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? 2003 microchip technology inc. preliminary ds39598d pic16f818/819 data sheet 18/20-pin enhanced flash microcontrollers with nanowatt technology
ds39598d-page ii preliminary ? 2003 microchip technology inc. information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. it is your responsibility to ensure that your application m eets with your specifications. no representation or warranty is given and no liability is assumed by microchip technol ogy incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. use of mi crochip?s products as critical components in life support syst ems is not authorized except with express written approval by microchip. no licenses are conveyed, implicitly or ot herwise, under any intellectual property rights. trademarks the microchip name and logo, the microchip logo, accuron, dspic, k ee l oq , mplab, pic, picmicro, picstart, pro mate and powersmart are registered trademarks of microchip technology incorporated in the u.s.a. and other countries. amplab, filterlab, micro id , mxdev, mxlab, picmaster, seeval and the embedded control solutions company are registered trademarks of micr ochip technology incorporated in the u.s.a. application maestro, dspicdem, dspicdem.net, ecan, economonitor, fansense, flexrom, fuzzylab, in-circuit serial programming, icsp, icepic, microport, migratable memory, mpasm, mplib, mplink, mpsim, pickit, picdem, picdem.net, powercal, powerinfo, powermate, powertool, rflab, rfpic, select mode, smartsensor, smartshunt, smar ttel and total endurance are trademarks of microchip technology incorporated in the u.s.a. and other countries. serialized quick turn programming (sqtp) is a service mark of microchip technology incorporated in the u.s.a. all other trademarks mentioned he rein are property of their respective companies. ? 2003, microchip technology incorporated, printed in the u.s.a., all rights reserved. printed on recycled paper. note the following details of the code protection feature on microchip devices: microchip products meet the specification cont ained in their particular microchip data sheet. microchip believes that its family of products is one of the mo st secure families of its kind on the market today, when used i n the intended manner and under normal conditions. there are dishonest and possibly illegal methods used to breach the code protection feature. all of these methods, to our knowledge, require using the microchip produc ts in a manner outside the operating specif ications contained in microchip's data sheets. most likely, the person doing so is engaged in theft of intellectual property. microchip is willing to work with the customer who is concerned about the integrity of their code. neither microchip nor any other semicondu ctor manufacturer can guarantee the security of their code. code protection does not mean that we are guaranteeing the product as ?unbreakable.? code protection is constantly evolving. we at microchip are comm itted to continuously improving t he code protection features of our products. attempts to break microchip?s c ode protection feature may be a violation of the digital millennium copyright act. if such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that act. microchip received qs-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona in july 1999 and mountain view, california in march 2002. the company?s quality system processes and procedures are qs-9000 compliant for its picmicro ? 8-bit mcus, k ee l oq ? code hopping devices, serial eeproms, microperipherals, non-volatile memory and analog products. in addition, microchip?s quality system for the design and manufacture of development systems is iso 9001 certified.
? 2003 microchip technology inc. preliminary ds39598d-page 1 pic16f818/819 low-power features: power managed modes: - primary run: xt, rc oscillator, 87 a, 1 mhz, 2v -intrc: 7 a, 31.25 khz, 2v - sleep: 0.2 a, 2v timer1 oscillator: 1.8 a, 32 khz, 2v watchdog timer: 0.7 a, 2v wide operating voltage range: - industrial: 2.0v to 5.5v oscillators: three crystal modes: - lp, xt, hs: up to 20 mhz two external rc modes one external clock mode: - ecio: up to 20 mhz internal oscillator block: - 8 user selectable frequencies: 31 khz, 125 khz, 250khz, 500khz, 1mhz , 2 mhz, 4 mhz, 8 mhz peripheral features: 16 i/o pins with individual direction control high sink/source current: 25 ma timer0: 8-bit timer/counter with 8-bit prescaler timer1: 16-bit timer/counter with prescaler, can be incremented during sleep via external crystal/clock timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler capture, compare, pwm (ccp) module: - capture is 16-bit, max. resolution is 12.5 ns - compare is 16-bit, max. resolution is 200 ns - pwm max. resolution is 10-bit 10-bit, 5-channel analog-to-digital converter synchronous serial port (ssp) with spi? (master/slave) and i 2 c? (slave) pin diagram special microcontroller features: 100,000 erase/write cycles enhanced flash program memory typical 1,000,000 typical erase/write cycles eeprom data memory typical eeprom data retention: > 40 years in-circuit serial programming tm (icsp tm ) via two pins processor read/write access to program memory low-voltage programming in-circuit debugging via two pins ra1/an1 ra0/an0 ra7/osc1/clki ra6/osc2/clko v dd rb7/t1osi/pgd rb6/t1oso/t1cki/pgc rb5/ss rb4/sck/scl ra2/an2/v ref - ra3/an3/v ref + ra4/an4/t0cki ra5/mclr /v pp vss rb0/int rb1/sdi/sda rb2/sdo/ccp1 rb3/ccp1/pgm ? 1 2 3 4 5 6 7 8 9 18 17 16 15 14 13 12 11 10 pic16f818/819 18-pin pdip, soic device program memory data memory i/o pins 10-bit a/d (ch) ccp (pwm) ssp timers 8/16-bit flash (bytes) # single word instructions sram (bytes) eeprom (bytes) spi slave i 2 c pic16f818 1792 1024 128 128 16 5 1 y y 2/1 pic16f819 3584 2048 256 256 16 5 1 y y 2/1 18/20-pin enhanced flas h microcontrollers with nanowatt technology
pic16f818/819 ds39598d-page 2 preliminary ? 2003 microchip technology inc. pin diagrams ra1/an1 ra0/an0 ra7/osc1/clki ra6/osc2/clko v dd rb7/t1osi/pgd rb6/t1oso/t1cki/pgc rb5/ss rb4/sck/scl ra2/an2/v ref - ra3/an3/v ref + ra4/an4/t0cki ra5/mclr /v pp vss rb0/int rb1/sdi/sda rb2/sdo/ccp1 rb3/ccp1/pgm ? 1 2 3 4 5 6 7 8 9 18 17 16 15 14 13 12 11 10 18-pin pdip, soic pic16f818/819 ra1/an1 ra0/an0 ra7/osc1/clki ra6/osc2/clko v dd rb7/t1osi/pgd rb6/t1oso/t1cki/pgc rb5/ss rb4/sck/scl ra2/an2/v ref - ra3/an3/v ref + ra4/an4/t0cki ra5/mclr /v pp v ss rb0/int rb1/sdi/sda rb2/sdo/ccp1 rb3/ccp1/pgm ? 1 2 3 4 5 6 7 8 9 20 19 18 17 16 15 14 13 12 20-pin ssop 10 11 v ss v dd pic16f818/819 28-pin qfn 16 2 ra2/an2/v ref - ra0/an0 ra4/an4/t0cki ra5/mclr /v pp nc v ss nc rb0/int rb1/sdi/sda ra3/an3/v ref + ra7/osc1/clki ra6/osc2/clko v dd nc v dd rb7/t1osi/pgd rb6/t1oso/t1cki/pgc rb5/ss rb4/sck/scl 7 pic16f818/819 1 3 6 5 4 15 21 19 20 17 18 22 28 26 27 23 24 25 14 8 10 9 13 12 11 v ss nc nc ra1/an1 rb2/sdo/ccp1 rb3/ccp1/pgm nc nc nc
? 2003 microchip technology inc. preliminary ds39598d-page 3 pic16f818/819 table of contents 1.0 device overview ............................................................................................................. ............................................................. 5 2.0 memory organization ......................................................................................................... .......................................................... 9 3.0 data eeprom and flash program memory........................................................................................ ...................................... 25 4.0 oscillator configurations ..................................... .............................................................. ......................................................... 33 5.0 i/o ports ................................................................................................................... .................................................................. 39 6.0 timer0 module ............................................................................................................... ............................................................ 53 7.0 timer1 module ............................................................................................................... ............................................................ 57 8.0 timer2 module ............................................................................................................... ............................................................ 63 9.0 capture/compare/pwm (ccp) module ............................................................................................ ......................................... 65 10.0 synchronous serial port (ssp) module ....................................................................................... .............................................. 71 11.0 analog-to-digital converter (a/d) module................................................................................... ............................................... 81 12.0 special features of the cpu................................................................................................ ...................................................... 89 13.0 instruction set summary .................................................................................................... ...................................................... 103 14.0 development support........................................................................................................ ....................................................... 111 15.0 electrical characteristics ................................................................................................. ......................................................... 117 16.0 dc and ac characteristics graphs and tables ................................................................................ .................................. 143 17.0 packaging information...................................................................................................... ........................................................ 145 appendix a: revision history .................................................................................................. .......................................................... 151 appendix b: device differences ................................................................................................. ....................................................... 151 index .......................................................................................................................... ........................................................................ 153 on-line support................................................................................................................ ................................................................. 159 systems information and upgrade hot line ....................................................................................... ............................................... 159 reader response ................................................................................................................ .............................................................. 160 pic16f818/819 product identification system .................................................................................... .............................................. 161 to our valued customers it is our intention to provide our valued customers with the best documentation possible to ensure successful use of your micro chip products. to this end, we will continue to improve our publications to better suit your needs. our publications will be refined and enhanced as new volumes and updates are introduced. if you have any questions or comments regar ding this publication, please contact the marketing communications department via e-mail at docerrors@mail.microchip.com or fax the reader response form in the back of this data sheet to (480) 792-4150. we welcome your feedback. most current data sheet to obtain the most up-to-date version of this data s heet, please register at our worldwide web site at: http://www.microchip.com you can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page . the last character of the literature number is the vers ion number, (e.g., ds30000a is version a of document ds30000). errata an errata sheet, describing minor operational differences fr om the data sheet and recommended workarounds, may exist for curren t devices. as device/doc umentation issues become known to us, we will publis h an errata sheet. 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pic16f818/819 ds39598d-page 4 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 5 pic16f818/819 1.0 device overview this document contains device specific information for the operation of the pic16f818/819 devices. additional information may be found in the picmicro ? mid-range mcu family reference manual (ds33023), which may be downloaded from the microchip web site. the reference manual should be considered a complemen- tary document to this data sheet, and is highly recommended reading for a better understanding of the device architecture and operation of the peripheral modules. the pic16f818/819 belongs to the mid-range family of the picmicro ? devices. the devices differ from each other in the amount of flash program memory, data memory and data eeprom (see table 1-1). a block diagram of the devices is shown in figure 1-1. these devices contain features that are new to the pic16 product line: internal rc oscillator with eight selectable frequencies, including 31.25 khz, 125 khz, 250 khz, 500 khz, 1 mhz, 2 mhz, 4 mhz and 8 mhz. the intrc can be configured as the system clock via the configuration bits. refer to section 4.5 ?internal oscillator block? and section 12.1 ?configuration bits? for further details. the timer1 module current consumption has been greatly reduced from 20 a (previous pic16 devices) to 1.8 a typical (32 khz at 2v), which is ideal for real-time clock applications. refer to section 6.0 ?timer0 module? for further details. the amount of oscillator selections has increased. the rc and intrc modes can be selected with an i/o pin configured as an i/o or a clock output (f osc /4). an external clock can be configured with an i/o pin. refer to section 4.0 ?oscillator configurations? for further details. table 1-1: available memory in pic16f818/819 devices there are 16 i/o pins that are user configurable on a pin-to-pin basis. some pins are multiplexed with other device functions. these functions include: external interrupt change on portb interrupt timer0 clock input low-power timer1 clock/oscillator capture/compare/pwm 10-bit, 5-channel analog-to-digital converter spi/i 2 c mclr (ra5) can be configured as an input table 1-2 details the pinout of the devices with descriptions and details for each pin. device program flash data memory data eeprom pic16f818 1k x 14 128 x 8 128 x 8 pic16f819 2k x14 256 x 8 256 x 8
pic16f818/819 ds39598d-page 6 preliminary ? 2003 microchip technology inc. figure 1-1: pic16f81 8/819 block diagram flash memory 1k/2k x 14 13 data bus 8 14 program bus instruction reg program counter 8-level stack (13-bit) ram file registers 128/256 x 8 direct addr 7 ram addr (1) 9 addr mux indirect addr fsr reg status reg mux alu w reg power-up timer oscillator start-up timer power-on reset watchdog timer instruction decode & control timing generation ra7/osc1/clki ra6/osc2/clko mclr v dd , v ss timer0 10-bit, 5-channel synchronous serial port porta 8 8 brown-out reset note 1: higher order bits are from the status register. ccp1 timer1 timer2 ra5/mclr /v pp ra6/osc2/clko ra4/an4/t0cki ra3/an3/v ref + ra2/an2/v ref - ra1/an1 8 3 program portb rb0/int rb1/sdi/sda rb2/sdo/ccp1 rb3/ccp1/pgm rb4/sck/scl rb5/ss rb6/t1oso/t1cki/pgc rb7/t1osi/pgd ra7/osc1/clki ra0/an0 128/256 bytes data ee a/d
? 2003 microchip technology inc. preliminary ds39598d-page 7 pic16f818/819 table 1-2: pic16f818/819 pinout descriptions pin name pdip/ soic pin# sso p pin# qfn pin# i/o/p type buffer type description porta is a bidirectional i/o port. ra0/an0 ra0 an0 17 19 23 i/o i ttl analog bidirectional i/o pin. analog input channel 0. ra1/an1 ra1 an1 18 20 24 i/o i ttl analog bidirectional i/o pin. analog input channel 1. ra2/an2/v ref - ra2 an2 v ref - 1126 i/o i i ttl analog analog bidirectional i/o pin. analog input channel 2. a/d reference voltage (low) input. ra3/an3/v ref + ra3 an3 v ref + 2227 i/o i i ttl analog analog bidirectional i/o pin. analog input channel 3. a/d reference voltage (high) input. ra4/an4/t0cki ra4 an4 t0cki 3328 i/o i i st analog st bidirectional i/o pin. analog input channel 4. clock input to the tmr0 timer/counter. ra5/mclr /v pp ra5 mclr v pp 441 i i p st st ? input pin. master clear (reset). input/programming voltage input. this pin is an active-low reset to the device. programming threshold voltage. ra6/osc2/clko ra6 osc2 clko 15 17 20 i/o o o st ? ? bidirectional i/o pin. oscillator crystal output. connects to crystal or resonator in crystal oscillator mode. in rc mode, this pin outputs clko signal which has 1/4 the frequency of osc1 and denotes the instruction cycle rate. ra7/osc1/clki ra7 osc1 clki 16 18 21 i/o i i st st/cmos (3) ? bidirectional i/o pin. oscillator crystal input. external clock source input. legend: i = input o = output i/o = input/output p = power ? = not used ttl = ttl input st = schmitt trigger input note 1: this buffer is a schmitt trigger input when configured as the external interrupt. 2: this buffer is a schmitt trigger input when used in serial programming mode. 3: this buffer is a schmitt trigger input when configured in rc oscillator mode and a cmos input otherwise.
