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small package 8-bit otp mcu HT48R005/ht46r005 revision: 1.00 november 29, 2011
table of contents features ...............................................................................................5 cpu features ........................................................................................................5 peripheral features ................................................................................................5 general description ............................................................................5 selection table ....................................................................................6 block diagram .....................................................................................6 pin assignment ...................................................................................6 pin description ....................................................................................7 HT48R005 ..............................................................................................................7 ht46r005 ..............................................................................................................8 absolute maximum ratings ...............................................................8 d.c. characteristics ............................................................................9 a.c. characteristics ..........................................................................10 adc characteristics..........................................................................11 power-on reset characteristics ......................................................11 system architecture .........................................................................12 clocking and pipelining ........................................................................................12 program counter ..................................................................................................13 stack ....................................................................................................................13 arithmetic and logic unit alu ...........................................................................13 program memory...............................................................................14 structure ...............................................................................................................14 special vectors .....................................................................................................14 look-up table .......................................................................................................14 table program example .......................................................................................15 data memory......................................................................................16 structure ...............................................................................................................16 special purpose data memory .............................................................................16 special function registers ..............................................................17 indirect addressing registers iar0, iar1 .........................................................17 memory pointers mp0, mp1 ..............................................................................17 accumulator acc .............................................................................................17 program counter low register pcl..................................................................18 status register status ...................................................................................18 input/output ports and control registers .............................................................18 HT48R005/ht46r005 rev. 1.00 ii november 29, 2011
system control registers ctrl0, ctrl1 .........................................................19 wake-up function register pawk ....................................................................19 pull-high registers papu ..................................................................................19 oscillator............................................................................................20 system oscillator overview ..................................................................................20 system clock configurations ................................................................................20 external crystal/resonator oscillator hxt ........................................................20 external rc oscillator erc ...............................................................................20 internal rc oscillator hirc ...............................................................................21 internal low speed oscillator lirc ...................................................................21 operating modes ...............................................................................21 mode switching ....................................................................................................21 standby current considerations ...........................................................................21 wake-up ...............................................................................................................22 watchdog timer ................................................................................23 watchdog timer operation ...................................................................................23 reset and initialisation .....................................................................24 reset functions ...................................................................................................24 reset initial conditions .........................................................................................25 HT48R005 ............................................................................................................26 ht46r005 ............................................................................................................27 input/output ports.............................................................................28 pull-high resistors ................................................................................................28 port a wake-up ....................................................................................................28 i/o port control registers .....................................................................................29 pin-shared functions ............................................................................................29 i/o pin structures .................................................................................................29 programming considerations ...............................................................................29 timer/event counters .......................................................................31 configuring the timer/event counter input clock source .....................................31 timer registers tmr.........................................................................................31 timer control registers tmr0c ........................................................................31 timer mode ..........................................................................................................33 event counter mode .............................................................................................33 pulse width capture mode ...................................................................................33 prescaler ..............................................................................................................34 pfd function .......................................................................................................34 i/o interfacing .......................................................................................................35 programming considerations ...............................................................................35 timer program example .......................................................................................36 HT48R005/ht46r005 rev. 1.00 iii november 29, 2011
analog to digital converter..............................................................37 a/d overview .......................................................................................................37 a/d converter register description ......................................................................37 a/d converter data registers adrl, adrh .....................................................37 a/d converter control registers adcr, acsr .................................................38 a/d operation .......................................................................................................39 a/d input pins ......................................................................................................40 summary of a/d conversion steps ......................................................................40 programming considerations ...............................................................................40 a/d transfer function ...........................................................................................41 a/d programming example ..................................................................................41 interrupts............................................................................................43 interrupt register ..................................................................................................43 interrupt operation ...............................................................................................43 interrupt priority .....................................................................................................44 external interrupt ..................................................................................................44 timer/event counter interrupt ..............................................................................46 programming considerations ...............................................................................46 configuration options ......................................................................46 application circuits ..........................................................................47 instruction set ...................................................................................48 introduction ..........................................................................................................48 instruction timing .................................................................................................48 moving and transferring data ..............................................................................48 arithmetic operations ...........................................................................................48 logical and rotate operations .............................................................................48 branches and control transfer .............................................................................48 table read operations .........................................................................................49 instruction set summary ......................................................................................49 instruction definition ........................................................................51 package information .........................................................................61 10-pin msop outline dimensions ........................................................................61 HT48R005/ht46r005 rev. 1.00 iv november 29, 2011
HT48R005/ht46r005 rev. 1.00 5 november 29, 2011 general description the ht46r005 and HT48R005 are a series of 8-bit high performance, risc architecture microcontrollers spe- cifically designed for a wide range of applications. the usual holtek microcontroller features of low power con- sumption, i/o flexibility, timer functions, oscillator op- tions, power down and wake-up functions, watchdog timer and low voltage reset, combine to provide devices with a huge range of functional options while still main- taining a high level of cost effectiveness. the fully inte - grated system oscillator hirc, which requires no external components and which has three frequency selections, opens up a huge range of new application possibilities for these devices, some of which may in- clude industrial control, consumer products, household appliances subsystem controllers, etc. features cpu features operating voltage: f sys = 12mhz: 2.2v~5.5v f sys = 16mhz: 3.0v~5.5v up to 0.33 s instruction cycle with 12mhz system clock at v dd =5v sleep mode and wake-up functions to reduce power consumption oscillator types: external high freuency crystal -- hxt external rc -- erc internal rc -- hirc two operational modes: normal, sleep fully integrated internal 4mhz, 8mhz and 12mhz oscillator requires no external components otp program memory: 0.5k 14 ram data memory: 32 8 watchdog timer function lirc oscillator function for watchdog timer all instructions executed in one or two instruction cycles table read instructions 63 powerful instructions 2-level subroutine nesting bit manipulation instruction low voltage reset function wide range of available package types peripheral features 6 bidirectional i/o lines 3 channel 12-bit adc external interrupt input shared with an i/o line single 8-bit programmable timer/event counter with overflow interrupt and prescaler buzzer driving pair supported package types: 10-pin msop
selection table part no. program memory data memory i/o 8-bit timer time base interrupt a/d buzzer stack package ext. int. HT48R005 0.5k 14 32 86 1 111 12 10msop ht46r005 0.5k 14 32 8 6 1 1 1 2 12-bit 31 2 10msop note: the internal clock in the table is a fully integrated rc oscillator requiring no external components which can be used as the system clock. block diagram the following block diagram illustrates the main functional blocks. pin assignment HT48R005/ht46r005 rev. 1.00 6 november 29, 2011

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pin description HT48R005 pin name function opt i/t o/t description pa0/bz pa0 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. bz ctrl0 cmos buzzer output pin pa1/bz pa1 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. bz ctrl0 buzzer complementary output pin pa2/tmr/int pa2 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. tmr st external timer clock input int st external interrupt input pa5/osc2 pa5 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. osc2 co osc oscillator pin pa6/osc1 pa6 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. osc1 co osc oscillator pin pa7/res pa7 pawk st nmos general purpose i/o. register enabled wake-up. res co st reset input vdd vdd pwr power supply vss vss pwr ground note: i/t: input type o/t: output type opt: optional by configuration option (co) or register option pwr: power co: configuration option st: schmitt trigger input cmos: cmos output HT48R005/ht46r005 rev. 1.00 7 november 29, 2011
ht46r005 pin name function opt i/t o/t description pa0/bz/an0 pa0 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. bz ctrl0 cmos buzzer output pin an0 adcr an a/d channel 0 pa1/bz / an1 pa1 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. bz ctrl0 buzzer complementary output pin an1 adcr an a/d channel 1 pa2/tmr/int/an2 pa2 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. tmr st external timer clock input int st external interrupt input an2 adcr an a/d channel 2 pa5/osc2 pa5 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. osc2 co osc oscillator pin pa6/osc1 pa6 papu pawk st cmos general purpose i/o. register enabled pull-up and wake-up. osc1 co osc oscillator pin pa7/res pa7 pawk st nmos general purpose i/o. register enabled wake-up. res co st reset input vdd vdd pwr power supply vss vss pwr ground note: i/t: input type o/t: output type opt: optional by configuration option (co) or register option pwr: power co: configuration option st: schmitt trigger input cmos: cmos output an: analog input pin absolute maximum ratings supply voltage ...........................v ss 0.3v to v ss +6.0v storage temperature ............................ 50 cto125 c input voltage..............................v ss 0.3v to v dd +0.3v operating temperature........................... 40 cto85 c i ol total ..............................................................100ma i oh total............................................................ 100ma total power dissipation .....................................500mw note: these are stress ratings only. stresses exceeding the range specified under absolute maximum ratings may cause substantial damage to the device. functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. HT48R005/ht46r005 rev. 1.00 8 november 29, 2011
d.c. characteristics ta=25 c symbol parameter test conditions min. typ. max. unit v dd conditions v dd operating voltage f sys =12mhz 2.2 5.5 v f sys =16mhz 3.0 5.5 v i dd1 operating current (crystal/rc osc) 3v no load, f sys =4mhz a/d disabled 1ma 5v 3ma i dd2 operating current (crystal/rc osc) 3v no load, f sys =8mhz a/d disabled 2ma 5v 4ma i dd3 operating current (crystal/rc osc) 5v no load, f sys =16mhz a/d disabled 7ma i stb1 standby current (wdtosc on) 3v no load, system halt 3 a 5v 10 a i stb2 standby current (wdtosc on) 3v no load, system halt 1 a 5v 2 a v il1 input low voltage for i/o, tmr and int 5v 0 1.5 v 0 0.2v dd v ih1 input high voltage for i/o, tcn and int 5v 3.5 5.0 v 0.8v dd v dd v il2 input low voltage (res ) 0 0.4v dd v v ih2 input high voltage (res ) 0.9v dd v dd v v lvr1 low voltage reset 1 v lvr = 2.10v 1.98 2.10 2.22 v v lvr2 low voltage reset 2 v lvr = 3.15v 2.98 3.15 3.32 v v lvr3 low voltage reset 3 v lvr = 4.20v 3.98 4.20 4.42 v i oh i/o port source current 3v v oh =0.9v dd 2 4 ma 5v 5 10 ma i ol1 i/o port sink current 3v v ol =0.1v dd 48 ma 5v 10 20 ma i ol2 pa7 sink current 5v v ol =0.1v dd 23 ma r ph pull-high resistance 3v 20 60 100 k 5v 10 30 50 k note: the standby current i stb1 and i stb2 are measured with all i/o pins in input mode and tied to v dd . HT48R005/ht46r005 rev. 1.00 9 november 29, 2011
a.c. characteristics ta=25 c symbol parameter test conditions min. typ. max. unit v dd conditions f sys system clock 2.2v~5.5v 400 12000 khz 3.0v~5.5v 400 16000 khz f hirc system clock (hirc) 3v/5v ta=25c 2% 4 +2% mhz 3v/5v ta=25c 2% 8 +2% mhz 5v ta=25c 2% 12 +2% mhz 3v/5v ta=0~70c 5% 4 +5% mhz 3v/5v ta=0~70c 5% 8 +5% mhz 5v ta=0~70c 5% 12 +5% mhz 2.2v~ 3.6v ta=0~70c 8% 4 +8% mhz 3.0v~ 5.5v ta=0~70c 8% 4 +8% mhz 3.0v~ 5.5v ta=0~70c 8% 8 +8% mhz 4.5v~ 5.5v ta=0~70c 8% 12 +8% mhz 2.2v~ 3.6v ta= 40c~85c 12% 4 +12% mhz 3.0v~ 5.5v ta= 40c~85c 12% 4 +12% mhz 3.0v~ 5.5v ta= 40c~85c 12% 8 +12% mhz 4.5v~ 5.5v ta= 40c~85c 12% 12 +12% mhz f erc system clock (erc) 5v ta=25 c, r=120k * 2% 4 +2% mhz 5v ta=0~70 c, r=120k * 5% 4 +5% mhz 5v ta= 40c~85c, r=120k * 7% 4 +7% mhz 2.2v~ 5.5v ta= 40c~85c, r=120k * 11% 4 +11% mhz f timer timer input frequency (tmr) 2.2v~5.5v 0 4000 khz 3.3v~5.5v 0 8000 khz 4.5v~5.5v 0 12000 khz f lirc lirc oscillator 3v 5 10 15 khz 5v 6.5 13.0 19.5 khz t res external reset low pulse width 1 s t sst system start-up time period wake up from halt mode 2 128 t sys t int interrupt pulse width 1 s t lvr low voltage width to reset 0.25 1 2 ms t rstd reset delay time 100 ms note: 1. t sys =1/f sys 2. *for f erc , as the resistor tolerance will influence the frequency a precision resistor is recommended. HT48R005/ht46r005 rev. 1.00 10 november 29, 2011
adc characteristics ta=25 c symbol parameter test conditions min. typ. max. unit v dd conditions dnl adc differential non-linearity 3v t ad =0.5s 2 2 lsb 5v inl adc integral non-linearity 3v t ad =0.5s 4 4 lsb 5v i adc additional power consumption if a/d converter is used 3v 0.5 0.75 ma 5v 1.0 1.5 ma power-on reset characteristics ta=25 c symbol parameter test conditions min. typ. max. unit v dd conditions v por vdd start voltage to ensure power-on reset 100 mv rr vdd vdd raising rate to ensure power-on reset 0.035 v/ms t por minimum time for vdd stays at v por to ensure power-on reset 1 ms HT48R005/ht46r005 rev. 1.00 11 november 29, 2011 " " "
HT48R005/ht46r005 rev. 1.00 12 november 29, 2011 system architecture a key factor in the high-performance features of the holtek range of microcontrollers is attributed to the inter - nal system architecture. the range of devices take ad - vantage of the usual features found within risc microcontrollers providing increased speed of operation and enhanced performance. the pipelining scheme is implemented in such a way that instruction fetching and instruction execution are overlapped, hence instructions are effectively executed in one cycle, with the exception of branch or call instructions. an 8-bit wide alu is used in practically all operations of the instruction set. it car - ries out arithmetic operations, logic operations, rotation, increment, decrement, branch decisions, etc. the inter - nal data path is simplified by moving data through the accumulator and the alu. certain internal registers are implemented in the data memory and can be directly or indirectly addressed. the simple addressing methods of these registers along with additional architectural fea - tures ensure that a minimum of external components is required to provide a functional i/o and a/d control sys - tem with maximum reliability and flexibility. clocking and pipelining the main system clock, derived from either a crys - tal/resonator or rc oscillator is subdivided into four in- ternally generated non-overlapping clocks, t1~t4. the program counter is incremented at the beginning of the t1 clock during which time a new instruction is fetched. the remaining t2~t4 clocks carry out the decoding and execution functions. in this way, one t1~t4 clock cycle forms one instruction cycle. although the fetching and execution of instructions takes place in consecutive in - struction cycles, the pipelining structure of the microcontroller ensures that instructions are effectively executed in one instruction cycle. the exception to this are instructions where the contents of the program counter are changed, such as subroutine calls or jumps, in which case the instruction will take one more instruction cycle to execute. for instructions involving branches, such as jump or call instructions, two instruction cycles are required to com - plete instruction execution. an extra cycle is required as the program takes one cycle to first obtain the actual jump or call address and then another cycle to actually execute the branch. the requirement for this extra cycle should be taken into account by programmers in timing sensitive applications. / 0 1 2 3
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HT48R005/ht46r005 rev. 1.00 13 november 29, 2011 program counter during program execution, the program counter is used to keep track of the address of the next instruction to be executed. it is automatically incremented by one each time an instruction is executed except for instructions, such as jmp or call that demand a jump to a non-consecutive program memory address. note that the program counter width varies with the program memory capacity depending upon which device is se - lected. however, it must be noted that only the lower 8 bits, known as the program counter low register, are directly addressable by user. when executing instructions requiring jumps to non-consecutive addresses such as a jump instruction, a subroutine call, interrupt or reset, etc., the microcontroller manages program control by loading the required address into the program counter. for condi - tional skip instructions, once the condition has been met, the next instruction, which has already been fetched during the present instruction execution, is dis - carded and a dummy cycle takes its place while the cor - rect instruction is obtained. device program counter program counter high byte pcl register HT48R005 ht46r005 pc9~pc8 pcl7~pcl0 the lower byte of the program counter, known as the program counter low register or pcl, is available for program control and is a readable and writeable regis- ter. by transferring data directly into this register, a short program jump can be executed directly, however, as only this low byte is available for manipulation, the jumps are limited to the present page of memory, that is 256 locations. when such program jumps are executed it should also be noted that a dummy cycle will be in - serted. the lower byte of the program counter is fully accessi - ble under program control. manipulating the pcl might cause program branching, so an extra cycle is needed to pre-fetch. further information on the pcl register can be found in the special function register section. stack this is a special part of the memory which is used to save the contents of the program counter only. the stack is neither part of the data or program memory space, and is neither readable nor writeable. the acti - vated level is indexed by the stack pointer, sp, and is neither readable nor writeable. at a subroutine call or in - terrupt acknowledge signal, the contents of the program counter are pushed onto the stack. at the end of a sub - routine or an interrupt routine, signaled by a return in - struction, ret or reti, the program counter is restored to its previous value from the stack. after a device reset, the stack pointer will point to the top of the stack. if the stack is full and an enabled interrupt takes place, the interrupt request flag will be recorded but the ac - knowledge signal will be inhibited. when the stack pointer is decremented, by ret or reti, the interrupt will be serviced. this feature prevents stack overflow al - lowing the programmer to use the structure more easily. however, when the stack is full, a call subroutine in - struction can still be executed which will result in a stack overflow. precautions should be taken to avoid such cases which might cause unpredictable program branching. arithmetic and logic unit alu the arithmetic-logic unit or alu is a critical area of the microcontroller that carries out arithmetic and logic op- erations of the instruction set. connected to the main microcontroller data bus, the alu receives related in- struction codes and performs the required arithmetic or logical operations after which the result will be placed in the specified register. as these alu calculation or oper - ations may result in carry, borrow or other status changes, the status register will be correspondingly up - dated to reflect these changes. the alu supports the following functions: arithmetic operations: add, addm, adc, adcm, sub, subm, sbc, sbcm, daa logic operations: and, or, xor, andm, orm, xorm, cpl, cpla rotation rra, rr, rrca, rrc, rla, rl, rlca, rlc increment and decrement inca, inc, deca, dec branch decision, jmp, sz, sza, snz, siz, sdz, siza, sdza, call, ret, reti !
