input and output multiplexers. a block diagram of the various comparator configurations is shown in figure 8-3. register 8-1: cmcon0 ? comparator co nfiguration register (address: 19h) r-0 r-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 c2out c1out c2inv c1inv cis cm2 cm1 cm0 bit 7 bit 0 bit 7 c2out : comparator 2 output bit when c2inv = 0 : 1 = c2 v in + > c2 v in - 0 = c2 v in + < c2 v in - when c2inv = 1 : 1 = c2 v in + < c2 v in - 0 = c2 v in + > c2 v in - bit 6 c1out : comparator 1 output bit when c1inv = 0 : 1 = c1 v in + > c1 v in - 0 = c1 v in + < c1 v in - when c1inv = 1 : 1 = c1 v in + < c1 v in - 0 = c1 v in + > c1 v in - bit 5 c2inv : comparator 2 output inversion bit 1 = c2 output inverted 0 = c2 output not inverted bit 4 c1inv : comparator 1 output inversion bit 1 = c1 output inverted 0 = c1 output not inverted bit 3 cis : comparator input switch bit when cm < 2: 0> = 010 : 1 = c1 v in - connects to ra0/an0 c2 v in - connects to rc0/an4 0 = c1 v in - connects to ra1/an1 c2 v in - connects to rc1/an5 when cm <2:0> = 001 : 1 = c1 v in - connects to ra0/an0 0 = c1 v in - connects to ra1/an1 bit 2-0 cm<2:0>: comparator mode bits figure 8-3 shows the comparator modes and cm<2:0> bit settings 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
pic16f684 ds41202c-page 56 preliminary ? 2004 microchip technology inc. 8.1 comparator operation a single comparator is shown in figure 8-1 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 8-1 represent the uncertainty due to input offsets and response time. the polarity of the comparator output can be inverted by setting the cxinv bits (cmcon0<5:4>). clearing cxinv results in a non-inverted output. a complete table showing the output state versus input conditions and the polarity bit is shown in table 8-1. table 8-1: output state vs. input conditions figure 8-1: single comparator 8.2 analog input connection considerations a simplified circuit for an analog input is shown in figure 8-2. 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 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 8-2: analog input model note: to use cin+ and cin- pins as analog inputs, the appropriate bits must be programmed in the cmcon0 (19h) register. input conditions cinv cxout v in - > v in + 00 v in - < v in + 01 v in - > v in + 11 v in - < v in + 10 note 1: when reading the port register, all pins configured as analog inputs will read as a ? 0 ?. pins configured as digital inputs will convert as analog inputs according to the input specification. 2: analog levels on any pin defined as a digital input may cause the input buffer to consume more current than is specified. ? + v in + v in - output v in? v in+ o utput output v in + v in - va rs < 10k a in c pin 5 pf v dd v t = 0.6v v t = 0.6v r ic leakage 500 na vss 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
? 2004 microchip technology inc. preliminary ds41202c-page 57 pic16f684 8.3 comparator configuration there are eight modes of operation for the compara- tors. the cmcon0 register is used to select these modes. figure 8-3 shows the eight possible modes. if the comparator mode is changed, the comparator output level may not be valid for the specified mode change delay shown in section 15.0 ?electrical specifications? . figure 8-3: comparator i/o operating modes note: comparator interrupts should be disabled during a comparator mode change. otherwise, a false interrupt may occur. c1 ra1/an1 v in - v in + ra0/an0 off (read as ? 0 ?) comparators reset (por default value) a a cm<2:0> = 000 c2 rc1/an5 v in - v in + rc0/an4 off (read as ? 0 ?) a a c1 ra1/an1 v in - v in + ra0/an0 c1out two independent comparators a a cm<2:0> = 100 c2 rc1/an5 v in - v in + rc0/an4 c2out a a c1 ra1/an1 v in - v in + ra0/an0 c1out two common reference comparators a d cm<2:0> = 011 c2 rc1/an5 v in - v in + rc0/an4 c2out a a c1 ra1/an1 v in - v in + ra0/an0 off (read as ? 0 ?) one independent comparator d d cm<2:0> = 101 c2 rc1/an5 v in - v in + rc0/an4 c2out a a c1 ra1/an1 v in - v in + ra0/an0 off (read as ? 0 ?) comparators off (lowest power) d d cm<2:0> = 111 c2 rc1/an5 v in - v in + rc0/an4 off (read as ? 0 ?) d d c1 ra1/an1 v in - v in + ra0/an0 c1out four inputs multiplexed to two comparators a a cm<2:0> = 010 c2 rc1/an5 v in - v in + rc0/an4 c2out a a from cv ref module cis = 0 cis = 1 cis = 0 cis = 1 c1 ra1/an1 v in - v in + ra2/c1out c1out two common reference comparators with outputs a d cm<2:0> = 110 c2 rc1/an5 v in - v in + rc0/an4 c2out a a d = digital input rc4/c2out c1 ra1/an1 v in - v in + ra0/an0 c1out three inputs multiplexed to two comparators a a cm<2:0> = 001 c2 rc1/an5 v in - v in + rc0/an4 c2out a a cis = 0 cis = 1 legend: a = analog input, ports always read ? 0 ? cis (cmcon0<3>) is the comparator input switch
pic16f684 ds41202c-page 58 preliminary ? 2004 microchip technology inc. figure 8-4: invertible comparator c1 output block diagram figure 8-5: invertible comparator c2 output block diagram d q en to c 1 o u t p i n rd cmcon set c1if bit multiplex d q en cl port pins nreset to data bus c1inv rd cmcon q3 c2sync d q en to c 2 o u t p in rd cmcon set c2if bit multiplex d q en cl port pins rd cmcon reset to data bus c2inv d q en tmr1 clock source (1) 0 1 to t m r 1 note 1: comparator 2 output is latched on falling edge of t1 clock source. q3
? 2004 microchip technology inc. preliminary ds41202c-page 59 pic16f684 register 8-2: cmcon1 ? comparator co nfiguration register (address: 1ah) 8.4 comparator outputs the comparator outputs are read through the cmcon0 register. these bits are read-only. the comparator outputs may also be directly output to the ra2 and rc4 i/o pins. when enabled, multiplexers in the output path of the ra2 and rc4 pins will switch and the output of each pin will be the unsynchronized output of the comparator. the uncertainty of each of the comparators is related to the input offset voltage and the response time given in the specifications. figure 8-4 and figure 8-5 show the output block diagram for comparator 1 and 2. the tris bits will still function as an output enable/ disable for the ra2 and rc4 pins while in this mode. the polarity of the comparator outputs can be changed using the c1inv and c2inv bits (cmcon0<5:4>). timer1 gate source can be configured to use the t1g pin or comparator 2 output as selected by the t1gss bit (cmcon1<1>). this feature can be used to time the duration or interval of analog events. the output of comparator 2 can also be synchronized with timer1 by setting the c2sync bit (cmcon1<0>). when enabled, the output of comparator 2 is latched on the falling edge of timer1 clock source. if a prescaler is used with timer1, comparator 2 is latched after the prescaler. to prevent a race condition, the comparator 2 output is latched on the falling edge of the timer1 clock source and timer1 increments on the rising edge of its clock source. see the comparator 2 block diagram (figure 8-5) and the timer1 block diagram (figure 6-1) for more information. it is recommended to synchronize comparator 2 with timer1 by setting the c2sync bit when comparator 2 is used as the timer1 gate source. this ensures timer1 does not miss an increment if comparator 2 changes during an increment. 8.5 comparator interrupts the comparator interrupt flags are set whenever there is a change in the output value of its respective compar- ator. software will need to maintain information about the status of the output bits, as read from cmcon0<7:6>, to determine the actual change that has occurred. the cxif bits, pir1<4:3>, are the comparator interrupt flags. this bit must be reset in software by clearing it to ? 0 ?. since it is also possible to write a ? 1 ? to this register, a simulated interrupt may be initiated. the cxie bits (pie1<4:3>) and the peie bit (intcon<6>) must be set to enable the interrupts. in addition, the gie bit must also be set. if any of these bits are cleared, the interrupt is not enabled, though the cxif bits will still be set if an interrupt condition occurs. the user, in the interrupt service routine, can clear the interrupt in the following manner: a) any read or write of cmcon0. this will end the mismatch condition. b) clear flag bit cxif. a mismatch condition will continue to set flag bit cxif. reading cmcon0 will end the mismatch condition and allow flag bit cxif to be cleared. u-0 u-0 u-0 u-0 u-0 u-0 r/w-1 r/w-0 ? ? ? ? ? ? t1gss c2sync bit 7 bit 0 bit 7-2: unimplemented : read as ? 0 ? bit 1 t1gss: timer1 gate source select bit 1 = timer1 gate source is t1g pin (ra4 must be configured as digital input) 0 = timer1 gate source is comparator 2 output bit 0 c2sync: comparator 2 synchronize bit 1 = c2 output synchronized with falling edge of timer1 clock 0 = c2 output not synchronized with timer1 clock 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 note: if a change in the cmcon0 register (cxout) should occur when a read operation is being executed (start of the q2 cycle), then the cxif (pir1<4:3>) interrupt flag may not get set.
pic16f684 ds41202c-page 60 preliminary ? 2004 microchip technology inc. 8.6 comparator reference the comparator module also allows the selection of an internally generated voltage reference for one of the comparator inputs. the vrcon register (register 8-3) controls the voltage reference module shown in figure 8-6. 8.6.1 configuring the voltage reference the voltage reference can output 32 distinct voltage levels, 16 in a high range and 16 in a low range. the following equation determines the output voltages: equation 8-1: 8.6.2 voltage reference accuracy/error the full range of v ss to v dd cannot be realized due to the construction of the module. the transistors on the top and bottom of the resistor ladder network (figure 8-6) keep cv ref from approaching v ss or v dd . the exception is when the module is disabled by clearing the vren bit (vrcon<7>). when disabled, the reference voltage is v ss when vr<3:0> is ? 0000 ? and the vrr (vrcon<5>) bit is set. this allows the comparators to detect a zero-crossing and not consume cv ref module current. the voltage reference is v dd derived and therefore, the cv ref output changes with fluctuations in v dd . the tested absolute accuracy of the comparator voltage reference can be found in section 15.0 ?electrical specifications? . figure 8-6: comparator voltage reference block diagram vrr = 1 (low range): cv ref = (vr3:vr0/24) x v dd vrr = 0 (high range): cv ref = (v dd /4) + (vr3:vr0 x v dd /32) vrr 8r vr3:vr0 16-1 analog 8r r r r r cv ref to 16 stages comparator input vren v dd mux vr3:vr0 = ? 0000 ? vren vrr
? 2004 microchip technology inc. preliminary ds41202c-page 61 pic16f684 8.7 comparator response time response time is the minimum time, after selecting a new reference voltage or input source, before the comparator output is ensured to have a valid level. if the internal reference is changed, the maximum delay of the internal voltage reference must be considered when using the comparator outputs. otherwise, the maximum delay of the comparators should be used (table 15-8). 8.8 operation during sleep the comparators and voltage reference, if enabled before entering sleep mode, remain active during sleep. this results in higher sleep currents than shown in the power-down specifications. the additional current consumed by the comparator and the voltage reference is shown separately in the specifications. to minimize power consumption while in sleep mode, turn off the comparator, cm<2:0> = 111 , and voltage reference, vrcon<7> = 0 . while the comparator is enabled during sleep, an inter- rupt will wake-up the device. if the gie bit (intcon<7>) is set, the device will jump to the inter- rupt vector (0004h), and if clear, continues execution with the next instruction. if the device wakes up from sleep, the contents of the cmcon0, cmcon1 and vrcon registers are not affected. 8.9 effects of a reset a device reset forces the cmcon0, cmcon1 and vrcon registers to their reset states. this forces the comparator module to be in the comparator reset mode, cm<2:0> = 000 and the voltage reference to its off state. thus, all potential inputs are analog inputs with the comparator and voltage reference disabled to consume the smallest current possible.
pic16f684 ds41202c-page 62 preliminary ? 2004 microchip technology inc. register 8-3: vrcon ? voltage reference control register (address: 99h) table 8-2: registers associated with comparator module r/w-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 vren ?vrr ? vr3 vr2 vr1 vr0 bit 7 bit 0 bit 7 vren: cv ref enable bit 1 = cv ref circuit powered on 0 = cv ref circuit powered down, no i dd drain and cv ref = v ss bit 6 unimplemented: read as ? 0 ? bit 5 vrr: cv ref range selection bit 1 = low range 0 = high range bit 4 unimplemented: read as ? 0 ? bit 3-0 vr<3:0>: cv ref value selection 0 vr<3:0> 15 when v rr = 1 : cv ref = (vr<3:0>/24) * v dd when v rr = 0 : cv ref = v dd /4 + (vr<3:0>/32) * v dd 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 address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets 0bh/8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 19h cmcon0 c2out c1out c2inv c1inv cis cm2 cm1 cm0 0000 0000 0000 0000 1ah cmcon1 ? ? ? ? ? ? t1gss c2sync ---- --10 ---- --10 85h trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 --11 1111 --11 1111 87h trisc ? ? trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 --11 1111 --11 1111 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 99h vrcon vren ?vrr ? vr3 vr2 vr1 vr0 0-0- 0000 0-0- 0000 legend: x = unknown, u = unchanged, ? = unimplemented, read as ? 0 ?. shaded cells are not used by the capture, compare or timer1 module.
? 2004 microchip technology inc. preliminary ds41202c-page 63 pic16f684 9.0 analog-to-digital converter (a/d) module the analog-to-digital converter (a/d) allows conver- sion of an analog input signal to a 10-bit binary repre- sentation of that signal. the pic16f684 has eight analog inputs, multiplexed into one sample and hold circuit. the output of the sample and hold is connected to the input of the converter. the converter generates a binary result via successive approximation and stores the result in a 10-bit register. the voltage reference used in the conversion is software selectable to either v dd or a voltage applied by the v ref pin. figure 9-1 shows the block diagram of the a/d on the pic16f684. figure 9-1: a/d block diagram 9.1 a/d configuration and operation there are three registers available to control the functionality of the a/d module: 1. ansel (register 9-1) 2. adcon0 (register 9-2) 3. adcon1 (register 9-3) 9.1.1 analog port pins the ans<7:0> bits (ansel<7:0>) and the tris bits control the operation of the a/d port pins. set the corresponding tris bits to set the pin output driver to its high-impedance state. likewise, set the correspond- ing ansel bit to disable the digital input buffer. 9.1.2 channel selection there are eight analog channels on the pic16f684, an0 through an7. the chs<2:0> bits (adcon0<4:2>) control which channel is connected to the sample and hold circuit. 9.1.3 voltage reference there are two options for the voltage reference to the a/d converter: either v dd is used, or an analog voltage applied to v ref is used. the vcfg bit (adcon0<6>) controls the voltage reference selection. if vcfg is set, then the voltage on the v ref pin is the reference; otherwise, v dd is the reference. ra0/an0 a/d ra1/an1/v ref ra2/an2 rc0/an4 v dd v ref adon go/done vcfg = 1 vcfg = 0 chs<2:0> adresh adresl 10 10 adfm v ss rc1/an5 rc2/an6 rc3/an7 ra4/an3 note: analog voltages on any pin that is defined as a digital input may cause the input buffer to conduct excess current.
pic16f684 ds41202c-page 64 preliminary ? 2004 microchip technology inc. 9.1.4 conversion clock the a/d conversion cycle requires 11 t ad . the source of the conversion clock is software selectable via the adcs bits (adcon1<6:4>). there are seven possible clock options: f osc /2 f osc /4 f osc /8 f osc /16 f osc /32 f osc /64 f rc (dedicated internal oscillator) for correct conversion, the a/d conversion clock (1/t ad ) must be selected to ensure a minimum t ad of 1.6 s. table 9-1 shows a few t ad calculations for selected frequencies. table 9-1: t ad vs. device operating frequencies 9.1.5 starting a conversion the a/d conversion is initiated by setting the go/done bit (adcon0<1>). when the conversion is complete, the a/d module: clears the go/done bit sets the adif flag (pir1<6>) generates an interrupt (if enabled) if the conversion must be aborted, the go/done bit can be cleared in software. the adresh:adresl registers will not be updated with the partially complete a/d conversion sample. instead, the adresh:adresl registers will retain the value of the previous conversion. after an aborted conversion, a 2t ad delay is required before another acquisition can be initiated. following the delay, an input acquisition is automatically started on the selected channel. figure 9-2: a/d conversion t ad cycles a/d clock source (t ad ) device frequency operation adcs2:adcs0 20 mhz 5 mhz 4 mhz 1.25 mhz 2 t osc 000 100 ns (2) 400 ns (2) 500 ns (2) 1.6 s 4 t osc 100 200 ns (2) 800 ns (2) 1.0 s (2) 3.2 s 8 t osc 001 400 ns (2) 1.6 s2.0 s6.4 s 16 t osc 101 800 ns (2) 3.2 s4.0 s 12.8 s (3) 32 t osc 010 1.6 s6.4 s 8.0 s (3) 25.6 s (3) 64 t osc 110 3.2 s 12.8 s (3) 16.0 s (3) 51.2 s (3) a/d rc x11 2-6 s (1,4) 2-6 s (1,4) 2-6 s (1,4) 2-6 s (1,4) legend: shaded cells are outside of recommended range. note 1: the a/d rc source has a typical t ad time of 4 s for v dd > 3.0v. 2: these values violate the minimum required t ad time. 3: for faster conversion times, the selection of another clock source is recommended. 4: when the device frequency is greater than 1 mhz, the a/d rc clock source is only recommended if the conversion will be performed during sleep. 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 9 set go bit holding capacitor is disconnected fr om analog input (typically 100 ns) b9 b8 b7 b6 b5 b4 b3 b2 t ad 10 t ad 11 b1 b0 t cy to t ad conversion starts adresh and adresl registers are loaded, go bit is cleared, adif bit is set, holding capacitor is connected to analog input
? 2004 microchip technology inc. preliminary ds41202c-page 65 pic16f684 9.1.6 conversion output the a/d conversion can be supplied in two formats: left or right shifted. the adfm bit (adcon0<7>) controls the output format. figure 9-3 shows the output formats. figure 9-3: 10-bit a/d result format register 9-1: ansel ? analog select register (address: 91h) adresh adresl (adfm = 0 )msb lsb bit 7bit 0bit 7bit 0 10-bit a/d result unimplemented: read as ? 0 ? (adfm = 1 ) msb lsb bit 7bit 0bit 7bit 0 unimplemented: read as ? 0 ? 10-bit a/d result r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 ans7 ans6 ans5 ans4 ans3 ans2 ans1 ans0 bit 7 bit 0 bit 7-0: ans<7:0> : analog select bits analog select between analog or digital function on pins an<7:0>, respectively. 1 = analog input. pin is assigned as analog input (1) . 0 = digital i/o. pin is assigned to port or special function. note 1: setting a pin to an analog input automatically disables the digital input circuitry, weak pull-ups, and interrupt-on-change if available. the corresponding tris bit must be set to input mode in order to allow external control of the voltage on the pin. 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
pic16f684 ds41202c-page 66 preliminary ? 2004 microchip technology inc. register 9-2: adcon0 ? a/d control register (address: 1fh) register 9-3: adcon1 ? a/d control register 1 (address: 9fh) r/w-0 r/w-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 adfm vcfg ? chs2 chs1 chs0 go/done adon bit 7 bit 0 bit 7 adfm: a/d result formed select bit 1 = right justified 0 = left justified bit 6 vcfg: voltage reference bit 1 = v ref pin 0 = v dd bit 5 unimplemented: read as ? 0 ? bit 4-2 chs<2:0>: analog channel select bits 000 = channel 00 (an0) 001 = channel 01 (an1) 010 = channel 02 (an2) 011 = channel 03 (an3) 100 = channel 04 (an4) 101 = channel 05 (an5) 110 = channel 06 (an6) 111 = channel 07 (an7) bit 1 go/done : a/d conversion status bit 1 = a/d conversion cycle in progress. setting this bit starts an a/d conversion cycle. this bit is automatically cleared by hardware when the a/d conversion has completed. 0 = a/d conversion completed/not in progress bit 0 adon: a/d conversion status bit 1 = a/d converter module is operating 0 = a/d converter is shut-off and consumes no operating current 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 u-0 r/w-0 r/w-0 r/w-0 u-0 u-0 u-0 u-0 ? adcs2 adcs1 adcs0 ? ? ? ? bit 7 bit 0 bit 7: unimplemented: read as ? 0 ? bit 6-4: adcs<2:0>: a/d conversion clock select bits 000 =f osc /2 001 =f osc /8 010 =f osc /32 x11 =f rc (clock derived from a dedicated internal oscillator = 500 khz max) 100 =f osc /4 101 =f osc /16 110 =f osc /64 bit 3-0: unimplemented: read as ? 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
? 2004 microchip technology inc. preliminary ds41202c-page 67 pic16f684 9.1.7 configuring the a/d 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 inputs. to determine sample time, see section 15.0 ?electri- cal specifications? . after this sample time has elapsed, the a/d conversion can be started. these steps should be followed for an a/d conversion: 1. configure the a/d module: configure analog/digital i/o (ansel) configure voltage reference (adcon0) select a/d input channel (adcon0) select a/d conversion clock (adcon1) turn on a/d module (adcon0) 2. configure a/d interrupt (if desired): clear adif bit (pir1<6>) set adie bit (pie1<6>) set peie and gie bits (intcon<7:6>) 3. wait the required acquisition time. 4. start conversion: set go/done bit (adcon0<0>) 5. wait for a/d conversion to complete, by either: polling for the go/done bit to be cleared (with interrupts disabled); or waiting for the a/d interrupt 6. read a/d result register pair (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 the next acquisition starts. example 9-1: a/d conversion ;this code block configures the a/d ;for polling, vdd reference, r/c clock ;and ra0 input. ; ;conversion start & wait for complete ;polling code included. ; bsf status,rp0 ;bank 1 movlw b?01110000? ;a/d rc clock movwf adcon1 bsf trisa,0 ;set ra0 to input bsf ansel,0 ;set ra0 to analog bcf status,rp0 ;bank 0 movlw b?10000001? ;right, vdd vref, an0 movwf adcon0 call sampletime ;wait min sample time bsf adcon0,go ;start conversion btfsc adcon0,go ;is conversion done? goto $-1 ;no, test again movf adresh,w ;read upper 2 bits movwf resulthi bsf status,rp0 ;bank 1 movf adresl,w ;read lower 8 bits movwf resultlo
pic16f684 ds41202c-page 68 preliminary ? 2004 microchip technology inc. 9.2 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 ana- log input model is shown in figure 9-4. 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 ) imped- ance varies over the device voltage (v dd ), see figure 9-4. the maximum recommended impedance for analog sources is 10 k ? . as the impedance is decreased, the acquisition time may be decreased. after the analog input channel is selected (changed), this acquisition must be done before the conversion can be started. to calculate the minimum acquisition time, equation 9-1 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. to calculate the minimum acquisition time, t acq , see the ? picmicro ? mid-range mcu family reference manual? (ds33023). equation 9-1: acquisition time figure 9-4: analog input model note 1: the reference voltage (v ref ) has no effect on the equation, since it cancels itself out. 2: the charge holding capacitor (c hold ) is not discharged after each conversion. 3: the maximum recommended impedance for analog sources is 10 k ? . this is required to meet the pin leakage specification. t acq = amplifier settling time + hold capacitor charging time + temperature coefficient = t amp + t c + t coff = 2 s + t c + [(temperature -25c)(0.05 s/c)] t c = c hold (r ic + r ss + r s ) in(1/2047) = -120 pf (1 k ? + 7 k ? + 10 k ? ) in(0.0004885) = 16.47 s t acq = 2 s + 16.47 s + [(50c-25c)(0.05 s/c)] = 19.72 s c pin va 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 = dac capacitance v ss 6v sampling switch 5v 4v 3v 2v 567891011 (k ? ) v dd = 120 pf 500 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
? 2004 microchip technology inc. preliminary ds41202c-page 69 pic16f684 9.3 a/d operation during sleep the a/d converter module can operate during sleep. this requires the a/d clock source to be set to the internal oscillator. when the rc clock source is selected, the a/d waits one instruction before starting the conversion. this allows the sleep instruction to be executed, thus eliminating much of the switching noise from the conversion. when the conversion is complete, the go/done bit is cleared and the result is loaded into the adresh:adresl registers. if the a/d interrupt is enabled, the device awakens from sleep. if the gie bit (intcon<7>) is set, the program counter is set to the interrupt vector (0004h), if gie is clear, the next instruction is executed. if the a/d inter- rupt is not enabled, the a/d module is turned off, although the adon bit remains set. when the a/d clock source is something other than rc, a sleep instruction causes the present conversion to be aborted, and the a/d module is turned off. the adon bit remains set. figure 9-5: a/d transfer function 9.4 effects of reset a device reset forces all registers to their reset state. thus, the a/d module is turned off and any pending conversion is aborted. the adresh:adresl registers are unchanged. 9.5 use of the eccp trigger an a/d conversion can be started by the ?special event trigger? of the eccp module. this requires that the ccp1m3:ccp1m0 bits (ccp1con<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 conversion and the timer1 counter will be reset to zero. timer1 is reset to automatically repeat the a/d acquisition period with minimal software overhead (moving the adresh:adresl to the desired location). the appropriate analog input channel must be selected and the minimum acquisition done before the ?special event trigger? sets the go/done bit (starts a conversion). if the a/d module is not enabled (adon is cleared), then the ?special event trigger? will be ignored by the a/d module, but will still reset the timer1 counter. see section 11.0 ?enhanced capture/compare/pwm (eccp) module? for more information. 3ffh 3feh a/d output code 3fdh 3fch 004h 003h 002h 001h 000h full-scale 3fbh 1 lsb ideal 0v zero-scale transition v ref transition 1 lsb ideal full-scale range analog input voltage
pic16f684 ds41202c-page 70 preliminary ? 2004 microchip technology inc. table 9-2: summary of a/d registers addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on: por, bod value on all other resets 05h porta ? ? ra5 ra4 ra3 ra2 ra1 ra0 --xx xxxx --uu uuuu 07h portc ? ? rc5 rc4 rc3 rc2 rc1 rc0 --xx xxxx --uu uuuu 0bh/ 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 1eh adresh most significant 8 bits of the left shifted a/d result or 2 bits of the right shifted result xxxx xxxx uuuu uuuu 1fh adcon0 adfm vcfg ? chs2 chs1 chs0 go/done adon 00-0 0000 00-0 0000 85h trisa ? ? trisa5 trisa4 trisa3 trisa2 trisa1 trisa0 --11 1111 --11 1111 87h trisc ? ? trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 --11 1111 --11 1111 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 91h ansel ans7 ans6 ans5 ans4 ans3 ans2 ans1 ans0 1111 1111 1111 1111 9eh adresl least significant 2 bits of the left shifted a/d result or 8 bits of the right shifted result xxxx xxxx uuuu uuuu 9fh adcon1 ? adcs2 adcs1 adcs0 ? ? ? ? -000 ---- -000 ---- legend: x = unknown, u = unchanged, ? = unimplemented read as ? 0 ?. shaded cells are not used for a/d module.