pic16f818/819 ds39598d-page 8 preliminary ? 2003 microchip technology inc. portb is a bidirectional i/o port. portb can be software programmed for internal weak pull-up on all inputs. rb0/int rb0 int 677 i/o i ttl st (1) bidirectional i/o pin. external interrupt pin. rb1/sdi/sda rb1 sdi sda 788 i/o i i/o ttl st st bidirectional i/o pin. spi data in. i 2 c data. rb2/sdo/ccp1 rb2 sdo ccp1 899 i/o o i/o ttl st st bidirectional i/o pin. spi data out. capture input, compare output, pwm output. rb3/ccp1/pgm rb3 ccp1 pgm 91010 i/o i/o i ttl st st bidirectional i/o pin. capture input, compare output, pwm output. low-voltage icsp programming enable pin. rb4/sck/scl rb4 sck scl 10 11 12 i/o i/o i ttl st st bidirectional i/o pin. interrupt-on-change pin. synchronous serial clock input/output for spi. synchronous serial clock input for i 2 c. rb5/ss rb5 ss 11 12 13 i/o i ttl ttl bidirectional i/o pin. interrupt-on-change pin. slave select for spi in slave mode. rb6/t1oso/t1cki/pgc rb6 t1oso t1cki pgc 12 13 15 i/o o i i ttl st st st (2) interrupt-on-change pin. timer1 oscillator output. timer1 clock input. in-circuit debugger and icsp programming clock pin. rb7/t1osi/pgd rb7 t1osi pgd 13 14 16 i/o i i ttl st st (2) interrupt-on-change pin. timer1 oscillator input. in-circuit debugger and icsp programming data pin. v ss 5 5, 6 3, 5 p ? ground reference for logic and i/o pins. v dd 14 15, 16 17, 19 p ? positive supply for logic and i/o pins. table 1-2: pic16f818/819 pinout descriptions (continued) pin name pdip/ soic pin# sso p pin# qfn pin# i/o/p type buffer type description legend: i = input o = output i/o = input/output p = power ? = not used ttl = ttl input st = schmitt trigger input note 1: this buffer is a schmitt trigger input when configured as the external interrupt. 2: this buffer is a schmitt trigger input when used in serial programming mode. 3: this buffer is a schmitt trigger input when configured in rc oscillator mode and a cmos input otherwise.
? 2003 microchip technology inc. preliminary ds39598d-page 9 pic16f818/819 2.0 memory organization there are two memory blocks in the pic16f818/819. these are the program memory and the data memory. each block has its own bus, so access to each block can occur during the same oscillator cycle. the data memory can be further broken down into the general purpose ram and the special function registers (sfrs). the operation of the sfrs that control the ?core? are described here. the sfrs used to control the peripheral modules are described in the section discussing each individual peripheral module. the data memory area also contains the data eeprom memory. this memory is not directly mapped into the data memory, but is indirectly mapped. that is, an indirect address pointer specifies the address of the data eeprom memory to read/write. the pic16f818 device?s 128 bytes of data eeprom memory have the address range 00h-7fh and the pic16f819 device?s 256 bytes of data eeprom memory have the address range 00h-ffh. more details on the eeprom memory can be found in section 3.0 ?data eeprom and flash program memory? . additional information on device memory may be found in the picmicro ? mid-range reference manual (ds33023). figure 2-1: program memory map and stack for pic16f818 2.1 program memory organization the pic16f818/819 devices have a 13-bit program counter capable of addressing an 8k x 14 program memory space. for the pic16f818, the first 1k x 14 (0000h-03ffh) is physically implemented (see figure 2-1). for the pic16f819, the first 2k x 14 is located at 0000h-07ffh (see figure 2-2). accessing a location above the physically implemented address will cause a wraparound. for example, the same instruc- tion will be accessed at locations 020h, 420h, 820h, c20h, 1020h, 1420h, 1820h and 1c20h. the reset vector is at 0000h and the interrupt vector is at 0004h. figure 2-2: program memory map and stack for pic16f819 pc<12:0> 13 0000h 0004h 0005h stack level 1 stack level 8 reset vector interrupt vector on-chip call, return retfie, retlw 1fffh stack level 2 program memory page 0 03ffh 0400h wraps to 0000h-03ffh pc<12:0> 13 0000h 0004h 0005h stack level 1 stack level 8 reset vector interrupt vector on-chip call, return retfie, retlw 1fffh stack level 2 program memory page 0 07ffh 0800h wraps to 0000h-07ffh
pic16f818/819 ds39598d-page 10 preliminary ? 2003 microchip technology inc. 2.2 data memory organization the data memory is partitioned into multiple banks that contain the general purpose registers and the special function registers. bits rp1 (status<6>) and rp0 (status<5>) are the bank select bits. each bank extends up to 7fh (128 bytes). the lower locations of each bank are reserved for the special function registers. above the special function regis- ters are general purpose registers, implemented as static ram. all implemented banks contain sfrs. some ?high use? sfrs from one bank may be mirrored in another bank for code reduction and quicker access (e.g., the status register is in banks 0-3). 2.2.1 general purpose register file the register file can be accessed either directly or indirectly through the file select register, fsr. rp1:rp0 bank 00 0 01 1 10 2 11 3 note: eeprom data memory description can be found in section 3.0 ?data eeprom and flash program memory? of this data sheet.
? 2003 microchip technology inc. preliminary ds39598d-page 11 pic16f818/819 figure 2-3: pic16f818 register file map indirect addr.(*) tmr0 pcl status fsr porta portb pclath intcon pir1 tmr1l tmr1h t1con tmr2 t2con sspbuf sspcon ccpr1l ccpr1h ccp1con option pcl status fsr trisa trisb pclath intcon pie1 pcon pr2 sspstat 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0ah 0bh 0ch 0dh 0eh 0fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1ah 1bh 1ch 1dh 1eh 1fh 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8ah 8bh 8ch 8dh 8eh 8fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9ah 9bh 9ch 9dh 9eh 9fh 20h a0h 7fh ffh bank 0 bank 1 file address indirect addr.(*) indirect addr.(*) pcl status fsr pclath intcon pcl status fsr pclath intcon 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10ah 10bh 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18ah 18bh 17fh 1ffh bank 2 bank 3 indirect addr.(*) tmr0 option adresh adcon0 adcon1 general purpose register accesses 20h-7fh trisb portb 96 bytes 10ch 10dh 10eh 10fh 110h 18ch 18dh 18eh 18fh 190h eedata eeadr eecon1 eedath eeadrh unimplemented data memory locations, read as ? 0 ?. * not a physical register. note 1: these registers are reserved; maintain these registers clear. file address file address file address sspadd 120h 11fh 1a0h 19fh general purpose register 32 bytes bfh c0h accesses 40h-7fh accesses 20h-7fh pir2 pie2 osccon osctune adresl eecon2 reserved (1) reserved (1)
pic16f818/819 ds39598d-page 12 preliminary ? 2003 microchip technology inc. figure 2-4: pic16f819 register file map indirect addr.(*) tmr0 pcl status fsr porta portb pclath intcon pir1 tmr1l tmr1h t1con tmr2 t2con sspbuf sspcon ccpr1l ccpr1h ccp1con option pcl status fsr trisa trisb pclath intcon pie1 pcon pr2 sspstat 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0ah 0bh 0ch 0dh 0eh 0fh 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 1ah 1bh 1ch 1dh 1eh 1fh 80h 81h 82h 83h 84h 85h 86h 87h 88h 89h 8ah 8bh 8ch 8dh 8eh 8fh 90h 91h 92h 93h 94h 95h 96h 97h 98h 99h 9ah 9bh 9ch 9dh 9eh 9fh 20h a0h 7fh ffh bank 0 bank 1 file address indirect addr.(*) indirect addr.(*) pcl status fsr pclath intcon pcl status fsr pclath intcon 100h 101h 102h 103h 104h 105h 106h 107h 108h 109h 10ah 10bh 180h 181h 182h 183h 184h 185h 186h 187h 188h 189h 18ah 18bh 17fh 1ffh bank 2 bank 3 indirect addr.(*) tmr0 option adresh adcon0 adcon1 general purpose register trisb portb 96 bytes 10ch 10dh 10eh 10fh 110h 18ch 18dh 18eh 18fh 190h eedata eeadr eecon1 eedath eeadrh unimplemented data memory locations, read as ? 0 ?. * not a physical register. note 1: these registers are reserved; maintain these registers clear. file address file address file address sspadd 120h 11fh 1a0h 19fh general purpose register 80 bytes efh f0h accesses 70h-7fh accesses 20h-7fh pir2 pie2 osccon osctune adresl eecon2 reserved (1) reserved (1) 16fh 170h accesses 70h-7fh general purpose register 80 bytes
? 2003 microchip technology inc. preliminary ds39598d-page 13 pic16f818/819 2.2.2 special function registers the special function registers are registers used by the cpu and peripheral modules for controlling the desired operation of the device. these registers are implemented as static ram. a list of these registers is given in table 2-1. the special function registers can be classified into two sets: core (cpu) and peripheral. those registers associated with the core functions are described in detail in this section. those related to the operation of the peripheral features are described in detail in the peripheral feature section. table 2-1: special function register summary address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: bank 0 00h (1) indf addressing this location uses contents of fsr to address data memory (not a physical register) 0000 0000 23 01h tmr0 timer0 module?s register xxxx xxxx 53, 17 02h (1) pcl program counter?s (pc) least significant byte 0000 0000 23 03h (1) status irp rp1 rp0 to pd z dc c 0001 1xxx 16 04h (1) fsr indirect data memory address pointer xxxx xxxx 23 05h porta porta data latch when written; porta pins when read xxx0 0000 39 06h portb portb data latch when written; portb pins when read xxxx xxxx 43 07h ? unimplemented ? ? 08h ? unimplemented ? ? 09h ? unimplemented ? ? 0ah (1,2) pclath ? ? ? write buffer for the upper 5 bits of the program counter ---0 0000 23 0bh (1) intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 18 0ch pir1 ?adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 20 0dh pir2 ? ? ? eeif ? ? ? ? ---0 ---- 21 0eh tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx 57 0fh tmr1h holding register for the most significant byte of the 16-bit tmr1 register xxxx xxxx 57 10h t1con ? ? t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on --00 0000 57 11h tmr2 timer2 module?s register 0000 0000 63 12h t2con ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 63 13h sspbuf synchronous serial port receive buffer/transmit register xxxx xxxx 71, 76 14h sspcon wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 71 15h ccpr1l capture/compare/pwm register (lsb) xxxx xxxx 66, 67, 68 16h ccpr1h capture/compare/pwm register (msb) xxxx xxxx 66, 67, 68 17h ccp1con ? ? ccp1x ccp1y ccp1m3 ccp1m2 ccp1m1 ccp1m0 --00 0000 66 18h ? unimplemented ? ? 19h ? unimplemented ? ? 1ah ? unimplemented ? ? 1bh ? unimplemented ? ? 1ch ? unimplemented ? ? 1dh ? unimplemented ? ? 1eh adresh a/d result register higher 2 bits xxxx xxxx 81 1fh adcon0 adcs1 adcs0 chs2 chs1 chs0 go/done ?adon 0000 00-0 81 legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as ? 0 ?, r = reserved. shaded locations are unimplemented, read as ? 0 ?. note 1: these registers can be addressed from any bank. 2: the upper byte of the program counter is not directly accessible. pclath is a holding register for the pc<12:8>, whose contents are transferred to the upper byte of the program counter. 3: pin 5 is an input only; the state of the trisa5 bit has no effect and will always read ? 1 ?.