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HT48R005/ht46r005 rev. 1.00 14 november 29, 2011 program memory the program memory is the location where the user code or program is stored. the device is supplied with one-time programmable, otp, memory where users can program their application code into the device. by using the appropriate programming tools, otp devices offer users the flexibility to freely develop their applica - tions which may be useful during debug or for products requiring frequent upgrades or program changes. structure the program memory has a capacity of 0.5k 14 to 2k 15. the program memory is addressed by the pro - gram counter and also contains data, table information and interrupt entries. table data, which can be setup in any location within the program memory, is addressed by separate table pointer registers. special vectors within the program memory, certain locations are re - served for special usage such as reset and interrupts. reset vector this vector is reserved for use by the device reset for program initialisation. after a device reset is initiated, the program will jump to this location and begin execution. external interrupt vector this vector is used by the external interrupt. if the ex- ternal interrupt pin on the device receives an edge transition, the program will jump to this location and begin execution if the external interrupt is enabled and the stack is not full. the external interrupt active edge transition type, whether high to low, low to high or both is specified in the ctrl1 register. timer/event counter interrupt vector this internal vector is used by the timer/event coun - ters. if a timer/event counter overflow occurs, the program will jump to its respective location and begin execution if the associated timer/event counter inter - rupt is enabled and the stack is not full. a/d interrupt vector this internal vector is used by the a/d converter. if a/d conversion complete , the program will jump to this location and begin execution if the a/d interrupt is enabled and the stack is not full. look-up table any location within the program memory can be defined as a look-up table where programmers can store fixed data. to use the look-up table, the table pointer must first be setup by placing the lower order address of the look up data to be retrieved in the table pointer register, tblp. this register defines the lower 8-bit address of the look-up table. after setting up the table pointer, the table data can be retrieved from the current program memory page or last program memory page using the tabrdc[m] or tabrdl [m] instructions, respectively. when these in - structions are executed, the lower order table byte from the program memory will be transferred to the user de- fined data memory register [m] as specified in the in- struction. the higher order table data byte from the program memory will be transferred to the tblh special register. any unused bits in this transferred higher order byte will be read as 0. * * ? $ / / ? ( 5 ! 7 9 9 ( 5 ! 7 9 9 * . ? * ? *
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HT48R005/ht46r005 rev. 1.00 15 november 29, 2011 the following diagram illustrates the addressing/data flow of the look-up table: table program example the accompanying example shows how the table pointer and table data is defined and retrieved from the device. this example uses raw table data located in the last page which is stored there using the org state - ment. the table pointer is setup here to have an initial value of 06h . this will ensure that the first data read from the data table will be at the program memory ad - dress 106h or 6 locations after the start of the last page. note that the value for the table pointer is refer - enced to the first address of the present page if the tabrdc [m] instruction is being used. the high byte of the table data which in this case is equal to zero will be transferred to the tblh register automatically when the tabrdl [m] instruction is executed. because the tblh register is a read-only register and cannot be restored, care should be taken to ensure its protection if both the main routine and interrupt service routine use the table read instructions. if using the table read instructions, the interrupt service routines may change the value of tblh and subsequently cause er - rors if used again by the main routine. as a rule it is rec - ommended that simultaneous use of the table read instructions should be avoided. however, in situations where simultaneous use cannot be avoided, the inter - rupts should be disabled prior to the execution of any main routine table-read instructions. note that all table related instructions require two instruction cycles to complete their operation. instruction table location bits b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 tabrdc [m] pc9 pc8 @7 @6 @5 @4 @3 @2 @1 @0 tabrdl [m] 1 1 @7 @6 @5 @4 @3 @2 @1 @0 table location note: pc9~pc8: current program counter bits @7~@0: table pointer tblp bits table read program example - 0.5k rom size tempreg1 db ? ; temporary register #1 tempreg2 db ? ; temporary register #2 : : mov a,06h ; initialise table pointer - note that this address is referenced mov tblp,a ; to the last page or present page : : tabrdl tempreg1 ; transfers value in table referenced by table pointer to tempregl ; data at prog. memory address 106h transferred to tempreg1 and tblh dec tblp ; reduce value of table pointer by one tabrdl tempreg2 ; transfers value in table referenced by table pointer to tempreg2 ; data at prog.memory address 105h transferred to tempreg2 and tblh ; in this example the data 1ah is transferred to ; tempreg1 and data 0fh to register tempreg2 ; the value 00h will be transferred to the high byte register tblh : : org 100h ; sets initial address of last page dc 00ah, 00bh, 00ch, 00dh, 00eh, 00fh, 01ah, 01bh : : : ? 7 0 b ? 1 : c : ! 9 ! 9 9 !
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HT48R005/ht46r005 rev. 1.00 16 november 29, 2011 data memory the data memory is a volatile area of 8-bit wide ram internal memory and is the location where temporary in - formation is stored. structure divided into two sections, the first of these is an area of ram where special function registers are located. these registers have fixed locations and are necessary for cor - rect operation of the device. many of these registers can be read from and written to directly under program con - trol, however, some remain protected from user manipu - lation. the second area of data memory is reserved for general purpose use. all locations within this area are read and write accessible under program control. the two sections of data memory, the special purpose and general purpose data memory are located at con - secutive locations. all are implemented in ram and are 8 bits wide but the length of each memory section is dic - tated by the type of microcontroller chosen. the start ad - dress of the data memory for all devices is the address 00h . all microcontroller programs require an area of read/write memory where temporary data can be stored and retrieved for use later. it is this area of ram memory that is known as general purpose data memory. this area of data memory is fully accessible by the user pro- gram for both read and write operations. by using the set [m].i and clr [m].i instructions individual bits can be set or reset under program control giving the user a large range of flexibility for bit manipulation in the data memory. special purpose data memory this area of data memory is where registers, necessary for the correct operation of the microcontroller, are stored. most of the registers are both readable and writeable but some are protected and are readable only, the details of which are located under the relevant spe - cial function register section. note that for locations that are unused, any read instruction to these addresses will return the value 00h. ! 7 9 9 0 ! 7 9 * * ? * $ ? . * ? * * % / ? - / ? - & data memory structure note: most of the data memory bits can be directly manipulated using the set [m].i and clr [m].i with the exception of a few dedicated bits. the data memory can also be accessed through the memory pointer registers. * * ? * $ ? * & ? * - ? * . ? * % ? * # ? * ' ? * ? * , ? * ? * ? *
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HT48R005/ht46r005 rev. 1.00 17 november 29, 2011 special function registers to ensure successful operation of the microcontroller, certain internal registers are implemented in the data memory area. these registers ensure correct operation of internal functions such as timers, interrupts, etc., as well as external functions such as i/o data control. the location of these registers within the data memory be - gins at the address 00h . any unused data memory lo - cations between these special function registers and the point where the general purpose memory begins is re - served and attempting to read data from these locations will return a value of 00h. indirect addressing registers iar0, iar1 the indirect addressing registers, iar0 and iar1, al - though having their locations in normal ram register space, do not actually physically exist as normal regis - ters. the method of indirect addressing for ram data manipulation uses these indirect addressing registers and memory pointers, in contrast to direct memory ad - dressing, where the actual memory address is speci - fied. actions on the iar0 and iar1 registers will result in no actual read or write operation to these registers but rather to the memory location specified by their corre - sponding memory pointer, mp0 or mp1. acting as a pair, iar0 with mp0 and iar1 with mp1 can together ac- cess data from the data memory. as the indirect ad- dressing registers are not physically implemented, reading the indirect addressing registers indirectly will return a result of 00h and writing to the registers indi- rectly will result in no operation. memory pointers mp0, mp1 two memory pointers, known as mp0 and mp1 are pro - vided. these memory pointers are physically imple - mented in the data memory and can be manipulated in the same way as normal registers providing a conve - nient way with which to indirectly address and track data. when any operation to the relevant indirect ad - dressing registers is carried out, the actual address that the microcontroller is directed to, is the address speci - fied by the related memory pointer. the following exam - ple shows how to clear a section of four data memory locations already defined as locations adres1 to adres4. accumulator acc the accumulator is central to the operation of any microcontroller and is closely related with operations carried out by the alu. the accumulator is the place where all intermediate results from the alu are stored. without the accumulator it would be necessary to write the result of each calculation or logical operation such as addition, subtraction, shift, etc., to the data memory resulting in higher programming and timing overheads. data transfer operations usually involve the temporary storage function of the accumulator; for example, when transferring data between one user defined register and another, it is necessary to do this by passing the data through the accumulator as no direct transfer between two registers is permitted. indirect addressing program example data .section
data
adres1 db ? adres2 db ? adres3 db ? adres4 db ? block db ? code .section at 0 code org 00h start: mov a,04h ; setup size of block mov block,a mov a,offset adres1 ; accumulator loaded with first ram address mov mp0,a ; setup memory pointer with first ram address loop: clr iar0 ; clear the data at address defined by mp0 inc mp0 ; increment memory pointer sdz block ; check if last memory location has been cleared jmp loop continue: the important point to note here is that in the example shown above, no reference is made to specific data memory addresses.
HT48R005/ht46r005 rev. 1.00 18 november 29, 2011 program counter low register pcl to provide additional program control functions, the low byte of the program counter is made accessible to pro - grammers by locating it within the special purpose area of the data memory. by manipulating this register, direct jumps to other program locations are easily imple - mented. loading a value directly into this pcl register will cause a jump to the specified program memory lo - cation, however, as the register is only 8-bit wide, only jumps within the current program memory page are per - mitted. when such operations are used, note that a dummy cycle will be inserted. status register status this 8-bit register contains the zero flag (z), carry flag (c), auxiliary carry flag (ac), overflow flag (ov), power down flag (pdf), and watchdog time-out flag (to). these arithmetic/logical operation and system manage - ment flags are used to record the status and operation of the microcontroller. with the exception of the to and pdf flags, bits in the status register can be altered by instructions like most other registers. any data written into the status register will not change the to or pdf flag. in addition, opera - tions related to the status register may give different re - sults due to the different instruction operations. the to flag can be affected only by a system power-up, a wdt time-out or by executing the clr wdt or halt in - struction. the pdf flag is affected only by executing the halt or clr wdt instruction or during a system power-up. the z, ov, ac and c flags generally reflect the status of the latest operations. in addition, on entering an interrupt sequence or execut - ing a subroutine call, the status register will not be pushed onto the stack automatically. if the contents of the status registers are important and if the interrupt rou - tine can change the status register, precautions must be taken to correctly save it. note that bits 0~3 of the status register are both readable and writeable bits. input/output ports and control registers within the area of special function registers, the port pa data i/o register and its associated control register pac plays a prominent role. this register is mapped to specific address within the data memory as shown in the data memory table. the data i/o registers, are used to transfer the appropriate output or input data on the port. the control registers specifies which pins of the port are set as inputs and which are set as outputs. to setup a pin as an input, the corresponding bit of the con - trol register must be set high, for an output it must be set status register bit76543210 name to pdf ov z ac c r/w r r r/w r/w r/w r/w por 00xxxx x unknown bit 7, 6 unimplemented, read as 0 bit 5 to : watchdog time-out flag 0: after power up or executing the clr wdt or halt instruction 1: a watchdog time-out occurred. bit 4 pdf : power down flag 0: after power up or executing the clr wdt instruction 1: by executing the halt instruction bit 3 ov : overflow flag 0: no overflow 1: an operation results in a carry into the highest-order bit but not a carry out of the highest-order bit or vice versa. bit 2 z : zero flag 0: the result of an arithmetic or logical operation is not zero 1: the result of an arithmetic or logical operation is zero bit 1 ac : auxiliary flag 0: no auxiliary carry 1: an operation results in a carry out of the low nibbles in addition, or no borrow from the high nibble into the low nibble in subtraction bit 0 c: carry flag 0: no carry-out 1: an operation results in a carry during an addition operation or if a borrow does not take place during a subtraction operation c is also affected by a rotate through carry instruction.