? 2004 microchip technology inc. preliminary ds41202c-page 71 pic16f684 10.0 data eeprom memory the eeprom data memory is readable and writable during normal operation (full v dd range). this memory is not directly mapped in the register file space. instead, it is indirectly addressed through the special function registers. there are four sfrs used to read and write this memory: eecon1 eecon2 (not a physically implemented register) eedat eeadr eedat holds the 8-bit data for read/write, and eeadr holds the address of the eeprom location being accessed. pic16f684 has 256 bytes of data eeprom with an address range from 0h to ffh. the eeprom data memory allows byte read and write. a byte write automatically erases the location and writes the new data (erase before write). the eeprom data memory is rated for high erase/write cycles. the write time is controlled by an on-chip timer. the write time will vary with voltage and temperature as well as from chip-to-chip. please refer to ac specifications in section 15.0 ?electrical specifications? for exact limits. when the data memory is code-protected, the cpu may continue to read and write the data eeprom memory. the device programmer can no longer access the data eeprom data and will read zeroes. additional information on the data eeprom is available in the ? picmicro ? mid-range mcu family reference manual? (ds33023). register 10-1: eedat ? eeprom data register (address: 9ah) register 10-2: eeadr ? eeprom address register (address: 9bh) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 eedat7 eedat6 eedat5 eedat4 eedat3 eedat2 eedat1 eedat0 bit 7 bit 0 bit 7-0 eedatn : byte value to write to or read from data eeprom bits 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 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 eeadr7 eeadr6 eeadr5 eeadr4 eeadr3 eeadr2 eeadr1 eeadr0 bit 7 bit 0 bit 7-0 eeadr : specifies one of 256 locations for eeprom read/write operation bits 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
pic16f684 ds41202c-page 72 preliminary ? 2004 microchip technology inc. 10.1 eecon1 and eecon2 registers eecon1 is the control register with four low-order bits physically implemented. the upper four bits are non- implemented and read as ? 0 ?s. control bits rd and wr initiate read and write, respectively. these bits cannot be cleared, only set in software. they are cleared in hardware at completion of the read or write operation. the inability to clear the wr bit in software prevents the accidental, premature termination of a write operation. the wren bit, when set, will allow a write operation. on power-up, the wren bit is clear. the wrerr bit is set when a write operation is interrupted by a mclr reset, or a wdt time-out reset during normal operation. in these situations, following reset, the user can check the wrerr bit, clear it and rewrite the location. the data and address will be cleared. there- fore, the eedat and eeadr registers will need to be re-initialized. interrupt flag, eeif bit (pir1<7>), is set when write is complete. this bit must be cleared in software. eecon2 is not a physical register. reading eecon2 will read all ? 0 ?s. the eecon2 register is used exclusively in the data eeprom write sequence. register 10-3: eecon1 ? eeprom control regist er (address: 9ch) note: the eecon1, eedat and eeadr registers should not be modified during a data eeprom write (wr bit = 1 ). u-0 u-0 u-0 u-0 r/w-x r/w-0 r/s-0 r/s-0 ? ? ? ? wrerr wren wr rd bit 7 bit 0 bit 7-4 unimplemented: read as ? 0 ? bit 3 wrerr: eeprom error flag bit 1 = a write operation is prematurely terminated (any mclr reset, any wdt reset during normal operation or bod detect) 0 = the write operation completed bit 2 wren: eeprom write enable bit 1 = allows write cycles 0 = inhibits write to the data eeprom bit 1 wr: write control bit 1 = initiates a write cycle (the bit is cleared by hardware once write is complete. the wr bit can only be set, not cleared, in software.) 0 = write cycle to the data eeprom is complete bit 0 rd: read control bit 1 = initiates an eeprom read (read takes one cycle. rd is cleared in hardware. the rd bit can only be set, not cleared, in software.) 0 = does not initiate an eeprom read legend: s = bit can only be set 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
? 2004 microchip technology inc. preliminary ds41202c-page 73 pic16f684 10.2 reading the eeprom data memory to read a data memory location, the user must write the address to the eeadr register and then set control bit rd (eecon1<0>), as shown in example 10-1. the data is available, in the very next cycle, in the eedat register. therefore, it can be read in the next instruction. eedat holds this value until another read, or until it is written to by the user (during a write operation). example 10-1: data eeprom read 10.3 writing to the eeprom data memory to write an eeprom data location, the user must first write the address to the eeadr register and the data to the eedat register. then the user must follow a specific sequence to initiate the write for each byte, as shown in example 10-2. example 10-2: data eeprom write the write will not initiate if the above sequence is not exactly followed (write 55h to eecon2, write aah to eecon2, then set wr bit) for each byte. we strongly recommend that interrupts be disabled during this code segment. a cycle count is executed during the required sequence. any number that is not equal to the required cycles to execute the required sequence will prevent the data from being written into the eeprom. additionally, the wren bit in eecon1 must be set to enable write. this mechanism prevents accidental writes to data eeprom due to errant (unexpected) code execution (i.e., lost programs). the user should keep the wren bit clear at all times, except when updating eeprom. the wren bit is not cleared by hardware. after a write sequence has been initiated, clearing the wren bit will not affect this write cycle. the wr bit will be inhibited from being set unless the wren bit is set. at the completion of the write cycle, the wr bit is cleared in hardware and the ee write complete interrupt flag bit (eeif) is set. the user can either enable this interrupt or poll this bit. the eeif bit (pir1<7>) register must be cleared by software. 10.4 write verify depending on the application, good programming practice may dictate that the value written to the data eeprom should be verified (see example 10-3) to the desired value to be written. example 10-3: write verify 10.4.1 using the data eeprom the data eeprom is a high-endurance, byte address- able array that has been optimized for the storage of frequently changing information. the maximum endurance for any eeprom cell is specified as dxxx. d120 or d120a specify a maximum number of writes to any eeprom location before a refresh is required of infrequently changing memory locations. 10.4.2 eeprom endurance a hypothetical data eeprom is 64 bytes long and has an endurance of 1m writes. it also has a refresh param- eter of 10m writes. if every memory location in the cell were written the maximum number of times, the data eeprom would fail after 64m write cycles. if every memory location save one were written the maximum number of times, the data eeprom would fail after 63m write cycles, but the one remaining location could fail after 10m cycles. if proper refreshes occurred, then the lone memory location would have to be refreshed six times for the data to remain correct. bsf status,rp0 ;bank 1 movlw config_addr ; movwf eeadr ;address to read bsf eecon1,rd ;ee read movf eedat,w ;move data to w bsf status,rp0 ;bank 1 bsf eecon1,wren ;enable write bcf intcon,gie ;disable ints movlw 55h ;unlock write movwf eecon2 ; movlw aah ; movwf eecon2 ; bsf eecon1,wr ;start the write bsf intcon,gie ;enable ints required sequence bsf status,rp0 ;bank 1 movf eedat,w ;eedat not changed ;from previous write bsf eecon1,rd ;yes, read the ;value written xorwf eedat,w btfss status,z ;is data the same goto write_err ;no, handle error : ;yes, continue
pic16f684 ds41202c-page 74 preliminary ? 2004 microchip technology inc. 10.5 protection against spurious write there are conditions when the user may not want to write to the data eeprom memory. to protect against spurious eeprom writes, various mechanisms have been built in. on power-up, wren is cleared. also, the power-up timer (64 ms duration) prevents eeprom write. the write initiate sequence and the wren bit together help prevent an accidental write during: brown-out power glitch software malfunction 10.6 data eeprom operation during code-protect data memory can be code-protected by programming the cpd bit in the configuration word register (register 12-1) to ? 0 ?. when the data memory is code-protected, the cpu is able to read and write data to the data eeprom. it is recommended to code-protect the program memory when code-protecting data memory. this prevents anyone from programming zeroes over the existing code (which will execute as nop s) to reach an added routine, programmed in unused program memory, which outputs the contents of data memory. programming unused locations in program memory to ? 0 ? will also help prevent data memory code protection from becoming breached. table 10-1: registers/bits associated with data eeprom addressname bit 7bit 6bit 5bit 4bit 3bit 2 bit 1bit 0 value on por, bod value on all other resets 0bh/8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 9ah eedat eedat7 eedat6 eedat5 eedat4 eedat3 eedat2 eedat1 eedat0 0000 0000 0000 0000 9bh eeadr eeadr7 eeadr6 eeadr5 eeadr eeadr eeadr eeadr eeadr 0000 0000 0000 0000 9ch eecon1 ? ? ? ? wrerr wren wr rd ---- x000 ---- q000 9dh eecon2 (1) eeprom control register 2 ---- ---- ---- ---- legend: x = unknown, u = unchanged, ? = unimplemented read as ? 0 ?, q = value depends upon condition. shaded cells are not used by data eeprom module. note 1: eecon2 is not a physical register.
? 2004 microchip technology inc. preliminary ds41202c-page 75 pic16f684 11.0 enhanced capture/compare/pwm (eccp) module the enhanced capture/compare/pwm (eccp) module contains a 16-bit register which can operate as a: 16-bit capture register 16-bit compare register pwm master/slave duty cycle register capture/compare/pwm register 1 (ccpr1) is comprised of two 8-bit registers: ccpr1l (low byte) and ccpr1h (high byte). the ccp1con register controls the operation of eccp. the special event trigger is generated by a compare match and will clear both tmr1h and tmr1l registers. table 11-1: eccp mode ? timer resources required register 11-1: ccp1con ? enhanced ccp operation register (address: 15h) eccp mode timer resource capture timer1 compare timer1 pwm timer2 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 p1m1 p1m0 dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 bit 7 bit 0 bit 7-6 p1m<1:0>: pwm output configuration bits if ccp1m<3:2> = 00, 01, 10 : xx = p1a assigned as capture/compare input; p1b, p1c, p1d assigned as port pins if ccp1m<3:2> = 11 : 00 = single output; p1a modulated; p1b, p1c, p1d 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 dc1b<1:0>: pwm duty cycle least significant bits capture mode: unused. compare mode: unused. pwm mode: these bits are the two lsbs of the pwm duty cycle. the eight msbs are found in ccpr1l. bit 3-0 ccp1m<3:0>: eccp mode select bits 0000 = capture/compare/pwm off (resets eccp module) 0001 = unused (reserved) 0010 = compare mode, toggle output on match (ccp1if bit is set) 0011 = unused (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, set output on match (ccp1if bit is set) 1001 = compare mode, clear output on match (ccp1if bit is set) 1010 = compare mode, generate software interrupt on match (ccp1if bit is set, ccp1 pin is unaffected) 1011 = compare mode, trigger special event (ccp1if bit is set; ccp1 resets tmr1or tmr2, and starts an a/d conversion, if the a/d module is enabled) 1100 = pwm mode; p1a, p1c active-high; p1b, p1d active-high 1101 = pwm mode; p1a, p1c active-high; p1b, p1d active-low 1110 = pwm mode; p1a, p1c active-low; p1b, p1d active-high 1111 = pwm mode; p1a, p1c active-low; p1b, p1d active-low 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
pic16f684 ds41202c-page 76 preliminary ? 2004 microchip technology inc. 11.1 capture mode in capture mode, ccpr1h:ccpr1l captures the 16-bit value of the tmr1 register when an event occurs on pin rc5/ccp1/p1a. an event is defined as one of the following and is configured by ccp1con<3:0>: every falling edge every rising edge every 4th rising edge every 16th rising edge when a capture is made, the interrupt request flag bit, ccp1if (pir1<5>), is set. the interrupt flag must be cleared in software. if another capture occurs before the value in register ccpr1 is read, the old captured value is overwritten by the new captured value. 11.1.1 ccp1 pin configuration in capture mode, the rc5/ccp1/p1a pin should be configured as an input by setting the trisc<5> bit. figure 11-1: capture mode operation block diagram 11.1.2 timer1 mode selection timer1 must be running in timer mode or synchro- nized counter mode for the eccp module to use the capture feature. in asynchronous counter mode, the capture operation may not work. 11.1.3 software interrupt when the capture mode is changed, a false capture interrupt may be generated. the user should keep bit ccp1ie (pie1<5>) clear to avoid false interrupts and should clear the flag bit ccp1if (pir1<5>) following any such change in operating mode. 11.1.4 eccp prescaler there are four prescaler settings specified by bits ccp1m<3:0> (ccp1con<3:0>). whenever the eccp module is turned off, or the eccp module is not in capture mode, the prescaler counter is cleared. 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 11-1 shows the recom- mended method for switching between capture prescalers. this example also clears the prescaler counter and will not generate the ?false? interrupt. example 11-1: changing between capture prescalers note: if the rc5/ccp1/p1a pin is configured as an output, a write to the port can cause a capture condition. ccpr1h ccpr1l tmr1h tmr1l set flag bit ccp1if (pir1<5>) capture enable q?s ccp1con<3:0> rc5/ccp1/p1a prescaler 1, 4, 16 and edge detect pin clrf ccp1con ;turn eccp module off movlw new_capt_ps ;load the w reg with ;the new prescaler ;move value and eccp on movwf ccp1con ;load ccp1con with this ;value
? 2004 microchip technology inc. preliminary ds41202c-page 77 pic16f684 11.2 compare mode in compare mode, the 16-bit ccpr1 register value is constantly compared against the tmr1 register pair value. when a match occurs, the rc5/ccp1/p1a pin is: driven high driven low remains unchanged the action on the pin is based on the value of control bits, ccp1m<3:0> (ccp1con<3:0>). at the same time, interrupt flag bit, ccp1if (pir1<5>), is set. figure 11-2: compare mode operation block diagram 11.2.1 ccp1 pin configuration the user must configure the rc5/ccp1/p1a pin as an output by clearing the trisc<5> bit. 11.2.2 timer1 mode selection timer1 must be running in timer mode or synchro- nized counter mode if the eccp module is using the compare feature. in asynchronous counter mode, the compare operation may not work. 11.2.3 software interrupt mode when generate software interrupt mode is chosen (ccp1m<3:0> = 1010 ), the ccp1 pin is not affected. the ccp1if (pir1<5>) bit is set, causing a eccp interrupt (if enabled). see register 11-1. 11.2.4 special event trigger in this mode (ccp1m<3:0> = 1011 ), an internal hardware trigger is generated, which may be used to initiate an action. see register 11-1. the special event trigger output of eccp resets the tmr1 register pair. this allows the ccpr1 register to effectively be a 16-bit programmable period register for timer1. the special event trigger output also starts an a/d conversion (if the a/d module is enabled). table 11-2: registers associated with capture, compare, and timer1 ccpr1h ccpr1l tmr1h tmr1l comparator qs r output logic special event trigger set flag bit ccp1if (pir1<5>) match rc5/ccp1/p1a trisc<5> ccp1con<3:0> mode select output enable pin special event trigger will: clear tmr1h and tmr1l registers not set interrupt flag bit tmr1f (pir1<0>) set the go/done bit (adcon0<1>) note: clearing the ccp1con register will force the rc5/ccp1/p1a compare output latch to the default low level. this is not the portc i/o data latch. note: the special event trigger from the eccp module will not set interrupt flag bit tmr1if (pir1<0>). addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets 0bh/ 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 0eh tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 0fh tmr1h holding register for the most significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 10h t1con t1ginv tmr1ge t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 0000 0000 uuuu uuuu 1ah cmcon1 ? ? ? ? ? ?t1gss c2sync ---- --10 ---- --10 13h ccpr1l capture/compare/pwm register 1 low byte xxxx xxxx uuuu uuuu 14h ccpr1h capture/compare/pwm register 1 high byte xxxx xxxx uuuu uuuu 15h ccp1con p1m1 p1m0 dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 0000 0000 0000 0000 87h trisc ? ?trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 --11 1111 --11 1111 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 legend: ? = unimplemented locations, read as ? 0 ?, u = unchanged, x = unknown. shaded cells are not used by the capture, compare or timer1 module.
pic16f684 ds41202c-page 78 preliminary ? 2004 microchip technology inc. 11.3 enhanced pwm mode the enhanced ccp module produces up to a 10-bit resolution pwm output and may have up to four outputs, depending on the selected operating mode. these outputs, designated p1a through p1d, are multiplexed with i/o pins on portc. the pin assignments are summarized in table 11-3. figure 11-3 shows a simplified block diagram of pwm operation. to configure i/o pins as pwm outputs, the proper pwm mode must be selected by setting the p1m<1:0> and ccp1m<3:0> bits (ccp1con<7:6> and ccp1con<3:0>, respectively). the appropriate trisc bits must also be set as outputs. figure 11-3: simplified block diagram of the enhanced pwm module 11.3.1 pwm output configurations the p1m<1:0> bits in the ccp1con register allows one of four configurations: single output half-bridge output full-bridge output, forward mode full-bridge output, reverse mode the general relationship of the outputs in all configurations is summarized in figure 11-3. table 11-3: pin assignments for various enhanced ccp modes ccpr1l ccpr1h (slave) comparator tmr2 comparator pr2 (1) rq s duty cycle registers ccp1con<5:4> clear timer2, toggle pwm pin and latch duty cycle note 1: the 8-bit timer tmr2 register is concatenated with the 2- bit internal q clock, or 2 bits of the prescaler to create the 10-bit time base. trisc<5> rc5/ccp1/p1a trisc<4> rc4/c2out/p1b trisc<3> rc3/an7/p1c trisc<2> rc2/an6/p1d output controller p1m<1:0> 2 ccp1m<3:0> 4 pwm1con ccp1/p1a p1b p1c p1d note: clearing the ccp1con register will force the pwm output latches to their default inactive levels. this is not the portc i/o data latch. eccp mode ccp1con configuration rc5 rc4 rc3 rc2 compatible ccp 00xx11xx ccp1 rc4/c2out rc3/an7 rc2/an6 dual pwm 10xx11xx p1a p1b rc3/an7 rc2/an6 quad pwm x1xx11xx p1a p1b p1c p1d legend: x = don?t care. shaded cells indicate pin assignments not used by eccp in a given mode. note 1: tris register values must be configured appropriately. 2: with eccp in dual or quad pwm mode, the c2out output control of portc must be disabled.