pic16f818/819 ds39598d-page 14 preliminary ? 2003 microchip technology inc. bank 1 80h (1) indf addressing this location uses contents of fsr to address data memory (not a physical register) 0000 0000 23 81h option rbpu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 17 82h (1) pcl program counter's (pc) least significant byte 0000 0000 23 83h (1) status irp rp1 rp0 to pd zdcc 0001 1xxx 16 84h (1) fsr indirect data memory address pointer xxxx xxxx 23 85h trisa trisa7 trisa6 trisa5 (3) porta data direction register (trisa<4:0> 1111 1111 39 86h trisb portb data direction register 1111 1111 43 87h ? unimplemented ? ? 88h ? unimplemented ? ? 89h ? unimplemented ? ? 8ah (1,2) pclath ? ? ? write buffer for the upper 5 bits of the pc ---0 0000 23 8bh (1) intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 18 8ch pie1 ?adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 19 8dh pie2 ? ? ? eeie ? ? ? ? ---0 ---- 21 8eh pcon ? ? ? ? ? ?por bor ---- --qq 22 8fh osccon ? ircf2 ircf1 ircf0 ? iofs ? ? -000 -0-- 38 90h (1) osctune ? ? tun5 tun4 tun3 tun2 tun1 tun0 --00 0000 36 91h ? unimplemented ? ? 92h pr2 timer2 period register 1111 1111 68 93h sspadd synchronous serial port (i 2 c mode) address register 0000 0000 71, 76 94h sspstat smp cke d/a psr/w ua bf 0000 0000 71 95h ? unimplemented ? ? 96h ? unimplemented ? ? 97h ? unimplemented ? ? 98h ? unimplemented ? ? 99h ? unimplemented ? ? 9ah ? unimplemented ? ? 9bh ? unimplemented ? ? 9ch ? unimplemented ? ? 9dh ? unimplemented ? ? 9eh adresl a/d result register lower byte xxxx xxxx 81 9fh adcon1 adfm adcs2 ? ? pcfg3 pcfg2 pcfg1 pcfg0 00-- 0000 81 table 2-1: special function register summary (continued) address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as ? 0 ?, r = reserved. shaded locations are unimplemented, read as ? 0 ?. note 1: these registers can be addressed from any bank. 2: the upper byte of the program counter is not directly accessible. pclath is a holding register for the pc<12:8>, whose contents are transferred to the upper byte of the program counter. 3: pin 5 is an input only; the state of the trisa5 bit has no effect and will always read ? 1 ?.
? 2003 microchip technology inc. preliminary ds39598d-page 15 pic16f818/819 bank 2 100h (1) indf addressing this location uses contents of fsr to address data memory (not a physical register) 0000 0000 23 101h tmr0 timer0 module?s register xxxx xxxx 53 102h (1 pcl program counter?s (pc) least significant byte 0000 0000 23 103h (1) status irp rp1 rp0 to pd zdcc 0001 1xxx 16 104h (1) fsr indirect data memory address pointer xxxx xxxx 23 105h ? unimplemented ? ? 106h portb portb data latch when written; portb pins when read xxxx xxxx 43 107h ? unimplemented ? ? 108h ? unimplemented ? ? 109h ? unimplemented ? ? 10ah (1,2) pclath ? ? ? write buffer for the upper 5 bits of the program counter ---0 0000 23 10bh (1) intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 18 10ch eedata eeprom data register low byte xxxx xxxx 25 10dh eeadr eeprom address register low byte xxxx xxxx 25 10eh eedath ? ? eeprom data register high byte --xx xxxx 25 10fh eeadrh ? ? ? ? ? eeprom address register high byte ---- -xxx 25 bank 3 180h (1) indf addressing this location uses contents of fsr to address data memory (not a physical register) 0000 0000 23 181h option rbpu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 17 182h (1) pcl program counter?s (pc) least significant byte 0000 0000 23 183h (1) status irp rp1 rp0 to pd zdcc 0001 1xxx 16 184h (1) fsr indirect data memory address pointer xxxx xxxx 23 185h ? unimplemented ? ? 186h trisb portb data direction register 1111 1111 43 187h ? unimplemented ? ? 188h ? unimplemented ? ? 189h ? unimplemented ? ? 18ah (1,2) pclath ? ? ? write buffer for the upper 5 bits of the program counter ---0 0000 23 18bh (1) intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 18 18ch eecon1 eepgd ? ? free wrerr wren wr rd x--x x000 25 18dh eecon2 eeprom control register 2 (not a physical register) ---- ---- 25 18eh ? reserved; maintain clear 0000 0000 ? 18fh ? reserved; maintain clear 0000 0000 ? table 2-1: special function register summary (continued) address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor details on page: legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as ? 0 ?, r = reserved. shaded locations are unimplemented, read as ? 0 ?. note 1: these registers can be addressed from any bank. 2: the upper byte of the program counter is not directly accessible. pclath is a holding register for the pc<12:8>, whose contents are transferred to the upper byte of the program counter. 3: pin 5 is an input only; the state of the trisa5 bit has no effect and will always read ? 1 ?.
pic16f818/819 ds39598d-page 16 preliminary ? 2003 microchip technology inc. 2.2.2.1 status register the status register, shown in register 2-1, contains the arithmetic status of the alu, the reset status and the bank select bits for data memory. the status register can be the destination for any instruction, as with any other register. if the status reg- ister is the destination for an instruction that affects the z, dc or c bits, then the write to these three bits is dis- abled. these bits are set or cleared according to the device logic. furthermore, the to and pd bits are not writable. therefore, the result of an instruction with the status register as destination may be different than intended. for example, clrf status , will clear the upper three bits and set the z bit. this leaves the status register as ? 000u u1uu ? (where u = unchanged). it is recommended, therefore, that only bcf, bsf, swapf and movwf instructions are used to alter the status register because these instructions do not affect the z, c or dc bits from the status register. for other instructions not affecting any status bits, see section 13.0 ?instruction set summary? . register 2-1: status register (address 03h, 83h, 103h, 183h) note: the c and dc bits operate as a borrow and digit borrow bit, respectively, in sub- traction. see the sublw and subwf instructions for examples. r/w-0 r/w-0 r/w-0 r-1 r-1 r/w-x r/w-x r/w-x irp rp1 rp0 to pd zdc c bit 7 bit 0 bit 7 irp: register bank select bit (used for indirect addressing) 1 = bank 2, 3 (100h-1ffh) 0 = bank 0, 1 (00h-ffh) bit 6-5 rp<1:0>: register bank select bits (used for direct addressing) 11 = bank 3 (180h-1ffh) 10 = bank 2 (100h-17fh) 01 = bank 1 (80h-ffh) 00 = bank 0 (00h-7fh) each bank is 128 bytes. bit 4 to : time-out bit 1 = after power-up, clrwdt instruction or sleep instruction 0 = a wdt time-out occurred bit 3 pd : power-down bit 1 = after power-up or by the clrwdt instruction 0 = by execution of the sleep instruction bit 2 z: zero bit 1 = the result of an arithmetic or logic operation is zero 0 = the result of an arithmetic or logic operation is not zero bit 1 dc: digit carry/borrow bit ( addwf , addlw , sublw and subwf instructions) (1) 1 = a carry-out from the 4th low order bit of the result occurred 0 = no carry-out from the 4th low order bit of the result bit 0 c: carry/borrow bit ( addwf , addlw , sublw and subwf instructions) (1,2) 1 = a carry-out from the most significant bit of the result occurred 0 = no carry-out from the most significant bit of the result occurred note 1: for borrow , the polarity is reversed. a subtraction is executed by adding the two?s complement of the second operand. 2: for rotate ( rrf , rlf ) instructions, this bit is loaded with either the high or low order bit of the source register. legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 17 pic16f818/819 2.2.2.2 option register the option register is a readable and writable register that contains various control bits to configure the tmr0 prescaler/wdt postscaler (single assignable register known also as the prescaler), the external int interrupt, tmr0 and the weak pull-ups on portb. register 2-2: option register (address 81h, 181h) note: to achieve a 1:1 prescaler assignment for the tmr0 register, assign the prescaler to the watchdog timer. r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 rbpu intedg t0cs t0se psa ps2 ps1 ps0 bit 7 bit 0 bit 7 rbpu : portb pull-up enable bit 1 = portb pull-ups are disabled 0 = portb pull-ups are enabled by individual port latch values bit 6 intedg: interrupt edge select bit 1 = interrupt on rising edge of rb0/int pin 0 = interrupt on falling edge of rb0/int pin bit 5 t0cs: tmr0 clock source select bit 1 = transition on ra4/t0cki pin 0 = internal instruction cycle clock (clko) bit 4 t0se: tmr0 source edge select bit 1 = increment on high-to-low transition on ra4/t0cki pin 0 = increment on low-to-high transition on ra4/t0cki pin bit 3 psa: prescaler assignment bit 1 = prescaler is assigned to the wdt 0 = prescaler is assigned to the timer0 module bit 2-0 ps2:ps0: prescaler rate select bits legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown bit value tmr0 rate wdt rate 000 1 : 2 1 : 1 001 1 : 4 1 : 2 010 1 : 8 1 : 4 011 1 : 16 1 : 8 100 1 : 32 1 : 16 101 1 : 64 1 : 32 110 1 : 128 1 : 64 111 1 : 256 1 : 128
pic16f818/819 ds39598d-page 18 preliminary ? 2003 microchip technology inc. 2.2.2.3 intcon register the intcon register is a readable and writable regis- ter that contains various enable and flag bits for the tmr0 register overflow, rb port change and external rb0/int pin interrupts. register 2-3: intcon: interrupt control register (address 0bh, 8bh, 10bh, 18bh) note: interrupt flag bits get set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global enable bit, gie (intcon<7>). user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-x gie peie tmr0ie inte rbie tmr0if intf rbif bit 7 bit 0 bit 7 gie: global interrupt enable bit 1 = enables all unmasked interrupts 0 = disables all interrupts bit 6 peie: peripheral interrupt enable bit 1 = enables all unmasked peripheral interrupts 0 = disables all peripheral interrupts bit 5 tmr0ie: tmr0 overflow interrupt enable bit 1 = enables the tmr0 interrupt 0 = disables the tmr0 interrupt bit 4 inte: rb0/int external interrupt enable bit 1 = enables the rb0/int external interrupt 0 = disables the rb0/int external interrupt bit 3 rbie: rb port change interrupt enable bit 1 = enables the rb port change interrupt 0 = disables the rb port change interrupt bit 2 tmr0if: tmr0 overflow interrupt flag bit 1 = tmr0 register has overflowed (must be cleared in software) 0 = tmr0 register did not overflow bit 1 intf: rb0/int external interrupt flag bit 1 = the rb0/int external interrupt occurred (must be cleared in software) 0 = the rb0/int external interrupt did not occur bit 0 rbif: rb port change interrupt flag bit a mismatch condition will continue to set flag bit rbif. reading portb will end the mismatch condition and allow flag bit rbif to be cleared. 1 = at least one of the rb7:rb4 pins changed state (must be cleared in software) 0 = none of the rb7:rb4 pins have changed state legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 19 pic16f818/819 2.2.2.4 pie1 register this register contains the individual enable bits for the peripheral interrupts. register 2-4: pie1: peripheral interrupt enable register 1 (address 8ch) note: bit peie (intcon<6>) must be set to enable any peripheral interrupt. u-0 r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 ?adie ? ? sspie ccp1ie tmr2ie tmr1ie bit 7 bit 0 bit 7 unimplemented: read as ? 0 ? bit 6 adie: a/d converter interrupt enable bit 1 = enables the a/d converter interrupt 0 = disables the a/d converter interrupt bit 5-4 unimplemented: read as ? 0 ? bit 3 sspie: synchronous serial port interrupt enable bit 1 = enables the ssp interrupt 0 = disables the ssp interrupt bit 2 ccp1ie: ccp1 interrupt enable bit 1 = enables the ccp1 interrupt 0 = disables the ccp1 interrupt bit 1 tmr2ie: tmr2 to pr2 match interrupt enable bit 1 = enables the tmr2 to pr2 match interrupt 0 = disables the tmr2 to pr2 match interrupt bit 0 tmr1ie: tmr1 overflow interrupt enable bit 1 = enables the tmr1 overflow interrupt 0 = disables the tmr1 overflow interrupt legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