HT48R005/ht46r005 rev. 1.00 19 november 29, 2011 low. during program initialisation, it is important to first setup the control registers to specify which pins are out - puts and which are inputs before reading data from or writing data to the i/o ports. one flexible feature of these registers is the ability to directly program single bits us - ing the set [m].i and clr [m].i instructions. the ability to change i/o pins from output to input and vice versa by manipulating specific bits of the i/o control reg - isters during normal program operation is a useful fea - ture of these devices. system control registers ctrl0, ctrl1 these registers are used to provide control over various internal functions. some of these include the buzzer control, external interrupt edge trigger type and watch - dog timer enable function. wake-up function register pawk when the microcontroller enters the sleep mode, vari - ous methods exist to wake the device up and continue with normal operation. one method is to allow a falling edge on the i/o pins to have a wake-up function. this register is used to select which port a i/o pins are used to have this wake-up function. pull-high registers papu the i/o pins, if configured as inputs, can have internal pull-high resistors connected, which eliminates the need for external pull-high resistors. this register selects which i/o pins are connected to internal pull-high resistors. ctrl0 register bit76543210 name bzen1 bzen0 r/w r/w r/w por 00 bit 7~4 unimplemented, read as 0 bit 3~2 bzen1, bzen0 : bz/bz enable/disable 00: both disabled 01: reserved 10: bz only enabled 11: bz and bz enabled when bz or bz is disabled, the i/o port will have general i/o functions. if enabled, the bz or bz outputs will still be controlled by the related i/o port control and data settings. refer to the buzzer function section for details. bit 1~04 unimplemented, read as 0 ctrl1 register bit76543210 name integ1 integ0 wdten3 wdten2 wdten1 wdten0 r/w r/w r/w r/w r/w r/w r/w por 1 0 1010 bit 7, 6 integ1, integ0 : external interrupt edge type 00: disable 01: rising edge trigger 10: falling edge trigger 11: dual edge trigger bit 5, 4 unimplemented, read as 0 bit 3~0 wdten3, wdten2, wdten1, wdten0 : wdt function enable 1010: wdt disabled other values: wdt enabled - recommended value is 0101 if the watchdog timer enable configuration option is selected, then the watchdog timer will always be enabled and the wdten3~wdten0 control bits will have no effect. note: the wdt is only disabled when both the wdt configuration option is disabled and when bits wdten3~wdten0=1010. the wdt is enabled when either the wdt configuration option is enabled or when bits wdten3~wdten01010.
HT48R005/ht46r005 rev. 1.00 20 november 29, 2011 oscillator various oscillator options offer the user a wide range of functions according to their various application require - ments. the flexible features of the oscillator functions ensure that the best optimisation can be achieved in terms of speed and power saving. oscillator selections and operation are selected through a combination of configuration options and registers. system oscillator overview in addition to being the source of the main system clock the oscillators also provide clock sources for the watch - dog timer function. external oscillators requiring some external components as well as a two fully integrated in - ternal oscillators, requiring no external components, are provided to form a wide range of both fast and slow sys - tem oscillators. type name freq. external crystal hxt 400khz~ 12mhz external rc erc 400khz~ 12mhz internal high speed rc hirc 4,8or 12mhz internal low speed rc lirc 13khz system clock configurations there are four system oscillators. three high speed os- cillators and one low speed oscillator. the high speed oscillators are the external crystal/ceramic oscillator - hxt, the external - erc, and the internal rc oscillator - hirc. the low speed oscillator is the internal 13khz (v dd =5v) oscillator - lirc. external crystal/resonator oscillator hxt the simple connection of a crystal across osc1 and osc2 will create the necessary phase shift and feed - back for oscillation. however, for some crystals and most resonator types, to ensure oscillation and accurate frequency generation, it is necessary to add two small value external capacitors, c1 and c2. the exact values of c1 and c2 should be selected in consultation with the crystal or resonator manufacturer
s specification. crystal oscillator c1 and c2 values crystal frequency c1 c2 12mhz 8pf 10pf 8mhz 8pf 10pf 4mhz 8pf 10pf 1mhz 100pf 100pf note: c1 and c2 values are for guidance only. crystal recommended capacitor values external rc oscillator erc using the erc oscillator only requires that a resistor, with a value between 24k and 1.5m , is connected between osc1 and vdd, and a capacitor is connected between osc and ground, providing a low cost oscilla - tor configuration. it is only the external resistor that de - termines the oscillation frequency; the external capacitor has no influence over the frequency and is connected for stability purposes only. device trimming during the manufacturing process and the inclusion of internal frequency compensation circuits are used to en- sure that the influence of the power supply voltage, tem- perature and process variations on the oscillation frequency are minimised. as a resistance/frequency ref- erence point, it can be noted that with an external 120k resistor connected and with a 5v voltage power supply and temperature of 25 degrees, the oscillator will have a frequency of 4mhz within a tolerance of 2%. here only the osc1 pin is used, which is shared with i/o pin pa6, leaving pin pa5 free for use as a normal i/o pin. #
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HT48R005/ht46r005 rev. 1.00 21 november 29, 2011 internal rc oscillator hirc the internal rc oscillator is a fully integrated system os - cillator requiring no external components. the internal rc oscillator has three fixed frequencies of either 4mhz, 8mhz or 12mhz. device trimming during the manufacturing process and the inclusion of internal fre - quency compensation circuits are used to ensure that the influence of the power supply voltage, temperature and process variations on the oscillation frequency are minimised. as a result, at a power supply of either 3v or 5v and at a temperature of 25 degrees, the fixed oscilla - tion frequency of 4mhz, 8mhz or 12mhz will have a tol - erance within 2%. note that if this internal system clock option is selected, as it requires no external pins for its operation, i/o pins pa5 and pa6 are free for use as nor - mal i/o pins. internal low speed oscillator lirc the lirc is a fully self-contained free running on-chip rc oscillator with a typical frequency of 13khz at 5v re- quiring no external components. when the device en- ters the sleep mode, the system clock will stop running but the wdt oscillator continues to free-run and to keep the watchdog active. however, to preserve power in cer- tain applications the lirc can be disabled via a configu- ration option. operating modes the system can be selected to operate in two modes. these modes are normal and sleep. operating mode osc1/osc2 configuration hxt erc hirc normal run run run sleep stop stop stop operating mode control mode switching the devices are switched between one mode and an - other using the halt instruction. the halt instruction forces the system into the sleep mode. when a halt instruction is executed, the system enters the sleep mode the following conditions exist: the system oscillator will stop running and the appli - cation program will stop at the halt instruction. the data memory contents and registers will maintain their present condition. the wdt will be cleared and resume counting if the wdt clock source is selected to come from the wdt oscillator. the wdt will stop if its clock source origi - nates from the system clock. the i/o ports will maintain their present condition. in the status register, the power down flag, pdf, will be set and the watchdog time-out flag, to, will be cleared. standby current considerations as the main reason for entering the sleep mode is to keep the current consumption of the mcu to as low a value as possible, perhaps only in the order of several micro-amps, there are other considerations which must also be taken into account by the circuit designer if the power consumption is to be minimised. special attention must be made to the i/o pins on the device. all high-impedance input pins must be con - nected to either a fixed high or low level as any floating input pins could create internal oscillations and result in % # b ! ! 7 ) < ! 7
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HT48R005/ht46r005 rev. 1.00 22 november 29, 2011 increased current consumption. care must also be taken with the loads, which are connected to i/o pins, which are setup as outputs. these should be placed in a condition in which minimum current is drawn or con - nected only to external circuits that do not draw current, such as other cmos inputs. if the configuration options have enabled the watchdog timer internal oscillator lirc then this will continue to run when in the sleep mode and will thus consume some power. for power sensitive applications it may be therefore preferable to use the system clock source for the watchdog timer. wake-up after the system enters the sleep mode, it can be woken up from one of various sources listed as follows: an external reset an external falling edge on pa0 to pa7 a system interrupt a wdt overflow if the system is woken up by an external reset, the de - vice will experience a full system reset, however, if the device is woken up by a wdt overflow, a watchdog timer reset will be initiated. although both of these wake-up methods will initiate a reset operation, the ac- tual source of the wake-up can be determined by exam- ining the to and pdf flags. the pdf flag is cleared by a system power-up or executing the clear watchdog timer instructions and is set when executing the halt instruction. the to flag is set if a wdt time-out occurs, and causes a wake-up that only resets the program counter and stack pointer, the other flags remain in their original status. pins pa0 to pa7 can be setup via the pawk register to permit a negative transition on the pin to wake-up the system. when a pa0 to pa7 pin wake-up occurs, the pro - gram will resume execution at the instruction following the halt instruction. if the system is woken up by an interrupt, then two possi - ble situations may occur. the first is where the related interrupt is disabled or the interrupt is enabled but the stack is full, in which case the program will resume exe - cution at the instruction following the halt instruction. in this situation, the interrupt which woke-up the device will not be immediately serviced, but will rather be ser - viced later when the related interrupt is finally enabled or when a stack level becomes free. the other situation is where the related interrupt is enabled and the stack is not full, in which case the regular interrupt response takes place. if an interrupt request flag is set to 1 be - fore entering the sleep mode, then any future interrupt requests will not generate a wake-up function of the re - lated interrupt will be ignored. no matter what the source of the wake-up event is, once a wake-up event occurs, there will be a time delay be - fore normal program execution resumes. consult the ta - ble for the related time. wake-up source oscillator type erc, irc hxt external res , power-on reset and lvr t rstd + t sst1 t rstd + t sst2 pa port t sst1 t sst2 interrupt wdt overflow note: 1. t rstd (reset delay time), t sys (system clock) 2. t rstd is power-on delay, typical time=100ms 3. t sst1 =2 t sys 4. t sst2 = 128 t sys wake-up delay time
HT48R005/ht46r005 rev. 1.00 23 november 29, 2011 watchdog timer the watchdog timer, also known as the wdt, is pro - vided to inhibit program malfunctions caused by the pro - gram jumping to unknown locations due to certain uncontrollable external events such as electrical noise. watchdog timer operation it operates by providing a device reset when the watch - dog timer counter overflows. note that if the watchdog timer function is not enabled, then any instructions re - lated to the watchdog timer will result in no operation. setting up the various watchdog timer options are con - trolled via the configuration options and two internal reg - isters wdts and ctrl1. enabling the watchdog timer can be controlled by both a configuration option and the wdten bits in the ctrl1 internal register in the data memory. configuration option ctrl1 register wdt function disable disable off disable enable on enable x on watchdog timer on/off control the watchdog timer will be disabled if bits wdten3~wdten0 in the ctrl1 register are written with the binary value 1010b and wdt configuration op- tion is disable. this will be the condition when the device is powered up. although any other data written to wdten3~wdten0 will ensure that the watchdog timer is enabled, for maximum protection it is recom- mended that the value 0101b is written to these bits. the watchdog timer clock can emanate from three dif- ferent sources, selected by configuration option. these are f sys /4, or lirc. it is important to note that when the system enters the sleep mode the instruction clock is stopped, therefore if the configuration options have se - lected f sys /4 as the watchdog timer clock source, the watchdog timer will cease to function. for systems that operate in noisy environments, using the lirc as the clock source is therefore the recommended choice. the division ratio of the prescaler is determined by bits 0, 1 and 2 of the wdts register, known as ws0, ws1 and ws2. if the watchdog timer internal clock source is se - lected and with the ws0, ws1 and ws2 bits of the wdts register all set high, the prescaler division ratio will be 1:128, which will give a maximum time-out period. under normal program operation, a watchdog timer time-out will initialise a device reset and set the status bit to. however, if the system is in the sleep mode, when a watchdog timer time-out occurs, the device will be woken up, the to bit in the status register will be set and only the program counter and stack pointer will be re - set. three methods can be adopted to clear the con - tents of the watchdog timer. the first is an external hardware reset, which means a low level on the external reset pin, the second is using the clear watchdog timer software instructions and the third is when a halt in - struction is executed. there are two methods of using software instructions to clear the watchdog timer, one of which must be chosen by configuration option. the first option is to use the single clr wdt instruction while the second is to use the two commands clr wdt1 and clr wdt2 . for the first option, a simple execution of clr wdt will clear the watchdog timer while for the second option, both clr wdt1 and clr wdt2 must both be executed to successfully clear the watchdog timer. note that for this second op- tion, if clr wdt1 is used to clear the watchdog timer, successive executions of this instruction will have no effect, only the execution of a clr wdt2 instruc - tion will clear the watchdog timer. similarly after the clr wdt2 instruction has been executed, only a suc - cessive clr wdt1 instruction can clear the watch - dog timer. $ % ! 0 f f & d f *