? 2004 microchip technology inc. preliminary ds41202c-page 79 pic16f684 11.3.2 pwm period a pwm output (figure 11-4 and figure 11-5) has a time base (period) and a time that the output is active (duty cycle). the pwm period is specified by writing to the pr2 register. the pwm period can be calculated using the following formula: equation 11-1: 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 appropriate pwm pin toggles. in dual pwm mode, this occurs after the dead band delay expires (exception: if pwm duty cycle = 0%, the pin will not be set) the pwm duty cycle is latched from ccpr1l into ccpr1h 11.3.3 pwm duty cycle the pwm duty cycle is specified by writing to the ccpr1l register and to the dc1b<1:0> (ccp1con<5:4>) bits. up to 10 bits of resolution is available. the ccpr1l contains the eight msbs and the dc1b<1:0> contains the two lsbs. ccpr1l and dc1b<1:0> can be written to at any time. in pwm mode, ccpr1h is a read-only register. this 10-bit value is represented by ccpr1l (ccp1con<5:4>). the following equation is used to calculate the pwm duty cycle in time: equation 11-2: when the ccpr1h and 2-bit latch match tmr2, concatenated with an internal 2-bit q clock or 2 bits of the tmr2 prescaler, the appropriate pwm pin is toggled. in dual pwm mode, the pin will be toggled after the dead band time has expired. the polarity (active-high or active-low) and mode of the signal are configured by the p1m<1:0> (ccp1con<7:6>) and ccp1m<3:0> (ccp1con<3:0>) bits. the maximum pwm resolution for a given pwm frequency is given by the formula: equation 11-3: 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 pwm delay register, which is loaded at either the duty cycle boundary or the period boundary (whichever comes first). because of the buffering, the module waits until the timer resets, instead of starting immedi- ately. 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 ). table 11-4: example pwm frequencies and resolutions (f osc = 20 mhz) note: the timer2 postscaler (see section 7.1 ?timer2 operation? ) 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 + [] 4t osc ? ? ? = (tmr2 prescale value) note: if the pwm duty cycle value is longer than the pwm period, the assigned pwm pin(s) will remain unchanged. pwm duty cycle ccpr1l:ccp1con<5:4> () ? = t osc ? (tmr2 prescale value) resolution f osc f pwm tmr2 prescaler ? ------------------------------------------------------------ - ?? ?? log 2 () log -------------------------------------------------------------------------- - bits = pwm frequency 1.22 khz (1) 4.88 khz (1) 19.53 khz 78.12 khz 156.3 khz 208.3 khz timer prescale (1, 4, 16) 16 4 1 1 1 1 pr2 value 0xff 0xff 0xff 0x3f 0x1f 0x17 maximum resolution (bits) 10 10 10 8 7 6.6 note 1: changing duty cycle will cause a glitch.
pic16f684 ds41202c-page 80 preliminary ? 2004 microchip technology inc. figure 11-4: pwm output relationships (active-high state) figure 11-5: 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) 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 * (pwm1con<6:0>) note 1: dead band delay is programmed using the pwm1con register ( section 11.3.6 ?programmable dead band delay? ). 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) 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 * (pwm1con<6:0>) note 1: dead band delay is programmed using the pwm1con register ( section 11.3.6 ?programmable dead band delay? ).
? 2004 microchip technology inc. preliminary ds41202c-page 81 pic16f684 11.3.4 half-bridge mode in the half-bridge output mode, two pins are used as outputs to drive push-pull loads. the pwm output sig- nal is output on the rc5/ccp1/p1a pin, while the com- plementary pwm output signal is output on the rc4/c2out/p1b pin (figure 11-6). this mode can be used for half-bridge applications, as shown in figure 11-7, 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 pdc<6:0> (pwm1con<6:0>) sets the number of instruction cycles before the output is driven active. if the value is greater than the duty cycle, the corre- sponding output remains inactive during the entire cycle. see section 11.3.6 ?programmable dead band delay? for more details of the dead band delay operations. since the p1a and p1b outputs are multiplexed with the portc<5:4> data latches, the trisc<5:4> bits must be cleared to configure p1a and p1b as outputs. figure 11-6: half-bridge pwm output figure 11-7: examples of half-bridge 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. pic16f684 p1a p1b fet driver fet driver v+ v- load + v - + v - fet driver fet driver v+ v- load fet driver fet driver pic16f684 p1a p1b standard half-bridge circuit (?push-pull?) half-bridge output driving a full-bridge circuit
pic16f684 ds41202c-page 82 preliminary ? 2004 microchip technology inc. 11.3.5 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 rc5/ccp1/p1a is continuously active and pin rc2/an6/p1d is modulated. in the reverse mode, rc3/an7/p1c pin is continuously active and rc4/c2out/p1b pin is modulated. these are illustrated in figure 11-8. p1a, p1b, p1c and p1d outputs are multiplexed with the portc<5:2> data latches. the trisc<5:2> bits must be cleared to make the p1a, p1b, p1c and p1d pins output. figure 11-8: 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. 2: output signal is shown as active-high.
? 2004 microchip technology inc. preliminary ds41202c-page 83 pic16f684 figure 11-9: example of full-bridge application 11.3.5.1 direction change in full-bridge mode in the full-bridge output mode, the p1m1 bit (ccp1con<7>) allows user to control the forward/reverse direction. when the application firm- ware 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, depending on the value of the t2ckps<1:0> bits (t2con<1:0>). during the interval from the switch of the unmodulated outputs to the beginning of the next period, the modulated out- puts (p1b and p1d) remain inactive. this relationship is shown in figure 11-10. note that in the full-bridge output mode, the eccp module does not provide any dead band delay. in general, 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 11-11 shows an example where the pwm direction changes from forward to reverse, at a near 100% duty cycle. at time t1, the output 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 11-9) 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 duty cycle for one 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. pic16f684 p1a p1c fet driver fet driver v+ v- load fet driver fet driver p1b p1d qa qb qd qc
pic16f684 ds41202c-page 84 preliminary ? 2004 microchip technology inc. figure 11-10: pwm direction change figure 11-11: pwm direction change at near 100% duty cycle dc period (1) signal note 1: the direction bit in the eccp control register (ccp 1con<7>) is written 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 (2) p1a (active-high) p1b (active-high) p1c (active-high) p1d (active-high) dc forward period reverse period p1a t on t off t = t off - t on p1b p1c p1d external switch d potential shoot-through current note 1: all signals are shown as active-high. 2: t on is the turn on delay of pow er switch qc and its driver. 3: t off is the turn off delay of power switch qd and its driver. external switch c t1 dc dc
? 2004 microchip technology inc. preliminary ds41202c-page 85 pic16f684 11.3.6 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 flowing 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 transi- tion from the non-active state to the active state. see figure 11-6 for illustration. the lower seven bits of the pwm1con register (register 11-2) sets the delay period in terms of microcontroller instruction cycles (t cy or 4 t osc ). 11.3.7 enhanced pwm auto-shutdown when the eccp 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 comparators or the int pin (or any combination 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 digital signal on the int 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 eccpas<2:0> bits (eccpas<6:4>). when a shutdown occurs, the output pins are asynchronously placed in their shutdown states, spec- ified by the pssac<1:0> and pssbd<1:0> bits (eccpas<3:0>). each pin pair (p1a/p1c and p1b/p1d) may be set to drive high, drive low, or be tri-stated (not driving). the eccpase bit (eccpas<7>) is also set to hold the enhanced pwm outputs in their shutdown states. the eccpase bit is set by hardware when a shutdown event occurs. if auto-restarts are not enabled, the eccpase bit is cleared by firmware when the cause of the shutdown clears. if auto-restarts are enabled, the eccpase bit is automatically cleared when the cause of the auto-shutdown has cleared. see section 11.3.7.1 ?auto-shutdown and auto-restart? for more information. register 11-2: pwm1con ? pwm configuration register (address: 16 h ) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 prsen pdc6 pdc5 pdc4 pdc3 pdc2 pdc1 pdc0 bit 7 bit 0 bit 7 prsen: pwm restart enable bit 1 = upon auto-shutdown, the eccpase bit clears automatically once the shutdown event goes away; the pwm restarts automatically. 0 = upon auto-shutdown, eccpase must be cleared in software to restart the pwm. bit 6-0 pdc<6:0>: pwm delay count bits number of f osc /4 (4*t osc ) cycles between the scheduled time when a pwm signal should transition active, and the actual time it transitions active. 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
pic16f684 ds41202c-page 86 preliminary ? 2004 microchip technology inc. register 11-3: eccpas ? enhanced capture/compare/pwm auto-shutdown control register (address: 17 h ) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 eccpase eccpas2 eccpas1 eccpas0 pssac1 pssac0 pssbd1 pssbd0 bit 7 bit 0 bit 7 eccpase: eccp auto-shutdown event status bit 1 = a shutdown event has occurred; eccp outputs are in shutdown state 0 = eccp outputs are operating bit 6-4 eccpas<2:0>: eccp auto-shutdown source select bits 000 = auto-shutdown is disabled 001 = comparator 1 output change 010 = comparator 2 output change 011 = either comparator 1 or 2 change 100 = v il on int pin 101 = v il on int pin or comparator 1 change 110 = v il on int pin or comparator 2 change 111 = v il on int pin or comparator 1 or comparator 2 change bit 3-2 pssacn: pin 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 pssbdn: pin 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 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
? 2004 microchip technology inc. preliminary ds41202c-page 87 pic16f684 11.3.7.1 auto-shutdown and auto-restart the auto-shutdown feature can be configured to allow auto-restarts of the module following a shutdown event. this is enabled by setting the prsen bit of the pwm1con register (pwm1con<7>). in shutdown mode with prsen = 1 (figure 11-12), the eccpase bit will remain set for as long as the cause of the shutdown continues. when the shutdown condi- tion clears, the eccpase bit is cleared. if prsen = 0 (figure 11-13), once a shutdown condition occurs, the eccpase bit will remain set until it is cleared by firm- ware. once eccpase is cleared, the enhanced pwm will resume at the beginning of the next pwm period. independent of the prsen bit setting, whether the auto-shutdown source is one of the comparators or int, the shutdown condition is a level. the eccpase bit cannot be cleared as long as the cause of the shut- down persists. the auto-shutdown mode can be forced by writing a ? 1 ? to the eccpase bit. 11.3.8 start-up considerations when the eccp 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). the ccp1m<1:0> 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 polar- ities must be selected before the pwm pins are config- ured as outputs. changing the polarity configuration 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 initial- ized. enabling the pwm pins for output at the same time as the eccp module may cause damage to the application circuit. the eccp 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 11-12: pwm auto-shutdown (prsen = 1 , auto-restart enabled) figure 11-13: pwm auto-shutdown (prsen = 0 , auto-restart disabled) note: writing to the eccpase bit is disabled while a shutdown condition is active. shutdown pwm eccpase bit activity event shutdown event occurs shutdown event clears pwm resumes normal pwm start of pwm period pwm period shutdown pwm eccpase bit activity event shutdown event occurs shutdown event clears pwm resumes normal pwm start of pwm period eccpase cleared by firmware pwm period
pic16f684 ds41202c-page 88 preliminary ? 2004 microchip technology inc. 11.3.9 operation in sleep mode in sleep mode, all clock sources are disabled. timer2 will not increment, and the state of the module will not change. if the eccp pin is driving a value, it will continue to drive that value. when the device wakes up, it will continue from this state. 11.3.9.1 operation with fail-safe clock monitor if the fail-safe clock monitor is enabled, a clock failure will force the eccp to be clocked from the internal oscillator clock source, which may have a different clock frequency than the primary clock. see section 3.0 ?clock sources? for additional details. 11.3.10 effects of a reset any reset 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. 11.3.11 setup for pwm operation the following steps should be taken when configuring the eccp module for pwm operation: 1. configure the pwm pins p1a and p1b (and p1c and p1d, if used) as inputs by setting the corresponding trisc bits. 2. set the pwm period by loading the pr2 register. 3. configure the eccp module for the desired pwm mode and configuration by loading the ccp1con register with the appropriate values: select one of the available output configurations and direction with the p1m<1:0> bits. select the polarities of the pwm output signals with the ccp1m<3:0> bits. 4. set the pwm duty cycle by loading the ccpr1l register and ccp1con<5:4> bits. 5. for half-bridge output mode, set the dead band delay by loading pwm1con<6:0> with the appropriate value. 6. if auto-shutdown operation is required, load the eccpas register: select the auto-shutdown sources using the eccpas<2:0> bits. select the shutdown states of the pwm output pins using pssac<1:0> and pssbd<1:0> bits. set the eccpase bit (eccpas<7>). configure the comparators using the cmcon0 register (register 8-1). configure the comparator inputs as analog inputs. 7. if auto-restart operation is required, set the prsen bit (pwm1con<7>). 8. configure and start tmr2: clear the tmr2 interrupt flag bit by clearing the tmr2if bit (pir1<1>). set the tmr2 prescale value by loading the t2ckps bits (t2con<1:0>). enable timer2 by setting the tmr2on bit (t2con<2>). 9. enable pwm outputs after a new pwm cycle has started: wait until tmr2 overflows (tmr2if bit is set). enable the ccp1/p1a, p1b, p1c and/or p1d pin outputs by clearing the respective trisc bits. clear the eccpase bit (eccpas<7>).
? 2004 microchip technology inc. preliminary ds41202c-page 89 pic16f684 table 11-5: registers associated with pwm and timer2 addr name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets 0bh/ 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 11h tmr2 timer2 module register 0000 0000 0000 0000 12h t2con ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 13h ccpr1l capture/compare/pwm register1 low byte xxxx xxxx uuuu uuuu 14h ccpr1h capture/compare/pwm register1 high byte xxxx xxxx uuuu uuuu 15h ccp1con p1m1 p1m0 dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 0000 0000 0000 0000 16h pwm1con prsen pdc6 pdc5 pdc4 pdc3 pdc2 pdc1 pdc0 0000 0000 0000 0000 17h eccpas eccpase eccpas2 eccpas1 eccpas0 pssac1 pssac0 pssbd1 pssbd0 0000 0000 0000 0000 87h trisc ? ? trisc5 trisc4 trisc3 trisc2 trisc1 trisc0 --11 1111 --11 1111 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 92h pr2 timer2 module period register 1111 1111 1111 1111 legend: ? = unimplemented locations, read as ? 0 ?, u = unchanged, x = unknown. shaded cells are not used by the capture, compare or timer1 module.
pic16f684 ds41202c-page 90 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 91 pic16f684 12.0 special features of the cpu the pic16f684 has a host of features intended to maximize system reliability, minimize cost through elimination of external components, provide power saving features and offer code protection. these features are: reset - power-on reset (por) - power-up timer (pwrt) - oscillator start-up timer (ost) - brown-out detect (bod) interrupts watchdog timer (wdt) oscillator selection sleep code protection id locations in-circuit serial programming the pic16f684 has two timers that offer necessary delays on power-up. one is the oscillator start-up timer (ost), intended to keep the chip in reset until the crystal oscillator is stable. the other is the power-up timer (pwrt), which provides a fixed delay of 64 ms (nominal) on power-up only, designed to keep the part in reset while the power supply stabilizes. there is also circuitry to reset the device if a brown-out occurs, which can use the power-up timer to provide at least a 64 ms reset. with these three functions-on-chip, most applications need no external reset circuitry. the sleep mode is designed to offer a very low -current power-down mode. the user can wake-up from sleep through: external reset watchdog timer wake-up an interrupt several oscillator options are also made available to allow the part to fit the application. the intosc option saves system cost while the lp crystal option saves power. a set of configuration bits are used to select various options (see register 12-1).
pic16f684 ds41202c-page 92 preliminary ? 2004 microchip technology inc. 12.1 configuration bits the configuration bits can be programmed (read as ? 0 ?), or left unprogrammed (read as ? 1 ?) to select various device configurations as shown in register 12-1. these bits are mapped in program memory location 2007h. register 12-1: config ? co nfiguration word (address: 2007h) note: address 2007h is beyond the user program memory space. it belongs to the special configuration memory space (2000h- 3fffh), which can be accessed only during programming. see ? pic12f6xx/16f6xx memory programming specification? (ds41204) for more information. ? ? fcmen ieso boden1 boden0 cpd cp mclre pwrte wdte fosc2 fosc1 fosc0 bit 13 bit 0 bit 13-12 unimplemented : read as ? 1 ? bit 11 fcmen: fail-safe clock monitor enabled bit 1 = fail-safe clock monitor is enabled 0 = fail-safe clock monitor is disabled bit 10 ieso: internal external switchover bit 1 = internal external switchover mode is enabled 0 = internal external switchover mode is disabled bit 9-8 boden<1:0>: brown-out detect selection bits (1) 11 = bod enabled 10 = bod enabled during operation and disabled in sleep 01 = bod controlled by sboden bit (pcon<4>) 00 = bod disabled bit 7 cpd : data code protection bit (2) 1 = data memory code protection is disabled 0 = data memory code protection is enabled bit 6 cp : code protection bit (3) 1 = program memory code protection is disabled 0 = program memory c ode protection is enabled bit 5 mclre: ra3/mclr pin function select bit (4) 1 = ra3/mclr pin function is mclr 0 = ra3/mclr pin function is digital input, mclr internally tied to v dd bit 4 pwrte : power-up timer enable bit 1 = pwrt disabled 0 = pwrt enabled bit 3 wdte: watchdog timer enable bit 1 = wdt enabled 0 = wdt disabled and can be enabled by swdten bit (wdtcon<0>) bit 2-0 fosc<2:0>: oscillator selection bits 111 = rc oscillator: clkout function on ra4/ osc2/clkout pin, rc on ra5/osc1/clkin 110 = rcio oscillator: i/o function on ra4/osc2/clkout pin, rc on ra5/osc1/clkin 101 = intosc oscillator: clkout function on ra4/osc2/clkout pin, i/o function on ra5/osc1/clkin 100 = intoscio oscillator: i/o function on ra4/os c2/clkout pin, i/o function on ra5/osc1/clkin 011 = ec: i/o function on ra4/osc2/clkout pin, clkin on ra5/osc1/clkin 010 = hs oscillator: high-speed crystal/resonator on ra4/osc2/clkout and ra5/osc1/clkin 001 = xt oscillator: crystal/resonator on ra4/osc2/clkout and ra5/osc1/clkin 000 = lp oscillator: low-power crystal on ra4/osc2/clkout and ra5/osc1/clkin note 1: enabling brown-out detect does not automatically enable power-up timer. 2: the entire data eeprom will be erased when the code protection is turned off. 3: the entire program memory will be erased when the code protection is turned off. 4: when mclr is asserted in intosc or rc mode, the internal clock oscillator is disabled. legend: r = readable 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
? 2004 microchip technology inc. preliminary ds41202c-page 93 pic16f684 12.2 calibration bits the brown-out detect (bod), power-on reset (por) and 8 mhz internal oscillator (hfintosc) are factory calibrated. these calibration values are stored in the calibration word register, as shown in register 12-2 and are mapped in program memory location 2008h. the calibration word register is not erased when the device is erased when using the procedure described in the ? pic12f6xx/16f6xx memory programming specification? (ds41204). therefore, it is not necessary to store and reprogram these values when the device is erased. register 12-2: calib ? calibration word (address: 2008h) note: address 2008h is beyond the user program memory space. it belongs to the special configuration memory space (2000h- 3fffh), which can be accessed only during programming. see ? pic12f6xx/16f6xx memory programming specification? (ds41204) for more information. ? fcal6 fcal5 fcal4 fcal3 fcal2 fcal1 fcal0 ? por1 por0 bod2 bod1 bod0 bit 13 bit 0 bit 13 unimplemented: read as ? 0 ? bit 12-6 fcal<6:0>: internal oscillator calibration bits 0111111 = maximum frequency . . 0000001 0000000 = center frequency 1111111 . . 1000000 = minimum frequency bit 5 unimplemented: read as ? 0 ? bit 4-3 por<1:0>: por calibration bits 00 = lowest por voltage 11 = highest por voltage bit 2-0 bod<2:0>: bod calibration bits 000 = reserved 001 = lowest bod voltage 111 = highest bod voltage legend: r = readable 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
pic16f684 ds41202c-page 94 preliminary ? 2004 microchip technology inc. 12.3 reset the pic16f684 differentiates between various kinds of reset: a) power-on reset (por) b) wdt reset during normal operation c) wdt reset during sleep d) mclr reset during normal operation e) mclr reset during sleep f) brown-out detect (bod) some registers are not affected in any reset condition; their status is unknown on por and unchanged in any other reset. most other registers are reset to a ?reset state? on: power-on reset mclr reset mclr reset during sleep wdt reset brown-out detect (bod) they are not affected by a wdt wake-up since this is viewed as the resumption of normal operation. to and pd bits are set or cleared differently in different reset situations, as indicated in table 12-2. these bits are used in software to determine the nature of the reset. see table 12-4 for a full description of reset states of all registers. a simplified block diagram of the on-chip reset circuit is shown in figure 12-1. the mclr reset path has a noise filter to detect and ignore small pulses. see section 15.0 ?electrical specifications? for pulse-width specifications. figure 12-1: simplified block diagram of on-chip reset circuit s r q external reset mclr /v pp pin v dd osc1/ wdt module v dd rise detect ost/pwrt lfintosc wdt time-out power-on reset ost 10-bit ripple counter pwrt chip_reset 11-bit ripple counter reset enable ost enable pwrt sleep brown-out (1) detect sboden boden clki pin note 1: refer to the configuration word register (register 12-1).