pic16f818/819 ds39598d-page 20 preliminary ? 2003 microchip technology inc. 2.2.2.5 pir1 register this register contains the individual flag bits for the peripheral interrupts. register 2-5: pir1: peripheral interrupt flag register 1 (address 0ch) note: interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding enable bit, or the global enable bit, gie (intcon<7>). user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. u-0 r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 ?adif ? ? sspif ccp1if tmr2if tmr1if bit 7 bit 0 bit 7 unimplemented: read as ? 0 ? bit 6 adif: a/d converter interrupt flag bit 1 = an a/d conversion completed 0 = the a/d conversion is not complete bit 5-4 unimplemented: read as ? 0 ? bit 3 sspif: synchronous serial port (ssp) interrupt flag bit 1 = the ssp interrupt condition has occurred and must be cleared in software before returning from the interrupt service routine. the conditions that will set this bit are a transmission/ reception has taken place. 0 = no ssp interrupt condition has occurred bit 2 ccp1if: ccp1 interrupt flag bit capture mode: 1 = a tmr1 register capture occurred (must be cleared in software) 0 = no tmr1 register capture occurred compare mode: 1 = a tmr1 register compare match occurred (must be cleared in software) 0 = no tmr1 register compare match occurred pwm mode: unused in this mode. bit 1 tmr2if: tmr2 to pr2 match interrupt flag bit 1 = tmr2 to pr2 match occurred (must be cleared in software) 0 = no tmr2 to pr2 match occurred bit 0 tmr1if: tmr1 overflow interrupt flag bit 1 = tmr1 register overflowed (must be cleared in software) 0 = tmr1 register did not overflow legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 21 pic16f818/819 2.2.2.6 pie2 register the pie2 register contains the individual enable bit for the eeprom write operation interrupt. register 2-6: pie2: peripheral interrupt enable register 2 (address 8dh) 2.2.2.7 pir2 register the pir2 register contains the flag bit for the eeprom write operation interrupt. . register 2-7: pir2: peripheral interrupt flag register 2 (address 0dh) u-0 u-0 u-0 r/w-0 u-0 u-0 u-0 u-0 ? ? ? eeie ? ? ? ? bit 7 bit 0 bit 7-5 unimplemented: read as ? 0 ? bit 4 eeie : eeprom write operation interrupt enable bit 1 = enable ee write interrupt 0 = disable ee write interrupt bit 3-0 unimplemented: read as ? 0 ? legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown note: interrupt flag bits are set when an interrupt condition occurs regardless of the state of its corresponding enable bit, or the global enable bit, gie (intcon<7>). user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. u-0 u-0 u-0 r/w-0 u-0 u-0 u-0 u-0 ? ? ? eeif ? ? ? ? bit 7 bit 0 bit 7-5 unimplemented: read as ? 0 ? bit 4 eeif : eeprom write operation interrupt enable bit 1 = enable ee write interrupt 0 = disable ee write interrupt bit 3-0 unimplemented: read as ? 0 ? legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
pic16f818/819 ds39598d-page 22 preliminary ? 2003 microchip technology inc. 2.2.2.8 pcon register the power control (pcon) register contains a flag bit to allow differentiation between a power-on reset (por), a brown-out reset, an external mclr reset and wdt reset. register 2-8: pcon: power control regist er (address 8eh) note: interrupt flag bits get set when an interrupt condition occurs regardless of the state of its corresponding enable bit or the global enable bit, gie (intcon<7>). user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. note: bor is unknown on power-on reset. it must then be set by the user and checked on subsequent resets to see if bor is clear, indicating a brown-out has occurred. the bor status bit is a ?don't care? and is not necessarily predictable if the brown- out circuit is disabled (by clearing the boren bit in the configuration word). u-0 u-0 u-0 u-0 u-0 u-0 r/w-0 r/w-x ? ? ? ? ? ?por bor bit 7 bit 0 bit 7-2 unimplemented: read as ? 0 ? bit 1 por : power-on reset status bit 1 = no power-on reset occurred 0 = a power-on reset occurred (must be set in software after a power-on reset occurs) bit 0 bor : brown-out reset status bit 1 = no brown-out reset occurred 0 = a brown-out reset occurred (must be set in software after a brown-out reset occurs) legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 23 pic16f818/819 2.3 pcl and pclath the program counter (pc) is 13 bits wide. the low byte comes from the pcl register, which is a readable and writable register. the upper bits (pc<12:8>) are not readable but are indirectly writable through the pclath register. on any reset, the upper bits of the pc will be cleared. figure 2-5 shows the two situations for the loading of the pc. the upper example in the figure shows how the pc is loaded on a write to pcl (pclath<4:0> pch). the lower example in the figure shows how the pc is loaded during a call or goto instruction (pclath<4:3> pch). figure 2-5: loading of pc in different situations 2.3.1 computed goto a computed goto is accomplished by adding an offset to the program counter ( addwf pcl ). when doing a table read using a computed goto method, care should be exercised if the table location crosses a pcl memory boundary (each 256-byte block). refer to the application note an556, ?implementing a table read? (ds00556). 2.3.2 stack the pic16f818/819 family has an 8-level deep x 13-bit wide hardware stack. the stack space is not part of either program or data space and the stack pointer is not readable or writable. the pc is pushed onto the stack when a call instruction is executed or an interrupt causes a branch. the stack is poped in the event of a return, retlw or a retfie instruction execution. pclath is not affected by a push or pop operation. the stack operates as a circular buffer. this means that after the stack has been pushed eight times, the ninth push overwrites the value that was stored from the first push. the tenth push overwrites the second push (and so on). 2.4 indirect addressing: indf and fsr registers the indf register is not a physical register. addressing indf actually addresses the register whose address is contained in the fsr register (fsr is a pointer ). this is indirect addressing. example 2-1: indirect addressing reading indf itself indirectly (fsr = 0 ) will produce 00h. writing to the indf register indirectly results in a no operation (although status bits may be affected). a simple program to clear ram locations, 20h-2fh, using indirect addressing is shown in example 2-2. example 2-2: how to clear ram using indirect addressing an effective 9-bit address is obtained by concatenating the 8-bit fsr register and the irp bit (status<7>) as shown in figure 2-6. pc 12 8 7 0 5 pclath<4:0> pclath instruction with alu goto,call opcode <10:0> 8 pc 12 11 10 0 11 pclath<4:3> pch pcl 87 2 pclath pch pcl pcl as destination note 1: there are no status bits to indicate stack overflow or stack underflow conditions. 2: there are no instructions/mnemonics called push or pop. these are actions that occur from the execution of the call, return, retlw and retfie instructions or the vectoring to an interrupt address. register file 05 contains the value 10h register file 06 contains the value 0ah load the value 05 into the fsr register a read of the indf register will return the value of 10h increment the value of the fsr register by one (fsr = 06) a read of the indf register now will return the value of 0ah movlw 0x20 ;initialize pointer movwf fsr ;to ram next clrf indf ;clear indf register incf fsr ;inc pointer btfss fsr,4 ;all done? goto next ;no, clear next continue : ;yes, continue
pic16f818/819 ds39598d-page 24 preliminary ? 2003 microchip technology inc. figure 2-6: direct/indirect addressing note 1: for register file map detail, see figure 2-3 or figure 2-4. data memory (1) indirect addressing direct addressing bank select location select rp1:rp0 6 0 from opcode irp fsr register 7 0 bank select location select 00 01 10 11 bank 0 bank 1 bank 2 bank 3 ffh 80h 7fh 00h 17fh 100h 1ffh 180h
? 2003 microchip technology inc. preliminary ds39598d-page 25 pic16f818/819 3.0 data eeprom and flash program memory the data eeprom and flash program memory are readable and writable during normal operation (over the full v dd range). this memory is not directly mapped in the register file space. instead, it is indirectly addressed through the special function registers. there are six sfrs used to read and write this memory: eecon1 eecon2 eedata eedath eeadr eeadrh when interfacing the data memory block, eedata holds the 8-bit data for read/write and eeadr holds the address of the eeprom location being accessed. these devices have 128 or 256 bytes of data eeprom, with an address range from 00h to 0ffh. addresses from 80h to ffh are unimplemented on the pic16f818 device and will read 00h. when writing to unimplemented locations, the charge pump will be turned off. when interfacing the program memory block, the eedata and eedath registers form a two-byte word that holds the 14-bit data for read/write and the eeadr and eeadrh registers form a two-byte word that holds the 13-bit address of the eeprom location being accessed. these devices have 1k or 2k words of program flash, with an address range from 0000h to 03ffh for the pic16f818 and 0000h to 07ffh for the pic16f819. addresses above the range of the respec- tive device will wraparound to the beginning of program memory. the eeprom data memory allows single byte read and write. the flash program memory allows single- word reads and four-word block writes. program memory writes must first start with a 32-word block erase, then write in 4-word blocks. a byte write in data eeprom memory automatically erases the location and writes the new data (erase before write). the write time is controlled by an on-chip timer. the write/erase voltages are generated by an on-chip charge pump, rated to operate over the voltage range of the device for byte or word operations. when the device is code-protected, the cpu may continue to read and write the data eeprom memory. depending on the settings of the write-protect bits, the device may or may not be able to write certain blocks of the program memory; however, reads of the program memory are allowed. when code-protected, the device programmer can no longer access data or program memory; this does not inhibit internal reads or writes. 3.1 eeadr and eeadrh the eeadrh:eeadr register pair can address up to a maximum of 256 bytes of data eeprom or up to a maximum of 8k words of program eeprom. when selecting a data address value, only the lsbyte of the address is written to the eeadr register. when select- ing a program address value, the msbyte of the address is written to the eeadrh register and the lsbyte is written to the eeadr register. if the device contains less memory than the full address reach of the address register pair, the most significant bits of the registers are not implemented. for example, if the device has 128 bytes of data eeprom, the most significant bit of eeadr is not implemented on access to data eeprom. 3.2 eecon1 and eecon2 registers eecon1 is the control register for memory accesses. control bit, eepgd, determines if the access will be a program or data memory access. when clear, as it is when reset, any subsequent operations will operate on the data memory. when set, any subsequent operations will operate on the program memory. control bits, rd and wr, initiate read and write, respectively. these bits cannot be cleared, only set in software. they are cleared in hardware at completion of the read or write operation. the inability to clear the wr bit in software prevents the accidental, premature termination of a write operation. the wren bit, when set, will allow a write or erase operation. on power-up, the wren bit is clear. the wrerr bit is set when a write (or erase) operation is interrupted by a mclr or a wdt time-out reset dur- ing normal operation. in these situations, following reset, the user can check the wrerr bit and rewrite the location. the data and address will be unchanged in the eedata and eeadr registers. interrupt flag bit, eeif in the pir2 register, is set when write is complete. it must be cleared in software. eecon2 is not a physical register. reading eecon2 will read all ? 0 ?s. the eecon2 register is used exclusively in the eeprom write sequence.