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HT48R005/ht46r005 rev. 1.00 24 november 29, 2011 wdts register bit76543210 name ws2 ws1 ws0 r/w r/w r/w r/w por 111 bit 7~3 : unimplemented, read as 0 bit 2~0 ws2, ws1, ws0 : wdt time-out period selection 000: 2 8 t wdtck 001: 2 9 t wdtck 010: 2 10 t wdtck 011: 2 11 t wdtck 100: 2 12 t wdtck 101: 2 13 t wdtck 110: 2 14 t wdtck 111: 2 15 t wdtck reset and initialisation a reset function is a fundamental part of any microcontroller ensuring that the device can be set to some predetermined condition irrespective of outside parameters. the most important reset condition is after power is first applied to the microcontroller. in this case, internal circuitry will ensure that the microcontroller, af- ter a short delay, will be in a well defined state and ready to execute the first program instruction. after this power-on reset, certain important internal registers will be set to defined states before the program com- mences. one of these registers is the program counter, which will be reset to zero forcing the microcontroller to begin program execution from the lowest program memory address. in addition to the power-on reset, situations may arise where it is necessary to forcefully apply a reset condition when the microcontroller is running. one example of this is where after power has been applied and the microcontroller is already running, the res line is force - fully pulled low. in such a case, known as a normal oper - ation reset, some of the microcontroller registers remain unchanged allowing the microcontroller to proceed with normal operation after the reset line is allowed to return high. another type of reset is when the watchdog timer overflows and resets the microcontroller. all types of re - set operations result in different register conditions be - ing setup. another reset exists in the form of a low voltage reset, lvr, where a full reset, similar to the res reset is imple - mented in situations where the power supply voltage falls below a certain threshold. reset functions there are five ways in which a microcontroller reset can occur, through events occurring both internally and ex - ternally: power-on reset the most fundamental and unavoidable reset is the one that occurs after power is first applied to the microcontroller. as well as ensuring that the program memory begins execution from the first memory ad - dress, a power-on reset also ensures that certain other registers are preset to known conditions. all the i/o port and port control registers will power up in a high condition ensuring that all pins will be first set to inputs. although the microcontroller has an internal rc reset function, if the vdd power supply rise time is not fast enough or does not stabilise quickly at power-on, the internal reset function may be incapable of providing proper reset operation. for this reason it is recom- mended that an external rc network is connected to the res pin, whose additional time delay will ensure that the res pin remains low for an extended period to allow the power supply to stabilise. during this time delay, normal operation of the microcontroller will be inhibited. after the res line reaches a certain voltage value, the reset delay time t rstd is invoked to provide an extra delay time after which the microcontroller will begin normal operation. the abbreviation sst in the figures stands for system start-up timer. for most applications a resistor connected between vdd and the res pin and a capacitor connected be - tween vss and the res pin will provide a suitable ex - ternal reset circuit. any wiring connected to the res pin should be kept as short as possible to minimise any stray noise interference. ( " ! 7 * 2 , " 6 6 note: t rstd is power-on delay, typical time=100ms power-on reset timing chart
HT48R005/ht46r005 rev. 1.00 25 november 29, 2011 for applications that operate within an environment where more noise is present the enhanced reset cir - cuit shown is recommended. more information regarding external reset circuits is located in application note ha0075e on the holtek website. res pin reset this type of reset occurs when the microcontroller is already running and the res pin is forcefully pulled low by external hardware such as an external switch. in this case as in the case of other reset, the program counter will reset to zero and program execution initi- ated from this point. low voltage reset lvr the microcontroller contains a low voltage reset cir - cuit in order to monitor the supply voltage of the de - vice. the lvr function is selected via a configuration option. if the supply voltage of the device drops to within a range of 0.9v~v lvr such as might occur when changing the battery, the lvr will automatically reset the device internally. for a valid lvr signal, a low sup - ply voltage, i.e., a voltage in the range between 0.9v~v lvr must exist for a time greater than that spec - ified by t lvr in the a.c. characteristics. if the low sup - ply voltage state does not exceed this value, the lvr will ignore the low supply voltage and will not perform a reset function. the actual v lvr value can be se - lected via configuration options. watchdog time-out reset during normal operation the watchdog time-out reset during normal opera - tion is the same as a hardware res pin reset except that the watchdog time-out flag to will be set to 1. watchdog time-out reset during sleep mode the watchdog time-out reset during sleep mode is a little different from other kinds of reset. most of the conditions remain unchanged except that the pro - gram counter and the stack pointer will be cleared to 0 and the to flag will be set to 1 . refer to the a.c. characteristics for t sst details. note: if the system clock source is provided by erc or hirc, the t sst is 2 clock cycles. if the system clock source is provided by hxt, the t sst is 128 clock cycles. reset initial conditions the different types of reset described affect the reset flags in different ways. these flags, known as pdf and to are located in the status register and are controlled by various microcontroller operations, such as the sleep function or watchdog timer. the reset flags are shown in the table: to pdf reset conditions 0 0 power-on reset uu res or lvr reset during normal mode operation 1u wdt time-out reset during normal mode operation 11 wdt time-out reset during sleep mode operation note: u stands for unchanged f ! 7 wdt time-out reset during sleep timing chart : " ! 7 6 note: t rstd is power-on delay, typical time=100ms low voltage reset timing chart 6 f ! 7 note: t rstd is power-on delay, typical time=100ms wdt time-out reset during normal operation timing chart ( ' * 2 $ d $ / $ * 8 d $ * * 8 " " * 2 * $ / j j " $ ) . $ . j - * * j note: * it is recommended that this component is added for added esd protection ** it is recommended that this component is added in environments where power line noise is significant external res circuit ( ! 7 * 2 , " * 2 . " 6 note: t rstd is power-on delay, typical time=100ms res reset timing chart
HT48R005/ht46r005 rev. 1.00 26 november 29, 2011 the following table indicates the way in which the various components of the microcontroller are affected after a power-on reset occurs. item condition after reset program counter reset to zero interrupts all interrupts will be disabled wdt clear after reset, wdt begins counting timer/event counter timer counter will be turned off prescaler the timer counter prescaler will be cleared input/output ports i/o ports will be setup as inputs stack pointer stack pointer will point to the top of the stack the different kinds of resets all affect the internal registers of the microcontroller in different ways. to ensure reliable continuation of normal program execution after a reset occurs, it is important to know what condition the microcontroller is in after a particular reset occurs. the following table describes how each type of reset affects each of the microcontroller internal registers. HT48R005 register power-on reset res or lvr reset wdt time-out (normal operation) wdt time-out (halt mode) pcl 0000 0000 0000 0000 0000 0000 0000 0000 mp0 1xxx xxxx 1uuu uuuu 1uuu uuuu 1uuu uuuu mp1 1xxx xxxx 1uuu uuuu 1uuu uuuu 1uuu uuuu acc xxxx xxxx uuuu uuuu uuuu uuuu uuuu uuuu tblp xxxx xxxx uuuu uuuu uuuu uuuu uuuu uuuu tblh xx xxxx uu uuuu uu uuuu uu uuuu wdts 111 111 111 uuu status 00 xxxx uu uuuu 1u uuuu 11 uuuu intc0 00 000 00 000 00 000 uu uuu tmr0 xxxx xxxx xxxx xxxx xxxx xxxx uuuu uuuu tmr0c 00 0 1000 00 0 1000 00 0 1000 uu u uuuu pa 111 111 111 111 111 111 uuu uuu pac 111 111 111 111 111 111 uuu uuu pawk 000 000 000 000 000 000 uuu uuu papu 00 000 00 000 00 000 uu uuu ctrl0 00 00 00 uu ctrl1 10 1010 10 1010 10 1010 uu uuuu note: - not implemented u means unchanged x means unknown
HT48R005/ht46r005 rev. 1.00 27 november 29, 2011 ht46r005 register power-on reset res or lvr reset wdt time-out (normal operation) wdt time-out (halt mode) pcl 0000 0000 0000 0000 0000 0000 0000 0000 mp0 1xxx xxxx 1uuu uuuu 1uuu uuuu 1uuu uuuu mp1 1xxx xxxx 1uuu uuuu 1uuu uuuu 1uuu uuuu acc xxxx xxxx uuuu uuuu uuuu uuuu uuuu uuuu tblp xxxx xxxx uuuu uuuu uuuu uuuu uuuu uuuu tblh xx xxxx uu uuuu uu uuuu uu uuuu wdts 111 111 111 uuu status 00 xxxx uu uuuu 1u uuuu 11 uuuu intc0 000 0000 000 0000 000 0000 uuu uuuu tmr0 xxxx xxxx xxxx xxxx xxxx xxxx uuuu uuuu tmr0c 00 0 1000 00 0 1000 00 0 1000 uu u uuuu pa 111 111 111 111 111 111 uuu uuu pac 111 111 111 111 111 111 uuu uuu pawk 000 000 000 000 000 000 uuu uuu papu 00 000 00 000 00 000 uu uuu ctrl0 00 00 00 uu ctrl1 10 1010 10 1010 10 1010 uu uuuu adrl xxxx xxxx xxxx uuuu adrh xxxx xxxx xxxx xxxx xxxx xxxx uuuu uuuu adcr 01 0 0000 01 0 0000 01 0 0000 uu u uuuu acsr 11 000 11 000 11 000 uu uuu note: - not implemented u means unchanged x means unknown
HT48R005/ht46r005 rev. 1.00 28 november 29, 2011 input/output ports holtek microcontrollers offer considerable flexibility on their i/o ports. most pins can have either an input or out - put designation under user program control. addi - tionally, as there are pull-high resistors and wake-up software configurations, the user is provided with an i/o structure to meet the needs of a wide range of applica - tion possibilities. for input operation, these ports are non-latching, which means the inputs must be ready at the t2 rising edge of instruction mov a,[m] , where m denotes the port ad - dress. for output operation, all the data is latched and remains unchanged until the output latch is rewritten. pull-high resistors many product applications require pull-high resistors for their switch inputs usually requiring the use of an external resistor. to eliminate the need for these external resis - tors, when configured as an input have the capability of being connected to an internal pull-high resistor. these pull-high resistors are selectable via a register known as papu located in the data memory. the pull-high resis - tors are implemented using weak pmos transistors. note that pin pa7 does not have a pull-high resistor se - lection. port a wake-up if the halt instruction is executed, the device will enter the sleep mode, where the system clock will stop result - ing in power being conserved, a feature that is important for battery and other low-power applications. various methods exist to wake-up the microcontroller, one of which is to change the logic condition on one of the pa0~pa2, pa5~pa7 pins from high to low. after a halt instruction forces the microcontroller into entering the sleep mode, the processor will remain in a low-power state until the logic condition of the selected wake-up pin on port a changes from high to low. this function is es - pecially suitable for applications that can be woken up via external switches. note that pins pa0~pa2, pa5~pa7 can be selected individually to have this wake-up feature using an internal register known as pawk, located in the data memory. pawk, pac, papu register register name por bit 76543210 pawk 00h pawk7 pawk6 pawk5 pawk2 pawk1 pawk0 pac ffh pac7 pac6 pac5 pac2 pac1 pac0 papu 00h papu6 papu5 papu2 papu1 papu0 unimplemented, read as 0 pawkn : pa wake-up function enable 0: disable 1: enable pacn : i/o type selection 0: output 1: input papun : pull-high function enable 0: disable 1: enable
HT48R005/ht46r005 rev. 1.00 29 november 29, 2011 i/o port control registers each port has its own control register, known as pac which controls the input/output configuration. with this control register, each i/o pin with or without pull-high re - sistors can be reconfigured dynamically under software control. for the i/o pin to function as an input, the corre - sponding bit of the control register must be written as a 1 . this will then allow the logic state of the input pin to be directly read by instructions. when the correspond - ing bit of the control register is written as a 0 , the i/o pin will be setup as a cmos output. if the pin is currently setup as an output, instructions can still be used to read the output register. however, it should be noted that the program will in fact only read the status of the output data latch and not the actual logic status of the output pin. pin-shared functions the flexibility of the microcontroller range is greatly en - hanced by the use of pins that have more than one func - tion. limited numbers of pins can force serious design constraints on designers but by supplying pins with multi-functions, many of these difficulties can be over - come. for some pins, the chosen function of the multi-function i/o pins is set by configuration options while for others the function is set by application pro- gram control. external interrupt input the external interrupt pin, int, is pin-shared with an i/o pin. to use the pin as an external interrupt input the correct bits in the intc0 register must be pro- grammed. the pin must also be setup as an input by setting pac2 bit in the port control register. a pull-high resistor can also be selected via the appro- priate port pull-high resistor register. note that even if the pin is setup as an external interrupt input the i/o function still remains. external timer/event counter input the timer/event counter pin, tmr is pin-shared with i/o pin. for this shared pin to be used as timer/event counter input, the timer/event counter must be con - figured to be in the event counter or pulse width cap - ture mode. this is achieved by setting the appropriate bits in the timer/event counter control register. the pins must also be setup as inputs by setting the ap - propriate bit in the port control register. pull-high re - sistor options can also be selected using the port pull-high resistor registers. note that even if the pin is setup as an external timer input the i/o function still re - mains. buzzer output the device contains a buzzer function whose single or dual outputs are pin-shared with i/o pins. the out - put function of these pin are chosen using the ctrl0 register. note that the corresponding bit of the port control register, must setup the pin as an output to en - able the bz, bz output. if the port control register has setup these pins as input, then these pins will function as normal logic input with the usual pull-high selec - tion, even if the buzzer function has been selected. a/d inputs each device in this series has either four or eight in - puts to the a/d converter. all of these analog inputs are pin-shared with i/o pins on port a. if these pins are to be used as a/d inputs and not as i/o pins then the corresponding pcrn bits in the a/d converter control register, adcr, must be properly setup. there are no configuration options associated with the a/d converter. if chosen as i/o pins, then full pull-high re - sistor configuration options remain, however if used as a/d inputs then any pull-high resistor configuration options associated with these pins will be automati - cally disconnected. i/o pin structures the diagrams illustrate the i/o pin internal structures. as the exact logical construction of the i/o pin may differ from these drawings, they are supplied as a guide only to assist with the functional understanding of the i/o pins. programming considerations within the user program, one of the first things to con - sider is port initialisation. after a reset, the i/o data reg - ister and i/o port control register will be set high. this means that all i/o pins will default to an input state, the level of which depends on the other connected circuitry and whether pull-high options have been selected. if the port control registers, are then programmed to setup some pins as outputs, these output pins will have an ini- tial high output value unless the associated port data register is first programmed. selecting which pins are in- puts and which are outputs can be achieved byte-wide by loading the correct value into the port control register or by programming individual bits in the port control reg - ister using the set [m].i and clr [m].i instructions. note that when using these bit control instructions, a read-modify-write operation takes place. the microcontroller must first read in the data on the entire port, modify it to the required new bit values and then re - write this data back to the output ports. pins pa0 to pa7 each have a wake-up functions, se - lected via the pawk register. when the device is in the sleep mode, various methods are available to wake the device up. one of these is a high to low transition of any of the these pins. single or multiple pins on port a can be setup to have this function. $ & - . $ & - . f ! b a
7 0 8 ! ! read modify write timing
HT48R005/ht46r005 rev. 1.00 30 november 29, 2011 f g ' i ! b ! !