? 2004 microchip technology inc. preliminary ds41202c-page 95 pic16f684 12.3.1 power-on reset the on-chip por circuit holds the chip in reset until v dd has reached a high enough level for proper operation. to take advantage of the por, simply connect the mclr pin through a resistor to v dd . this will eliminate external rc components usually needed to create power-on reset. a maximum rise time for v dd is required. see section 15.0 ?electrical specifi- cations? for details. if the bod is enabled, the maxi- mum rise time specification does not apply. the bod circuitry will keep the device in reset until v dd reaches v bod (see section 12.3.5 ?brown-out detect (bod)? ). when the device starts normal operation (exits the reset condition), device operating parameters (i.e., 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. for additional information, refer to application note an607, ?power-up trouble shooting? (ds00607). 12.3.2 m clr pic16f684 has a noise filter in the mclr reset path. the filter will detect and ignore small pulses. it should be noted that a wdt reset does not drive mclr pin low. the behavior of the esd protection on the mclr pin has been altered from early devices of this family. voltages applied to the pin that exceed its specification can result in both mclr resets and excessive current beyond the device specification during the esd event. for this reason, microchip recommends that the mclr pin no longer be tied directly to v dd . the use of an rc network, as shown in figure 12-2, is suggested. an internal mclr option is enabled by clearing the mclre bit in the configuration word register. when cleared, mclr is internally tied to v dd and an internal weak pull-up is enabled for the mclr pin. in-circuit serial programming is not affected by selecting the internal mclr option. figure 12-2: recommended mclr circuit 12.3.3 power-on reset (por) the on-chip por circuit holds the chip in reset until v dd has reached a high enough level for proper operation. to take advantage of the por, simply connect the mclr pin through a resistor to v dd . this will eliminate external rc components usually needed to create power-on reset. a maximum rise time for v dd is required. see section 15.0 ?electrical specifi- cations? for details. if the bod is enabled, the maxi- mum rise time specification does not apply. the bod circuitry will keep the device in reset until v dd reaches v bod (see section 12.3.5 ?brown-out detect (bod)? ). when the device starts normal operation (exits the reset condition), device operating parameters (i.e., 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. for additional information, refer to application note an607, ?power-up trouble shooting? (ds00607). note: the por circuit does not produce an internal reset when v dd declines. to re-enable the por, v dd must reach vss for a minimum of 100 s. note: the por circuit does not produce an internal reset when v dd declines. to re-enable the por, v dd must reach vss for a minimum of 100 s. v dd pic16f684 mclr r1 1k ? ( or greater) c1 0.1 f (optional, not critical)
pic16f684 ds41202c-page 96 preliminary ? 2004 microchip technology inc. 12.3.4 power-up timer (pwrt) the power-up timer provides a fixed 64 ms (nominal) time-out on power-up only, from por or brown-out detect. the power-up timer operates from the 31 khz lfintosc oscillator. for more information, see section 3.4 ?internal clock modes? . the chip is kept in reset as long as pwrt is active. the pwrt delay allows the v dd to rise to an acceptable level. a config- uration bit, pwrte , can disable (if set) or enable (if cleared or programmed) the power-up timer. the power-up timer should be enabled when brown-out detect is enabled, although it is not required. the power-up timer delay will vary from chip-to-chip and vary due to: v dd variation temperature variation process variation see dc parameters for details ( section 15.0 ?electrical specifications? ). 12.3.5 brown-out detect (bod) the boden0 and boden1 bits in the configuration word register select one of four bod modes. two modes have been added to allow software or hardware control of the bod enable. when boden<1:0> = 01 , the sboden bit (pcon<4>) enables/disables the bod allowing it to be controlled in software. by select- ing boden<1:0>, the bod is automatically disabled in sleep to conserve power and enabled on wake-up. in this mode, the sboden bit is disabled. see register 12-1 for the configuration word definition. if v dd falls below v bod for greater than parameter (t bod ) (see section 15.0 ?electrical specifica- tions? ), the brown-out situation will reset the device. this will occur regardless of v dd slew rate. a reset is not insured to occur if v dd falls below v bod for less than parameter (t bod ). on any reset (power-on, brown-out detect, watchdog timer, etc.), the chip will remain in reset until v dd rises above v bod (see figure 12-3). the power-up timer will now be invoked, if enabled and will keep the chip in reset an additional 64 ms. if v dd drops below v bod while the power-up timer is running, the chip will go back into a brown-out detect and the power-up timer will be re-initialized. once v dd rises above v bod , the power-up timer will execute a 64 ms reset. 12.3.6 bod calibration the pic16f684 stores the bod calibration values in fuses located in the calibration word register (2008h). the calibration word register is not erased when using the specified bulk erase sequence in the ? pic12f6xx/ 16f6xx memory programming specification ? (ds41204) and thus, does not require reprogramming. figure 12-3: brown-out situations note: the power-up timer is enabled by the pwrte bit in the configuration word register. note: address 2008h is beyond the user program memory space. it belongs to the special configuration memory space (2000h- 3fffh), which can be accessed only during programming. see ? pic12f6xx/16f6xx memory programming specification? (ds41204) for more information. 64 ms (1) v bod v dd internal reset v bod v dd internal reset 64 ms (1) < 64 ms 64 ms (1) v bod v dd internal reset note 1: 64 ms delay only if pwrte bit is programmed to ? 0 ?.
? 2004 microchip technology inc. preliminary ds41202c-page 97 pic16f684 12.3.7 time-out sequence on power-up, the time-out sequence is as follows: first, pwrt time-out is invoked after por has expired, then ost is activated after the pwrt time-out has expired. the total time-out will vary based on oscillator configu- ration and pwrte bit status. for example, in ec mode with pwrte bit erased (pwrt disabled), there will be no time-out at all. figure 12-4, figure 12-5 and figure 12-6 depict time-out sequences. the device can execute code from the intosc while ost is active by enabling two-speed start-up or fail-safe monitor (see section 3.6.2 ?two-speed start-up sequence? and section 3.7 ?fail-safe clock monitor? ). since the time-outs occur from the por pulse, if mclr is kept low long enough, the time-outs will expire. then, bringing mclr high will begin execution immediately (see figure 12-5). this is useful for testing purposes or to synchronize more than one pic16f684 device operating in parallel. table 12-5 shows the reset conditions for some special registers, while table 12-4 shows the reset conditions for all the registers. 12.3.8 power control (pcon) register the power control register pcon (address 8eh) has two status bits to indicate what type of reset that last occurred. bit 0 is bod (brown-out). bod is unknown on power- on reset. it must then be set by the user and checked on subsequent resets to see if bod = 0 , indicating that a brown-out has occurred. the bod status bit is a ?don?t care? and is not necessarily predictable if the brown-out circuit is disabled (boden<1:0> = 00 in the configuration word register). bit 1 is por (power-on reset). it is a ? 0 ? on power-on reset and unaffected otherwise. the user must write a ? 1 ? to this bit following a power-on reset. on a subsequent reset, if por is ? 0 ?, it will indicate that a power-on reset has occurred (i.e., v dd may have gone too low). for more information, see section 4.2.3 ?ultra low- power wake-up? and section 12.3.5 ?brown-out detect (bod)? . table 12-1: time-out in various situations table 12-2: status/pcon bits and their significance table 12-3: summary of registers associated with brown-out oscillator configuration power-up brown-out detect wake-up from sleep pwrte = 0 pwrte = 1 pwrte = 0 pwrte = 1 xt, hs, lp t pwrt + 1024 t osc 1024 t osc t pwrt + 1024 t osc 1024 t osc 1024 t osc rc, ec, intosc t pwrt ?t pwrt ?? por bod to pd condition 0u11 power-on reset 1011 brown-out detect uu0u wdt reset uu00 wdt wake-up uuuu mclr reset during normal operation uu10 mclr reset during sleep legend: u = unchanged, x = unknown address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bod value on all other resets (1) 03h status irp rp1 rpo to pd z dc c 0001 1xxx 000q quuu 8eh pcon ? ? ulpwue sboden ? ?por bod --01 --qq --0u --uu legend: u = unchanged, x = unknown, ? = unimplemented bit, reads as ? 0 ?, q = value depends on condition. shaded cells are not used by bod. note 1: other (non power-up) resets include mclr reset and watchdog timer reset during normal operation.
pic16f684 ds41202c-page 98 preliminary ? 2004 microchip technology inc. figure 12-4: time-out sequence on power-up (delayed mclr ): case 1 figure 12-5: time-out sequence on power-up (delayed mclr ): case 2 figure 12-6: time-out sequence on power-up (mclr with v dd ) t pwrt t ost v dd mclr internal por pwrt time-out ost time-out internal reset v dd mclr internal por pwrt time-out ost time-out internal reset t pwrt t ost t pwrt t ost v dd mclr internal por pwrt time-out ost time-out internal reset
? 2004 microchip technology inc. preliminary ds41202c-page 99 pic16f684 table 12-4: initialization condition for register register address power-on reset mclr reset wdt reset brown-out detect (1) wake-up from sleep through interrupt wake-up from sleep through wdt time-out w? xxxx xxxx uuuu uuuu uuuu uuuu indf 00h/80h xxxx xxxx xxxx xxxx uuuu uuuu tmr0 01h xxxx xxxx uuuu uuuu uuuu uuuu pcl 02h/82h 0000 0000 0000 0000 pc + 1 (3) status 03h/83h 0001 1xxx 000q quuu (4) uuuq quuu (4) fsr 04h/84h xxxx xxxx uuuu uuuu uuuu uuuu porta 05h --xx xx00 --00 0000 --uu uuuu portc 07h --xx xx00 --00 0000 --uu uuuu pclath 0ah/8ah ---0 0000 ---0 0000 ---u uuuu intcon 0bh/8bh 0000 0000 0000 0000 uuuu uuuu (2) pir1 0ch 0000 0000 0000 0000 uuuu uuuu (2) tmr1l 0eh xxxx xxxx uuuu uuuu uuuu uuuu tmr1h 0fh xxxx xxxx uuuu uuuu uuuu uuuu t1con 10h 0000 0000 uuuu uuuu -uuu uuuu tmr2 11h 0000 0000 0000 0000 uuuu uuuu t2con 12h -000 0000 -000 0000 -uuu uuuu ccpr1l 13h xxxx xxxx uuuu uuuu uuuu uuuu ccpr1h 14h xxxx xxxx uuuu uuuu uuuu uuuu ccp1con 15h 0000 0000 0000 0000 uuuu uuuu pwm1con 16h 0000 0000 0000 0000 uuuu uuuu eccpas 17h 0000 0000 0000 0000 uuuu uuuu wdtcon 18h ---0 1000 ---0 1000 ---u uuuu cmcon0 19h 0000 0000 0000 0000 uuuu uuuu cmcon1 1ah ---- --10 ---- --10 ---- --uu adresh 1eh xxxx xxxx uuuu uuuu uuuu uuuu adcon0 1fh 00-0 0000 00-0 0000 uu-u uuuu option_reg 81h 1111 1111 1111 1111 uuuu uuuu trisa 85h --11 1111 --11 1111 --uu uuuu trisc 87h --11 1111 --11 1111 --uu uuuu pie1 8ch 0000 0000 0000 0000 uuuu uuuu pcon 8eh --01 --0x --0u --uu (1, 5) --uu --uu osccon 8fh -110 x000 -110 x000 -uuu uuuu osctune 90h ---0 0000 ---u uuuu ---u uuuu ansel 91h 1111 1111 1111 1111 uuuu uuuu pr2 92h 1111 1111 1111 1111 1111 1111 legend: u = unchanged, x = unknown, ? = unimplemented bit, reads as ? 0 ?, q = value depends on condition. note 1: if v dd goes too low, power-on reset will be activated and registers will be affected differently. 2: one or more bits in intcon and/or pir1 will be affected (to cause wake-up). 3: when the wake-up is due to an interrupt and the gie bit is set, the pc is loaded with the interrupt vector (0004h). 4: see table 12-5 for reset value for specific condition. 5: if reset was due to brown-out, then bit 0 = 0 . all other resets will cause bit 0 = u .
pic16f684 ds41202c-page 100 preliminary ? 2004 microchip technology inc. table 12-5: initialization condition for special registers wpua 95h --11 -111 --11 -111 uuuu uuuu ioca 96h --00 0000 --00 0000 --uu uuuu vrcon 99h 0-0- 0000 0-0- 0000 u-u- uuuu eedat 9ah 0000 0000 0000 0000 uuuu uuuu eeadr 9bh 0000 0000 0000 0000 uuuu uuuu eecon1 9ch ---- x000 ---- q000 ---- uuuu eecon2 9dh ---- ---- ---- ---- ---- ---- adresl 9eh xxxx xxxx uuuu uuuu uuuu uuuu adcon1 9fh -000 ---- -000 ---- -uuu ---- condition program counter status register pcon register power-on reset 000h 0001 1xxx --01 --0x mclr reset during normal operation 000h 000u uuuu --0u --uu mclr reset during sleep 000h 0001 0uuu --0u --uu wdt reset 000h 0000 uuuu --0u --uu wdt wake-up pc + 1 uuu0 0uuu --uu --uu brown-out detect 000h 0001 1uuu --01 --10 interrupt wake-up from sleep pc + 1 (1) uuu1 0uuu --uu --uu legend: u = unchanged, x = unknown, ? = unimplemented bit, reads as ? 0 ?. note 1: when the wake-up is due to an interrupt and global interrupt enable bit, gie, is set, the pc is loaded with the interrupt vector (0004h) after execution of pc + 1. table 12-4: initialization condition for register (continued) register address power-on reset mclr reset wdt reset (continued) brown-out detect (1) wake-up from sleep through interrupt wake-up from sleep through wdt time-out (continued) legend: u = unchanged, x = unknown, ? = unimplemented bit, reads as ? 0 ?, q = value depends on condition. note 1: if v dd goes too low, power-on reset will be activated and registers will be affected differently. 2: one or more bits in intcon and/or pir1 will be affected (to cause wake-up). 3: when the wake-up is due to an interrupt and the gie bit is set, the pc is loaded with the interrupt vector (0004h). 4: see table 12-5 for reset value for specific condition. 5: if reset was due to brown-out, then bit 0 = 0 . all other resets will cause bit 0 = u .
? 2004 microchip technology inc. preliminary ds41202c-page 101 pic16f684 12.4 interrupts the pic16f684 has 11 sources of interrupt: external interrupt ra2/int tmr0 overflow interrupt porta change interrupts 2 comparator interrupts a/d interrupt timer1 overflow interrupt timer2 match interrupt eeprom data write interrupt fail-safe clock monitor interrupt enhanced ccp interrupt the interrupt control register (intcon) and peripheral interrupt request register 1 (pir1) record individual interrupt requests in flag bits. the intcon register also has individual and global interrupt enable bits. a global interrupt enable bit, gie (intcon<7>), enables (if set) all unmasked interrupts, or disables (if cleared) all interrupts. individual interrupts can be disabled through their corresponding enable bits in the intcon register and pie1 register. gie is cleared on reset. the return from interrupt instruction, retfie , exits the interrupt routine, as well as sets the gie bit, which re-enables unmasked interrupts. the following interrupt flags are contained in the intcon register: int pin interrupt porta change interrupt tmr0 overflow interrupt the peripheral interrupt flags are contained in the special register, pir1. the corresponding interrupt enable bit is contained in special register, pie1. the following interrupt flags are contained in the pir1 register: eeprom data write interrupt a/d interrupt 2 comparator interrupts timer1 overflow interrupt timer2 match interrupt fail-safe clock monitor interrupt enhanced ccp interrupt when an interrupt is serviced: the gie is cleared to disable any further interrupt. the return address is pushed onto the stack. the pc is loaded with 0004h. for external interrupt events, such as the int pin or porta change interrupt, the interrupt latency will be three or four instruction cycles. the exact latency depends upon when the interrupt event occurs (see figure 12-8). the latency is the same for one or two- cycle instructions. once in the interrupt service routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. the interrupt flag bit(s) must be cleared in software before re-enabling interrupts to avoid multiple interrupt requests. for additional information on timer1, timer2, comparators, a/d, data eeprom or enhanced ccp modules, refer to the respective peripheral section. 12.4.1 ra2/int interrupt external interrupt on ra2/int pin is edge-triggered; either rising if the intedg bit (option<6>) is set, or falling, if the intedg bit is clear. when a valid edge appears on the ra2/int pin, the intf bit (intcon<1>) is set. this interrupt can be disabled by clearing the inte control bit (intcon<4>). the intf bit must be cleared in software in the interrupt service routine before re-enabling this interrupt. the ra2/int interrupt can wake-up the processor from sleep, if the inte bit was set prior to going into sleep. the status of the gie bit decides whether or not the processor branches to the interrupt vector following wake-up (0004h). see section 12.7 ?power-down mode (sleep)? for details on sleep and figure 12-10 for timing of wake-up from sleep through ra2/int interrupt. note 1: individual interrupt flag bits are set, regardless of the status of their corresponding mask bit or the gie bit. 2: when an instruction that clears the gie bit is executed, any interrupts that were pending for execution in the next cycle are ignored. the interrupts, which were ignored, are still pending to be serviced when the gie bit is set again. note: the ansel (91h) and cmcon0 (19h) registers must be initialized to configure an analog channel as a digital input. pins configured as analog inputs will read ? 0 ?.
pic16f684 ds41202c-page 102 preliminary ? 2004 microchip technology inc. 12.4.2 tmr0 interrupt an overflow (ffh 00h) in the tmr0 register will set the t0if (intcon<2>) bit. the interrupt can be enabled/disabled by setting/clearing t0ie (intcon<5>) bit. see section 5.0 ?timer0 module? for operation of the timer0 module. 12.4.3 porta interrupt an input change on porta change sets the raif (intcon<0>) bit. the interrupt can be enabled/ disabled by setting/clearing the raie (intcon<3>) bit. plus, individual pins can be configured through the ioca register. figure 12-7: interrupt logic note: if a change on the i/o pin should occur when the read operation is being executed (start of the q2 cycle), then the raif interrupt flag may not get set. tmr1if tmr1ie c1if c1ie t0if t0ie intf inte raif raie gie peie wake-up (if in sleep mode) interrupt to cpu eeie eeif adif adie ioc-ra0 ioca0 ioc-ra1 ioca1 ioc-ra2 ioca2 ioc-ra3 ioca3 ioc-ra4 ioca4 ioc-ra5 ioca5 tmr2if tmr2ie ccp1if ccp1ie osfif osfie c2if c2ie
? 2004 microchip technology inc. preliminary ds41202c-page 103 pic16f684 figure 12-8: int pin interrupt timing table 12-6: summary of interrupt registers addressnamebit 7bit 6bit 5bit 4bit 3bit 2 bit 1bit 0 value on por, bod value on all other resets 0bh, 8bh intcon gie peie t0ie inte raie t0if intf raif 0000 0000 0000 0000 0ch pir1 eeif adif ccp1if c2if c1if osfif tmr2if tmr1if 0000 0000 0000 0000 8ch pie1 eeie adie ccp1ie c2ie c1ie osfie tmr2ie tmr1ie 0000 0000 0000 0000 legend: x = unknown, u = unchanged, ? = unimplemented read as ? 0 ?, q = value depends upon condition. shaded cells are not used by the interrupt module. q2 q1 q3 q4 q2 q1 q3 q4 q2 q1 q3 q4 q2 q1 q3 q4 q2 q1 q3 q4 osc1 clkout int pin intf flag (intcon<1>) gie bit (intcon<7>) instruction flow pc instruction fetched instruction executed interrupt latency pc pc + 1 pc + 1 0004h 0005h inst (0004h) inst (0005h) dummy cycle inst (pc) inst (pc + 1) inst (pc ? 1) inst (0004h) dummy cycle inst (pc) ? note 1: intf flag is sampled here (every q1). 2: asynchronous interrupt latency = 3-4 t cy . synchronous latency = 3 t cy , where t cy = instruction cycle time. latency is the same whether inst (pc) is a single cycle or a 2-cycle instruction. 3: clkout is available only in intosc and rc oscillator modes. 4: for minimum width of int pulse, refer to ac specifications in section 15.0 ?electrical specifications? . 5: intf is enabled to be set any time during the q4-q1 cycles. (1) (2) (3) (4) (5) (1)
pic16f684 ds41202c-page 104 preliminary ? 2004 microchip technology inc. 12.5 context saving during interrupts during an interrupt, only the return pc value is saved on the stack. typically, users may wish to save key registers during an interrupt (e.g., w and status registers). this must be implemented in software. since the lower 16 bytes of all banks are common in the pic16f684 (see figure 2-2), temporary holding registers, w_temp and status_temp, should be placed in here. these 16 locations do not require banking and therefore, make it easier to context save and restore. the same code shown in example 12-1 can be used to: store the w register store the status register execute the isr code restore the status (and bank select bit register) restore the w register example 12-1: saving status and w registers in ram note: the pic16f684 normally does not require saving the pclath. however, if computed goto s are used in the isr and the main code, the pclath must be saved and restored in the isr. movwf w_temp ;copy w to temp register swapf status,w ;swap status to be saved into w clrf status ;bank 0, regardless of current bank, clears irp,rp1,rp0 movwf status_temp ;save status to bank zero status_temp register : :(isr) ;insert user code here : swapf status_temp,w ;swap status_temp register into w ;(sets bank to original state) movwf status ;move w into status register swapf w_temp,f ;swap w_temp swapf w_temp,w ;swap w_temp into w
? 2004 microchip technology inc. preliminary ds41202c-page 105 pic16f684 12.6 watchdog timer (wdt) for pic16f684, the wdt has been modified from previous pic16 devices. the new wdt is code and functionally compatible with previous pic16 wdt modules and adds a 16-bit prescaler to the wdt. this allows the user to have a scaler value for the wdt and tmr0 at the same time. in addition, the wdt time-out value can be extended to 268 seconds. wdt is cleared under certain conditions described in table 12-7. 12.6.1 wdt oscillator the wdt derives its time base from the 31 khz lfintosc. the lts bit does not reflect that the lfintosc is enabled. the value of wdtcon is ? ---0 1000 ? on all resets. this gives a nominal time base of 16 ms, which is compatible with the time base generated with previous pic16 microcontroller versions. a new prescaler has been added to the path between the intrc and the multiplexers used to select the path for the wdt. this prescaler is 16 bits and can be programmed to divide the intrc by 32 to 65536, giving the wdt a nominal range of 1 ms to 268s. 12.6.2 wdt control the wdte bit is located in the configuration word register. when set, the wdt runs continuously. when the wdte bit in the configuration word register is set, the swdten bit (wdtcon<0>) has no effect. if wdte is clear, then the swdten bit can be used to enable and disable the wdt. setting the bit will enable it and clearing the bit will disable it. the psa and ps<2:0> bits (option_reg) have the same function as in previous versions of the pic16 family of microcontrollers. see section 5.0 ?timer0 module? for more information. figure 12-9: watchdog timer block diagram note: when the oscillator start-up timer (ost) is invoked, the wdt is held in reset, because the wdt ripple counter is used by the ost to perform the oscillator delay count. when the ost count has expired, the wdt will begin counting (if enabled). table 12-7: wdt status conditions wdt wdte = 0 cleared clrwdt command oscillator fail detected exit sleep + system clock = t1osc, extrc, intrc, extclk exit sleep + system clock = xt, hs, lp cleared until the end of ost 31 khz psa 16-bit wdt prescaler from tmr0 clock source prescaler (1) 8 ps<2:0> psa wdt time-out to tmr0 wdtps<3:0> wdte from the configuration word register 1 1 0 0 swdten from wdtcon lfintosc clock note 1: this is the shared timer0/wdt prescaler. see section 5.4 ?prescaler? for more information.
pic16f684 ds41202c-page 106 preliminary ? 2004 microchip technology inc. register 12-3: wdtcon ? watchdog timer control register (address: 18h) table 12-8: summary of watchdog timer registers u-0 u-0 u-0 r/w-0 r/w-1 r/w-0 r/w-0 r/w-0 ? ? ? wdtps3 wdtps2 wdtps1 wdtps0 swdten bit 7 bit 0 bit 7-5 unimplemented: read as ? 0 ? bit 4-1 wdtps<3:0>: watchdog timer period select bits bit value = prescale rate 0000 = 1:32 0001 = 1:64 0010 = 1:128 0011 = 1:256 0100 = 1:512 (reset value) 0101 = 1:1024 0110 = 1:2048 0111 = 1:4096 1000 = 1:8192 1001 = 1:16384 1010 = 1:32768 1011 = 1:65536 1100 = reserved 1101 = reserved 1110 = reserved 1111 = reserved bit 0 swdten: software enable or disable the watchdog timer (1) 1 = wdt is turned on 0 = wdt is turned off (reset value) note 1: if wdte configuration bit = 1 , then wdt is always enabled, irrespective of this control bit. if wdte configuration bit = 0 , then it is possible to turn wdt on/off with this control bit. 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 address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 18h wdtcon ? ? ? wdtps3 wdtps2 wstps1 wdtps0 swdten 81h option_reg rapu intedg t0cs t0se psa ps2 ps1 ps0 2007h (1) config cpd cp mclre pwrte wdte fosc2 fosc1 fosc0 legend: shaded cells are not used by the watchdog timer. note 1: see register 12-1 for operation of all configuration word register bits.