pic16f818/819 ds39598d-page 26 preliminary ? 2003 microchip technology inc. register 3-1: eecon1: eeprom access control register 1 (address 18ch) r/w-x u-0 u-0 r/w-x r/w-x r/w-0 r/s-0 r/s-0 eepgd ? ? free wrerr wren wr rd bit 7 bit 0 bit 7 eepgd : program/data eeprom select bit 1 = accesses program memory 0 = accesses data memory reads ? 0 ? after a por; this bit cannot be changed while a write operation is in progress. bit 6-5 unimplemented: read as ? 0 ? bit 4 free: eeprom forced row erase bit 1 = erase the program memory row addressed by eeadrh:eeadr on the next wr command 0 = perform write-only bit 3 wrerr: eeprom error flag bit 1 = a write operation is prematurely terminated (any mclr or any wdt reset during normal operation) 0 = the write operation completed bit 2 wren: eeprom write enable bit 1 = allows write cycles 0 = inhibits write to the eeprom bit 1 wr: write control bit 1 = initiates a write cycle. the bit is cleared by hardware once write is complete. the wr bit can only be set (not cleared) in software. 0 = write cycle to the eeprom is complete bit 0 rd: read control bit 1 = initiates an eeprom read, rd is cleared in hardware. the rd bit can only be set (not cleared) in software. 0 = does not initiate an eeprom read legend: r = readable bit w = writable bit s = set only u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 27 pic16f818/819 3.3 reading data eeprom memory to read a data memory location, the user must write the address to the eeadr register, clear the eepgd con- trol bit (eecon1<7>) and then set control bit, rd (eecon1<0>). the data is available in the very next cycle in the eedata register; therefore, it can be read in the next instruction (see example 3-1). eedata will hold this value until another read or until it is written to by the user (during a write operation). the steps to reading the eeprom data memory are: 1. write the address to eeadr. make sure that the address is not larger than the memory size of the device. 2. clear the eepgd bit to point to eeprom data memory. 3. set the rd bit to start the read operation. 4. read the data from the eedata register. example 3-1: data eeprom read 3.4 writing to data eeprom memory to write an eeprom data location, the user must first write the address to the eeadr register and the data to the eedata register. then, the user must follow a specific write sequence to initiate the write for each byte. the write will not initiate if the write sequence is not exactly followed (write 55h to eecon2, write aah to eecon2, then set wr bit) for each byte. we strongly recommend that interrupts be disabled during this code segment (see example 3-2). additionally, the wren bit in eecon1 must be set to enable write. this mechanism prevents accidental writes to data eeprom due to errant (unexpected) code execution (i.e., lost programs). the user should keep the wren bit clear at all times except when updating eeprom. the wren bit is not cleared by hardware after a write sequence has been initiated, clearing the wren bit will not affect this write cycle. the wr bit will be inhibited from being set unless the wren bit is set. at the completion of the write cycle, the wr bit is cleared in hardware and the ee write complete interrupt flag bit (eeif) is set. the user can either enable this interrupt or poll this bit. eeif must be cleared by software. the steps to write to eeprom data memory are: 1. if step 10 is not implemented, check the wr bit to see if a write is in progress. 2. write the address to eeadr. make sure that the address is not larger than the memory size of the device. 3. write the 8-bit data value to be programmed in the eedata register. 4. clear the eepgd bit to point to eeprom data memory. 5. set the wren bit to enable program operations. 6. disable interrupts (if enabled). 7. execute the special five instruction sequence: write 55h to eecon2 in two steps (first to w, then to eecon2) write aah to eecon2 in two steps (first to w, then to eecon2) set the wr bit 8. enable interrupts (if using interrupts). 9. clear the wren bit to disable program operations. 10. at the completion of the write cycle, the wr bit is cleared and the eeif interrupt flag bit is set (eeif must be cleared by firmware). if step 1 is not implemented, then firmware should check for eeif to be set, or wr to clear, to indicate the end of the program cycle. example 3-2: data eeprom write banksel eeadr ; select bank of eeadr movf addr, w ; movwf eeadr ; data memory address ; to read banksel eecon1 ; select bank of eecon1 bcf eecon1, eepgd ; point to data memory bsf eecon1, rd ; ee read banksel eedata ; select bank of eedata movf eedata, w ; w = eedata banksel eecon1 ; select bank of ; eecon1 btfsc eecon1, wr ; wait for write goto $-1 ; to complete banksel eeadr ; select bank of ; eeadr movf addr, w ; movwf eeadr ; data memory ; address to write movf value, w ; movwf eedata ; data memory value ; to write banksel eecon1 ; select bank of ; eecon1 bcf eecon1, eepgd ; point to data ; memory bsf eecon1, wren ; enable writes bcf intcon, gie ; disable ints. movlw 55h ; movwf eecon2 ; write 55h movlw aah ; movwf eecon2 ; write aah bsf eecon1, wr ; set wr bit to ; begin write bsf intcon, gie ; enable ints. bcf eecon1, wren ; disable writes required sequence
pic16f818/819 ds39598d-page 28 preliminary ? 2003 microchip technology inc. 3.5 reading flash program memory to read a program memory location, the user must write two bytes of the address to the eeadr and eeadrh registers, set the eepgd control bit (eecon1<7>) and then set control bit, rd (eecon1<0>). once the read control bit is set, the program memory flash controller will use the second instruction cycle to read the data. this causes the second instruction immediately following the ? bsf eecon1, rd ? instruction to be ignored. the data is available in the very next cycle in the eedata and eedath registers; therefore, it can be read as two bytes in the following instructions. eedata and eedath registers will hold this value until another read or until it is written to by the user (during a write operation). example 3-3: flash program read 3.6 erasing flash program memory the minimum erase block is 32 words. only through the use of an external programmer, or through icsp control, can larger blocks of program memory be bulk erased. word erase in the flash array is not supported. when initiating an erase sequence from the micro- controller itself, a block of 32 words of program memory is erased. the most significant 11 bits of the eeadrh:eeadr point to the block being erased. eeadr< 4:0> are ignored. the eecon1 register commands the erase operation. the eepgd bit must be set to point to the flash pro- gram memory. the wren bit must be set to enable write operations. the free bit is set to select an erase operation. for protection, the write initiate sequence for eecon2 must be used. after the ? bsf eecon1, wr ? instruction, the processor requires two cycles to set up the erase operation. the user must place two nop instructions after the wr bit is set. the processor will halt internal operations for the typical 2 ms, only during the cycle in which the erase takes place. this is not sleep mode, as the clocks and peripherals will continue to run. after the erase cycle, the processor will resume operation with the third instruction after the eecon1 write instruction. 3.6.1 flash program memory erase sequence the sequence of events for erasing a block of internal program memory location is: 1. load eeadrh:eeadr with address of row being erased. 2. set eepgd bit to point to program memory; set wren bit to enable writes and set free bit to enable the erase. 3. disable interrupts. 4. write 55h to eecon2. 5. write aah to eecon2. 6. set the wr bit. this will begin the row erase cycle. 7. the cpu will stall for duration of the erase. banksel eeadrh ; select bank of eeadrh movf addrh, w ; movwf eeadrh ; ms byte of program ; address to read movf addrl, w ; movwf eeadr ; ls byte of program ; address to read banksel eecon1 ; select bank of eecon1 bsf eecon1, eepgd ; point to program ; memory bsf eecon1, rd ; ee read ; nop ; any instructions ; here are ignored as nop ; program memory is ; read in second cycle ; after bsf eecon1,rd banksel eedata ; select bank of eedata movf eedata, w ; datal = eedata movwf datal ; movf eedath, w ; datah = eedath movwf datah ;
? 2003 microchip technology inc. preliminary ds39598d-page 29 pic16f818/819 example 3-4: erasing a flash program memory row banksel eeadrh ; select bank of eeadrh movf addrh, w ; movwf eeadrh ; ms byte of program address to erase movf addrl, w ; movwf eeadr ; ls byte of program address to erase erase_row banksel eecon1 ; select bank of eecon1 bsf eecon1, eepgd ; point to program memory bsf eecon1, wren ; enable write to memory bsf eecon1, free ; enable row erase operation ; bcf intcon, gie ; disable interrupts (if using) movlw 55h ; movwf eecon2 ; write 55h movlw aah ; movwf eecon2 ; write aah bsf eecon1, wr ; start erase (cpu stall) nop ; any instructions here are ignored as processor ; halts to begin erase sequence nop ; processor will stop here and wait for erase complete ; after erase processor continues with 3rd instruction bcf eecon1, wren ; disable writes bsf intcon, gie ; enable interrupts (if using)
pic16f818/819 ds39598d-page 30 preliminary ? 2003 microchip technology inc. 3.7 writing to flash program memory flash program memory may only be written to if the destination address is in a segment of memory that is not write-protected, as defined in bits wrt1:wrt0 of the device configuration word (register 12-1). flash program memory must be written in four-word blocks. a block consists of four words with sequential addresses, with a lower boundary defined by an address, where eeadr<1:0> = 00 . at the same time, all block writes to program memory are done as write- only operations. the program memory must first be erased. the write operation is edge-aligned and cannot occur across boundaries. to write to the program memory, the data must first be loaded into the buffer registers. there are four 14-bit buffer registers and they are addressed by the low 2 bits of eeadr. loading data into the buffer registers is accomplished via the eeadr, eeadt, eecon1 and eecon2 registers as follows: set eecon1 pgd and wren write address to eeadrh:eeadr write data to eedata:eedath write 55, aa to eecon2 set wr bit in eecon1 there are 4 buffer register words and all four locations must be written to with correct data. after the ? bsf eecon1, wr ? instruction, if eeadr xxxxxx11 , then a short write will occur. this short write-only transfers the data to the buffer register. the wr bit will be cleared in hardware after 1 cycle. the core will not halt and there will be no eewhlt signal generated. after the ? bsf eecon1, wr ? instruction, if eeadr = xxxxxx11 , then a long write will occur. this will simultaneously transfer the data from eedath:eedata to the buffer registers and begin the write of all four words. the processor will execute the next instruction and then ignore the subsequent instruction. the user should place nop instructions into the second words. the processor will then halt internal operations for typically 2 msec in which the write takes place. this is not a sleep mode, as the clocks and peripherals will continue to run. after the write cycle, the processor will resume operation with the 3rd instruction after the eecon1 write instruction. after each long write, the 4 buffer registers will be reset to 3fff. figure 3-1: block writes to flash program memory 14 14 14 14 program memory buffer register eeadr<1:0> = 00 buffer register eeadr<1:0> = 01 buffer register eeadr<1:0> = 10 buffer register eeadr<1:0> = 11 eedata eedath 75 07 0 6 8 first word of block to be written to flash automatically after this word is written transferred all buffers are
? 2003 microchip technology inc. preliminary ds39598d-page 31 pic16f818/819 an example of the complete four-word write sequence is shown in example 3-5. the initial address is loaded into the eeadrh:eeadr register pair; the four words of data are loaded using indirect addressing, assuming that a row erase sequence has already been performed. example 3-5: writing to flash program memory ; this write routine assumes the following: ; 1. the 32 words in the erase block have already been erased. ; 2. a valid starting address (the least significant bits = '00') is loaded into eeadrh:eeadr ; 3. this example is starting at 0x100, this is an application dependent setting. ; 4. the 8 bytes (4 words) of data are loaded, starting at an address in ram called array. ; 5. this is an example only, location of data to program is application dependent. ; 6. word_block is located in data memory. banksel eecon1 ;prepare for write procedure bsf eecon1, eepgd ;point to program memory bsf eecon1, wren ;allow write cycles banksel word_block movlw .4 movwf word_block ;prepare for 4 words to be written banksel eeadrh ;start writing at 0x100 movlw 0x01 movwf eeadrh ;load high address movlw 0x00 movwf eeadr ;load low address banksel array movlw array ;initialize fsr to start of data movwf fsr loop banksel eedata movf indf, w ;indirectly load eedata movwf eedata incf fsr,f ;increment data pointer movf indf, w ;indirectly load eedath movwf eedath incf fsr, f ;increment data pointer banksel eecon1 movlw 0x55 ;required sequence movwf eecon2 movlw 0xaa movwf eecon2 bsf eecon1, wr ;set wr bit to begin write nop ;instructions here are ignored as processor nop banksel eeadr incf eeadr, f ;load next word address banksel word_block decfsz word_block, f ;have 4 words been written? goto loop ;no, continue with writing banksel eecon1 bcf eecon1, wren ;yes, 4 words complete, disable writes bsf intcon, gie ;enable interrupts required sequence
pic16f818/819 ds39598d-page 32 preliminary ? 2003 microchip technology inc. 3.8 protection against spurious write there are conditions when the device should not write to the data eeprom memory. to protect against spu- rious eeprom writes, various mechanisms have been built-in. on power-up, wren is cleared. also, the power-up timer (72 ms duration) prevents an eeprom write. the write initiate sequence and the wren bit together help prevent an accidental write during brown-out, power glitch or software malfunction. 3.9 operation during code-protect when the data eeprom is code-protected, the micro- controller can read and write to the eeprom normally. however, all external access to the eeprom is disabled. external write access to the program memory is also disabled. when program memory is code-protected, the microcon- troller can read and write to program memory normally as well as execute instructions. writes by the device may be selectively inhibited to regions of the memory depending on the setting of bits, wrt1:wrt0, of the configuration word (see section 12.1 ?configuration bits? for addi- tional information). external access to the memory is also disabled. table 3-1: registers/bits associated with data eeprom and flash program memories address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on power-on reset value on all other resets 10ch eedata eeprom/flash data register low byte xxxx xxxx uuuu uuuu 10dh eeadr eeprom/flash address register low byte xxxx xxxx uuuu uuuu 10eh eedath ? ? eeprom/flash data register high byte --xx xxxx --uu uuuu 10fh eeadrh ? ? ? ? ? eeprom/flash address register high byte ---- -xxx ---- -uuu 18ch eecon1 eepgd ? ? free wrerr wren wr rd x--x x000 x--x q000 18dh eecon2 eeprom control register 2 (not a physical register) ---- ---- ---- ---- 0dh pir2 ? ? ? eeif ? ? ? ? ---0 ---- ---0 ---- 8dh pie2 ? ? ?eeie ? ? ? ? ---0 ---- ---0 ---- legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?, q = value depends upon condition. shaded cells are not used by data eeprom or flash program memory.