7 ! ! f
7
1 9 ! b
7 f ! ! ! ! k
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g k ' ( f ! 8 9 3 ' 4 ( a ' 7 pa7 nmos input/output port " i f ! 8 9 7 0 f ! 8 9 ! b ! ! k
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7 f ! ! ! ! 9 k k 7 f ! 8 7 7 9 7 7 ? 1 7 0 generic input/output ports
HT48R005/ht46r005 rev. 1.00 31 november 29, 2011 timer/event counters the provision of timers form an important part of any microcontroller, giving the designer a means of carrying out time related functions. the devices contain from one count-up timer of 8-bit capacity. as the timer has three different operating modes, it can be configured to oper - ate as a general timer, an external event counter or as a pulse width capture device. the provision of an internal prescaler to the clock circuitry on gives added range to the timer. there are two types of registers related to the timer/event counters. the first is the register that con - tains the actual value of the timer and into which an ini - tial value can be preloaded. reading from this register retrieves the contents of the timer/event counter. the second type of associated register is the timer control register which defines the timer options and deter - mines how the timer is to be used. the device can have the timer clock configured to come from the internal clock source. in addition, the timer clock source can also be configured to come from an external timer pin. configuring the timer/event counter input clock source the timer/event counter clock source can originate from various sources, an internal clock or an external pin. the internal clock source source is used when the timer is in the timer mode or in the pulse width capture mode. for some timer/event counters, this internal clock source is first divided by a prescaler, the division ratio of which is conditioned by the timer control regis- ter bits t0psc0~t0psc2. for timer/event counter, the internal clock source is fro the f sys . an external clock source is used when the timer is in the event counting mode, the clock source being provided on an external timer pin tmr. depending upon the con - dition of the t0eg bit, each high to low, or low to high transition on the external timer pin will increment the counter by one. timer registers tmr the timer register is special function register located in the special purpose data memory and is the place where the actual timer value is stored. this register is known as tmr0. the value in the timer registers in - creases by one each time an internal clock pulse is re - ceived or an external transition occurs on the external timer pin. the timer will count from the initial value loaded by the preload register to the full count of ffh at which point the timer overflows and an internal interrupt signal is generated. the timer value will then be reset with the initial preload register value and continue count - ing. note that to achieve a maximum full range count of ffh, the preload register must first be cleared to all zeros. it should be noted that after power-on, the preload regis - ters will be in an unknown condition. note that if the timer/event counter is in an off condition and data is written to its preload register, this data will be immedi - ately written into the actual counter. however, if the counter is enabled and counting, any new data written into the preload data register during this period will re - main in the preload register and will only be written into the actual counter the next time an overflow occurs. timer control registers tmr0c the flexible features of the holtek microcontroller timer/event counters enable them to operate in three different modes, the options of which are determined by the contents of their respective control register. the timer control register is known as tmr0c. it is the timer control register together with its corresponding timer register that control the full operation of the timer/event counter. before the timer can be used, it is essential that the timer control register is fully pro- grammed with the right data to ensure its correct opera - tion, a process that is normally carried out during program initialisation. to choose which of the three modes the timer is to oper - ate in, either in the timer mode, the event counting mode or the pulse width capture mode, bits 7 and 6 of the timer control register, which are known as the bit pair t0m1/t0m0, must be set to the required logic levels. the timer-on bit, which is bit 4 of the timer control reg - ister and known as t0on, provides the basic on/off con - (
b
7 * ) 7 ! b (
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* * $ * * a ; * ( 8-bit timer/event counter structure
HT48R005/ht46r005 rev. 1.00 32 november 29, 2011 tmr0c register bit76543210 name t0m1 t0m0 t0on t0eg t0psc2 t0psc1 t0psc0 r/w r/w r/w r/w r/w r/w r/w r/w por 0 0 01000 bit 7,6 t0m1, t0m0 : timer operation mode selection 00: no mode available 01: event counter mode 10: timer mode 11: pulse width capture mode bit 5 unimplemented, read as 0 bit 4 t0on : timer/event counter counting enable 0: disable 1: enable bit 3 t0eg: event counter active edge selection 0: count on raising edge 1: count on falling edge pulse width capture active edge selection 0: start counting on falling edge, stop on rasing edge 1: start counting on raising edge, stop on falling edge bit 2~0 t0psc2, t0psc1, t0psc0 : timer prescaler rate selection timer internal clock= 000: f tp 001: f tp /2 010: f tp /4 011: f tp /8 100: f tp /16 101: f tp /32 110: f tp /64 111: f tp /128
HT48R005/ht46r005 rev. 1.00 33 november 29, 2011 trol of the respective timer. setting the bit high allows the counter to run, clearing the bit stops the counter. bits 0~2 of the timer control register determine the division ratio of the input clock prescaler. the prescaler bit set - tings have no effect if an external clock source is used. if the timer is in the event count or pulse width capture mode, the active transition edge level type is selected by the logic level of bit 3 of the timer control register which is known as t0eg. timer mode in this mode, the timer/event counter can be utilised to measure fixed time intervals, providing an internal inter - rupt signal each time the timer/event counter over - flows. to operate in this mode, the operating mode select bit pair, t0m1/t0m0, in the timer control regis - ter must be set to the correct value as shown. control register operating mode select bits for the timer mode bit7 bit6 10 in this mode the internal clock is used as the timer clock. the timer input clock source is either f sys or f sys /4. however, this timer clock source is further divided by a prescaler, the value of which is determined by the bits t0psc2~t0psc0 in the timer control register. the timer-on bit, t0on must be set high to enable the timer to run. each time an internal clock high to low transition occurs, the timer increments by one; when the timer is full and overflows, an interrupt signal is generated and the timer will reload the value already loaded into the preload register and continue counting. a timer overflow condition and corresponding internal interrupt is one of the wake-up sources, however, the internal interrupts can be disabled by ensuring that the t0eg bits of the intc0 register are reset to zero. event counter mode in this mode, a number of externally changing logic events, occurring on the external timer tmr pin, can be recorded by the timer/event counter. to operate in this mode, the operating mode select bit pair, t0m1/t0m0, in the timer control register must be set to the correct value as shown. control register operating mode select bits for the event counter mode bit7 bit6 01 in this mode, the external timer tmr pin, is used as the timer/event counter clock source, however it is not di - vided by the internal prescaler. after the other bits in the timer control register have been setup, the enable bit t0on, which is bit 4 of the timer control register, can be set high to enable the timer/event counter to run. if the active edge select bit, t0eg, which is bit 3 of the timer control register, is low, the timer/event counter will increment each time the external timer pin receives a low to high transition. if the t0eg is high, the counter will increment each time the external timer pin receives a high to low transition. when it is full and overflows, an interrupt signal is generated and the timer/event coun - ter will reload the value already loaded into the preload register and continue counting. the interrupt can be dis - abled by ensuring that the timer/event counter inter - rupt enable bit in the corresponding interrupt control register, is reset to zero. as the external timer pin is shared with an i/o pin, to en - sure that the pin is configured to operate as an event counter input pin, two things have to happen. the first is to ensure that the operating mode select bits in the timer control register place the timer/event counter in the event counting mode, the second is to ensure that the port control register configures the pin as an input. it should be noted that in the event counting mode, even if the microcontroller is in the sleep mode, the timer/event counter will continue to record externally changing logic events on the timer input tmr pin. as a result when the timer overflows it will generate a timer interrupt and corresponding wake-up source. pulse width capture mode in this mode, the timer/event counter can be utilised to measure the width of external pulses applied to the ex - ternal timer pin. to operate in this mode, the operating mode select bit pair, t0m1/t0m0, in the timer control register must be set to the correct value as shown. 0
7 7 0 ! 7 9 6 $ 6 & 6 ) 6 ) 6 $ timer mode timing chart 6 & ( 5 ! 7 ( 0
6 - 6 $ event counter mode timing chart (t0eg=1)
HT48R005/ht46r005 rev. 1.00 34 november 29, 2011 control register operating mode select bits for the pulse width capture mode bit7 bit6 11 in this mode the internal clock, f sys or f sys /4, is used as the internal clock for the 8-bit timer/event counter. however, the clock source, f sys , for the 8-bit timer is fur - ther divided by a prescaler, the value of which is deter - mined by the prescaler rate select bits t0psc2~t0psc0, which are bits 2~0 in the timer con - trol register. after the other bits in the timer control register have been setup, the enable bit t0on, which is bit 4 of the timer control register, can be set high to en - able the timer/event counter, however it will not actu - ally start counting until an active edge is received on the external timer pin. if the active edge select bit t0eg, which is bit 3 of the timer control register, is low, once a high to low transi - tion has been received on the external timer pin, the timer/event counter will start counting until the external timer pin returns to its original high level. at this point the enable bit will be automatically reset to zero and the timer/event counter will stop counting. if the active edge select bit is high, the timer/event counter will be - gin counting once a low to high transition has been re - ceived on the external timer pin and stop counting when the external timer pin returns to its original low level. as before, the enable bit will be automatically reset to zero and the timer/event counter will stop counting. it is im- portant to note that in the pulse width capture mode, the enable bit is automatically reset to zero when the exter- nal control signal on the external timer pin returns to its original level, whereas in the other two modes the en- able bit can only be reset to zero under program control. the residual value in the timer/event counter, which can now be read by the program, therefore represents the length of the pulse received on the tmr pin. as the enable bit has now been reset, any further transitions on the external timer pin will be ignored. the timer cannot begin further pulse width capture until the enable bit is set high again by the program. in this way, single shot pulse measurements can be easily made. it should be noted that in this mode the timer/event counter is controlled by logical transitions on the external timer pin and not by the logic level. when the timer/event counter is full and overflows, an interrupt signal is gener - ated and the timer/event counter will reload the value al - ready loaded into the preload register and continue counting. the interrupt can be disabled by ensuring that the timer/event counter interrupt enable bit in the corre - sponding interrupt control register, is reset to zero. as the tmr pin is shared with an i/o pin, to ensure that the pin is configured to operate as a pulse width capture pin, two things have to happen. the first is to ensure that the operating mode select bits in the timer control register place the timer/event counter in the pulse width capture mode, the second is to ensure that the port control register configures the pin as an input. prescaler bits t0psc0~t0psc2 of the tmrc register can be used to define a division ratio for the internal clock source of the timer/event counter enabling longer time out periods to be setup. pfd function operating similar to a programmable frequency divider, the buzzer function within the microcontroller provides a means of producing a variable frequency output suitable for applications, such as piezo-buzzer driving or other interfaces requiring a precise frequency generator. bz and bz pins are a complimentary pair and pin-shared with i/o pins, pa0 and pa1. the function is selected via the ctrl0 register, however, if not se- lected, the pins can operate as normal i/o pins. note that the bz pin is the inverse of the bz pin generating a kind of differential output and supplying more power to connected interfaces such as buzzers. the ctrl0 reg- ister can select a single bz pin or the complimentary pair bz and bz . the accompanying table illustrates the truth table of pa0/bz and pa1/bz . the timer overflow signal is the clock source for the buzzer circuit. the output frequency is controlled by load - ing the required values into the timer prescaler and timer registers to give the required division ratio. the counter will begin to count-up from this preload register value until full, at which point an overflow signal is generated, caus - ing both the bz and bz outputs to change state. the counter will then be automatically reloaded with the preload register value and continue counting-up. 6 $ 6 & 6 - 6 . ( 5 ! 7 9 * ) c 1 * ( l * 0 ! 7 9 0
0 ! 7 9 ! 9 7 b ! a ! 7 7 b a $ 2 pulse width capture mode timing chart (tneg=0)
HT48R005/ht46r005 rev. 1.00 35 november 29, 2011 if the ctrl0 register has selected the buzzer function, then for both buzzer outputs to operate, it is essential that the port a control register pac bit 0 and pac bit 1 are setup as outputs. if only one pin is setup as an out - put, the other pin can still be used as a normal data input pin. however, if both pins are setup as inputs then the buzzer will not function. the buzzer outputs will only be activated if bit pa0 is set to 1 . this output data bit is used as the on/off control bit for the buzzer outputs. note that the bz and bz outputs will both be low if the pa0 output data bit is cleared to 0 . the condition of data bit pa1 has no effect on the overall control of the bz and bz pins. using this method of frequency generation, and if a crystal oscillator is used for the system clock, very pre - cise values of frequency can be generated. i/o interfacing the timer/event counter, when configured to run in the event counter or pulse width measurement mode, re - quires the use of an external timer pin for its operation. as this pin is a shared pin it must be configured correctly to ensure that it is setup for use as a timer/event coun - ter input pin. this is achieved by ensuring that the mode select bits in the timer/event counter control register, select either the event counter or pulse width measure- ment mode. additionally the corresponding pac port control register bit must be set high to ensure that the pin is setup as an input. any pull-high resistor connected to this pin will remain valid even if the pin is used as a timer/event counter input. programming considerations when configured to run in the timer mode, the internal system clock is used as the timer clock source and is therefore synchronised with the overall operation of the microcontroller. in this mode when the appropriate timer register is full, the microcontroller will generate an inter - nal interrupt signal directing the program flow to the re - spective internal interrupt vector. for the pulse width measurement mode, the internal system clock is also used as the timer clock source but the timer will only run when the correct logic condition appears on the external timer input pin. as this is an external event and not syn - chronized with the internal timer clock, the microcontroller will only see this external event when the next timer clock pulse arrives. as a result, there may be small differences in measured values requiring pro - grammers to take this into account during programming. the same applies if the timer is configured to be in the event counting mode, which again is an external event and not synchronized with the internal system or timer clock. a 7 c
7 0 8 * ! ! + 9 ! * + 9 ! $ buzzer function bzen1 bzen0 pac register pac0 pac register pac1 pa register pa0 pa register pa1 output function i i o o i x pa0=bz, pa1=bz i i o o o x pa0=0, pa1=0 i o o i i x pa0=bz, pa1=input i x o i o x pa0=0, pa1=input x c i i x d pa0=input, pa1=d x x i i x x pa0=input, pa1=input note: the bzen1 and bzen0 bits are located in the ctrl0 register; i : input; o : output; don
t care; d : data 0 or 1; c : cmos output structure. pa0/pa1 i/o funcion control
HT48R005/ht46r005 rev. 1.00 36 november 29, 2011 when the timer/event counter is read, or if data is writ - ten to the preload register, the clock is inhibited to avoid errors, however as this may result in a counting error, this should be taken into account by the programmer. care must be taken to ensure that the timers are prop - erly initialised before using them for the first time. the associated timer enable bits in the interrupt control reg - ister must be properly set otherwise the internal interrupt associated with the timer will remain inactive. the edge select, timer mode and clock source control bits in timer control register must also be correctly set to ensure the timer is properly configured for the required application. it is also important to ensure that an initial value is first loaded into the timer registers before the timer is switched on; this is because after power-on the initial values of the timer registers are unknown. after the timer has been initialized the timer can be turned on and off by controlling the enable bit in the timer control regis - ter. when the timer/event counter overflows, its corre - sponding interrupt request flag in the interrupt control register will be set. if the timer/event counter interrupt is enabled this will in turn generate an interrupt signal. however irrespective of whether the interrupts are en - abled or not, a timer/event counter overflow will also generate a wake-up signal if the device is in a power-down condition. this situation may occur if the timer/event counter is in the event counting mode and if the external signal continues to change state. in such a case, the timer/event counter will continue to count these external events and if an overflow occurs the de - vice will be woken up from its power-down condition. to prevent such a wake-up from occurring, the timer inter - rupt request flag should first be set high before issuing the halt instruction to enter the power down mode. timer program example the program shows how the timer/event counter regis - ters are setup along with how the interrupts are enabled and managed. note how the timer/event counter is turned on, by setting bit 4 of the timer control register. the timer/event counter can be turned off in a similar way by clearing the same bit. this example program sets the timer/event counters to be in the timer mode, which uses the internal system clock as their clock source. pfd programming example org 04h ; external interrupt vector org 08h ; timer counter interrupt vector jmp tmr0int ; jump here when timer overflows :: org 20h ; main program :: ;internal timer interrupt routine tmr0int: : ; timer main program placed here : : begin: ;setup timer registers mov a,09bh ; setup timer preload value mov tmr0,a mov a,081h ; setup timer control register mov tmr0c,a ; timer mode and prescaler set to /2 ;setup interrupt register mov a,005h ; enable master interrupt and timer interrupt mov intc0,a :: set tmr0c.4 ; start timer ::
HT48R005/ht46r005 rev. 1.00 37 november 29, 2011 analog to digital converter the need to interface to real world analog signals is a common requirement for many electronic systems. however, to properly process these signals by a microcontroller, they must first be converted into digital signals by a/d converters. by integrating the a/d con - version electronic circuitry into the microcontroller, the need for external components is reduced significantly with the corresponding follow-on benefits of lower costs and reduced component space requirements. a/d overview the ht46r005 contains a 3-channel analog to digital converter which can directly interface to external analog signals, such as that from sensors or other control sig - nals and convert these signals directly into either a 12-bit digital value. the accompanying block diagram shows the overall in - ternal structure of the a/d converter, together with its as - sociated registers. a/d converter register description overall operation of the a/d converter is controlled us - ing four registers. a read only register pair exists to store the adc data 12-bit value. the remaining two registers are control registers which setup the operating and con - trol function of the a/d converter. a/d converter data registers adrl, adrh as the devices contain an internal 12-bit a/d converter, they require two data registers to store the converted value. these are a high byte register, known as adrh, and a low byte register, known as adrl. after the con - version process takes place, these registers can be di - rectly read by the microcontroller to obtain the digitised conversion value. only the high byte register, adrh, utilises its full 8-bit contents. the low byte register uti - lises only 4 bit of its 8-bit contents as it contains only the lowest bits of the 12-bit converted value. in the following table, d0~d11 is the a/d conversion data result bits.