? 2004 microchip technology inc. preliminary ds41202c-page 107 pic16f684 12.7 power-down mode (sleep) the power-down mode is entered by executing a sleep instruction. if the watchdog timer is enabled: wdt will be cleared but keeps running. pd bit in the status register is cleared. to bit is set. oscillator driver is turned off. i/o ports maintain the status they had before sleep was executed (driving high, low or high-impedance). for lowest current consumption in this mode, all i/o pins should be either at v dd or v ss , with no external circuitry drawing current from the i/o pin and the comparators and cv ref should be disabled. i/o pins that are high-impedance inputs should be pulled high or low externally to avoid switching currents caused by floating inputs. the t0cki input should also be at v dd or v ss for lowest current consumption. the contribution from on-chip pull-ups on porta should be considered. the mclr pin must be at a logic high level. 12.7.1 wake-up from sleep the device can wake-up from sleep through one of the following events: 1. external reset input on mclr pin. 2. watchdog timer wake-up (if wdt was enabled). 3. interrupt from ra2/int pin, porta change or a peripheral interrupt. the first event will cause a device reset. the two latter events are considered a continuation of program execution. the to and pd bits in the status register can be used to determine the cause of device reset. the pd bit, which is set on power-up, is cleared when sleep is invoked. to bit is cleared if wdt wake-up occurred. the following peripheral interrupts can wake the device from sleep: 1. tmr1 interrupt. timer1 must be operating as an asynchronous counter. 2. eccp capture mode interrupt. 3. special event trigger (timer1 in asynchronous mode using an external clock). 4. a/d conversion (when a/d clock source is rc). 5. eeprom write operation completion. 6. comparator output changes state. 7. interrupt-on-change. 8. external interrupt from int pin. other peripherals cannot generate interrupts since during sleep, no on-chip clocks are present. when the sleep instruction is being executed, the next instruction (pc + 1) is prefetched. for the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). wake-up is regardless of the state of the gie bit. if the gie bit is clear (disabled), the device continues execution at the instruction after the sleep instruction. if the gie bit is set (enabled), the device executes the instruction after the sleep instruction, then branches to the interrupt address (0004h). in cases where the execution of the instruction following sleep is not desirable, the user should have a nop after the sleep instruction. the wdt is cleared when the device wakes up from sleep, regardless of the source of wake-up. 12.7.2 wake-up using interrupts when global interrupts are disabled (gie cleared) and any interrupt source has both its interrupt enable bit and interrupt flag bit set, one of the following will occur: if the interrupt occurs before the execution of a sleep instruction, the sleep instruction will complete as a nop . therefore, the wdt and wdt prescaler and postscaler (if enabled) will not be cleared, the to bit will not be set and the pd bit will not be cleared. if the interrupt occurs during or after the execution of a sleep instruction, the device will immediately wake-up from sleep. the sleep instruction will be completely executed before the wake-up. therefore, the wdt and wdt prescaler and postscaler (if enabled) will be cleared, the to bit will be set and the pd bit will be cleared. even if the flag bits were checked before executing a sleep instruction, it may be possible for flag bits to become set before the sleep instruction completes. to determine whether a sleep instruction executed, test the pd bit. if the pd bit is set, the sleep instruction was executed as a nop . to ensure that the wdt is cleared, a clrwdt instruction should be executed before a sleep instruction. note: it should be noted that a reset generated by a wdt time-out does not drive mclr pin low. note: if the global interrupts are disabled (gie is cleared), but any interrupt source has both its interrupt enable bit and the correspond- ing interrupt flag bits set, the device will immediately wake-up from sleep. the sleep instruction is completely executed.
pic16f684 ds41202c-page 108 preliminary ? 2004 microchip technology inc. figure 12-10: wake-up from sleep through interrupt 12.8 code protection if the code protection bit(s) have not been programmed, the on-chip program memory can be read out using icsp ? for verification purposes. 12.9 id locations four memory locations (2000h-2003h) are designated as id locations where the user can store checksum or other code identification numbers. these locations are not accessible during normal execution but are readable and writable during program/verify mode. only the least significant 7 bits of the id locations are used. 12.10 in-circuit serial programming the pic16f684 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 programming voltage this allows customers to manufacture boards with unprogrammed devices and then program the micro- controller just before shipping the product. this also allows the most recent firmware or a custom firmware to be programmed. the device is placed into a program/verify mode by holding the ra0 and ra1 pins low, while raising the mclr (v pp ) pin from v il to v ihh . see the ? pic12f6xx/ 16f6xx memory programming specification? (ds41204) for more information. ra0 becomes the programming data and ra1 becomes the programming clock. both ra0 and ra1 are schmitt trigger inputs in this mode. after reset, to place the device into program/verify mode, the program counter (pc) is at location 00h. a 6-bit command is then supplied to the device. depending on the command, 14 bits of program data are then supplied to or from the device, depending on whether the command was a load or a read. for complete details of serial programming, please refer to the ? pic12f6xx/16f6xx memory programming specification? (ds41204). a typical in-circuit serial programming connection is shown in figure 12-11. q1 q2 q3 q4 q1 q2 q3 q4 q1 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 clkout (4) int pin intf flag (intcon<1>) gie bit (intcon<7>) instruction flow pc instruction fetched instruction executed pc pc + 1 pc + 2 inst(pc) = sleep inst(pc ? 1) inst(pc + 1) sleep processor in sleep interrupt latency (3) inst(pc + 2) inst(pc + 1) inst(0004h) inst(0005h) inst(0004h) dummy cycle pc + 2 0004h 0005h dummy cycle t ost (2) pc + 2 note 1: xt, hs or lp oscillator mode assumed. 2: t ost = 1024 t osc (drawing not to scale). this delay does not apply to ec and rc oscillator modes. 3: gie = ? 1 ? assumed. in this case after wake-up, the processor jumps to 0004h. if gie = ? 0 ?, execution will continue in-line. 4: clkout is not available in xt, hs, lp or ec oscillator modes, but shown here for timing reference. note: the entire data eeprom and flash program memory will be erased when the code protection is turned off. see the ? pic12f6xx/16f6xx memory program- ming specification? (ds41204) for more information.
? 2004 microchip technology inc. preliminary ds41202c-page 109 pic16f684 figure 12-11: typical in-circuit serial programming connection 12.11 in-circuit debugger since in-circuit debugging requires access to the data and mclr pins, mplab ? icd 2 development with an 14-pin device is not practical. a special 20-pin pic16f684 icd device is used with mplab icd 2 to provide separate clock, data and mclr pins and frees all normally available pins to the user. a special debugging adapter allows the icd device to be used in place of a pic16f684 device. the debugging adapter is the only source of the icd device. when the icd pin on the pic16f684 icd device is held low, the in-circuit debugger functionality is enabled. this function allows simple debugging functions when used with mplab icd 2. when the microcontroller has this feature enabled, some of the resources are not available for general use. table 12-9 shows which features are consumed by the background debugger. table 12-9: debugger resources for more information, see ? mplab ? icd 2 in-circuit debugger user?s guide? (ds51331), available on microchip?s web site (www.microchip.com). figure 12-12: 20-pin icd pinout external connector signals to n o r m a l connections to n o rm a l connections pic16f684 v dd v ss mclr /v pp /ra3 ra1 ra0 +5v 0v v pp clk data i/o * * * * * isolation devices (as required) resource description i/o pins icdclk, icddata stack 1 level program memory address 0h must be nop 700h-7ffh 20-pin pdip pic16f684 -icd in-circuit debug device nc icdmclr /v pp v dd ra5 ra4 ra3 icdclk icddata vss ra0 icd nc ra1 ra2 rc5 rc4 rc3 rc0 rc1 rc2 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11
pic16f684 ds41202c-page 110 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 111 pic16f684 13.0 instruction set summary the pic16f684 instruction set is highly orthogonal and is comprised of three basic categories: byte-oriented operations bit-oriented operations literal and control operations each pic16 instruction is a 14-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 formats for each of the categories is presented in figure 13-1, while the various opcode fields are summarized in table 13-1. table 13-2 lists the instructions recognized by the mpasm tm assembler. a complete description of each instruction is also available in the ? picmicro ? mid- range mcu family reference manual? (ds33023). for byte-oriented instructions, ? f ? represents a file register designator and ? d ? represents a destination designator. the file register designator specifies which file register is to be used by the instruction. the destination designator specifies where the result of the operation is to be placed. if ? d ? is zero, the result is placed in the w register. if ? d ? is one, the result is placed in the file register specified in the instruction. for bit-oriented instructions, ? b ? represents a bit field designator, which selects the bit affected by the operation, while ? f ? represents the address of the file in which the bit is located. for literal and control operations, ? k ? represents an 8-bit or 11-bit constant, or literal value. one instruction cycle consists of four oscillator periods; for an oscillator frequency of 4 mhz, this gives a normal instruction execution time of 1 s. all instructions are executed within a single instruction cycle, unless a conditional test is true, or the program counter is changed as a result of an instruction. when this occurs, the execution takes two instruction cycles, with the second cycle executed as a nop . all instruction examples use the format ? 0xhh ? to represent a hexadecimal number, where ? h ? signifies a hexadecimal digit. 13.1 read-modify-write operations any instruction that specifies a file register as part of the instruction performs a read-modify-write (r-m-w) operation. the register is read, the data is modified, and the result is stored according to either the instruc- tion, or the destination designator ? d ?. a read operation is performed on a register even if the instruction writes to that register. for example, a clrf gpio instruction will read gpio, clear all the data bits, then write the result back to gpio. this example would have the unintended result of clearing the condition that set the gpif flag. table 13-1: opcode field descriptions figure 13-1: general format for instructions note: to maintain upward compatibility with future products, do not use the option and tris instructions. field description f register file address (0x00 to 0x7f) w working register (accumulator) b bit address within an 8-bit file register k literal field, constant data or label x don?t care location (= 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. d destination select; d = 0 : store result in w, d = 1 : store result in file register f. default is d = 1. pc program counter to time-out bit pd power-down bit byte-oriented file register operations 13 8 7 6 0 d = 0 for destination w opcode d f (file #) d = 1 for destination f f = 7-bit file register address bit-oriented file register operations 13 10 9 7 6 0 opcode b (bit #) f (file #) b = 3-bit bit address f = 7-bit file register address literal and control operations 13 8 7 0 opcode k (literal) k = 8-bit immediate value 13 11 10 0 opcode k (literal) k = 11-bit immediate value general call and goto instructions only
pic16f684 ds41202c-page 112 preliminary ? 2004 microchip technology inc. table 13-2: pic16f684 instruction set mnemonic, operands description cycles 14-bit opcode status affected notes msb lsb byte-oriented file register operations addwf andwf clrf clrw comf decf decfsz incf incfsz iorwf movf movwf nop rlf rrf subwf swapf xorwf f, d f, d f ? f, d f, d f, d f, d f, d f, d f, d f ? f, d f, d f, d f, d f, d add w and f and w with f clear f clear w complement f decrement f decrement f, skip if 0 increment f increment f, skip if 0 inclusive or w with f move f move w to f no operation rotate left f through carry rotate right f through carry subtract w from f swap nibbles in f exclusive or w with f 1 1 1 1 1 1 1 (2) 1 1 (2) 1 1 1 1 1 1 1 1 1 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0111 0101 0001 0001 1001 0011 1011 1010 1111 0100 1000 0000 0000 1101 1100 0010 1110 0110 dfff dfff lfff 0xxx dfff dfff dfff dfff dfff dfff dfff lfff 0xx0 dfff dfff dfff dfff dfff ffff ffff ffff xxxx ffff ffff ffff ffff ffff ffff ffff ffff 0000 ffff ffff ffff ffff ffff c, dc, z z z z z z z z z c c c, dc, z z 1, 2 1, 2 2 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 bit-oriented file register operations bcf bsf btfsc btfss f, b f, b f, b f, b bit clear f bit set f bit test f, skip if clear bit test f, skip if set 1 1 1 (2) 1 (2) 01 01 01 01 00bb 01bb 10bb 11bb bfff bfff bfff bfff ffff ffff ffff ffff 1, 2 1, 2 3 3 literal and control operations addlw andlw call clrwdt goto iorlw movlw retfie retlw return sleep sublw xorlw k k k ? k k k ? k ? ? k k add literal and w and literal with w call subroutine clear watchdog timer go to address inclusive or literal with w move literal to w return from interrupt return with literal in w return from subroutine go into standby mode subtract w from literal exclusive or literal with w 1 1 2 1 2 1 1 2 2 2 1 1 1 11 11 10 00 10 11 11 00 11 00 00 11 11 111x 1001 0kkk 0000 1kkk 1000 00xx 0000 01xx 0000 0000 110x 1010 kkkk kkkk kkkk 0110 kkkk kkkk kkkk 0000 kkkk 0000 0110 kkkk kkkk kkkk kkkk kkkk 0100 kkkk kkkk kkkk 1001 kkkk 1000 0011 kkkk kkkk c, dc, z z to , pd z to , pd c, dc, z z note 1: when an i/o register is modified as a function of itself (e.g., movf gpio, 1 ), 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 tm r0 register (and where applicable, d = 1 ), the prescaler will be cleared if assigned to the timer0 module. 3: if the program counter (pc) is modified, or a conditional te st is true, the instruction requires two cycles. the second cycle is executed as a nop . note: additional information on the mid-range instruction set is available in the ? picmicro ? mid-range mcu family reference manual ? (ds33023).
? 2004 microchip technology inc. preliminary ds41202c-page 113 pic16f684 13.2 instruction descriptions addlw add literal and w syntax: [ label ] addlw k operands: 0 k 255 operation: (w) + k (w) status affected: c, dc, z description: the contents of the w register are added to the eight-bit literal ?k? and the result is placed in the w register. addwf add w and f syntax: [ label ] addwf f,d operands: 0 f 127 d [ 0,1 ] operation: (w) + (f) (destination) status affected: c, dc, z description: add the contents of the w register with register ?f?. if ?d? is ? 0 ?, the result is stored in the w register. if ?d? is ? 1 ?, the result is stored back in register ?f?. andlw and literal with w syntax: [ label ] andlw k operands: 0 k 255 operation: (w) .and. (k) (w) status affected: z description: the contents of w register are and?ed with the eight-bit literal ?k?. the result is placed in the w register. andwf and w with f syntax: [ label ] andwf f,d operands: 0 f 127 d [ 0,1 ] operation: (w) .and. (f) (destination) status affected: z description: and the w register with register ?f?. if ?d? is ? 0 ?, the result is stored in the w register. if ?d? is ? 1 ?, the result is stored back in register ?f?. bcf bit clear f syntax: [ label ] bcf f,b operands: 0 f 127 0 b 7 operation: 0 (f) status affected: none description: bit ?b? in register ?f? is cleared. bsf bit set f syntax: [ label ] bsf f,b operands: 0 f 127 0 b 7 operation: 1 (f) status affected: none description: bit ?b? in register ?f? is set. btfsc bit test, skip if clear syntax: [ label ] btfsc f,b operands: 0 f 127 0 b 7 operation: skip if (f) = 0 status affected: none description: if bit ?b? in register ?f? is ? 1 ?, the next instruction is executed. if bit ?b?, in register ?f?, is ? 0 ?, the next instruction is discarded, and a nop is executed instead, making this a 2-cycle instruction.
pic16f684 ds41202c-page 114 preliminary ? 2004 microchip technology inc. btfss bit test f, skip if set syntax: [ label ] btfss f,b operands: 0 f 127 0 b < 7 operation: skip if (f) = 1 status affected: none description: if bit ?b? in register ?f? is ? 0 ?, the next instruction is executed. if bit ?b? is ? 1 ?, then the next instruction is discarded and a nop is executed instead, making this a 2-cycle instruction. call call subroutine syntax: [ label ] call k operands: 0 k 2047 operation: (pc)+ 1 tos, k pc<10:0>, (pclath<4:3>) pc<12:11> status affected: none description: call subroutine. first, return address (pc + 1) is pushed onto the stack. the eleven-bit immediate address is loaded into pc bits <10:0>. the upper bits of the pc are loaded from pclath. call is a two-cycle instruction. clrf clear f syntax: [ label ] clrf f operands: 0 f 127 operation: 00h (f) 1 z status affected: z description: the contents of register ?f? are cleared and the z bit is set. clrw clear w syntax: [ label ] clrw operands: none operation: 00h (w) 1 z status affected: z description: w register is cleared. zero bit (z) is set. clrwdt clear watchdog timer syntax: [ label ] clrwdt operands: none operation: 00h wdt 0 wdt prescaler, 1 to 1 pd status affected: to , pd description: clrwdt instruction resets the watchdog timer. it also resets the prescaler of the wdt. status bits to and pd are set. comf complement f syntax: [ label ] comf f,d operands: 0 f 127 d [0,1] operation: (f ) (destination) status affected: z 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?. decf decrement f syntax: [ label ] decf f,d operands: 0 f 127 d [0,1] operation: (f) - 1 (destination) status affected: z description: decrement register ?f?. if ?d? is ? 0 ?, the result is stored in the w register. if ?d? is ? 1 ?, the result is stored back in register ?f?.