? 2003 microchip technology inc. preliminary ds39598d-page 33 pic16f818/819 4.0 oscillator configurations 4.1 oscillator types the pic16f818/819 can be operated in eight different oscillator modes. the user can program three configu- ration bits (f osc 2:f osc 0) to select one of these eight modes (modes 5-8 are new pic16 oscillator configurations): 1. lp low-power crystal 2. xt crystal/resonator 3. hs high-speed crystal/resonator 4. rc external resistor/capacitor with f osc /4 output on ra6 5. rcio external resistor/capacitor with i/o on ra6 6. intio1 internal oscillator with f osc /4 output on ra6 and i/o on ra7 7. intio2 internal oscillator with i/o on ra6 and ra7 8. ecio external clock with i/o on ra6 4.2 crystal oscillator/ceramic resonators in xt, lp or hs modes, a crystal or ceramic resonator is connected to the osc1/clki and osc2/clko pins to establish oscillation (see figure 4-1 and figure 4-2). the pic16f818/819 oscillator design requires the use of a parallel cut crystal. use of a series cut crystal may give a frequency out of the crystal manufacturer?s specifications. figure 4-1: crystal operation (hs, xt or lp osc configuration) table 4-1: capacitor selection for crystal oscillator (for design guidance only) note 1: see table 4-1 for typical values of c1 and c2. 2: a series resistor (r s ) may be required for at strip cut crystals. 3: r f varies with the crystal chosen (typically between 2 m ? to 10 m ?) . c1 (1) c2 (1) xtal osc2 r s (2) osc1 r f (3) sleep to internal logic pic16f818/819 osc type crystal freq typical capacitor values tested: c1 c2 lp 32 khz 33 pf 33 pf 200 khz 15 pf 15 pf xt 200 khz 56 pf 56 pf 1 mhz 15 pf 15 pf 4 mhz 15 pf 15 pf hs 4 mhz 15 pf 15 pf 8 mhz 15 pf 15 pf 20 mhz 15 pf 15 pf capacitor values are for design guidance only. these capacitors were tested with the crystals listed below for basic start-up and operation. these values were not optimized. different capacitor values may be required to produce acceptable oscillator operation. the user should test the performance of the oscillator over the expected v dd and temperature range for the application. see the notes following this table for additional information. note 1: higher capacitance increases the stability of oscillator but also increases the start-up time. 2: since each crystal has its own character- istics, the user should consult the crystal manufacturer for appropriate values of external components. 3: rs may be required in hs mode, as well as xt mode, to avoid overdriving crystals with low drive level specification. 4: always verify oscillator performance over the v dd and temperature range that is expected for the application.
pic16f818/819 ds39598d-page 34 preliminary ? 2003 microchip technology inc. figure 4-2: ceramic resonator operation (hs or xt osc configuration) table 4-2: ceramic resonators (for design guidance only) 4.3 external clock input the ecio oscillator mode requires an external clock source to be connected to the osc1 pin. there is no oscillator start-up time required after a power-on reset or after an exit from sleep mode. in the ecio oscillator mode, the osc2 pin becomes an additional general purpose i/o pin. the i/o pin becomes bit 6 of porta (ra6). figure 4-3 shows the pin connections for the ecio oscillator mode. figure 4-3: external clock input operation (ecio configuration) typical capacitor values used: mode freq osc1 osc2 xt 455 khz 2.0 mhz 4.0 mhz 56 pf 47 pf 33 pf 56 pf 47 pf 33 pf hs 8.0 mhz 16.0 mhz 27 pf 22 pf 27 pf 22 pf capacitor values are for design guidance only. these capacitors were tested with the resonators listed below for basic start-up and operation. these values were not optimized. different capacitor values may be required to produce acceptable oscillator operation. the user should test the performance of the oscillator over the expected v dd and temperature range for the application. see the notes following this table for additional information. note: when using resonators with frequencies above 3.5 mhz, the use of hs mode rather than xt mode, is recommended. hs mode may be used at any v dd for which the controller is rated. if hs is selected, it is possible that the gain of the oscillator will overdrive the resonator. therefore, a series resistor should be placed between the osc2 pin and the resonator. as a good starting point, the recommended value of r s is 330 ?. note 1: see table 4-2 for typical values of c1 and c2. 2: a series resistor (r s ) may be required. 3: r f varies with the resonator chosen (typically between 2 m ? to 10 m ?) . c1 (1) c2 (1) res osc2 r s (2) osc1 r f (3) sleep to internal logic pic16f818/819 osc1/clki i/o (osc2) ra6 clock from ext. system pic16f818/819
? 2003 microchip technology inc. preliminary ds39598d-page 35 pic16f818/819 4.4 rc oscillator for timing insensitive applications, the ?rc? and ?rcio? device options offer additional cost savings. the rc oscillator frequency is a function of the supply voltage, the resistor (r ext ) and capacitor (c ext ) val- ues and the operating temperature. in addition to this, the oscillator frequency will vary from unit to unit due to normal manufacturing variation. furthermore, the dif- ference in lead frame capacitance between package types will also affect the oscillation frequency, espe- cially for low c ext values. the user also needs to take into account variation due to tolerance of external r and c components used. figure 4-4 shows how the r/c combination is connected. in the rc oscillator mode, the oscillator frequency divided by 4 is available on the osc2 pin. this signal may be used for test purposes or to synchronize other logic. figure 4-4: rc oscillator mode the rcio oscillator mode (figure 4-5) functions like the rc mode except that the osc2 pin becomes an additional general purpose i/o pin. the i/o pin becomes bit 6 of porta (ra6). figure 4-5: rcio oscillator mode 4.5 internal oscillator block the pic16f818/819 devices include an internal oscil- lator block which generates two different clock signals; either can be used as the system?s clock source. this can eliminate the need for external oscillator circuits on the osc1 and/or osc2 pins. the main output (intosc) is an 8 mhz clock source which can be used to directly drive the system clock. it also drives the intosc postscaler which can provide a range of clock frequencies from 125 khz to 4 mhz. the other clock source is the internal rc oscillator (intrc) which provides a 31.25 khz (32 s nominal period) output. the intrc oscillator is enabled by selecting the intrc as the system clock source or when any of the following are enabled: power-up timer watchdog timer these features are discussed in greater detail in section 12.0 ?special features of the cpu? . the clock source frequency (intosc direct, intrc direct or intosc postscaler) is selected by configuring the ircf bits of the osccon register (register 4-2). 4.5.1 intrc modes using the internal oscillator as the clock source can eliminate the need for up to two external oscillator pins, which can then be used for digital i/o. two distinct configurations are available: in intio1 mode, the osc2 pin outputs f osc /4 while osc1 functions as ra7 for digital input and output. in intio2 mode, osc1 functions as ra7 and osc2 functions as ra6, both for digital input and output. osc2/clko c ext r ext pic16f818/819 osc1 f osc /4 internal clock v dd v ss recommended values: 3 k ? r ext 100 k ? c ext > 20 pf c ext r ext pic16f818/819 osc1 internal clock v dd v ss recommended values: 3 k ? r ext 100 k ? c ext > 20 pf i/o (osc2) ra6 note: throughout this data sheet, when referring specifically to a generic clock source, the term ?intrc? may also be used to refer to the clock modes using the internal oscilla- tor block. this is regardless of whether the actual frequency used is intosc (8 mhz), the intosc postscaler or intrc (31.25 khz).
pic16f818/819 ds39598d-page 36 preliminary ? 2003 microchip technology inc. 4.5.2 osctune register the internal oscillator?s output has been calibrated at the factory but can be adjusted in the application. this is done by writing to the osctune register (register 4-1). the tuning sensitivity is constant throughout the tuning range. the osctune register has a tuning range of 12.5%. when the osctune register is modified, the intosc and intrc frequencies will begin shifting to the new fre- quency. the intrc clock will reach the new frequency within 8 clock cycles (approximately 8 * 32 s = 256 s); the intosc clock will stabilize within 1 ms. code execu- tion continues during this shift. there is no indication that the shift has occurred. operation of features that depend on the 31.25 khz intrc clock source frequency, such as the wdt, fail-safe clock monitor and peripherals, will also be affected by the change in frequency. register 4-1: osctune: oscillator tuning register u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? tun5 tun4 tun3 tun2 tun1 tun0 bit 7 bit 0 bit 7-6 unimplemented: read as ? 0 ? bit 5-0 tun<5:0>: frequency tuning bits 011111 = maximum frequency 011110 = 000001 = 000000 = center frequency. oscillator module is running at the calibrated frequency. 111111 = 100000 = minimum frequency legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? -n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 37 pic16f818/819 4.5.3 oscillator control register the osccon register (register 4-2) controls several aspects of the system clock?s operation. the internal oscillator select bits, ircf2:ircf0, select the frequency output of the internal oscillator block that is used to drive the system clock. the choices are the intrc source (31.25 khz), the intosc source (8 mhz) or one of the six frequencies derived from the intosc postscaler (125 khz to 4 mhz). changing the configuration of these bits has an immediate change on the internal oscillator?s output. 4.5.4 modifying the ircf bits the ircf bits can be modified at any time regardless of which clock source is currently being used as the sys- tem clock. the internal oscillator allows users to change the frequency during run time. this is achieved by mod- ifying the ircf bits in the osccon register. the sequence of events that occur after the ircf bits are modified is dependent upon the initial value of the ircf bits before they are modified. if the intrc (31.25 khz, ircf<2:0> = 000 ) is running and the ircf bits are modified to any other value than ? 000 ?, a 4 ms clock switch delay is turned on. code execution continues at a higher than expected frequency while the new frequency stabilizes. time sensitive code should wait for the iofs bit in the osccon register to become set before continuing. this bit can be monitored to ensure that the frequency is stable before using the system clock in time critical applications. if the ircf bits are modified while the internal oscillator is running at any other frequency than intrc (31.25 khz, ircf<2:0> 000 ), there is no need for a 4 ms clock switch delay. the new intosc frequency will be stable immediately after the eight falling edges. the iofs bit will remain set after clock switching occurs. 4.5.5 clock transition sequence when the ircf bits are modified following are three different sequences for switching the internal rc oscillator frequency. clock before switch: 31.25 khz (ircf<2:0> = 000 ) 1. ircf bits are modified to an intosc/intosc postscaler frequency. 2. the clock switching circuitry waits for a falling edge of the current clock, at which point clko is held low. 3. the clock switching circuitry then waits for eight falling edges of requested clock, after which it switches clko to this new clock source. 4. the iofs bit is clear to indicate that the clock is unstable and a 4 ms delay is started. time dependent code should wait for iofs to become set. 5. switchover is complete. clock before switch: one of intosc/intosc postscaler (ircf<2:0> 000 ) 1. ircf bits are modified to intrc (ircf<2:0> = 000 ). 2. the clock switching circuitry waits for a falling edge of the current clock, at which point clko is held low. 3. the clock switching circuitry then waits for eight falling edges of requested clock, after which it switches clko to this new clock source. 4. oscillator switchover is complete. clock before switch: one of intosc/intosc postscaler (ircf<2:0> 000 ) 1. ircf bits are modified to a different intosc/ intosc postscaler frequency. 2. the clock switching circuitry waits for a falling edge of the current clock, at which point clko is held low. 3. the clock switching circuitry then waits for eight falling edges of requested clock, after which it switches clko to this new clock source. 4. the iofs bit is set. 5. oscillator switchover is complete. note: caution must be taken when modifying the ircf bits using bcf or bsf instructions. it is possible to modify the ircf bits to a fre- quency that may be out of the v dd specifi- cation range; for example, v dd = 2.0v and ircf = 111 (8 mhz).
pic16f818/819 ds39598d-page 38 preliminary ? 2003 microchip technology inc. figure 4-6: pic16f818/ 819 clock diagram register 4-2: osccon register pic18f818/819 config (f osc 2:f osc 0) osc1 osc2 sleep lp, xt, hs, rc, ec cpu peripherals postscaler mux mux 8 mhz 4 mhz 2 mhz 1 mhz 500 khz 125 khz 250 khz osccon<6:4> 111 110 101 100 011 010 001 000 31.25 khz 31.25 khz source internal oscillator block wdt 31.25 khz 8 mhz internal oscillator (intrc) (intosc) u-0 r/w-0 r/w-0 r/w-0 u-0 r-0 u-0 u-0 ? ircf2 ircf1 ircf0 ?iofs ? ? bit 7 bit 0 bit 7 unimplemented: read as ? 0 ? bit 6-4 ircf2:ircf0: internal oscillator frequency select bits 111 = 8 mhz (8 mhz source drives clock directly) 110 = 4 mhz 101 = 2 mhz 100 = 1 mhz 011 = 500 khz 010 = 250 khz 001 = 125 khz 000 = 31.25 khz (intrc source drives clock directly) bit 3 unimplemented: read as ? 0 ? bit 2 iofs: intosc frequency stable bit 1 = frequency is stable 0 = frequency is not stable bit 1-0 unimplemented: read as ? 0 ? legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 39 pic16f818/819 5.0 i/o ports some pins for these i/o ports are multiplexed with an alternate function for the peripheral features on the device. in general, when a peripheral is enabled, that pin may not be used as a general purpose i/o pin. additional information on i/o ports may be found in the picmicro ? mid-range reference manual (ds33023). 5.1 porta and the trisa register porta is an 8-bit wide, bidirectional port. the corre- sponding data direction register is trisa. setting a trisa bit (= 1 ) will make the corresponding porta pin an input (i.e., put the corresponding output driver in a high-impedance mode). clearing a trisa bit (= 0 ) will make the corresponding porta pin an output (i.e., put the contents of the output latch on the selected pin). reading the porta register, reads the status of the pins, whereas writing to it will write to the port latch. all write operations are read-modify-write operations. therefore, a write to a port implies that the port pins are read, this value is modified and then written to the port data latch. pin ra4 is multiplexed with the timer0 module clock input and with an analog input to become the ra4/an4/ t0cki pin. the ra4/an4/t0cki pin is a schmitt trigger input and full cmos output driver. pin ra5 is multiplexed with the master clear module input. the ra5/mclr /v pp pin is a schmitt trigger input. pin ra6 is multiplexed with the oscillator module input and external oscillator output. pin ra7 is multiplexed with the oscillator module input and external oscillator input. pin ra6/osc2/clko and pin ra7/osc1/clki are schmitt trigger inputs and full cmos output drivers. pins ra<1:0> are multiplexed with analog inputs. pins ra<3:2> are multiplexed with analog inputs and v ref inputs. pins ra<3:0> have ttl inputs and full cmos output drivers. example 5-1: initializing porta table 5-1: porta functions table 5-2: summary of registers associated with porta note: on a power-on reset, the pins porta<4:0> are configured as analog inputs and read as ? 0 ?. banksel porta ; select bank of porta clrf porta ; initialize porta by ; clearing output ; data latches banksel adcon1 ; select bank of adcon1 movlw 0x06 ; configure all pins movwf adcon1 ; as digital inputs movlw 0xff ; value used to ; initialize data ; direction movwf trisa ; set ra<7:0> as inputs name bit# buffer function ra0/an0 bit 0 ttl input/output or analog input. ra1/an1 bit 1 ttl input/output or analog input. ra2/an2 bit 2 ttl input/output, analog input or v ref- . ra3/an3/v ref bit 3 ttl input/output, analog input or v ref+. ra4/an4/t0cki bit 4 st input/output, analog input or external clock input for timer0. ra5/mclr /v pp bit 5 st input, master clear (reset) or programming voltage input. ra6/osc2/clko bit 6 st input/output, connects to crystal or resonator, oscillator output or 1/4 the frequency of osc1 and denotes the instruction cycle in rc mode. ra7/osc1/clki bit 7 st/cmos (1) input/output, connects to crystal or resonator or oscillator input. legend: ttl = ttl input, st = schmitt trigger input note 1: this buffer is a schmitt trigger input when configured in rc oscillator mode and a cmos input otherwise. address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 05h porta (1) ra7 ra6 ra5 ra4 ra3 ra2 ra1 ra0 xxx0 0000 uuu0 0000 85h trisa trisa7 trisa6 trisa5 porta data direction register 1111 1111 1111 1111 9fh adcon1 adfm adcs2 ? ? pcfg3 pcfg2 pcfg1 pcfg0 00-- 0000 00-- 0000 legend: x = unknown, u = unchanged, - = unimplemented locations read as ? 0 ?. shaded cells are not used by porta. note 1: porta pin 5 is an input only; the state of the trisa5 bit has no effect and will always read ? 1 ?.