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a/d converter structure in the following table, d0~d11 is the a/d conversion data result bits. register bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 adrl d3 d2 d1 d0 adrh d11 d10 d9 d8 d7 d6 d5 d4 adcr start eocb pcr2 pcr1 pcr0 acs1 acs0 acsr test adonb adcs2 adcs1 adcs0 a/d data registers
HT48R005/ht46r005 rev. 1.00 38 november 29, 2011 adrh, adrl register adrh adrl bit7654321076543210 name d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 r/wrrrrrrrrrrrr porxxxxxxxxxxxx x unknown unimplemented, read as 0 d11~d0 : adc conversion data adcr register bit76543210 name start eocb pcr2 pcr1 pcr0 acs1 acs0 r/w r/w r r/w r/w r/w r/w r/w por 0 1 00000 bit 7 start : start the a/d conversion 01 0 : start 0 1 : reset the a/d converter and set eocb to 1 this bit is used to initiate an a/d conversion process. the bit is normally low but if set high and then cleared low again, the a/d converter will initiate a conversion process. when the bit is set high the a/d converter will be reset. bit 6 eocb : end of a/d conversion flag 0: a/d conversion ended 1: a/d conversion in progress this read only flag is used to indicate when an a/d conversion process has completed. when the conversion process is running the bit will be high. bit 5 unimplemented, read as 0 bit 4 pcr2 : define pa2 is a/d input or not 0: not a/d input 1: a/d input, an2 bit 3 pcr1 : define pa1 is a/d input or not 0: not a/d input 1: a/d input, an1 bit 2 pcr0 : define pa0 is a/d input or not 0: not a/d input 1: a/d input, an0 note that if the pcr2~pcr0 bits are all cleared to 0 , then the adc module will enter power down mode to reduce the power consumption. bit 2~0 acs1, acs0 : select a/d channel 00: an0 01: an1 10: an2 11: reserved a/d converter control registers adcr, acsr to control the function and operation of the a/d con - verter, two control registers known as adcr and acsr are provided. these 8-bit registers define functions such as the selection of which analog channel is con - nected to the internal a/d converter, which pins are used as analog inputs and which are used as normal i/os, the a/d clock source as well as controlling the start function and monitoring the a/d converter end of con - version status. the pcr2~pcr0 bits in the adcr register define the channel number. as the device contains only one actual analog to digital converter circuit, each of the individual 3 analog inputs must be routed to the converter. it is the function of the acs1~acs0 bits in the adcr register to determine which analog channel is actually connected to the internal a/d converter.
HT48R005/ht46r005 rev. 1.00 39 november 29, 2011 a/d operation the start bit in the adcr register is used to start and reset the a/d converter. when the microcontroller sets this bit from low to high and then low again, an analog to digital conversion cycle will be initiated. when the start bit is brought from low to high but not low again, the eocb bit in the adcr register will be set high and the analog to digital converter will be reset. it is the start bit that is used to control the overall start opera- tion of the internal analog to digital converter. the eocb bit in the adcr register is used to indicate when the analog to digital conversion process is com - plete. this bit will be automatically set to "0" by the microcontroller after a conversion cycle has ended. in addition, the corresponding a/d interrupt request flag will be set in the interrupt control register, and if the inter - rupts are enabled, an appropriate internal interrupt sig - nal will be generated. this a/d internal interrupt signal will direct the program flow to the associated a/d inter - nal interrupt address for processing. if the a/d internal interrupt is disabled, the microcontroller can be used to poll the eocb bit in the adcr register to check whether it has been cleared as an alternative method of detect - ing the end of an a/d conversion cycle. the adc module power is managed by the adonb in the acsr register and the pcrn bits in the adcr regis - ter. the accompanying table illustrates the power con - trol for the adc module. as we can see from this table, the adc module can be disabled by setting the pcrn bits to 0 or the adonb bit to 0 .it
s recommended to disable the adc module to reduce power consumption when the a/d converter function is not being used. note that the adc module on or off will not be affected by entering the halt mode. pcrn bits halt instruction adonb bit adc on/off = 0 x x off >0 x 0 on > 0 x 1 off note: x: don
t care a/d converter on/off control the clock source for the a/d converter, which originates from the system clock f sys , can be chosen to be either f sys or a subdivided version of f sys .the division ratio value is determined by the adcs2~adcs0 bits in the acsr register. although the a/d clock source is determined by the sys - tem clock f sys , and by bits adcs2~adcs0, there are some limitations on the maximum a/d clock source speed that can be selected. as the minimum value of per - missible a/d clock period, t adck ,is0.5 s, care must be taken for system clock frequencies equal to or greater than 4mhz. for example, if the system clock operates at a frequency of 4mhz, the adcs2~adcs0 bits should not be set to 100 . doing so will give a/d clock periods that are less than the minimum a/d clock period which may result in inaccurate a/d conversion values. refer to the following table for examples, where values marked with an asterisk * show where, depending upon the de - vice, special care must be taken, as the values may be less than the specified minimum a/d clock period. acsr register bit76543210 name test adonb adcs2 adcs1 adcs0 r/w r/w r/w r/w r/w r/w por 1 0 000 bit 7 test : for test mode use only bit 6 adonb : adc module power on/off control bit 0: adc module power on 1: adc module power off note: 1. it is recommended to set adonb=1 before entering sleep for saving power. 2. adonb=1 will power down the adc module. bit 5~3 unimplemented, read as 0 bit 2~0 adcs2~adcs0 : select a/d converter clock source 000: f sys /2 001: f sys /8 010: f sys /32 011: undefined, can
t be used. 100: f sys 101: f sys /4 110: f sys /16 111: undefined, can
t be used. these three bits are used to select the clock source for the a/d converter.
HT48R005/ht46r005 rev. 1.00 40 november 29, 2011 f sys a/d clock period (t adck ) adcs2, adcs1, adcs0=000 (f sys /2) adcs2, adcs1, adcs0=001 (f sys /8) adcs2, adcs1, adcs0=010 (f sys /32) adcs2, adcs1, adcs0=100 (f sys) adcs2, adcs1, adcs0=101 (f sys /4) adcs2, adcs1, adcs0=110 (f sys /16) adcs2, adcs1, adcs0=011, 111 1mhz 2s8 s32 s1 s4 s16 s undefined 2mhz 1s4 s16 s 500ns 2s8 s undefined 4mhz 500ns 2s8 s 250ns* 1s4 s undefined 8mhz 250ns* 1s4 s 125ns* 500ns 2s undefined 12mhz 167ns* 667ns 2.67s 83ns* 333ns* 1s undefined a/d clock period examples a/d input pins all of the a/d analog input pins are pin-shared with the i/o pins on port a as well as other functions. the pcr2~ pcr0 bits in the adcr register, determine whether the input pins are setup as a/d converter analog inputs or whether they have other functions. if the pcr2~pcr0 bits for its corresponding pin is set high then the pin will be setup to be an a/d converter input and the original pin functions disabled. in this way, pins can be changed under program control to change their function between a/d inputs and other functions. all pull-high resistors, which are setup through register programming, will be automatically disconnected if the pins are setup as a/d inputs. note that it is not necessary to first setup the a/d pin as an input in the pac port control register to enable the a/d input as when the pcr2~pcr0 bits enable an a/d input, the status of the port control register will be overridden. summary of a/d conversion steps the following summarises the individual steps that should be executed in order to implement an a/d con - version process. step 1 select the required a/d conversion clock by correctly programming bits adcs2~adcs0 in the acsr regis - ter. step 2 select which pins are to be used as a/d inputs and configure them by correctly programming the pcr2~pcr0 bits in the adcr register. step 3 enable the a/d by clearing the adonb bit in the acsr register to zero. step 4 select which channel is to be connected to the internal a/d converter by correctly programming the acs1~acs0 bits which are also contained in the adcr register. step 5 if the interrupts are to be used, the interrupt control registers must be correctly configured to ensure the a/d converter interrupt function is active. the master interrupt control bit, emi, and the a/d converter inter - rupt bit, eadi, must both be set high to do this. step 6 the analog to digital conversion process can now be initialised by setting the start bit in the adcr regis - ter from low to high and then low again. note that this bit should have been originally cleared to zero. step 7 to check when the analog to digital conversion pro - cess is complete, the eocb bit in the adcr register can be polled. the conversion process is complete when this bit goes low. when this occurs the a/d data registers adrl and adrh can be read to obtain the conversion value. as an alternative method, if the in- terrupts are enabled and the stack is not full, the pro- gram can wait for an a/d interrupt to occur. note: when checking for the end of the conversion process, if the method of polling the eocb bit in the adcr register is used, the interrupt enable step above can be omitted. the accompanying diagram shows graphically the vari - ous stages involved in an analog to digital conversion process and its associated timing. after an a/d conver - sion process has been initiated by the application pro - gram, the microcontroller internal hardware will begin to carry out the conversion, during which time the program can continue with other functions. the time taken for the a/d conversion is 16t adck where t adck is equal to the a/d clock period. programming considerations when programming, special attention must be given to the pcr[2:0] bits in the register. if these bits are all cleared to zero no external pins will be selected for use as a/d input pins allowing the pins to be used as normal i/o pins. when this happens the internal a/d circuitry will be power down. setting the adonb bit high has the ability to power down the internal a/d circuitry, which may be an important consideration in power sensitive applications.
HT48R005/ht46r005 rev. 1.00 41 november 29, 2011 a/d transfer function as the devices contain a 12-bit a/d converter, its full-scale converted digitised value is equal to fffh. since the full-scale analog input value is equal to the v dd voltage, this gives a single bit analog input value of v dd divided by 4096. 1 lsb= (v dd ) 4096 the a/d converter input voltage value can be calcu - lated using the following equation: a/d input voltage = a/d output digital value (v dd ) 4096 the diagram shows the ideal transfer function between the analog input value and the digitised output value for the a/d converter. except for the digitised zero value, the subsequent digitised values will change at a point 0.5 lsb below where they would change without the off - set, and the last full scale digitised value will change at a point 1.5 lsb below the vdd level. a/d programming example the following two programming examples illustrate how to setup and implement an a/d conversion. in the first example, the method of polling the eocb bit in the adcr register is used to detect when the conversion cycle is complete, whereas in the second example, the a/d interrupt is used to determine when the conversion is complete.
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HT48R005/ht46r005 rev. 1.00 42 november 29, 2011 example: using an eocb polling method to detect the end of conversion clr adi ; disable adc interrupt mov a,00000001b mov acsr,a ; select f sys /8 as a/d clock and adonb=0 mov a,00100000b ; setup adcr register to configure port as a/d inputs mov adcr,a ; and select an0 to be connected to the a/d converter : : start_conversion: clr start set start ; reset a/d clr start ; start a/d polling_eoc: sz eocb ; poll the adcr register eocb bit to detect end ; of a/d conversion jmp polling_eoc ; continue polling mov a,adrl ; read low byte conversion result value mov adrl_buffer,a ; save result to user defined register mov a,adrh ; read high byte conversion result value mov adrh_buffer,a ; save result to user defined register : jmp start_conversion ; start next a/d conversion note: to power off adc module, it is necessary to set adonb as 1. example: using the interrupt method to detect the end of conversion clr adi ; disable adc interrupt mov a,00000001b mov acsr,a ; select f sys /8 as a/d clock and adonb=0 mov a,00100000b ; setup adcr register to configure port as a/d inputs mov adcr,a ; and select an0 to be connected to the a/d : : start_conversion: clr start set start ; reset a/d clr start ; start a/d clr adf ; clear adc interrupt request flag set adi ; enable adc interrupt set emi ; enable global interrupt : : : ; adc interrupt service routine adc_: mov acc_stack,a ; save acc to user defined memory mov a,status mov status_stack,a ; save status to user defined memory : : mov a,adrl ; read low byte conversion result value mov adrl_buffer,a ; save result to user defined register mov a,adrh ; read high byte conversion result value mov adrh_buffer,a ; save result to user defined register : : exit_isr: mov a,status_stack mov status,a ; restore status from user defined memory mov a,acc_stack ; restore acc from user defined memory clr adf ; clear adc interrupt flag reti note: to power off adc module, it is necessary to set adonb as 1.