? 2004 microchip technology inc. preliminary ds41202c-page 115 pic16f684 decfsz decrement f, skip if 0 syntax: [ label ] decfsz f,d operands: 0 f 127 d [0,1] operation: (f) - 1 (destination); skip if result = 0 status affected: none description: the contents of register ?f? are decremented. if ?d? is ? 0 ?, the result is placed in the w register. if ?d? is ? 1 ?, the result is placed back in register ?f?. if the result is ? 1 ?, the next instruction is executed. if the result is ? 0 ?, then a nop is executed instead, making it a 2-cycle instruction. goto unconditional branch syntax: [ label ] goto k operands: 0 k 2047 operation: k pc<10:0> pclath<4:3> pc<12:11> status affected: none description: goto is an unconditional branch. the eleven-bit immediate value is loaded into pc bits <10:0>. the upper bits of pc are loaded from pclath<4:3>. goto is a two-cycle instruction. incf increment f syntax: [ label ] incf f,d operands: 0 f 127 d [0,1] operation: (f) + 1 (destination) status affected: z description: the contents of register ?f? are incremented. if ?d? is ? 0 ?, the result is placed in the w register. if ?d? is ? 1 ?, the result is placed back in register ?f?. incfsz increment f, skip if 0 syntax: [ label ] incfsz f,d operands: 0 f 127 d [0,1] operation: (f) + 1 (destination), skip if result = 0 status affected: none description: the contents of register ?f? are incremented. if ?d? is ? 0 ?, the result is placed in the w register. if ?d? is ? 1 ?, the result is placed back in register ?f?. if the result is ? 1 ?, the next instruction is executed. if the result is ? 0 ?, a nop is executed instead, making it a 2-cycle instruction. iorlw inclusive or literal with w syntax: [ label ] iorlw k operands: 0 k 255 operation: (w) .or. k (w) status affected: z description: the contents of the w register are or?ed with the eight-bit literal ?k?. the result is placed in the w register. iorwf inclusive or w with f syntax: [ label ] iorwf f,d operands: 0 f 127 d [0,1] operation: (w) .or. (f) (destination) status affected: z description: inclusive or the w register with register ?f?. if ?d? is ? 0 ?, the result is placed in the w register. if ?d? is ? 1 ?, the result is placed back in register ?f?.
pic16f684 ds41202c-page 116 preliminary ? 2004 microchip technology inc. movf move f syntax: [ label ] movf f,d operands: 0 f 127 d [0,1] operation: (f) (dest) status affected: z description: the contents of register f is moved to a destination dependent upon the status of d. if d = 0 , destination is w register. if d = 1 , the destination is file register f itself. d = 1 is useful to test a file register since status flag z is affected. words: 1 cycles: 1 example movf fsr, 0 after instruction w= value in fsr register z= 1 movlw move literal to w syntax: [ label ] movlw k operands: 0 k 255 operation: k (w) status affected: none description: the eight bit literal ?k? is loaded into w register. the don?t cares will assemble as ? 0 ?s. words: 1 cycles: 1 example movlw 0x5a after instruction w= 0x5a movwf move w to f syntax: [ label ] movwf f operands: 0 f 127 operation: (w) (f) status affected: none description: move data from w register to register ?f?. words: 1 cycles: 1 example movw f option before instruction option = 0xff w = 0x4f after instruction option = 0x4f w = 0x4f nop no operation syntax: [ label ] nop operands: none operation: no operation status affected: none description: no operation. words: 1 cycles: 1 example nop
? 2004 microchip technology inc. preliminary ds41202c-page 117 pic16f684 retfie return from interrupt syntax: [ label ] retfie operands: none operation: tos pc, 1 gie status affected: none description: return from interrupt. stack is poped and top-of-stack (tos) is loaded in the pc. interrupts are enabled by setting global interrupt enable bit, gie (intcon<7>). this is a two-cycle instruction. words: 1 cycles: 2 example retfie after interrupt pc = tos gie = 1 retlw return with literal in w syntax: [ label ] retlw k operands: 0 k 255 operation: k (w); tos pc status affected: none description: the w register is loaded with the eight bit literal ?k?. the program counter is loaded from the top of the stack (the return address). this is a two-cycle instruction. words: 1 cycles: 2 example table call table;w contains table ;offset value ;w now has table value addwf pc ;w = offset retlw k1 ;begin table retlw k2 ; retlw kn ; end of table before instruction w = 0x07 after instruction w = value of k8 return return from subroutine syntax: [ label ] return operands: none operation: tos pc status affected: none description: return from subroutine. the stack is poped and the top of the stack (tos) is loaded into the program counter. this is a two-cycle instruction. rlf rotate left f through carry syntax: [ label ] rlf f,d operands: 0 f 127 d [0,1] operation: see description below status affected: c 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 the w register. if ?d? is ? 1 ?, the result is stored back in register ?f?. words: 1 cycles: 1 example rlf reg1,0 before instruction reg1 = 1110 0110 c=0 after instruction reg1 = 1110 0110 w = 1100 1100 c=1 register f c
pic16f684 ds41202c-page 118 preliminary ? 2004 microchip technology inc. rrf rotate right f through carry syntax: [ label ] rrf f,d operands: 0 f 127 d [0,1] operation: see description below status affected: c 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 the w register. if ?d? is ? 1 ?, the result is placed back in register ?f?. sleep enter sleep mode syntax: [ label ] sleep operands: none operation: 00h wdt, 0 wdt prescaler, 1 to , 0 pd status affected: to , pd description: the power-down status bit, pd is cleared. time-out status bit, to is set. watchdog timer and its prescaler are cleared. the processor is put into sleep mode with the oscillator stopped. sublw subtract w from literal syntax: [ label ] sublw k operands: 0 k 255 operation: k - (w) ( w) status affected: c, dc, z description: the w register is subtracted (2?s complement method) from the eight-bit literal ?k?. the result is placed in the w register. register f c subwf subtract w from f syntax: [ label ] subwf f,d operands: 0 f 127 d [0,1] operation: (f) - (w) ( destination) status affected: c, dc, z description: subtract (2?s complement method) w register from register ?f?. if ?d? is ? 0 ?, the result is stored in the w register. if ?d? is ? 1 ?, the result is stored back in register ?f?. swapf swap nibbles in f syntax: [ label ] swapf f,d operands: 0 f 127 d [0,1] operation: (f<3:0>) (destination<7:4>), (f<7:4>) (destination<3:0>) status affected: none description: the upper and lower nibbles of register ?f? are exchanged. if ?d? is ? 0 ?, the result is placed in the w register. if ?d? is ? 1 ?, the result is placed in register ?f?. xorlw exclusive or literal with w syntax: [ label ] xorlw k operands: 0 k 255 operation: (w) .xor. k ( w) status affected: z description: the contents of the w register are xor?ed with the eight-bit literal ?k?. the result is placed in the w register.
? 2004 microchip technology inc. preliminary ds41202c-page 119 pic16f684 xorwf exclusive or w with f syntax: [ label ] xorwf f,d operands: 0 f 127 d [0,1] operation: (w) .xor. (f) ( destination) status affected: z description: exclusive or the contents of the w register with register ?f?. if ?d? is ? 0 ?, the result is stored in the w register. if ?d? is ? 1 ?, the result is stored back in register ?f?.
pic16f684 ds41202c-page 120 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 121 pic16f684 14.0 development support the picmicro ? 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 c17 and mplab c18 c compilers -mplink tm object linker/ mplib tm object librarian - mplab c30 c compiler - mplab asm30 assembler/linker/library simulators - mplab sim software simulator - mplab dspic30 software simulator emulators - mplab ice 2000 in-circuit emulator - mplab ice 4000 in-circuit emulator in-circuit debugger - mplab icd 2 device programmers -pro mate ? ii universal device programmer - picstart ? plus development programmer - mplab pm3 device programmer low-cost demonstration boards - picdem tm 1 demonstration board - picdem.net tm demonstration board - picdem 2 plus demonstration board - picdem 3 demonstration board - picdem 4 demonstration board - picdem 17 demonstration board - picdem 18r demonstration board - picdem lin demonstration board - picdem usb demonstration board evaluation kits -k ee l oq ? - picdem msc -microid ? -can - powersmart ? -analog 14.1 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 ? based application that contains: an interface to 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 mouse over variable inspection extensive on-line help the mplab ide allows you to: edit your source files (either assembly or c) one touch assemble (or compile) and download to picmicro 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 increasing flexibility and power. 14.2 mpasm assembler the mpasm assembler is a full-featured, universal macro assembler for all picmicro 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 ref- erence, 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
pic16f684 ds41202c-page 122 preliminary ? 2004 microchip technology inc. 14.3 mplab c17 and mplab c18 c compilers the mplab c17 and mplab c18 code development systems are complete ansi c compilers for microchip?s pic17cxxx and pic18cxxx family of microcontrollers. 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. 14.4 mplink object linker/ mplib object librarian the mplink object linker combines relocatable objects created by the mpasm assembler and the mplab c17 and mplab c18 c compilers. 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 14.5 mplab c30 c compiler the mplab c30 c compiler is a full-featured, ansi compliant, optimizing compiler that translates standard ansi c programs into dspic30f assembly language source. the compiler also supports many command line options and language extensions to take full advantage of the dspic30f device hardware capabili- ties and afford fine control of the compiler code generator. mplab c30 is distributed with a complete ansi c standard library. all library functions have been vali- dated and conform to the ansi c library standard. the library includes functions for string manipulation, dynamic memory allocation, data conversion, time- keeping and math functions (trigonometric, exponential and hyperbolic). the compiler provides symbolic information for high-level source debugging with the mplab ide. 14.6 mplab asm30 assembler, linker and librarian mplab asm30 assembler produces relocatable machine code from symbolic assembly language for dspic30f devices. mplab c30 compiler uses the assembler to produce it?s 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 14.7 mplab sim software simulator the mplab sim software simulator allows code devel- opment in a pc hosted environment by simulating the picmicro series microcontrollers on an instruction level. on any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any pin. the execu- tion can be performed in single-step, execute until break or trace mode. the mplab sim simulator fully supports symbolic debugging using the mplab c17 and mplab c18 c compilers, as well as the mpasm assembler. the software simulator offers the flexibility to develop and debug code outside of the laboratory environment, making it an excellent, economical software development tool. 14.8 mplab sim30 software simulator the mplab sim30 software simulator allows code development in a pc hosted environment by simulating the dspic30f series microcontrollers on an instruction level. on any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any of the pins. the mplab sim30 simulator fully supports symbolic debugging using the mplab c30 c compiler and mplab asm30 assembler. the simulator runs in either a command line mode for automated tasks, or from mplab ide. this high-speed simulator is designed to debug, analyze and optimize time intensive dsp routines.
? 2004 microchip technology inc. preliminary ds41202c-page 123 pic16f684 14.9 mplab ice 2000 high-performance universal in-circuit emulator the mplab ice 2000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for picmicro 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 sys- tem with enhanced trace, trigger and data monitoring features. interchangeable processor modules allow the system to be easily reconfigured for emulation of differ- ent processors. the universal architecture of the mplab ice in-circuit emulator allows expansion to support new picmicro 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. 14.10 mplab ice 4000 high-performance universal in-circuit emulator the mplab ice 4000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for high- end picmicro microcontrollers. software control of the mplab ice in-circuit emulator is provided by the mplab integrated development environment, which allows editing, building, downloading and source debugging from a single environment. the mplab icd 4000 is a premium emulator system, providing the features of mplab ice 2000, but with increased emulation memory and high-speed perfor- mance for dspic30f and pic18xxxx devices. its advanced emulator features include complex triggering and timing, up to 2 mb of emulation memory and the ability to view variables in real-time. the mplab ice 4000 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. 14.11 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 picmicro mcus and can be used to develop for these and other picmicro microcontrollers. 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-stepping and watching variables, 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 picmicro devices. 14.12 pro mate ii universal device programmer the pro mate ii is a universal, ce compliant device programmer with programmable voltage verification at v ddmin and v ddmax for maximum reliability. it features an lcd display for instructions and error messages and a modular detachable socket assembly to support various package types. in stand-alone mode, the pro mate ii device programmer can read, verify and program picmicro devices without a pc connection. it can also set code protection in this mode. 14.13 mplab pm3 device programmer the mplab pm3 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 modular 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 picmicro devices without a pc connection. it can also set code protection in this mode. mplab pm3 connects to the host pc via an rs- 232 or usb cable. mplab pm3 has high-speed com- munications and optimized algorithms for quick pro- gramming of large memory devices and incorporates an sd/mmc card for file storage and secure data appli- cations.
pic16f684 ds41202c-page 124 preliminary ? 2004 microchip technology inc. 14.14 picstart plus development programmer the picstart plus development programmer is an easy-to-use, low-cost, prototype programmer. it con- nects 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 picmicro devices 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. 14.15 picdem 1 picmicro demonstration board the picdem 1 demonstration board demonstrates the capabilities of the pic16c5x (pic16c54 to pic16c58a), pic16c61, pic16c62x, pic16c71, pic16c8x, pic17c42, pic17c43 and pic17c44. all necessary hardware and software is included to run basic demo programs. the sample microcontrollers provided with the picdem 1 demonstration board can be programmed with a pro mate ii device program- mer or a picstart plus development programmer. the picdem 1 demonstration board can be connected to the mplab ice in-circuit emulator for testing. a prototype area extends the circuitry for additional appli- cation components. features include an rs-232 interface, a potentiometer for simulated analog input, push button switches and eight leds. 14.16 picdem.net internet/ethernet demonstration board the picdem.net demonstration board is an internet/ ethernet demonstration board using the pic18f452 microcontroller and tcp/ip firmware. the board supports any 40-pin dip device that conforms to the standard pinout used by the pic16f877 or pic18c452. this kit features a user friendly tcp/ip stack, web server with html, a 24l256 serial eeprom for xmodem download to web pages into serial eeprom, icsp/mplab icd 2 interface con- nector, an ethernet interface, rs-232 interface and a 16 x 2 lcd display. also included is the book and cd-rom ?tcp/ip lean, web servers for embedded systems,? by jeremy bentham 14.17 picdem 2 plus demonstration board the picdem 2 plus demonstration board supports many 18, 28 and 40-pin microcontrollers, including pic16f87x and pic18fxx2 devices. all the neces- sary hardware and software is included to run the dem- onstration programs. the sample microcontrollers provided with the picdem 2 demonstration board can be programmed with a pro mate ii device program- mer, picstart plus development programmer, or mplab icd 2 with a universal programmer adapter. the mplab icd 2 and mplab ice in-circuit emulators may also be used with the picdem 2 demonstration board to test firmware. a prototype area extends the circuitry for additional application components. some of the features include an rs-232 interface, a 2 x 16 lcd display, a piezo speaker, an on-board temperature sensor, four leds and sample pic18f452 and pic16f877 flash microcontrollers. 14.18 picdem 3 pic16c92x demonstration board the picdem 3 demonstration board supports the pic16c923 and pic16c924 in the plcc package. all the necessary hardware and software is included to run the demonstration programs. 14.19 picdem 4 8/14/18-pin demonstration board the picdem 4 can be used to demonstrate the capa- bilities of the 8, 14 and 18-pin pic16xxxx and pic18xxxx mcus, including the pic16f818/819, pic16f87/88, pic16f62xa and the pic18f1320 family of microcontrollers. picdem 4 is intended to showcase the many features of these low pin count parts, including lin and motor control using eccp. special provisions are made for low-power operation with the supercapacitor circuit and jumpers allow on- board hardware to be disabled to eliminate current draw in this mode. included on the demo board are pro- visions for crystal, rc or canned oscillator modes, a five volt regulator for use with a nine volt wall adapter or battery, db-9 rs-232 interface, icd connector for programming via icsp and development with mplab icd 2, 2 x 16 liquid crystal display, pcb footprints for h- bridge motor driver, lin transceiver and eeprom. also included are: header for expansion, eight leds, four potentiometers, three push buttons and a proto- typing area. included with the kit is a pic16f627a and a pic18f1320. tutorial firmware is included along with the user?s guide.
? 2004 microchip technology inc. preliminary ds41202c-page 125 pic16f684 14.20 picdem 17 demonstration board the picdem 17 demonstration board is an evaluation board that demonstrates the capabilities of several microchip microcontrollers, including pic17c752, pic17c756a, pic17c762 and pic17c766. a pro- grammed sample is included. the pro mate ii device programmer, or the picstart plus development pro- grammer, can be used to reprogram the device for user tailored application development. the picdem 17 demonstration board supports program download and execution from external on-board flash memory. a generous prototype area is available for user hardware expansion. 14.21 picdem 18r pic18c601/801 demonstration board the picdem 18r demonstration board serves to assist development of the pic18c601/801 family of microchip microcontrollers. it provides hardware implementation of both 8-bit multiplexed/demultiplexed and 16-bit memory modes. the board includes 2 mb external flash memory and 128 kb sram memory, as well as serial eeprom, allowing access to the wide range of memory types supported by the pic18c601/801. 14.22 picdem lin pic16c43x demonstration board the powerful lin hardware and software kit includes a series of boards and three picmicro microcontrollers. the small footprint pic16c432 and pic16c433 are used as slaves in the lin communication and feature on-board lin transceivers. a pic16f874 flash microcontroller serves as the master. all three micro- controllers are programmed with firmware to provide lin bus communication. 14.23 pickit tm 1 flash starter kit a complete ?development system in a box?, the pickit flash starter kit includes a convenient multi-section board for programming, evaluation and development of 8/14-pin flash pic ? microcontrollers. powered via usb, the board operates under a simple windows gui. the pickit 1 starter kit includes the user?s guide (on cd rom), pickit 1 tutorial software and code for various applications. also included are mplab ? ide (integrated development environment) software, software and hardware ?tips ?n tricks for 8-pin flash pic ? microcontrollers? handbook and a usb interface cable. supports all current 8/14-pin flash pic microcontrollers, as well as many future planned devices. 14.24 picdem usb pic16c7x5 demonstration board the picdem usb demonstration board shows off the capabilities of the pic16c745 and pic16c765 usb microcontrollers. this board provides the basis for future usb products. 14.25 evaluation and programming tools in addition to the picdem series of circuits, microchip has a line of evaluation kits and demonstration software for these products. k ee l oq evaluation and programming tools for microchip?s hcs secure data products can developers kit for automotive network applications analog design boards and filter design software powersmart battery charging evaluation/ calibration kits irda ? development kit microid development and rflab tm development software seeval ? designer kit for memory evaluation and endurance calculations picdem msc demo boards for switching mode power supply, high-power ir driver, delta sigma adc and flow rate sensor check the microchip web page and the latest product selector guide for the complete list of demonstration and evaluation kits.
pic16f684 ds41202c-page 126 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 127 pic16f684 15.0 electrical specifications absolute maximum ratings (?) ambient temperature under bias................................................................................................. .........-40 to +125c storage temperature ............................................................................................................ ............ -65c to +150c voltage on v dd with respect to v ss ................................................................................................... -0.3v to +6.5v voltage on mclr with respect to vss ............................................................................................... -0.3v to +1 3.5v voltage on all other pins with respect to v ss ........................................................................... -0.3v to (v dd + 0.3v) total power dissipation (1) ............................................................................................................................... 800 mw maximum current out of v ss pin ..................................................................................................................... 300 ma maximum current into v dd pin ........................................................................................................................ 250 ma input clamp current, i ik (v i < 0 or v i > v dd ) ............................................................................................................... 20 ma output clamp current, i ok (vo < 0 or vo >v dd ) ......................................................................................................... 20 ma maximum output current sunk by any i/o pin..................................................................................... ............... 25 ma maximum output current sourced by any i/o pin .................................................................................. ............ 25 ma maximum current sunk by porta and portc (combined) .......................................................................... 200 ma maximum current sourced porta and portc (combined) .......................................................................... 200 ma note 1: power dissipation is calculated as follows: p dis = v dd x {i dd ? i oh } + {(v dd ? v oh ) x i oh } + (v o l 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. note: voltage spikes below v ss at the mclr pin, inducing currents greater than 80 ma, may cause latch-up. thus, a series resistor of 50-100 ? should be used when applying a ?low? level to the mclr pin, rather than pulling this pin directly to v ss .
pic16f684 ds41202c-page 128 preliminary ? 2004 microchip technology inc. figure 15-1: pic16f684 voltage-frequency graph, -40c t a +125c 5.5 2.0 3.5 2.5 0 3.0 4.0 4.5 5.0 4 frequency (mhz) v dd (volts) note 1: the shaded region indicates the permissible combinations of voltage and frequency. 816 12 20 10
? 2004 microchip technology inc. preliminary ds41202c-page 129 pic16f684 15.1 dc characteristics: pic16f684 -i (industrial) pic16f684 -e (extended) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. sym characteristic min typ? max units conditions d001 d001c d001d v dd supply voltage 2.0 3.0 4.5 ? ? ? 5.5 5.5 5.5 v v v f osc < = 4 mhz: f osc < = 10 mhz f osc < = 20 mhz d002 v dr ram data retention voltage (1) 1.5* ? ? v device in sleep mode d003 v por v dd start voltage to ensure internal power-on reset signal ?v ss ?vsee section 12.3.3 ?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 12.3.3 ?power-on reset (por)? for details. d005 v bod brown-out detect ?2.1? v * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: this is the limit to which v dd can be lowered in sleep mode without losing ram data.
pic16f684 ds41202c-page 130 preliminary ? 2004 microchip technology inc. 15.2 dc characteristics: pic16f684-i (industrial) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device characteristics min typ? max units conditions v dd note d010 supply current (i dd ) (1, 2) ?9tbd a2.0f osc = 32 khz lp oscillator mode ?18tbd a3.0 ?35tbd a5.0 d011 ? 110 tbd a2.0f osc = 1 mhz xt oscillator mode ? 190 tbd a3.0 ? 330 tbd a5.0 d012 ? 220 tbd a2.0f osc = 4 mhz xt oscillator mode ? 370 tbd a3.0 ? 0.6 tbd ma 5.0 d013 ? 70 tbd a2.0f osc = 1 mhz ec oscillator mode ? 140 tbd a3.0 ? 260 tbd a5.0 d014 ? 180 tbd a2.0f osc = 4 mhz ec oscillator mode ? 320 tbd a3.0 ? 580 tbd a5.0 d015 ? tbd tbd a2.0f osc = 31 khz intrc mode ?tbdtbd a3.0 ?tbdtbdma 5.0 d016 ? 340 tbd a2.0f osc = 4 mhz intosc mode ? 500 tbd a3.0 ? 0.8 tbd ma 5.0 d017 ? 180 tbd a2.0f osc = 4 mhz extrc mode ? 320 tbd a3.0 ? 580 tbd a5.0 d018 ? 2.1 tbd ma 4.5 f osc = 20 mhz hs oscillator mode ? 2.4 tbd ma 5.0 legend: tbd = to be determined. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: the peripheral current is the sum of the base i dd or i pd and the additional current consumed when this peripheral is enabled. the peripheral ? current can be determined by subtracting the base i dd or i pd current from this limit. max values should be used when calculating total current consumption. 4: 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 .
? 2004 microchip technology inc. preliminary ds41202c-page 131 pic16f684 d020 power-down base current(i pd ) (4) ? 0.99 tbd na 2.0 wdt, bod, comparators, v ref and t1osc disabled ? 1.2 tbd na 3.0 ? 2.9 tbd na 5.0 d021 ? 0.3 tbd a 2.0 wdt current ?1.8tbd a3.0 ?8.4tbd a5.0 d022 ? 58 tbd a 3.0 bod current (2) ? 109 tbd a5.0 d023 ? 3.3 tbd a 2.0 comparator current (3) ?6.1tbd a3.0 ?11.5tbd a5.0 d024 ? 58 tbd a2.0cv ref current (1) ?85tbd a3.0 ? 138 tbd a5.0 d025 ? 4.0 tbd a 2.0 t1osc current (1) ?4.6tbd a3.0 ?6.0tbd a5.0 d026 ? 1.2 tbd na 3.0 a/d current (1) ? 0.0022 tbd a5.0 15.2 dc characteristics: pic16f684-i (industrial) (continued) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device characteristics min typ? max units conditions v dd note legend: tbd = to be determined. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: the peripheral current is the sum of the base i dd or i pd and the additional current consumed when this peripheral is enabled. the peripheral ? current can be determined by subtracting the base i dd or i pd current from this limit. max values should be used when calculating total current consumption. 4: 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 .
pic16f684 ds41202c-page 132 preliminary ? 2004 microchip technology inc. 15.3 dc characteristics: pic16f684 -e (extended) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40 c t a +125 c for extended param no. device characteristics min typ? max units conditions v dd note d010e supply current (i dd ) ?9tbd a2.0f osc = 32 khz lp oscillator mode ?18tbd a3.0 ?35tbd a5.0 d011e ? 110 tbd a2.0f osc = 1 mhz xt oscillator mode ? 190 tbd a3.0 ? 330 tbd a5.0 d012e ? 220 tbd a2.0f osc = 4 mhz xt oscillator mode ? 370 tbd a3.0 ? 0.6 tbd ma 5.0 d013e ? 70 tbd a2.0f osc = 1 mhz ec oscillator mode ? 140 tbd a3.0 ? 260 tbd a5.0 d014e ? 180 tbd a2.0f osc = 4 mhz ec oscillator mode ? 320 tbd a3.0 ? 580 tbd a5.0 d015e ? tbd tbd a2.0f osc = 31 khz intrc mode ?tbdtbd a3.0 ?tbdtbdma 5.0 d016e ? 340 tbd a2.0f osc = 4 mhz intosc mode ? 500 tbd a3.0 ? 0.8 tbd ma 5.0 d017e ? 180 tbd a2.0f osc = 4 mhz extrc mode ? 320 tbd a3.0 ? 580 tbd a5.0 d018e ? 2.1 tbd ma 4.5 f osc = 20 mhz hs oscillator mode ? 2.4 tbd ma 5.0 legend: tbd = to be determined. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: the peripheral current is the sum of the base i dd or i pd and the additional current consumed when this peripheral is enabled. the peripheral ? current can be determined by subtracting the base i dd or i pd current from this limit. max values should be used when calculating total current consumption. 4: 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 .