pic16f818/819 ds39598d-page 40 preliminary ? 2003 microchip technology inc. figure 5-1: block diagram of ra0/an0:ra1/an1 pins figure 5-2: block diagram of ra3/an3/v ref + pin figure 5-3: block diagram of ra2/an2/v ref - pin figure 5-4: block diagram of ra4/an4/t0cki pin data bus q d q ck p n wr porta wr trisa data latch tris latch rd trisa rd porta analog v ss v dd i/o pin q d q ck input mode d q en ttl input buffer v dd to a/d module channel input v ss data bus q d q ck p n wr porta wr trisa data latch tris latch rd trisa rd porta analog v ss v dd i/o pin q d q ck input mode d q en v dd to a/d module channel input to a/d module v ref + input v ss ttl input buffer data bus q d q ck p n wr porta wr trisa data latch tris latch rd trisa rd porta analog v ss v dd i/o pin q d q ck input mode d q en v dd to a/d module channel input to a/d module v ref - input v ss ttl input buffer data bus q d q ck p n wr porta wr trisa data latch tris latch rd trisa rd porta analog v ss v dd i/o pin q d q ck input mode d q en v dd to a/d module channel input tmr0 clock input v ss schmitt trigger input buffer
? 2003 microchip technology inc. preliminary ds39598d-page 41 pic16f818/819 figure 5-5: block diagram of ra5/mclr /v pp pin figure 5-6: block diagra m of ra6/osc2/clko pin d q en mclr filter ra5/mclr /v pp rd port mclr circuit mclre mclre data bus rd tris schmitt trigger buffer v ss v ss schmitt trigger input buffer data bus q d q ck p n wr porta wr trisa data latch tris latch rd trisa rd porta v ss v dd ra6/osc2/clko q d q ck d q en oscillator circuit from osc1 (f osc = 1x0,011 ) p n v ss v dd clko (f osc /4) v dd note 1: i/o pins have protection diodes to v dd and v ss . 2: clko signal is 1/4 of the f osc frequency. (f osc = 1x1 ) v ss schmitt trigger input buffer (f osc = 1x0,011 )
pic16f818/819 ds39598d-page 42 preliminary ? 2003 microchip technology inc. figure 5-7: block diagra m of ra7/osc1/clki pin data bus q d q ck wr porta wr trisa data latch tris latch rd trisa rd porta q d q ck d q en oscillator circuit ra7/osc1/clki p n v ss v dd f osc = 10x v dd note 1: i/o pins have protection diodes to v dd and v ss . (f osc = 011 ) f osc = 10x from osc2 v ss schmitt trigger input buffer
? 2003 microchip technology inc. preliminary ds39598d-page 43 pic16f818/819 5.2 portb and the trisb register portb is an 8-bit wide, bidirectional port. the corre- sponding data direction register is trisb. setting a trisb bit (= 1 ) will make the corresponding portb pin an input (i.e., put the corresponding output driver in a high-impedance mode). clearing a trisb bit (= 0 ) will make the corresponding portb pin an output (i.e., put the contents of the output latch on the selected pin). each of the portb pins has a weak internal pull-up. a single control bit can turn on all the pull-ups. this is per- formed by clearing bit rbpu (option<7>). the weak pull-up is automatically turned off when the port pin is configured as an output. the pull-ups are disabled on a power-on reset. four of portb?s pins, rb7:rb4, have an interrupt-on- change feature. only pins configured as inputs can cause this interrupt to occur (i.e., any rb7:rb4 pin configured as an output is excluded from the interrupt- on-change comparison). the input pins (of rb7:rb4) are compared with the old value latched on the last read of portb. the ?mismatch? outputs of rb7:rb4 are or?d together to generate the rb port change interrupt with flag bit, rbif (intcon<0>). this interrupt can wake the device from sleep. the user, in the interrupt service routine, can clear the interrupt in the following manner: a) any read or write of portb. this will end the mismatch condition. b) clear flag bit rbif. a mismatch condition will continue to set flag bit rbif. reading portb will end the mismatch condition and allow flag bit rbif to be cleared. the interrupt-on-change feature is recommended for wake-up on key depression operation and operations where portb is only used for the interrupt-on-change feature. polling of portb is not recommended while using the interrupt-on-change feature. rb0/int is an external interrupt input pin and is configured using the intedg bit (option<6>). portb is multiplexed with several peripheral functions (see table 5-3). portb pins have schmitt trigger input buffers. when enabling peripheral functions, care should be taken in defining tris bits for each portb pin. some peripherals override the tris bit to make a pin an out- put, while other peripherals override the tris bit to make a pin an input. since the tris bit override is in effect while the peripheral is enabled, read-modify- write instructions ( bsf, bcf, xorwf ) with trisb as destination should be avoided. the user should refer to the corresponding peripheral section for the correct tris bit settings.
pic16f818/819 ds39598d-page 44 preliminary ? 2003 microchip technology inc. table 5-3: portb functions table 5-4: summary of registers associated with portb name bit# buffer function rb0/int bit 0 ttl/st (1) input/output pin or external interrupt input. internal software programmable weak pull-up. rb1/sdi/sda bit 1 ttl/st (5) input/output pin, spi data input pin or i 2 c data i/o pin. internal software programmable weak pull-up. rb2/sdo/ccp1 bit 2 ttl/st (4) input/output pin, spi data output pin or capture input/compare output/pwm output pin. internal software programmable weak pull-up. rb3/ccp1/pgm (3) bit 3 ttl/st (2) input/output pin, capture input/compare output/pwm output pin or programming in lvp mode. internal software programmable weak pull-up. rb4/sck/scl bit 4 ttl/st (5) input/output pin or spi and i 2 c clock pin (with interrupt-on-change). internal software programmable weak pull-up. rb5/ss bit 5 ttl input/output pin or spi slave select pin (with interrupt-on-change). internal software programmable weak pull-up. rb6/t1oso/t1cki/ pgc bit 6 ttl/st (2) input/output pin, timer1 oscillator output pin, timer1 clock input pin or serial programming clock (with interrupt-on-change). internal software programmable weak pull-up. rb7/t1osi/pgd bit 7 ttl/st (2) input/output pin, timer1 oscillator input pin or serial programming data (with interrupt-on-change). internal software programmable weak pull-up. legend: ttl = ttl input, st = schmitt trigger input note 1: this buffer is a schmitt trigger input when configured as the external interrupt. 2: this buffer is a schmitt trigger input when used in serial programming mode. 3: low-voltage icsp programming (lvp) is enabled by default which disables the rb3 i/o function. lvp must be disabled to enable rb3 as an i/o pin and allow maximum compatibility to the other 18-pin mid-range devices. 4: this buffer is a schmitt trigger input when configured for ccp or ssp mode. 5: this buffer is a schmitt trigger input when configured for spi or i 2 c mode. address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 06h, 106h portb rb7 rb6 rb5 rb4 rb3 rb2 rb1 rb0 xxxx xxxx uuuu uuuu 86h, 186h trisb portb data direction register 1111 1111 1111 1111 81h, 181h option rbpu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 1111 1111 legend: x = unknown, u = unchanged. shaded cells are not used by portb.
? 2003 microchip technology inc. preliminary ds39598d-page 45 pic16f818/819 figure 5-8: block diagram of rb0 pin note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. data latch rbpu (2) p v dd q d ck q d ck q d en data bus wr wr rd trisb rd portb weak pull-up rd portb i/o pin (1) ttl input buffer tris latch to int0 or ccp portb trisb
pic16f818/819 ds39598d-page 46 preliminary ? 2003 microchip technology inc. figure 5-9: block diagram of rb1 pin data latch rbpu (2) p v dd q d ck q d ck q d en data bus wr wr rd trisb rd portb weak pull-up rd portb sda (3) i/o pin (1) ttl input buffer schmitt trigger buffer tris latch note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropr iate tris bit(s) and clear the rbpu bit. 3: the sda schmitt conforms to the i 2 c specification. 1 0 sda output p n v ss v dd q sda drive port /sspen select i 2 c mode sdi portb trisb
? 2003 microchip technology inc. preliminary ds39598d-page 47 pic16f818/819 figure 5-10: block diagram of rb2 pin data latch rbpu (2) p v dd q d ck q d ck q d en data bus wr wr rd trisb rd portb weak pull-up rd portb i/o pin (1) ttl input buffer tris latch note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. 0 1 0 1 ccpmx ccp sdo module select portb trisb
pic16f818/819 ds39598d-page 48 preliminary ? 2003 microchip technology inc. figure 5-11: block diagram of rb3 pin data latch rbpu (2) p v dd q d ck q d ck q d en data bus wr wr rd trisb rd portb weak pull-up rd portb i/o pin (1) ttl input buffer tris latch portb note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. 0 1 ccp to pgm or ccp ccp1 = 1000,1001,11xx and ccpmx = 0 ccp1 = 0100, 0101, 0110, 0111 and ccpmx = 0 or lvp = 1 trisb
? 2003 microchip technology inc. preliminary ds39598d-page 49 pic16f818/819 figure 5-12: block diagram of rb4 pin data latch from other rbpu (2) p v dd i/o pin (1) q d ck q d ck qd en qd en data bus wr wr set rbif tris latch rd trisb rd portb rb7:rb4 pins weak pull-up rd portb latch ttl input buffer q3 q1 portb note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. 3: the scl schmitt conforms to the i 2 c specification. sck sck/scl 1 0 port /sspen scl (3) p n v ss v dd scl drive trisb
pic16f818/819 ds39598d-page 50 preliminary ? 2003 microchip technology inc. figure 5-13: block diagram of rb5 pin data latch from other rbpu (2) p v dd i/o pin (1) q d ck q d ck qd en qd en data bus wr wr set rbif tris latch rd trisb rd portb rb7:rb4 pins weak pull-up rd portb latch q3 q1 portb ss port /sspen note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. trisb ttl input buffer
? 2003 microchip technology inc. preliminary ds39598d-page 51 pic16f818/819 figure 5-14: block diagram of rb6 pin data latch from other rbpu (2) p v dd i/o pin (1) q d ck q d ck qd en qd en data bus wr wr set rbif tris latch rd trisb rd portb rb7:rb4 pins weak pull-up rd portb latch q3 q1 portb note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. pgc/t1cki t1oscen/icd/ from t1osco output ttl input buffer t1oscen trisb program mode
pic16f818/819 ds39598d-page 52 preliminary ? 2003 microchip technology inc. figure 5-15: block diagram of rb7 pin data latch from other rbpu (2) p v dd i/o pin (1) q d ck q d ck qd en qd en data bus wr t1oscen set rbif tris latch rd trisb rd portb rb7:rb4 pins weak pull-up rd portb latch q3 q1 portb note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit. pgd pgd 1 0 port /program mode/icd analog ttl input buffer input mode to t1osci input 1 0 pgd drven t1oscen wr trisb
? 2003 microchip technology inc. preliminary ds39598d-page 53 pic16f818/819 6.0 timer0 module the timer0 module timer/counter has the following features: 8-bit timer/counter readable and writable 8-bit software programmable prescaler internal or external clock select interrupt on overflow from ffh to 00h edge select for external clock additional information on the timer0 module is available in the picmicro ? mid-range mcu family reference manual (ds33023). figure 6-1 is a block diagram of the timer0 module and the prescaler shared with the wdt. 6.1 timer0 operation timer0 operation is controlled through the option reg- ister (see register 2-2). timer mode is selected by clearing bit t0cs (option<5>). in timer mode, the timer0 module will increment every instruction cycle (without prescaler). if the tmr0 register is written, the increment is inhibited for the following two instruction cycles. the user can work around this by writing an adjusted value to the tmr0 register. counter mode is selected by setting bit t0cs (option<5>). in counter mode, timer0 will increment either on every rising or falling edge of pin ra4/an4/ t0cki. the incrementing edge is determined by the timer0 source edge select bit, t0se (option<4>). clearing bit t0se selects the rising edge. restrictions on the external clock input are discussed in detail in section 6.3 ?using timer0 with an external clock? . the prescaler is mutually exclusively shared between the timer0 module and the watchdog timer. the prescaler is not readable or writable. section 6.4 ?prescaler? details the operation of the prescaler. 6.2 timer0 interrupt the tmr0 interrupt is generated when the tmr0 reg- ister overflows from ffh to 00h. this overflow sets bit, tmr0if (intcon<2>). the interrupt can be masked by clearing bit, tmr0ie (intcon<5>). bit tmr0if must be cleared in software by the timer0 module interrupt service routine before re-enabling this inter- rupt. the tmr0 interrupt cannot awaken the processor from sleep since the timer is shut-off during sleep. figure 6-1: block diagram of the timer0/wdt prescaler ra4/t0cki t0se pin m u x clko (= f osc /4) sync 2 cycles tmr0 reg 8-bit prescaler 8 - to - 1mux m u x m u x 31.25 khz wdt timer psa 0 1 0 1 wdt time-out ps2:ps0 8 note: t0cs, t0se, psa, ps2:ps0 are (option<5:0>). psa wdt enable bit m u x 0 1 0 1 data bus set flag bit tmr0if on overflow 8 psa t0cs prescaler