HT48R005/ht46r005 rev. 1.00 43 november 29, 2011 interrupts interrupts are an important part of any microcontroller system. when an external event or an internal function such as a timer/event counter require microcontroller attention, their corresponding interrupt will enforce a temporary suspension of the main program allowing the microcontroller to direct attention to their respective needs. the devices contain a single external interrupt and mul - tiple internal interrupts. the external interrupt is con - trolled by the action of the external interrupt pin, while the internal interrupt is controlled by the timer/event counters overflow. interrupt register overall interrupt control, which means interrupt enabling and request flag setting, is controlled by using the regis - ter, intc0. by controlling the appropriate enable bits in this registers each individual interrupt can be enabled or disabled. also when an interrupt occurs, the corre - sponding request flag will be set by the microcontroller. the global enable flag if cleared to zero will disable all interrupts. interrupt operation a timer/event counter overflow or an active edge on the external interrupt pin will all generate an interrupt re- quest by setting their corresponding request flag, if their appropriate interrupt enable bit is set. when this hap- pens, the program counter, which stores the address of the next instruction to be executed, will be transferred onto the stack. the program counter will then be loaded with a new address which will be the value of the corre - sponding interrupt vector. the microcontroller will then fetch its next instruction from this interrupt vector. the instruction at this vector will usually be a jmp statement which will jump to another section of program which is known as the interrupt service routine. here is located the code to control the appropriate interrupt. the inter - rupt service routine must be terminated with a reti in - struction, which retrieves the original program counter address from the stack and allows the microcontroller to continue with normal execution at the point where the in - terrupt occurred. the various interrupt enable bits, together with their as - sociated request flags, are shown in the following dia - gram with their order of priority. once an interrupt subroutine is serviced, all the other in - terrupts will be blocked, as the emi bit will be cleared au - tomatically. this will prevent any further interrupt nesting from occurring. however, if other interrupt requests oc - cur during this interval, although the interrupt will not be immediately serviced, the request flag will still be re - corded. if an interrupt requires immediate servicing while the program is already in another interrupt service routine, the emi bit should be set after entering the rou- tine, to allow interrupt nesting. if the stack is full, the in- terrupt request will not be acknowledged, even if the related interrupt is enabled, until the stack pointer is decremented. if immediate service is desired, the stack must be prevented from becoming full. ! 0 ! 7 7
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HT48R005/ht46r005 rev. 1.00 44 november 29, 2011 when an interrupt request is generated it takes 2 or 3 in - struction cycle before the program jumps to the interrupt vector. if the device is in the sleep mode and is woken up by an interrupt request then it will take 3 cycles be - fore the program jumps to the interrupt vector. interrupt priority interrupts, occurring in the interval between the rising edges of two consecutive t2 pulses, will be serviced on the latter of the two t2 pulses, if the corresponding inter- rupts are enabled. in case of simultaneous requests, the following table shows the priority that is applied. these can be masked by resetting the emi bit. ht46r005 interrupt source priority vector external interrupt 1 04h timer/event counter overflow 2 08h a/d conversion complete 4 10h HT48R005 interrupt source priority vector external interrupt 1 04h timer/event counter overflow 2 08h in cases where both external and internal interrupts are enabled and where an external and internal interrupt oc - curs simultaneously, the external interrupt will always have priority and will therefore be serviced first. suitable masking of the individual interrupts using the interrupt registers can prevent simultaneous occurrences. external interrupt for an external interrupt to occur, the global interrupt en - able bit, emi, and external interrupt enable bit, inte, must first be set. an actual external interrupt will take place when the external interrupt request flag, intf, is set, a situation that will occur when an edge transition appears on the external int line. the type of transition that will trigger an external interrupt, whether high to low, low to high or both is determined by the integ0 and integ1 bits, which are bits 6 and 7 respectively, in the ctrl1 control register. these two bits can also disable the external interrupt function. integ1 integ0 edge trigger type 0 0 external interrupt disable 0 1 rising edge trigger 1 0 falling edge trigger 1 1 both edge trigger the external interrupt pin is pin-shared with the i/o pin and can only be configured as an external interrupt pin if the corresponding external interrupt enable bit in the intc0 register has been set and the edge trigger type has been selected using the ctrl1 register. the pin must also be setup as an input by setting the corre- sponding bit in the port control register. when the inter- rupt is enabled, the stack is not full and a transition appears on the external interrupt pin, a subroutine call to the external interrupt vector at location 04h, will take place. when the interrupt is serviced, the external inter - rupt request flag, intf, will be automatically reset and the emi bit will be automatically cleared to disable other interrupts. note that any pull-high resistor connections on this pin will remain valid even if the pin is used as an external interrupt input. wait for 2 ~ 3 instruction cycles main program isr entry enable bit set ? main program reti (it will set emi automatically) automatically disable interrupt clear emi & request flag interrupt request or interrupt flag set by instruction y n interrupt flow
HT48R005/ht46r005 rev. 1.00 45 november 29, 2011 intc0 register HT48R005 bit76543210 name t0f intf t0e inte emi r/w r/w r/w r/w r/w r/w por 00 000 bit 7~6 unimplemented, read as 0 bit 5 t0f : timer/event counter interrupt request flag 0: inactive 1: active bit 4 intf : external interrupt request flag 0: inactive 1: active bit 3 unimplemented, read as 0 bit 2 t0e : timer/event counter interrupt enable 0: disable 1: enable bit 1 inte : external interrupt enable 0: disable 1: enable bit 0 emi : master interrupt global enable 0: disable 1: enable ht46r005 bit76543210 name adf t0f intf ade t0eg inte emi r/w r/w r/w r/w r/w r/w r/w r/w por 0000000 bit 7 unimplemented, read as 0 bit 6 adf : a/d conversion interrupt request flag 0: inactive 1: active bit 5 t0f : timer/event counter interrupt request flag 0: inactive 1: active bit 4 intf : external interrupt request flag 0: inactive 1: active bit 3 ade : a/d conversion interrupt enable 0: disable 1: enable bit 2 t0eg : timer/event counter interrupt enable 0: disable 1: enable bit 1 inte : external interrupt enable 0: disable 1: enable bit 0 emi : master interrupt global enable 0: disable 1: enable
HT48R005/ht46r005 rev. 1.00 46 november 29, 2011 timer/event counter interrupt for a timer/event counter interrupt to occur, the global interrupt enable bit, emi, and the corresponding timer interrupt enable bit, t0eg, must first be set. an actual timer/event counter interrupt will take place when the timer/event counter request flag, t0f, is set, a situation that will occur when the relevant timer/event counter overflows. when the interrupt is enabled, the stack is not full and a timer/event counter overflow occurs, a subroutine call to the relevant timer interrupt vector, will take place. when the interrupt is serviced, the timer in - terrupt request flag, t0f, will be automatically reset and the emi bit will be automatically cleared to disable other interrupts. programming considerations by disabling the interrupt enable bits, a requested inter - rupt can be prevented from being serviced, however, once an interrupt request flag is set, it will remain in this condition in the interrupt register until the corresponding interrupt is serviced or until the request flag is cleared by a software instruction. it is recommended that programs do not use the call subroutine instruction within the interrupt subroutine. interrupts often occur in an unpredictable manner or need to be serviced immediately in some applications. if only one stack is left and the interrupt is not well con - trolled, the original control sequence will be damaged once a call subroutine is executed in the interrupt subroutine. all of these interrupts have the capability of waking up the processor when in the sleep mode. only the program counter is pushed onto the stack. if the contents of the register or status register are altered by the interrupt service program, which may corrupt the desired control sequence, then the contents should be saved in advance. configuration options configuration options refer to certain options within the mcu that are programmed into the otp program memory de- vice during the programming process. during the development process, these options are selected using the ht-ide software development tools. as these options are programmed into the device using the hardware programming tools, once they are selected they cannot be changed later by the application software. all options must be defined for proper system function, the details of which are shown in the table. no. options 1 watchdog timer: enable or disable 2 watchdog timer clock source: lirc or f sys /4 3 clrwdt instructions: 1 or 2 instructions 4 system oscillator configuration: hxt, hirc, erc 5 lvr function: enable or disable 6 lvr voltage: 2.1v, 3.15v or 4.2v 7 res or pa7 pin function 8 internal rc: 4mhz, 8mhz or 12mhz
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HT48R005/ht46r005 rev. 1.00 48 november 29, 2011 instruction set introduction central to the successful operation of any microcontroller is its instruction set, which is a set of pro - gram instruction codes that directs the microcontroller to perform certain operations. in the case of holtek microcontrollers, a comprehensive and flexible set of over 60 instructions is provided to enable programmers to implement their application with the minimum of pro - gramming overheads. for easier understanding of the various instruction codes, they have been subdivided into several func - tional groupings. instruction timing most instructions are implemented within one instruc - tion cycle. the exceptions to this are branch, call, or ta - ble read instructions where two instruction cycles are required. one instruction cycle is equal to 4 system clock cycles, therefore in the case of an 8mhz system oscillator, most instructions would be implemented within 0.5 s and branch or call instructions would be im - plemented within 1 s. although instructions which re - quire one more cycle to implement are generally limited to the jmp, call, ret, reti and table read instruc- tions, it is important to realize that any other instructions which involve manipulation of the program counter low register or pcl will also take one more cycle to imple- ment. as instructions which change the contents of the pcl will imply a direct jump to that new address, one more cycle will be required. examples of such instruc- tions would be clr pcl or mov pcl, a . for the case of skip instructions, it must be noted that if the re- sult of the comparison involves a skip operation then this will also take one more cycle, if no skip is involved then only one cycle is required. moving and transferring data the transfer of data within the microcontroller program is one of the most frequently used operations. making use of three kinds of mov instructions, data can be transferred from registers to the accumulator and vice-versa as well as being able to move specific imme - diate data directly into the accumulator. one of the most important data transfer applications is to receive data from the input ports and transfer data to the output ports. arithmetic operations the ability to perform certain arithmetic operations and data manipulation is a necessary feature of most microcontroller applications. within the holtek microcontroller instruction set are a range of add and subtract instruction mnemonics to enable the necessary arithmetic to be carried out. care must be taken to en - sure correct handling of carry and borrow data when re - sults exceed 255 for addition and less than 0 for subtraction. the increment and decrement instructions inc, inca, dec and deca provide a simple means of increasing or decreasing by a value of one of the values in the destination specified. logical and rotate operations the standard logical operations such as and, or, xor and cpl all have their own instruction within the holtek microcontroller instruction set. as with the case of most instructions involving data manipulation, data must pass through the accumulator which may involve additional programming steps. in all logical data operations, the zero flag may be set if the result of the operation is zero. another form of logical data manipulation comes from the rotate instructions such as rr, rl, rrc and rlc which provide a simple means of rotating one bit right or left. different rotate instructions exist depending on pro - gram requirements. rotate instructions are useful for serial port programming applications where data can be rotated from an internal register into the carry bit from where it can be examined and the necessary serial bit set high or low. another application where rotate data operations are used is to implement multiplication and division calculations. branches and control transfer program branching takes the form of either jumps to specified locations using the jmp instruction or to a sub- routine using the call instruction. they differ in the sense that in the case of a subroutine call, the program must return to the instruction immediately when the sub - routine has been carried out. this is done by placing a return instruction ret in the subroutine which will cause the program to jump back to the address right after the call instruction. in the case of a jmp instruction, the program simply jumps to the desired location. there is no requirement to jump back to the original jumping off point as in the case of the call instruction. one special and extremely useful set of branch instructions are the conditional branches. here a decision is first made re - garding the condition of a certain data memory or indi - vidual bits. depending upon the conditions, the program will continue with the next instruction or skip over it and jump to the following instruction. these instructions are the key to decision making and branching within the pro - gram perhaps determined by the condition of certain in - put switches or by the condition of internal data bits.
HT48R005/ht46r005 rev. 1.00 49 november 29, 2011 bit operations the ability to provide single bit operations on data mem - ory is an extremely flexible feature of all holtek microcontrollers. this feature is especially useful for output port bit programming where individual bits or port pins can be directly set high or low using either the set [m].i or clr [m].i instructions respectively. the fea - ture removes the need for programmers to first read the 8-bit output port, manipulate the input data to ensure that other bits are not changed and then output the port with the correct new data. this read-modify-write pro - cess is taken care of automatically when these bit oper - ation instructions are used. table read operations data storage is normally implemented by using regis - ters. however, when working with large amounts of fixed data, the volume involved often makes it inconve - nient to store the fixed data in the data memory. to over - come this problem, holtek microcontrollers allow an area of program memory to be setup as a table where data can be directly stored. a set of easy to use instruc - tions provides the means by which this fixed data can be referenced and retrieved from the program memory. other operations in addition to the above functional instructions, a range of other instructions also exist such as the halt in - struction for power-down operations and instructions to control the operation of the watchdog timer for reliable program operations under extreme electric or electro - magnetic environments. for their relevant operations, refer to the functional related sections. instruction set summary the following table depicts a summary of the instruction set categorised according to function and can be con - sulted as a basic instruction reference using the follow - ing listed conventions. table conventions: x: bits immediate data m: data memory address a: accumulator i: 0~7 number of bits addr: program memory address mnemonic description cycles flag affected arithmetic add a,[m] addm a,[m] add a,x adc a,[m] adcm a,[m] sub a,x sub a,[m] subm a,[m] sbc a,[m] sbcm a,[m] daa [m] add data memory to acc add acc to data memory add immediate data to acc add data memory to acc with carry add acc to data memory with carry subtract immediate data from the acc subtract data memory from acc subtract data memory from acc with result in data memory subtract data memory from acc with carry subtract data memory from acc with carry, result in data memory decimal adjust acc for addition with result in data memory 1 1 note 1 1 1 note 1 1 1 note 1 1 note 1 note z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov z, c, ac, ov c logic operation and a,[m] or a,[m] xor a,[m] andm a,[m] orm a,[m] xorm a,[m] and a,x or a,x xor a,x cpl [m] cpla [m] logical and data memory to acc logical or data memory to acc logical xor data memory to acc logical and acc to data memory logical or acc to data memory logical xor acc to data memory logical and immediate data to acc logical or immediate data to acc logical xor immediate data to acc complement data memory complement data memory with result in acc 1 1 1 1 note 1 note 1 note 1 1 1 1 note 1 z z z z z z z z z z z increment & decrement inca [m] inc [m] deca [m] dec [m] increment data memory with result in acc increment data memory decrement data memory with result in acc decrement data memory 1 1 note 1 1 note z z z z
HT48R005/ht46r005 rev. 1.00 50 november 29, 2011 mnemonic description cycles flag affected rotate rra [m] rr [m] rrca [m] rrc [m] rla [m] rl [m] rlca [m] rlc [m] rotate data memory right with result in acc rotate data memory right rotate data memory right through carry with result in acc rotate data memory right through carry rotate data memory left with result in acc rotate data memory left rotate data memory left through carry with result in acc rotate data memory left through carry 1 1 note 1 1 note 1 1 note 1 1 note none none c c none none c c data move mov a,[m] mov [m],a mov a,x move data memory to acc move acc to data memory move immediate data to acc 1 1 note 1 none none none bit operation clr [m].i set [m].i clear bit of data memory set bit of data memory 1 note 1 note none none branch jmp addr sz [m] sza [m] sz [m].i snz [m].i siz [m] sdz [m] siza [m] sdza [m] call addr ret ret a,x reti jump unconditionally skip if data memory is zero skip if data memory is zero with data movement to acc skip if bit i of data memory is zero skip if bit i of data memory is not zero skip if increment data memory is zero skip if decrement data memory is zero skip if increment data memory is zero with result in acc skip if decrement data memory is zero with result in acc subroutine call return from subroutine return from subroutine and load immediate data to acc return from interrupt 2 1 note 1 note 1 note 1 note 1 note 1 note 1 note 1 note 2 2 2 2 none none none none none none none none none none none none none table read tabrdc [m] tabrdl [m] read table (current page) to tblh and data memory read table (last page) to tblh and data memory 2 note 2 note none none miscellaneous nop clr [m] set [m] clr wdt clr wdt1 clr wdt2 swap [m] swapa [m] halt no operation clear data memory set data memory clear watchdog timer pre-clear watchdog timer pre-clear watchdog timer swap nibbles of data memory swap nibbles of data memory with result in acc enter power down mode 1 1 note 1 note 1 1 1 1 note 1 1 none none none to, pdf to, pdf to, pdf none none to, pdf note: 1. for skip instructions, if the result of the comparison involves a skip then two cycles are required, if no skip takes place only one cycle is required. 2. any instruction which changes the contents of the pcl will also require 2 cycles for execution. 3. for the clr wdt1 and clr wdt2 instructions the to and pdf flags may be affected by the execution status. the to and pdf flags are cleared after both clr wdt1 and clr wdt2 instructions are consecutively executed. otherwise the to and pdf flags remain unchanged.