? 2004 microchip technology inc. preliminary ds41202c-page 133 pic16f684 d020e power-down base current (i pd ) (4) ? 0.00099 tbd a 2.0 wdt, bod, comparators, v ref and t1osc disabled ? 0.0012 tbd a3.0 ? 0.0029 tbd a5.0 d021e ? 0.3 tbd a 2.0 wdt current ?1.8tbd a3.0 ?8.4tbd a5.0 d022e ? 58 tbd a 3.0 bod current ? 109 tbd a5.0 d023e ? 3.3 tbd a 2.0 comparator current (3) ?6.1tbd a3.0 ?11.5tbd a5.0 d024e ? 58 tbd a2.0cv ref current ?85tbd a3.0 ? 138 tbd a5.0 d025e ? 4.0 tbd a 2.0 t1osc current ?4.6tbd a3.0 ?6.0tbd a5.0 d026e ? 0.0012 tbd a 3.0 a/d current (3) ? 0.0022 tbd a5.0 15.3 dc characteristics: pic16f684 -e (extended) (continued) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40 c t a +125 c for extended param no. device characteristics min typ? max units conditions v dd note legend: tbd = to be determined. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt disabled. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: the peripheral current is the sum of the base i dd or i pd and the additional current consumed when this peripheral is enabled. the peripheral ? current can be determined by subtracting the base i dd or i pd current from this limit. max values should be used when calculating total current consumption. 4: 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 .
pic16f684 ds41202c-page 134 preliminary ? 2004 microchip technology inc. 15.4 dc characteristics: pic16f684 -i (industrial) pic16f684 -e (extended) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. sym characteristic min typ? max units conditions v il input low voltage i/o port: d030 with ttl buffer vss ? 0.8 v 4.5v v dd 5.5v d030a vss ? 0.15 v dd v otherwise d031 with schmitt trigger buffer vss ? 0.2 v dd v entire range d032 mclr , osc1 (rc mode) v ss ?0.2 v dd v d033 osc1 (xt and lp modes) (1) v ss ?0.3v d033a osc1 (hs mode) (1) v ss ?0.3 v dd v v ih input high voltage i/o ports: ? d040 d040a with ttl buffer 2.0 (0.25 v dd + 0.8) ? ? v dd v dd v v 4.5v v dd 5.5v otherwise d041 with schmitt trigger buffer 0.8 v dd ?v dd v entire range d042 mclr 0.8 v dd ?v dd v d043 osc1 (xt and lp modes) 1.6 ? v dd v (note 1) d043a osc1 (hs mode) 0.7 v dd ?v dd v (note 1) d043b osc1 (rc mode) 0.9 v dd ?v dd v d070 i pur porta weak pull-up current 50* 250 400* av dd = 5.0v, v pin = v ss i il input leakage current (2) d060 i/o ports ? 0 . 1 1 av ss v pin v dd , pin at high-impedance d061 mclr (3) ? 0 . 1 5 av ss v pin v dd d063 osc1 ? 0 . 1 5 av ss v pin v dd , xt, hs and lp oscillator configuration v ol output low voltage d080 i/o ports ? ? 0.6 v i ol = 8.5 ma, v dd = 4.5v (ind.) d083 osc2/clkout (rc mode) ? ? 0.6 v i ol = 1.6 ma, v dd = 4.5v (ind.) i ol = 1.2 ma, v dd = 4.5v (ext.) legend: tbd = to be determined. * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: in rc oscillator configuration, the osc1/clkin pin is a schmitt trigger input. it is not recommended to use an external clock in rc mode. 2: negative current is defined as current sourced by the pin. 3: 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. 4: see section 10.4.1 ?using the data eeprom? for additional information.
? 2004 microchip technology inc. preliminary ds41202c-page 135 pic16f684 v oh output high voltage d090 i/o ports v dd ? 0.7 ? ? v i oh = -3.0 ma, v dd = 4.5v (ind.) d092 osc2/clkout (rc mode) v dd ? 0.7 ? ? v i oh = -1.3 ma, v dd = 4.5v (ind.) i oh = -1.0 ma, v dd = 4.5v (ext.) d100 i ulp ultra low-power wake-up current ? 200 ? na capacitive loading specs on output pins d100 cosc2 osc2 pin ? ? 15* pf in xt, hs and lp modes when external clock is used to drive osc1 d101 c io all i/o pins ? ? 50* pf data eeprom memory d120 e d byte endurance 100k 1m ? e/w -40 c t a +85c d120a e d byte endurance 10k 100k ? e/w +85c t a +125c d121 v drw v dd for read/write v min ? 5.5 v using eecon1 to read/write v min = minimum operating voltage d122 t dew erase/write cycle time ? 5 6 ms d123 t retd characteristic retention 40 ? ? year provided no other specifications are violated d124 t ref number of total erase/write cycles before refresh (4) 1m 10m ? e/w -40 c t a +85c program flash memory d130 e p cell endurance 10k 100k ? e/w -40 c t a +85c d130a e d cell endurance 1k 10k ? e/w +85c t a +125c d131 v pr v dd for read v min ?5.5vv min = minimum operating voltage d132 v pew v dd for erase/write 4.5 ? 5.5 v d133 t pew erase/write cycle time ? 2 2.5 ms d134 t retd characteristic retention 40 ? ? year provided no other specifications are violated 15.4 dc characteristics: pic16f684 -i (industrial) pic16f684 -e (extended) (continued) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. sym characteristic min typ? max units conditions legend: tbd = to be determined. * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: in rc oscillator configuration, the osc1/clkin pin is a schmitt trigger input. it is not recommended to use an external clock in rc mode. 2: negative current is defined as current sourced by the pin. 3: 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. 4: see section 10.4.1 ?using the data eeprom? for additional information.
pic16f684 ds41202c-page 136 preliminary ? 2004 microchip technology inc. 15.5 timing parameter symbology the timing parameter symbols have been created with one of the following formats: figure 15-2: load conditions 1. tpps2pps 2. tpps t f frequency t time lowercase letters (pp) and their meanings: pp cc ccp1 osc osc1 ck clkout 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 t1cki mc mclr wr wr uppercase letters and their meanings: s ffall pperiod hhigh rrise i invalid (high-impedance) v valid l low z high-impedance v dd /2 c l r l pin pin v ss v ss c l legend: r l =464 ? c l = 50 pf for all pins 15 pf for osc2 output load condition 1 load condition 2
? 2004 microchip technology inc. preliminary ds41202c-page 137 pic16f684 15.6 ac characteristics: pic16f684 (industrial, extended) figure 15-3: external clock timing table 15-1: external clock timing requirements standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions f osc external clkin frequency (1) dc ? 37 khz lp oscillator mode dc ? 4 mhz xt oscillator mode dc ? 20 mhz hs oscillator mode dc ? 20 mhz ec oscillator mode oscillator frequency (1) 5 ? 37 khz lp oscillator mode ?4 ?mhzintosc mode dc ? 4 mhz rc oscillator mode 0.1 ? 4 mhz xt oscillator mode 1 ? 20 mhz hs oscillator mode 1t osc external clkin period (1) 27 ? ? s lp oscillator mode 50 ? ns hs oscillator mode 50 ? ns ec oscillator mode 250 ? ns xt oscillator mode oscillator period (1) 27 200 s lp oscillator mode ?250 ? nsintosc mode 250 ? ? ns rc oscillator mode 250 ? 10,000 ns xt oscillator mode 50 ? 1,000 ns hs oscillator mode 2t cy instruction cycle time (1) 200 t cy dc ns t cy = 4/f osc 3 tosl, to sh external clkin (osc1) high external clkin low 2* ? ? s lp oscillator, t osc l/h duty cycle 20* ? ? ns hs oscillator, t osc l/h duty cycle 100 * ? ? ns xt oscillator, t osc l/h duty cycle 4tosr, to sf external clkin rise external clkin fall ? ? 50* ns lp oscillator ? ? 25* ns xt oscillator ? ? 15* ns hs oscillator * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: instruction cycle period (t cy ) equals four times the input oscillator time base period. 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 osc1 pin. when an external clock input is used, the ?max? cycle time limit is ?dc? (no clock) for all devices. osc1 clkout q4 q1 q2 q3 q4 q1 1 2 3 3 4 4
pic16f684 ds41202c-page 138 preliminary ? 2004 microchip technology inc. table 15-2: precision internal oscillator parameters figure 15-4: clkout and i/o timing standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic freq tolerance min typ? max units conditions f10 f osc internal calibrated intosc frequency (1) 1% ? 8.00 tbd mhz v dd and temperature tbd 2% ? 8.00 tbd mhz 2.5v v dd 5.5v 0 c t a +85 c 5% ? 8.00 tbd mhz 2.0v v dd 5.5v -40 c t a +85 c (ind.) -40 c t a +125 c (ext.) f14 t iosc st oscillator wake-up from sleep start-up time* ??tbdtbd sv dd = 2.0v, -40 c to +85 c ??tbdtbd sv dd = 3.0v, -40 c to +85 c ??tbdtbd sv dd = 5.0v, -40 c to +85 c legend: tbd = to be determined. * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: to ensure these oscillator frequency tolerances, v dd and v ss must be capacitively decoupled as close to the device as possible. 0.1uf and 0.01uf values in parallel are recommended. osc1 clkout i/o pin (input) i/o pin (output) q4 q1 q2 q3 10 13 14 17 20, 21 22 23 19 18 15 11 12 16 old value new value
? 2004 microchip technology inc. preliminary ds41202c-page 139 pic16f684 table 15-3: clkout and i/o timing requirements standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions 10 tosh2ckl osc1 to clout ? 75 200 ns (note 1) 11 tosh2ckh osc1 to clout ? 75 200 ns (note 1) 12 tckr clkout rise time ? 35 100 ns (note 1) 13 tckf clkout fall time ? 35 100 ns (note 1) 14 tckl2iov clkout to port out valid ? ? 20 ns (note 1) 15 tiov2ckh port in valid before clkout t osc + 200 ns ? ? ns (note 1) 16 tckh2ioi port in hold after clkout 0 ? ? ns (note 1) 17 tosh2iov osc1 (q1 cycle) to port out valid ? 50 150* ns ? ? 300 ns 18 tosh2ioi osc1 (q2 cycle) to port input invalid (i/o in hold time) 100 ? ? ns 19 tiov2osh port input valid to osc1 (i/o in setup time) 0??ns 20 tior port output rise time ?1040ns 21 tiof port output fall time ?1040ns 22 tinp int pin high or low time 25 ? ? ns 23 trbp porta change int high or low time t cy ??ns * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. note 1: measurements are taken in rc mode where clkout output is 4 x t osc .
pic16f684 ds41202c-page 140 preliminary ? 2004 microchip technology inc. figure 15-5: reset, watchdog timer, oscillator start-up timer and power-up timer timing figure 15-6: brown-out detect timing and characteristics v dd mclr internal por pwrt time-out osc time-out internal reset watchdog timer reset 33 32 30 31 34 i/o pins 34 v bod reset (due to bod) v dd (device in brown-out detect) (device not in brown-out detect) 64 ms time-out (1) 35 note 1: 64 ms delay only if pwrte bit in the configuration word register is programmed to ? 0 ?.
? 2004 microchip technology inc. preliminary ds41202c-page 141 pic16f684 table 15-4: reset, watchdog timer, oscillator start-up timer, power-up timer, and brown-out detect requirements standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions 30 t mc lmclr pulse width (low) 2 11 ? 18 ? 24 s ms v dd = 5v, -40c to +85c extended temperature 31 t wdt watchdog timer time-out period (no prescaler) 10 10 17 17 25 30 ms ms v dd = 5v, -40c to +85c extended temperature 32 t ost oscillation start-up timer period ? 1024t osc ??t osc = osc1 period 33* t pwrt power-up timer period 28* tbd 64 tbd 132* tbd ms ms v dd = 5v, -40c to +85c extended temperature 34 t ioz i/o high-impedance from mclr low or watchdog timer reset ??2.0 s v bod brown-out detect voltage 2.025 ? 2.175 v 35 t bod brown-out detect pulse width 100* ? ? sv dd v bod (d005) legend: tbd = to be determined. * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested.
pic16f684 ds41202c-page 142 preliminary ? 2004 microchip technology inc. figure 15-7: timer0 and timer1 external clock timings table 15-5: timer0 and timer1 external clock requirements standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions 40* tt0h t0cki high pulse width no prescaler 0.5 t cy + 20 ? ? ns with prescaler 10 ? ? ns 41* tt0l t0cki low pulse width no prescaler 0.5 t cy + 20 ? ? ns with prescaler 10 ? ? ns 42* tt0p t0cki period greater of: 20 or t cy + 40 n ? ? ns n = prescale value (2, 4, ..., 256) 45* tt1h t1cki high time synchronous, no prescaler 0.5 t cy + 20 ? ? ns synchronous, with prescaler 15 ? ? ns asynchronous 30 ? ? ns 46* tt1l t1cki low time synchronous, no prescaler 0.5 t cy + 20 ? ? ns synchronous, with prescaler 15 ? ? ns asynchronous 30 ? ? ns 47* tt1p t1cki input period synchronous greater of: 30 or t cy + 40 n ? ? ns n = prescale value (1, 2, 4, 8) asynchronous 60 ? ? ns ft1 timer1 oscillator input frequency range (oscillator enabled by setting bit t1oscen) dc ? 200* khz 48 tckeztmr1 delay from external clock edge to timer increment 2 t osc *?7 t osc *? * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. t0cki t1cki 40 41 42 45 46 47 48 tmr0 or tmr1
? 2004 microchip technology inc. preliminary ds41202c-page 143 pic16f684 figure 15-8: capture/compare/pwm timings (eccp) table 15-6: capture/compare/pwm requirements (eccp) table 15-7: comparator specifications standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. symbol characteristic min typ? max units conditions 50* tccl ccp1 input low time no prescaler 0.5t cy + 20 ? ? ns with prescaler 20 ? ? ns 51* tcch ccp1 input high time no prescaler 0.5t cy + 20 ? ? ns with prescaler 20 ? ? ns 52* tccp ccp1 input period 3t cy + 40 n ? ? ns n = prescale value (1, 4 or 16) 53* tccr ccp1 output rise time ? 25 50 ns 54* tccf ccp1 output fall time ? 25 45 ns * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. comparator specifications standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c sym characteristics min typ max units comments v os input offset voltage ? 5.0 10 mv v cm input common mode voltage 0 ? v dd ? 1.5 v c mrr common mode rejection ratio +55* ? ? db t rt response time (1) ? 150 400* ns t mc 2 co v comparator mode change to output valid ?? 10* s * these parameters are characterized but not tested. 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 ? 1.5v. note: refer to figure 15-2 for load conditions. (capture mode) 50 51 52 53 54 ccp1 (compare or pwm mode) ccp1
pic16f684 ds41202c-page 144 preliminary ? 2004 microchip technology inc. table 15-8: comparator voltage reference specifications table 15-9: pic16f684 a/d converter characteristics : voltage reference specifications standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c sym. characteristics min typ max units comments resolution ? ? v dd /24* v dd /32 ? ? lsb lsb low range (vrr = 1 ) high range (vrr = 0 ) absolute accuracy ? ? ? ? 1/4* 1/2* lsb lsb low range (vrr = 1 ) high range (vrr = 0 ) unit resistor value (r) ? 2k* ? ? settling time (1) ?? 10* s * these parameters are characterized but not tested. note 1: settling time measured while vrr = 1 and vr<3:0> transitions from ? 0000 ? to ? 1111 ?. standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions a01 n r resolution ? ? 10 bits bit a02 e abs total absolute error* (1) ?? 1lsbv ref = 5.0v a03 e il integral error ? ? 1lsbv ref = 5.0v a04 e dl differential error ? ? 1 lsb no missing codes to 10 bits v ref = 5.0v a05 e fs full-scale range 2.2* ? 5.5* v a06 e off offset error ? ? 1lsbv ref = 5.0v a07 e gn gain error ? ? 1lsbv ref = 5.0v a10 ? monotonicity ? guaranteed (2) ??v ss v ain v ref + a20 a20a v ref reference voltage 2.2 2.5 ?? v dd + 0.3 v absolute minimum to ensure 10-bit accuracy a25 v ain analog input voltage v ss ?v ref v a30 z ain recommended impedance of analog voltage source ?? 10k ? a50 i ref v ref input current* (3) 10 ? 1000 a during v ain acquisition. based on differential of v hold to v ain . ?? 10 a during a/d conversion cycle. * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: total absolute error includes integral, differential, offset and gain errors. 2: the a/d conversion result never decreases with an increase in the input voltage and has no missing codes. 3: v ref current is from external v ref or v dd pin, whichever is selected as reference input. 4: when a/d is off, it will not consume any current other than leakage current. the power-down current specification includes any such leakage from the a/d module.
? 2004 microchip technology inc. preliminary ds41202c-page 145 pic16f684 figure 15-9: pic16f684 a/d conversion timing (normal mode) table 15-10: pic16f684 a/d conversion requirements standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions 130 t ad a/d clock period 1.6 ? ? st osc -based, v ref 3.0v 3.0* ? ? st osc -based, v ref full range 130 t ad a/d internal rc oscillator period 3.0* 6.0 9.0* s adcs<1:0> = 11 (rc mode) at v dd = 2.5v 2.0* 4.0 6.0* sat v dd = 5.0v 131 t cnv conversion time (not including acquisition time) (1) ?11?t ad set go bit to new data in a/d result register 132 t acq acquisition time 5* 11.5 ? ? ? s s the minimum time is the amplifier settling time. this may be used if the ?new? input voltage has not changed by more than 1 lsb (i.e., 4.1 mv @ 4.096v) from the last sampled voltage (as stored on c hold ). 134 t go q4 to a/d clock start ?t osc /2 ? ? 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. * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: adresh and adresl registers may be read on the following t cy cycle. 2: see table 9-1 for minimum conditions. 131 130 132 bsf adcon0, go q4 a/d clk a/d data adres adif go sample old_data sampling stopped done new_data 987 3210 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. 1 t cy 6 134 (t osc /2) (1) 1 t cy
pic16f684 ds41202c-page 146 preliminary ? 2004 microchip technology inc. figure 15-10: pic16f684 a/d conversion timing (sleep mode) table 15-11: pic16f684 a/d conversion requirements (sleep mode) standard operating conditions (unless otherwise stated) operating temperature -40c t a +125c param no. sym characteristic min typ? max units conditions 130 t ad a/d internal rc oscillator period 3.0* 6.0 9.0* s adcs<1:0> = 11 (rc mode) at v dd = 2.5v 2.0* 4.0 6.0* sat v dd = 5.0v 131 t cnv conversion time (not including acquisition time) (1) ?11?t ad 132 t acq acquisition time (2) 5* 11.5 ? ? ? s s the minimum time is the amplifier settling time. this may be used if the ?new? input voltage has not changed by more than 1 lsb (i.e., 4.1 mv @ 4.096v) from the last sampled voltage (as stored on c hold ). 134 t go q4 to a/d clock start ?t osc /2 + t cy ? ? 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. * these parameters are characterized but not tested. ? data in ?typ? column is at 5.0v, 25 c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: adres register may be read on the following t cy cycle. 2: see table 9-1 for minimum conditions. 131 130 bsf adcon0, go q4 a/d clk a/d data adres adif go sample old_data sampling stopped done new_data 9 7 3210 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. 134 6 8 132 1 t cy (t osc /2 + t cy ) (1) 1 t cy
? 2004 microchip technology inc. preliminary ds41202c-page 147 pic16f684 16.0 dc and ac characteristics graphs and tables graphs are not available at this time.
pic16f684 ds41202c-page 148 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 149 pic16f684 17.0 packaging information 17.1 package marking information xxxxxxxxxxxxxx 14-lead pdip (skinny dip) example xxxxxxxxxxxxxx yywwnnn 16f684-i 0415017 xxxxxxxxxxx 14-lead soic xxxxxxxxxxx yywwnnn example 16f684-e 0415017 14-lead tssop nnn xxxxxxxx yyww example 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 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. * standard picmicro device marking consists of microchip part number, year code, week code, and traceability code. for picmicro device marking beyond this, certain price adders apply. please check with your microchip sales office. for qtp devices, any special marking adders are included in qtp price. 017 16f684 0415
pic16f684 ds41202c-page 150 preliminary ? 2004 microchip technology inc. 17.2 package details the following sections give the technical details of the packages. 14-lead plastic dual in-line (p) ? 300 mil (pdip) e1 n d 1 2 eb e c a a1 b b1 l a2 p units inches* millimeters dimension limits min nom max min nom max number of pins n 14 14 pitch p .100 2.54 top to seating plane a .140 .155 .170 3.56 3.94 4.32 molded package thickness a2 .115 .130 .145 2.92 3.30 3.68 base to seating plane a1 .015 0.38 shoulder to shoulder width e .300 .313 .325 7.62 7.94 8.26 molded package width e1 .240 .250 .260 6.10 6.35 6.60 overall length d .740 .750 .760 18.80 19.05 19.30 tip to seating plane l .125 .130 .135 3.18 3.30 3.43 lead thickness c .008 .012 .015 0.20 0.29 0.38 upper lead width b1 .045 .058 .070 1.14 1.46 1.78 lower lead width b .014 .018 .022 0.36 0.46 0.56 overall row spacing eb .310 .370 .430 7.87 9.40 10.92 mold draft angle top 5 10 15 5 10 15 5 10 15 5 10 15 mold draft angle bottom * controlling parameter notes: dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010? (0.254mm) per side. jedec equivalent: ms-001 drawing no. c04-005 significant characteristic
? 2004 microchip technology inc. preliminary ds41202c-page 151 pic16f684 14-lead plastic small outline (sl) ? narrow, 150 mil (soic) foot angle 048048 15 12 0 15 12 0 mold draft angle bottom 15 12 0 15 12 0 mold draft angle top 0.51 0.42 0.36 .020 .017 .014 b lead width 0.25 0.23 0.20 .010 .009 .008 c lead thickness 1.27 0.84 0.41 .050 .033 .016 l foot length 0.51 0.38 0.25 .020 .015 .010 h chamfer distance 8.81 8.69 8.56 .347 .342 .337 d overall length 3.99 3.90 3.81 .157 .154 .150 e1 molded package width 6.20 5.99 5.79 .244 .236 .228 e overall width 0.25 0.18 0.10 .010 .007 .004 a1 standoff 1.55 1.42 1.32 .061 .056 .052 a2 molded package thickness 1.75 1.55 1.35 .069 .061 .053 a overall height 1.27 .050 p pitch 14 14 n number of pins max nom min max nom min dimension limits millimeters inches* units 2 1 d p n b e e1 h l c 45 a2 a a1 * controlling parameter notes: dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010? (0.254mm) per side. jedec equivalent: ms-012 drawing no. c04-065 significant characteristic
pic16f684 ds41202c-page 152 preliminary ? 2004 microchip technology inc. 14-lead plastic thin shrink small outline (st) ? 4.4 mm (tssop) 8 4 0 8 4 0 foot angle 10 5 0 10 5 0 mold draft angle bottom 10 5 0 10 5 0 mold draft angle top 0.30 0.25 0.19 .012 .010 .007 b lead width 0.20 0.15 0.09 .008 .006 .004 c lead thickness 0.70 0.60 0.50 .028 .024 .020 l foot length 5.10 5.00 4.90 .201 .197 .193 d molded package length 4.50 4.40 4.30 .177 .173 .169 e1 molded package width 6.50 6.38 6.25 .256 .251 .246 e overall width 0.15 0.10 0.05 .006 .004 .002 a1 standoff 0.95 0.90 0.85 .037 .035 .033 a2 molded package thickness 1.10 .043 a overall height 0.65 .026 p pitch 14 14 n number of pins max nom min max nom min dimension limits millimeters* inches units l c 2 1 d n b p e1 e a2 a1 a * controlling parameter notes: dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .005? (0.127mm) per side. jedec equivalent: mo-153 drawing no. c04-087 significant characteristic
? 2004 microchip technology inc. preliminary ds41202c-page 153 pic16f684 appendix a: data sheet revision history revision a this is a new data sheet. revision b rewrites of the oscillator and special features of the cpu sections. general corrections to figures and formatting. appendix b: migrating from other picmicro ? devices this discusses some of the issues in migrating from other picmicro devices to the pic16f6xx family of devices. b.1 pic16f676 to pic16f684 table b-1: feature comparison feature pic16f676 pic16f684 max operating speed 20 mhz 20 mhz max program memory (words) 1024 2048 sram (bytes) 64 128 a/d resolution 10-bit 10-bit data eeprom (bytes) 128 256 timers (8/16-bit) 1/1 2/1 oscillator modes 8 8 brown-out detect y y internal pull-ups ra0/1/2/4/5 ra0/1/2/4/5, mclr interrupt-on-change ra0/1/2/3/4/5 ra0/1/2/3/4/5 comparator 1 2 eccp n y ultra low-power wake-up ny extended wdt n y software control option of wdt/bod ny intosc frequencies 4 mhz 32 khz- 8mhz clock switching n y note: this device has been designed to perform to the parameters of its data sheet. it has been tested to an electrical specification designed to determine its conformance with these parameters. due to process differences in the manufacture of this device, this device may have different performance characteristics than its earlier version. these differences may cause this device to perform differently in your application than the earlier version of this device.
pic16f684 ds41202c-page 154 preliminary ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. preliminary ds41202c-page 155 pic16f684 index a a/d ...................................................................................... 63 acquisition requirements ........................................... 68 analog port pins ......................................................... 63 associated registers .................................................. 70 block diagram............................................................. 63 calculating acquisition time....................................... 68 channel selection....................................................... 63 configuration and operation....................................... 63 configuring.................................................................. 67 configuring interrupt ................................................... 67 conversion clock........................................................ 64 effects of a reset........................................................ 69 internal sampling switch (r ss ) impedance................ 68 operation during sleep .............................................. 69 output format............................................................. 65 reference voltage (v ref )........................................... 63 source impedance...................................................... 68 special event trigger.................................................. 69 specifications............................................ 144, 145, 146 starting a conversion ................................................. 64 using the eccp trigger ............................................. 69 absolute maximum ratings .............................................. 127 ac characteristics industrial and extended ............................................ 137 load conditions ........................................................ 136 adcon0 register............................................................... 66 adcon1 register............................................................... 66 analog front-end (afe) power-on reset ......................................................... 95 analog input connection considerations............................ 56 analog-to-digital converter. see a/d ansel register.................................................................. 65 assembler mpasm assembler................................................... 121 b block diagrams a/d .............................................................................. 63 analog input model ............................................... 56, 68 capture mode operation ............................................ 76 comparator 1 .............................................................. 58 comparator 2 .............................................................. 58 comparator modes ..................................................... 57 comparator voltage reference (cv ref ) .................... 60 compare ..................................................................... 77 fail-safe clock monitor (fscm) ................................. 27 in-circuit serial programming connections.............. 109 interrupt logic ........................................................... 102 mclr circuit............................................................... 95 on-chip reset circuit ................................................. 94 pic16f684.................................................................... 5 pwm (enhanced)........................................................ 78 ra0 pins ..................................................................... 35 ra1 pins ..................................................................... 36 ra2 pin....................................................................... 37 ra3 pin....................................................................... 37 ra4 pin....................................................................... 38 ra5 pin....................................................................... 38 rc0 and rc1 pins...................................................... 40 rc2 and rc3 pins...................................................... 41 rc4 pin....................................................................... 41 rc5 pin....................................................................... 42 resonator operation................................................... 21 system clock.............................................................. 19 timer1 ........................................................................ 49 timer2 ........................................................................ 54 tmr0/wdt prescaler ................................................ 45 watchdog timer (wdt)............................................ 105 brown-out detect (bod)..................................................... 96 associated .................................................................. 97 calibration .................................................................. 96 specifications ........................................................... 141 timing and characteristics ....................................... 140 c c compilers mplab c17.............................................................. 122 mplab c18.............................................................. 122 mplab c30.............................................................. 122 calib register ................................................................... 93 calibration bits.................................................................... 93 capture module. see enhanced capture/compare/pwm (eccp) ccp1con register............................................................ 75 ccpr1h register............................................................... 75 ccpr1l register ............................................................... 75 cmcon0 register.............................................................. 55 cmcon1 register.............................................................. 59 code examples assigning prescaler to timer0.................................... 47 assigning prescaler to wdt....................................... 47 changing between capture prescalers ..................... 76 data eeprom read.................................................. 73 data eeprom write .................................................. 73 indirect addressing..................................................... 17 initializing a/d............................................................. 67 initializing porta ...................................................... 31 initializing portc ...................................................... 40 saving status and w registers in ram ................... 104 ultra low-power wake-up initialization...................... 34 write verify ................................................................. 73 code protection ................................................................ 108 comparator voltage reference (cv ref )............................ 60 accuracy/error............................................................ 60 associated registers ................................................... 62 configuring ................................................................. 60 effects of a reset ....................................................... 61 response time .......................................................... 61 specifications ........................................................... 144 comparators....................................................................... 55 associated registers.................................................. 62 c2out as t1 gate............................................... 50, 59 configurations ............................................................ 57 effects of a reset ....................................................... 61 interrupts .................................................................... 59 operation.................................................................... 56 operation during sleep .............................................. 61 outputs ....................................................................... 59 response time .......................................................... 61 specifications ........................................................... 143 synchronizing c2out w/ timer1 ............................... 59 compare module. see enhanced capture/compare/pwm (eccp) config register ............................................................... 92 configuration bits ............................................................... 92 cpu features ..................................................................... 91
pic16f684 ds41202c-page 156 preliminary ? 2004 microchip technology inc. d data eeprom memory associated registers .................................................. 74 code protection .................................................... 71, 74 data memory......................................................................... 7 dc characteristics extended and industrial ............................................ 134 industrial and extended ............................................ 129 demonstration boards picdem 1 ................................................................. 124 picdem 17 ............................................................... 125 picdem 18r ............................................................ 125 picdem 2 plus ......................................................... 124 picdem 3 ................................................................. 124 picdem 4 ................................................................. 124 picdem lin ............................................................. 125 picdem usb............................................................ 125 picdem.net internet/ethernet .................................. 124 development support ....................................................... 121 device overview ................................................................... 5 e eccp. see enhanced capture/compare/pwm (eccp) eccpas register ............................................................... 86 eeadr register ................................................................. 71 eecon1 register ............................................................... 72 eecon2 register ............................................................... 72 eedat register.................................................................. 71 eeprom data memory avoiding spurious write.............................................. 74 reading....................................................................... 73 write verify ................................................................. 73 writing ......................................................................... 73 electrical specifications .................................................... 127 enhanced capture/compare/pwm (eccp) ....................... 75 associated registers.................................................... 89 associated registers w/ capture/compare/timer1 ..... 77 capture mode ............................................................. 76 prescaler............................................................. 76 ccp1 pin configuration .............................................. 76 compare mode ........................................................... 77 ccp1 pin configuration...................................... 77 software interrupt mode ..................................... 77 special event trigger and a/d conversions....... 77 special trigger output ........................................ 77 timer1 mode selection ....................................... 77 enhanced pwm mode ................................................ 78 auto-restart ......................................................... 87 auto-shutdown .............................................. 85, 87 direction change in full-bridge output mode .... 83 duty cycle........................................................... 79 effects of reset................................................... 88 example pwm frequencies and resolutions..... 79 full-bridge application example ......................... 83 full-bridge mode................................................. 82 half-bridge application examples....................... 81 half-bridge mode ................................................ 81 operation in power managed modes ................. 88 operation with fail-safe clock monitor .............. 88 output configurations ......................................... 78 output relationships (active-high and active-low) 80 output relationships diagram ............................ 80 period.................................................................. 79 programmable dead band delay ....................... 85 setup for operation ............................................ 88 shoot-through current........................................ 85 start-up considerations...................................... 87 tmr2 to pr2 match ........................................... 53 specifications ........................................................... 143 timer resources ........................................................ 75 errata .................................................................................... 3 evaluation and programming tools.................................. 125 f fail-safe clock monitor ...................................................... 27 fail-safe mode ........................................................... 27 reset and wake-up from sleep.................................. 28 firmware instructions ....................................................... 111 fuses. see configuration bits g general purpose register file ............................................. 8 i id locations...................................................................... 108 in-circuit debugger........................................................... 109 in-circuit serial programming (icsp)............................... 108 indirect addressing, indf and fsr registers..................... 17 instruction format............................................................. 111 instruction set................................................................... 111 addlw..................................................................... 113 addwf..................................................................... 113 andlw..................................................................... 113 andwf..................................................................... 113 bcf .......................................................................... 113 bsf........................................................................... 113 btfsc ...................................................................... 113 btfss ...................................................................... 114 call......................................................................... 114 clrf ........................................................................ 114 clrw ....................................................................... 114 clrwdt .................................................................. 114 comf ....................................................................... 114 decf ........................................................................ 114 decfsz ................................................................... 115 goto ....................................................................... 115 incf ......................................................................... 115 incfsz..................................................................... 115 iorlw ...................................................................... 115 iorwf...................................................................... 115 movf ....................................................................... 116 movlw .................................................................... 116 movwf .................................................................... 116 nop .......................................................................... 116 retfie ..................................................................... 117 retlw ..................................................................... 117 return................................................................... 117 rlf ........................................................................... 118 rrf .......................................................................... 118 sleep ...................................................................... 118 sublw ..................................................................... 118 subwf..................................................................... 119 swapf ..................................................................... 119 xorlw .................................................................... 119 xorwf .................................................................... 119 summary table ........................................................ 112 intcon register................................................................ 13 internal oscillator block intosc specifications ................................................... 138
? 2004 microchip technology inc. preliminary ds41202c-page 157 pic16f684 internal sampling switch (r ss ) impedance ........................ 68 interrupts........................................................................... 101 a/d .............................................................................. 67 associated registers ................................................ 103 capture ....................................................................... 76 comparators ............................................................... 59 compare ..................................................................... 77 context saving.......................................................... 104 data eeprom memory write .................................... 72 interrupt-on-change.................................................... 33 porta interrupt-on-change .................................... 102 ra2/int .................................................................... 101 tmr0 ........................................................................ 102 tmr1 .......................................................................... 50 tmr2 to pr2 match ................................................... 54 tmr2 to pr2 match (pwm) ....................................... 53 intosc specifications ..................................................... 138 ioca register..................................................................... 33 l load conditions ................................................................ 136 m mclr .................................................................................. 95 internal ........................................................................ 95 memory organization............................................................ 7 data .............................................................................. 7 data eeprom memory.............................................. 71 program ........................................................................ 7 migrating from other picmicro devices ............................ 153 mplab asm30 assembler, linker, librarian ................... 122 mplab icd 2 in-circuit debugger ................................... 123 mplab ice 2000 high-performance universal in-circuit emulator ................................................... 123 mplab ice 4000 high-performance universal in-circuit emulator ................................................... 123 mplab integrated development environment software .. 121 mplab pm3 device programmer .................................... 123 mplink object linker/mplib object librarian ................ 122 o opcode field descriptions ............................................. 111 option_reg register ...................................................... 12 osccon register.............................................................. 29 oscillator associated registers.................................................... 29 oscillator configurations ..................................................... 19 oscillator specifications.................................................... 137 oscillator start-up timer (ost) specifications............................................................ 141 oscillator switching fail-safe clock monitor............................................... 27 two-speed clock start-up.......................................... 25 p p1a/p1b/p1c/p1d. see enhanced capture/compare/pwm (eccp) ................................ 78 packaging ......................................................................... 149 marking ..................................................................... 149 pdip details.............................................................. 150 pcl and pclath ............................................................... 17 computed goto........................................................ 17 stack ........................................................................... 17 pcon register ................................................................... 97 pickit 1 flash starter kit................................................... 125 picstart plus development programmer ..................... 124 pie1 register ..................................................................... 14 pin diagram .......................................................................... 2 pinout descriptions pic16f684 ................................................................... 6 pir1 register ..................................................................... 15 porta ............................................................................... 31 additional pin functions ............................................. 31 interrupt-on-change ........................................... 33 ultra low-power wake-up............................ 31, 34 weak pull-up ...................................................... 31 associated registers ................................................... 39 pin descriptions and diagrams .................................. 36 ra0............................................................................. 36 ra1............................................................................. 36 ra2............................................................................. 37 ra3............................................................................. 37 ra4............................................................................. 38 ra5............................................................................. 38 specifications ........................................................... 139 portc ............................................................................... 40 associated registers.................................................. 29 associated registers ................................................... 43 p1a/p1b/p1c/p1d. see enhanced capture/compare/pwm (eccp)........................ 40 specifications ........................................................... 139 power-down mode (sleep)............................................... 107 power-on reset (por)....................................................... 95 power-up timer (pwrt) .................................................... 96 specifications ........................................................... 141 precision internal oscillator parameters .......................... 138 prescaler shared wdt/timer0................................................... 47 switching prescaler assignment ................................ 47 pro mate ii universal device programmer ................... 123 product identification ........................................................ 161 program memory .................................................................. 7 map and stack.............................................................. 7 programming, device instructions.................................... 111 pwm mode. see enhanced capture/compare/pwm ........ 78 pwm1con register........................................................... 85 r read-modify-write operations ......................................... 111 registers adcon0 (a/d control 0)............................................ 66 adcon1 (a/d control 1)............................................ 66 ansel (analog select) .............................................. 65 calib (calibration word) ........................................... 93 ccp1con (enhanced ccp operation) ..................... 75 ccpr1h..................................................................... 75 ccpr1l ..................................................................... 75 cmcon0 (comparator control 0) .............................. 55 cmcon1 (comparator control 1) .............................. 59 config (configuration word) ................................... 92 data memory map ........................................................ 8 eccpas (enhanced ccp auto-shutdown control) ... 86 eeadr (eeprom address) ...................................... 71 eecon1 (eeprom control 1) .................................. 72 eecon2 (eeprom control 2) .................................. 72 eedat (eeprom data) ............................................ 71 intcon (interrupt control) ........................................ 13 ioca (interrupt-on-change porta) .......................... 33 option_reg ............................................................ 46 option_reg (option) .............................................. 12 osccon (oscillator control)..................................... 29 pcon (power control) ............................................... 97
pic16f684 ds41202c-page 158 preliminary ? 2004 microchip technology inc. pie1 (peripheral interrupt enable 1) ........................... 14 pir1 (peripheral interrupt register 1) ........................ 15 porta........................................................................ 31 portc ....................................................................... 43 pwm1con (enhanced pwm configuration) ............. 85 reset values............................................................... 99 reset values (special registers) ............................... 100 special function registers ........................................... 8 special register summary ......................................... 10 status .......................................................................... 11 t1con (timer1 control)............................................. 51 t2con (timer2 control)............................................. 53 trisa (tri-state porta) ........................................... 32 trisc (tri-state portc) ........................................... 43 vrcon (voltage reference control) ......................... 62 wdtcon (watchdog timer control)........................ 106 wpua (weak pull-up porta) ................................... 32 reset................................................................................... 94 revision history ................................................................ 153 s shoot-through current ........................................................ 85 software simulator (mplab sim)..................................... 122 software simulator (mplab sim30)................................. 122 special event trigger.......................................................... 69 special function registers ................................................... 8 status register.................................................................... 11 t time-out sequence............................................................. 97 timer0 ................................................................................. 45 associated registers .................................................. 47 external clock............................................................. 46 interrupt....................................................................... 45 operation .................................................................... 45 specifications............................................................ 142 t0cki .......................................................................... 46 timer1 ................................................................................. 49 associated registers.................................................... 52 asynchronous counter mode ..................................... 52 reading and writing ........................................... 52 interrupt....................................................................... 50 modes of operations................................................... 50 operation during sleep .............................................. 52 oscillator ..................................................................... 52 prescaler..................................................................... 50 specifications............................................................ 142 timer1 gate inverting gate ..................................................... 50 selecting source........................................... 50, 59 synchronizing c2out w/ timer1 ....................... 59 tmr1h register ......................................................... 49 tmr1l register.......................................................... 49 timer2 ................................................................................. 53 associated registers .................................................. 54 operation .................................................................... 53 postscaler ................................................................... 53 pr2 register............................................................... 53 prescaler..................................................................... 53 tmr2 register............................................................ 53 tmr2 to pr2 match interrupt ............................... 53, 54 timing diagrams a/d conversion ......................................................... 145 a/d conversion (sleep mode) .................................. 146 brown-out detect (bod) ........................................... 140 brown-out detect situations ....................................... 96 clkout and i/o ...................................................... 138 comparator output ..................................................... 56 enhanced capture/compare/pwm (eccp)............. 143 external clock........................................................... 137 fail-safe clock monitor (fscm)................................. 28 full-bridge pwm output............................................. 82 half-bridge pwm output ............................................ 81 int pin interrupt ....................................................... 103 pwm auto-shutdown auto-restart disabled.......................................... 87 auto-restart enabled........................................... 87 pwm direction change .............................................. 84 pwm direction change at near 100% duty cycle..... 84 pwm output (active-high) ......................................... 80 pwm output (active-low) .......................................... 80 reset, wdt, ost and power-up timer ................... 140 time-out sequence case 1 ................................................................ 98 case 2 ................................................................ 98 case 3 ................................................................ 98 timer0 and timer1 external clock ........................... 142 timer1 incrementing edge ......................................... 50 two speed start-up.................................................... 26 wake-up from interrupt............................................. 108 timing parameter symbology .......................................... 136 trisa register................................................................... 32 trisc register................................................................... 43 two-speed clock start-up mode........................................ 25 u ultra low-power wake-up............................................ 31, 34 ultra low-power wake-up .................................................... 6 v voltage reference. see comparator voltage reference (cv ref ) vrcon register ................................................................ 62 v ref . s ee a/d reference voltage w wake-up using interrupts ................................................. 107 watchdog timer (wdt).................................................... 105 associated registers ................................................. 106 clock source ............................................................ 105 modes....................................................................... 105 period ....................................................................... 105 specifications ........................................................... 141 wdtcon register ........................................................... 106 wpua register................................................................... 32 www, on-line support .................... ................................... 3
? 2004 microchip technology inc. preliminary ds41202c-page 159 pic16f684 on-line support microchip provides on-line support on the microchip world wide web site. the web site is used by microchip as a means to make files and information easily available to customers. to view the site, the user must have access to the internet and a web browser, such as netscape ? or microsoft ? internet explorer. files are also available for ftp download from our ftp site. connecting to the microchip internet web site the microchip web site is available at the following url: www.microchip.com the file transfer site is available by using an ftp service to connect to: ftp://ftp.microchip.com the web site and file transfer site provide a variety of services. users may download files for the latest development tools, data sheets, application notes, user?s guides, articles and sample programs. a vari- ety of microchip specific business information is also available, including listings of microchip sales offices, distributors and factory representatives. other data available for consideration is: latest microchip press releases technical support section with frequently asked questions design tips device errata job postings microchip consultant program member listing links to other useful web sites related to microchip products conferences for products, development systems, technical information and more listing of seminars and events systems information and upgrade hot line the systems information and upgrade line provides system users a listing of the latest versions of all of microchip?s development systems software products. plus, this line provides information on how customers can receive the most current upgrade kits. the hot line numbers are: 1-800-755-2345 for u.s. and most of canada, and 1-480-792-7302 for the rest of the world. 042003
pic16f684 ds41202c-page 160 preliminary ? 2004 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: (______) _________ - _________ ds41202c pic16f684 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?
? 2004 microchip technology inc. preliminary ds41202c-page 161 pic16f684 product identification system to order or obtain information, e.g. , on pricing or delivery, refer to the factory or the listed sales office. * jw devices are uv erasable and can be programmed to any device c onfiguration. jw devices meet the electrical requirement of each oscillator type. part no. x /xx xxx pattern package temperature range device device 16f: standard v dd range 16ft: (tape and reel) temperature range i = -40 c to +85 c e= -40 c to +125 c package p = pdip sl = soic (gull wing, 150 mil body) st = tssop(4.4 mm) pattern 3-digit pattern code for qtp (blank otherwise) examples: a) pic16f684-e/p 301 = extended temp., pdip package, 20 mhz, qtp pattern #301 b) pic16f684-i/so = industrial temp., soic package, 20 mhz
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