instruction definition adc a,[m] add data memory to acc with carry description the contents of the specified data memory, accumulator and the carry flag are added. the result is stored in the accumulator. operation acc acc+[m]+c affected flag(s) ov, z, ac, c adcm a,[m] add acc to data memory with carry description the contents of the specified data memory, accumulator and the carry flag are added. the result is stored in the specified data memory. operation [m] acc+[m]+c affected flag(s) ov, z, ac, c add a,[m] add data memory to acc description the contents of the specified data memory and the accumulator are added. the result is stored in the accumulator. operation acc acc + [m] affected flag(s) ov, z, ac, c add a,x add immediate data to acc description the contents of the accumulator and the specified immediate data are added. the result is stored in the accumulator. operation acc acc+x affected flag(s) ov, z, ac, c addm a,[m] add acc to data memory description the contents of the specified data memory and the accumulator are added. the result is stored in the specified data memory. operation [m] acc + [m] affected flag(s) ov, z, ac, c and a,[m] logical and data memory to acc description data in the accumulator and the specified data memory perform a bitwise logical and op - eration. the result is stored in the accumulator. operation acc acc and [m] affected flag(s) z and a,x logical and immediate data to acc description data in the accumulator and the specified immediate data perform a bitwise logical and operation. the result is stored in the accumulator. operation acc acc and x affected flag(s) z andm a,[m] logical and acc to data memory description data in the specified data memory and the accumulator perform a bitwise logical and op - eration. the result is stored in the data memory. operation [m] acc and [m] affected flag(s) z HT48R005/ht46r005 rev. 1.00 51 november 29, 2011
call addr subroutine call description unconditionally calls a subroutine at the specified address. the program counter then in - crements by 1 to obtain the address of the next instruction which is then pushed onto the stack. the specified address is then loaded and the program continues execution from this new address. as this instruction requires an additional operation, it is a two cycle instruc - tion. operation stack program counter + 1 program counter addr affected flag(s) none clr [m] clear data memory description each bit of the specified data memory is cleared to 0. operation [m] 00h affected flag(s) none clr [m].i clear bit of data memory description bit i of the specified data memory is cleared to 0. operation [m].i 0 affected flag(s) none clr wdt clear watchdog timer description the to, pdf flags and the wdt are all cleared. operation wdt cleared to 0 pdf 0 affected flag(s) to, pdf clr wdt1 pre-clear watchdog timer description the to, pdf flags and the wdt are all cleared. note that this instruction works in conjunc- tion with clr wdt2 and must be executed alternately with clr wdt2 to have effect. re- petitively executing this instruction without alternately executing clr wdt2 will have no effect. operation wdt cleared to 0 pdf 0 affected flag(s) to, pdf clr wdt2 pre-clear watchdog timer description the to, pdf flags and the wdt are all cleared. note that this instruction works in conjunc - tion with clr wdt1 and must be executed alternately with clr wdt1 to have effect. re - petitively executing this instruction without alternately executing clr wdt1 will have no effect. operation wdt cleared to 0 pdf 0 affected flag(s) to, pdf HT48R005/ht46r005 rev. 1.00 52 november 29, 2011
cpl [m] complement data memory description each bit of the specified data memory is logically complemented (1
s complement). bits which previously contained a 1 are changed to 0 and vice versa. operation [m] [m] affected flag(s) z cpla [m] complement data memory with result in acc description each bit of the specified data memory is logically complemented (1
s complement). bits which previously contained a 1 are changed to 0 and vice versa. the complemented result is stored in the accumulator and the contents of the data memory remain unchanged. operation acc [m] affected flag(s) z daa [m] decimal-adjust acc for addition with result in data memory description convert the contents of the accumulator value to a bcd ( binary coded decimal) value re - sulting from the previous addition of two bcd variables. if the low nibble is greater than 9 or if ac flag is set, then a value of 6 will be added to the low nibble. otherwise the low nibble remains unchanged. if the high nibble is greater than 9 or if the c flag is set, then a value of 6 will be added to the high nibble. essentially, the decimal conversion is performed by add - ing 00h, 06h, 60h or 66h depending on the accumulator and flag conditions. only the c flag may be affected by this instruction which indicates that if the original bcd sum is greater than 100, it allows multiple precision decimal addition. operation [m] acc + 00h or [m] acc + 06h or [m] acc + 60h or [m] acc + 66h affected flag(s) c dec [m] decrement data memory description data in the specified data memory is decremented by 1. operation [m] [m] 1 affected flag(s) z deca [m] decrement data memory with result in acc description data in the specified data memory is decremented by 1. the result is stored in the accu - mulator. the contents of the data memory remain unchanged. operation acc [m] 1 affected flag(s) z halt enter power down mode description this instruction stops the program execution and turns off the system clock. the contents of the data memory and registers are retained. the wdt and prescaler are cleared. the power down flag pdf is set and the wdt time-out flag to is cleared. operation to 0 pdf 1 affected flag(s) to, pdf HT48R005/ht46r005 rev. 1.00 53 november 29, 2011
inc [m] increment data memory description data in the specified data memory is incremented by 1. operation [m] [m]+1 affected flag(s) z inca [m] increment data memory with result in acc description data in the specified data memory is incremented by 1. the result is stored in the accumu - lator. the contents of the data memory remain unchanged. operation acc [m]+1 affected flag(s) z jmp addr jump unconditionally description the contents of the program counter are replaced with the specified address. program execution then continues from this new address. as this requires the insertion of a dummy instruction while the new address is loaded, it is a two cycle instruction. operation program counter addr affected flag(s) none mov a,[m] move data memory to acc description the contents of the specified data memory are copied to the accumulator. operation acc [m] affected flag(s) none mov a,x move immediate data to acc description the immediate data specified is loaded into the accumulator. operation acc x affected flag(s) none mov [m],a move acc to data memory description the contents of the accumulator are copied to the specified data memory. operation [m] acc affected flag(s) none nop no operation description no operation is performed. execution continues with the next instruction. operation no operation affected flag(s) none or a,[m] logical or data memory to acc description data in the accumulator and the specified data memory perform a bitwise logical or oper - ation. the result is stored in the accumulator. operation acc acc or [m] affected flag(s) z HT48R005/ht46r005 rev. 1.00 54 november 29, 2011
or a,x logical or immediate data to acc description data in the accumulator and the specified immediate data perform a bitwise logical or op - eration. the result is stored in the accumulator. operation acc acc or x affected flag(s) z orm a,[m] logical or acc to data memory description data in the specified data memory and the accumulator perform a bitwise logical or oper - ation. the result is stored in the data memory. operation [m] acc or [m] affected flag(s) z ret return from subroutine description the program counter is restored from the stack. program execution continues at the re - stored address. operation program counter stack affected flag(s) none ret a,x return from subroutine and load immediate data to acc description the program counter is restored from the stack and the accumulator loaded with the specified immediate data. program execution continues at the restored address. operation program counter stack acc x affected flag(s) none reti return from interrupt description the program counter is restored from the stack and the interrupts are re-enabled by set- ting the emi bit. emi is the master interrupt global enable bit. if an interrupt was pending when the reti instruction is executed, the pending interrupt routine will be processed be- fore returning to the main program. operation program counter stack emi 1 affected flag(s) none rl [m] rotate data memory left description the contents of the specified data memory are rotated left by 1 bit with bit 7 rotated into bit 0. operation [m].(i+1) [m].i; (i = 0~6) [m].0 [m].7 affected flag(s) none rla [m] rotate data memory left with result in acc description the contents of the specified data memory are rotated left by 1 bit with bit 7 rotated into bit 0. the rotated result is stored in the accumulator and the contents of the data memory re - main unchanged. operation acc.(i+1) [m].i; (i = 0~6) acc.0 [m].7 affected flag(s) none HT48R005/ht46r005 rev. 1.00 55 november 29, 2011
rlc [m] rotate data memory left through carry description the contents of the specified data memory and the carry flag are rotated left by 1 bit. bit 7 replaces the carry bit and the original carry flag is rotated into bit 0. operation [m].(i+1) [m].i; (i = 0~6) [m].0 c c [m].7 affected flag(s) c rlca [m] rotate data memory left through carry with result in acc description data in the specified data memory and the carry flag are rotated left by 1 bit. bit 7 replaces the carry bit and the original carry flag is rotated into the bit 0. the rotated result is stored in the accumulator and the contents of the data memory remain unchanged. operation acc.(i+1) [m].i; (i = 0~6) acc.0 c c [m].7 affected flag(s) c rr [m] rotate data memory right description the contents of the specified data memory are rotated right by 1 bit with bit 0 rotated into bit 7. operation [m].i [m].(i+1); (i = 0~6) [m].7 [m].0 affected flag(s) none rra [m] rotate data memory right with result in acc description data in the specified data memory and the carry flag are rotated right by 1 bit with bit 0 ro- tated into bit 7. the rotated result is stored in the accumulator and the contents of the data memory remain unchanged. operation acc.i [m].(i+1); (i = 0~6) acc.7 [m].0 affected flag(s) none rrc [m] rotate data memory right through carry description the contents of the specified data memory and the carry flag are rotated right by 1 bit. bit 0 replaces the carry bit and the original carry flag is rotated into bit 7. operation [m].i [m].(i+1); (i = 0~6) [m].7 c c [m].0 affected flag(s) c rrca [m] rotate data memory right through carry with result in acc description data in the specified data memory and the carry flag are rotated right by 1 bit. bit 0 re - places the carry bit and the original carry flag is rotated into bit 7. the rotated result is stored in the accumulator and the contents of the data memory remain unchanged. operation acc.i [m].(i+1); (i = 0~6) acc.7 c c [m].0 affected flag(s) c HT48R005/ht46r005 rev. 1.00 56 november 29, 2011
sbc a,[m] subtract data memory from acc with carry description the contents of the specified data memory and the complement of the carry flag are sub - tracted from the accumulator. the result is stored in the accumulator. note that if the result of subtraction is negative, the c flag will be cleared to 0, otherwise if the result is positive or zero, the c flag will be set to 1. operation acc acc [m] c affected flag(s) ov, z, ac, c sbcm a,[m] subtract data memory from acc with carry and result in data memory description the contents of the specified data memory and the complement of the carry flag are sub - tracted from the accumulator. the result is stored in the data memory. note that if the re - sult of subtraction is negative, the c flag will be cleared to 0, otherwise if the result is positive or zero, the c flag will be set to 1. operation [m] acc [m] c affected flag(s) ov, z, ac, c sdz [m] skip if decrement data memory is 0 description the contents of the specified data memory are first decremented by 1. if the result is 0 the following instruction is skipped. as this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. if the result is not 0 the program proceeds with the following instruction. operation [m] [m] 1 skip if [m] = 0 affected flag(s) none sdza [m] skip if decrement data memory is zero with result in acc description the contents of the specified data memory are first decremented by 1. if the result is 0, the following instruction is skipped. the result is stored in the accumulator but the specified data memory contents remain unchanged. as this requires the insertion of a dummy in- struction while the next instruction is fetched, it is a two cycle instruction. if the result is not 0, the program proceeds with the following instruction. operation acc [m] 1 skip if acc = 0 affected flag(s) none set [m] set data memory description each bit of the specified data memory is set to 1. operation [m] ffh affected flag(s) none set [m].i set bit of data memory description bit i of the specified data memory is set to 1. operation [m].i 1 affected flag(s) none HT48R005/ht46r005 rev. 1.00 57 november 29, 2011
siz [m] skip if increment data memory is 0 description the contents of the specified data memory are first incremented by 1. if the result is 0, the following instruction is skipped. as this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. if the result is not 0 the program proceeds with the following instruction. operation [m] [m]+1 skip if [m] = 0 affected flag(s) none siza [m] skip if increment data memory is zero with result in acc description the contents of the specified data memory are first incremented by 1. if the result is 0, the following instruction is skipped. the result is stored in the accumulator but the specified data memory contents remain unchanged. as this requires the insertion of a dummy in - struction while the next instruction is fetched, it is a two cycle instruction. if the result is not 0 the program proceeds with the following instruction. operation acc [m]+1 skip if acc = 0 affected flag(s) none snz [m].i skip if bit i of data memory is not 0 description if bit i of the specified data memory is not 0, the following instruction is skipped. as this re - quires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. if the result is 0 the program proceeds with the following instruction. operation skip if [m].i 0 affected flag(s) none sub a,[m] subtract data memory from acc description the specified data memory is subtracted from the contents of the accumulator. the result is stored in the accumulator. note that if the result of subtraction is negative, the c flag will be cleared to 0, otherwise if the result is positive or zero, the c flag will be set to 1. operation acc acc [m] affected flag(s) ov, z, ac, c subm a,[m] subtract data memory from acc with result in data memory description the specified data memory is subtracted from the contents of the accumulator. the result is stored in the data memory. note that if the result of subtraction is negative, the c flag will be cleared to 0, otherwise if the result is positive or zero, the c flag will be set to 1. operation [m] acc [m] affected flag(s) ov, z, ac, c sub a,x subtract immediate data from acc description the immediate data specified by the code is subtracted from the contents of the accumu - lator. the result is stored in the accumulator. note that if the result of subtraction is nega - tive, the c flag will be cleared to 0, otherwise if the result is positive or zero, the c flag will be set to 1. operation acc acc x affected flag(s) ov, z, ac, c HT48R005/ht46r005 rev. 1.00 58 november 29, 2011
swap [m] swap nibbles of data memory description the low-order and high-order nibbles of the specified data memory are interchanged. operation [m].3~[m].0 [m].7 ~ [m].4 affected flag(s) none swapa [m] swap nibbles of data memory with result in acc description the low-order and high-order nibbles of the specified data memory are interchanged. the result is stored in the accumulator. the contents of the data memory remain unchanged. operation acc.3 ~ acc.0 [m].7 ~ [m].4 acc.7 ~ acc.4 [m].3 ~ [m].0 affected flag(s) none sz [m] skip if data memory is 0 description if the contents of the specified data memory is 0, the following instruction is skipped. as this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. if the result is not 0 the program proceeds with the following instruc - tion. operation skip if [m] = 0 affected flag(s) none sza [m] skip if data memory is 0 with data movement to acc description the contents of the specified data memory are copied to the accumulator. if the value is zero, the following instruction is skipped. as this requires the insertion of a dummy instruc - tion while the next instruction is fetched, it is a two cycle instruction. if the result is not 0 the program proceeds with the following instruction. operation acc [m] skip if [m] = 0 affected flag(s) none sz [m].i skip if bit i of data memory is 0 description if bit i of the specified data memory is 0, the following instruction is skipped. as this re- quires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. if the result is not 0, the program proceeds with the following instruction. operation skip if [m].i = 0 affected flag(s) none tabrdc [m] read table (current page) to tblh and data memory description the low byte of the program code (current page) addressed by the table pointer (tblp) is moved to the specified data memory and the high byte moved to tblh. operation [m] program code (low byte) tblh program code (high byte) affected flag(s) none tabrdl [m] read table (last page) to tblh and data memory description the low byte of the program code (last page) addressed by the table pointer (tblp) is moved to the specified data memory and the high byte moved to tblh. operation [m] program code (low byte) tblh program code (high byte) affected flag(s) none HT48R005/ht46r005 rev. 1.00 59 november 29, 2011
xor a,[m] logical xor data memory to acc description data in the accumulator and the specified data memory perform a bitwise logical xor op - eration. the result is stored in the accumulator. operation acc acc xor [m] affected flag(s) z xorm a,[m] logical xor acc to data memory description data in the specified data memory and the accumulator perform a bitwise logical xor op - eration. the result is stored in the data memory. operation [m] acc xor [m] affected flag(s) z xor a,x logical xor immediate data to acc description data in the accumulator and the specified immediate data perform a bitwise logical xor operation. the result is stored in the accumulator. operation acc acc xor x affected flag(s) z HT48R005/ht46r005 rev. 1.00 60 november 29, 2011
package information note that the package information provided here is for consultation purposes only. as this information may be updated at regu - lar intervals users are reminded to consult the holtek website ( http://www.holtek.com.tw/english/literature/package.pdf ) for the latest version of the package information. 10-pin msop outline dimensions symbol dimensions in inch min. nom. max. a 0.043 a1 0.000 0.006 a2 0.030 0.033 0.037 b 0.007 0.011 c 0.010 d 0.018 e 0.193 e1 0.118 e 0.020 l 0.016 0.024 0.031 l1 0.037 08 symbol dimensions in mm min. nom. max. a 1.10 a1 0.00 0.15 a2 0.75 0.85 0.95 b 0.17 0.27 c 0.25 d 3.00 e 4.90 e1 3.00 e 0.50 l 0.40 0.60 0.80 l1 0.95 08 HT48R005/ht46r005 rev. 1.00 61 november 29, 2011 $ ( $ & * 2 $ * 3 .
) ( 4 : (
$ % # $ * : $
HT48R005/ht46r005 rev. 1.00 62 november 29, 2011 holtek semiconductor inc. (headquarters) no.3, creation rd. ii, science park, hsinchu, taiwan tel: 886-3-563-1999 fax: 886-3-563-1189 http://www.holtek.com.tw holtek semiconductor inc. (taipei sales office) 4f-2, no. 3-2, yuanqu st., nankang software park, taipei 115, taiwan tel: 886-2-2655-7070 fax: 886-2-2655-7373 fax: 886-2-2655-7383 (international sales hotline) holtek semiconductor inc. (shenzhen sales office) 5f, unit a, productivity building, no.5 gaoxin m 2nd road, nanshan district, shenzhen, china 518057 tel: 86-755-8616-9908, 86-755-8616-9308 fax: 86-755-8616-9722 holtek semiconductor (usa), inc. (north america sales office) 46729 fremont blvd., fremont, ca 94538 tel: 1-510-252-9880 fax: 1-510-252-9885 http://www.holtek.com copyright 2011 by holtek semiconductor inc. the information appearing in this data sheet is believed to be accurate at the time of publication. however, holtek as - sumes no responsibility arising from the use of the specifications described. the applications mentioned herein are used solely for the purpose of illustration and holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. holtek
s products are not authorized for use as critical components in life support devices or systems. holtek reserves the right to alter its products without prior notification. for the most up-to-date information, please visit our web site at http://www.holtek.com.tw.

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