pic16f818/819 ds39598d-page 54 preliminary ? 2003 microchip technology inc. 6.3 using timer0 with an external clock when no prescaler is used, the external clock input is the same as the prescaler output. the synchronization of t0cki with the internal phase clocks is accom- plished by sampling the prescaler output on the q2 and q4 cycles of the internal phase clocks. therefore, it is necessary for t0cki to be high for at least 2 t osc (and a small rc delay of 20 ns) and low for at least 2 t osc (and a small rc delay of 20 ns). refer to the electrical specification of the desired device. 6.4 prescaler there is only one prescaler available which is mutually exclusively shared between the timer0 module and the watchdog timer. a prescaler assignment for the timer0 module means that there is no prescaler for the watchdog timer and vice versa. this prescaler is not readable or writable (see figure 6-1). the psa and ps2:ps0 bits (option<3:0>) determine the prescaler assignment and prescale ratio. when assigned to the timer0 module, all instructions writing to the tmr0 register (e.g., clrf 1, movwf 1, bsf 1,x ....etc.) will clear the prescaler. when assigned to wdt, a clrwdt instruction will clear the prescaler along with the watchdog timer. the prescaler is not readable or writable. register 6-1: option_reg register note: writing to tmr0 when the prescaler is assigned to timer0 will clear the prescaler count but will not change the prescaler assignment. r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 rbpu intedg t0cs t0se psa ps2 ps1 ps0 bit 7 bit 0 bit 7 rbpu bit 6 intedg bit 5 t0cs : tmr0 clock source select bit 1 = transition on t0cki pin 0 = internal instruction cycle clock (clko) bit 4 t0se : tmr0 source edge select bit 1 = increment on high-to-low transition on t0cki pin 0 = increment on low-to-high transition on t0cki pin bit 3 psa : prescaler assignment bit 1 = prescaler is assigned to the wdt 0 = prescaler is assigned to the timer0 module bit 2-0 ps2:ps0 : prescaler rate select bits legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown note: to avoid an unintended device reset, the instruction sequence shown in the picmicro ? mid-range mcu family reference manual (ds33023) must be exe- cuted when changing the prescaler assignment from timer0 to the wdt. this sequence must be followed even if the wdt is disabled. 000 001 010 011 100 101 110 111 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 1 : 1 1 : 2 1 : 4 1 : 8 1 : 16 1 : 32 1 : 64 1 : 128 bit value tmr0 rate wdt rate
? 2003 microchip technology inc. preliminary ds39598d-page 55 pic16f818/819 example 6-1: changing the prescaler assignment from timer0 to wdt example 6-2: changing the prescaler assignment from wdt to timer0 table 6-1: registers associated with timer0 banksel option ; select bank of option movlw b'xx0x0xxx' ; select clock source and prescale value of movwf option ; other than 1:1 banksel tmr0 ; select bank of tmr0 clrf tmr0 ; clear tmr0 and prescaler banksel option ; select bank of option movlw b'xxxx1xxx' ; select wdt, do not change prescale value movwf option clrwdt ; clears wdt and prescaler movlw b'xxxx1xxx' ; select new prescale value and wdt movwf option clrwdt ; clear wdt and prescaler banksel option ; select bank of option movlw b'xxxx0xxx' ; select tmr0, new prescale movwf option ; value and clock source address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 01h,101h tmr0 timer0 module register xxxx xxxx uuuu uuuu 0bh,8bh, 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 81h,181h option rbpu intedg t0cs t0se psa ps2 ps1 ps0 1111 1111 1111 1111 legend: x = unknown, u = unchanged, - = unimplemented locations read as ? 0 ?. shaded cells are not used by timer0.
pic16f818/819 ds39598d-page 56 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 57 pic16f818/819 7.0 timer1 module the timer1 module is a 16-bit timer/counter consisting of two 8-bit registers (tmr1h and tmr1l) which are readable and writable. the tmr1 register pair (tmr1h:tmr1l) increments from 0000h to ffffh and rolls over to 0000h. the tmr1 interrupt, if enabled, is generated on overflow which is latched in interrupt flag bit, tmr1if (pir1<0>). this interrupt can be enabled/disabled by setting/clearing tmr1 interrupt enable bit, tmr1ie (pie1<0>). timer1 can also be used to provide real-time clock (rtc) functionality to applications with only a minimal addition of external components and code overhead. 7.1 timer1 operation timer1 can operate in one of three modes: as a timer as a synchronous counter as an asynchronous counter the operating mode is determined by the clock select bit, tmr1cs (t1con<1>). in timer mode, timer1 increments every instruction cycle. in counter mode, it increments on every rising edge of the external clock input. timer1 can be enabled/disabled by setting/clearing control bit, tmr1on (t1con<0>). timer1 also has an internal ?reset input?. this reset can be generated by the ccp1 module as the special event trigger (see section 9.1 ?capture mode? ). register 7-1 shows the timer1 control register. when the timer1 oscillator is enabled (t1oscen is set), the rb6/t1oso/t1cki/pgc and rb7/t1osi/ pgd pins become inputs. that is, the trisb<7:6> value is ignored and these pins read as ? 0 ?. additional information on timer modules is available in the picmicro ? mid-range mcu family reference manual (ds33023). register 7-1: t1con: timer1 control regist er (address 10h) u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on bit 7 bit 0 bit 7-6 unimplemented: read as ? 0 ? bit 5-4 t1ckps1:t1ckps0: timer1 input clock prescale select bits 11 = 1:8 prescale value 10 = 1:4 prescale value 01 = 1:2 prescale value 00 = 1:1 prescale value bit 3 t1oscen: timer1 oscillator enable control bit 1 = oscillator is enabled 0 = oscillator is shut-off (the oscillator inverter is turned off to eliminate power drain) bit 2 t1sync : timer1 external clock input synchronization control bit tmr1cs = 1 : 1 = do not synchronize external clock input 0 = synchronize external clock input tmr1cs = 0 : this bit is ignored. timer1 uses the internal clock when tmr1cs = 0 . bit 1 tmr1cs: timer1 clock source select bit 1 = external clock from pin rb6/t1oso/t1cki/pgc (on the rising edge) 0 = internal clock (f osc /4) bit 0 tmr1on: timer1 on bit 1 = enables timer1 0 = stops timer1 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
pic16f818/819 ds39598d-page 58 preliminary ? 2003 microchip technology inc. 7.2 timer1 operation in timer mode timer mode is selected by clearing the tmr1cs (t1con<1>) bit. in this mode, the input clock to the timer is f osc /4. the synchronize control bit, t1sync (t1con<2>), has no effect since the internal clock is always in sync. 7.3 timer1 counter operation timer1 may operate in asynchronous or synchronous mode depending on the setting of the tmr1cs bit. when timer1 is being incremented via an external source, increments occur on a rising edge. after timer1 is enabled in counter mode, the module must first have a falling edge before the counter begins to increment. 7.4 timer1 operation in synchronized counter mode counter mode is selected by setting bit tmr1cs. in this mode, the timer increments on every rising edge of clock input on pin rb7/t1osi/pgd when bit t1oscen is set, or on pin rb6/t1oso/t1cki/pgc when bit t1oscen is cleared. if t1sync is cleared, then the external clock input is synchronized with internal phase clocks. the synchro- nization is done after the prescaler stage. the prescaler stage is an asynchronous ripple counter. in this configuration, during sleep mode, timer1 will not increment even if the external clock is present, since the synchronization circuit is shut-off. the prescaler however, will continue to increment. figure 7-1: timer1 incrementing edge figure 7-2: timer1 block diagram t1cki (default high) t1cki (default low) note: arrows indicate counter increments. tmr1h tmr1l t1osc t1sync tmr1cs t1ckps1:t1ckps0 q clock t1oscen enable oscillator (1) f osc /4 internal clock tmr1on on/off prescaler 1, 2, 4, 8 synchronize det 1 0 0 1 synchronized clock input 2 rb7/t1osi/pgd rb6/t1oso/t1cki/pgc note 1: when the t1oscen bit is cleared, the inverter is turned off. this e liminates power drain. set flag bit tmr1if on overflow tmr1
? 2003 microchip technology inc. preliminary ds39598d-page 59 pic16f818/819 7.5 timer1 operation in asynchronous counter mode if control bit, t1sync (t1con<2>), is set, the external clock input is not synchronized. the timer continues to increment asynchronous to the internal phase clocks. the timer will continue to run during sleep and can generate an interrupt on overflow that will wake-up the processor. however, special precautions in software are needed to read/write the timer. in asynchronous counter mode, timer1 cannot be used as a time base for capture or compare operations. 7.5.1 reading and writing timer1 in asynchronous counter mode reading tmr1h or tmr1l while the timer is running from an external asynchronous clock will ensure a valid read (taken care of in hardware). however, the user should keep in mind that reading the 16-bit timer in two 8-bit values itself poses certain problems, since the timer may overflow between the reads. for writes, it is recommended that the user simply stop the timer and write the desired values. a write conten- tion may occur by writing to the timer registers while the register is incrementing. this may produce an unpredictable value in the timer register. reading the 16-bit value requires some care. the example codes provided in example 7-1 and example 7-2 demonstrate how to write to and read timer1 while it is running in asynchronous mode. example 7-1: writing a 16-bit free running timer example 7-2: reading a 16-bit free running timer ; all interrupts are disabled clrf tmr1l ; clear low byte, ensures no rollover into tmr1h movlw hi_byte ; value to load into tmr1h movwf tmr1h, f ; write high byte movlw lo_byte ; value to load into tmr1l movwf tmr1h, f ; write low byte ; re-enable the interrupt (if required) continue ; continue with your code ; all interrupts are disabled movf tmr1h, w ; read high byte movwf tmph movf tmr1l, w ; read low byte movwf tmpl movf tmr1h, w ; read high byte subwf tmph, w ; sub 1st read with 2nd read btfsc status,z ; is result = 0 goto continue ; good 16-bit read ; tmr1l may have rolled over between the read of the high and low bytes. ; reading the high and low bytes now will read a good value. movf tmr1h, w ; read high byte movwf tmph movf tmr1l, w ; read low byte movwf tmpl ; re-enable the interrupt (if required) continue ; continue with your code
pic16f818/819 ds39598d-page 60 preliminary ? 2003 microchip technology inc. 7.6 timer1 oscillator a crystal oscillator circuit is built between pins t1osi (input) and t1oso (amplifier output). it is enabled by setting control bit, t1oscen (t1con<3>). the oscil- lator is a low-power oscillator, rated up to 32.768 khz. it will continue to run during sleep. it is primarily intended for a 32 khz crystal. the circuit for a typical lp oscillator is shown in figure 7-3. table 7-1 shows the capacitor selection for the timer1 oscillator. the user must provide a software time delay to ensure proper oscillator start-up. figure 7-3: external components for the timer1 lp oscillator table 7-1: capacitor selection for the timer1 oscillator 7.7 timer1 oscillator layout considerations the timer1 oscillator circuit draws very little power during operation. due to the low-power nature of the oscillator, it may also be sensitive to rapidly changing signals in close proximity. the oscillator circuit, shown in figure 7-3, should be located as close as possible to the microcontroller. there should be no circuits passing within the oscillator circuit boundaries other than v ss or v dd . if a high-speed circuit must be located near the oscilla- tor, a grounded guard ring around the oscillator circuit, as shown in figure 7-4, may be helpful when used on a single sided pcb or in addition to a ground plane. figure 7-4: oscillator circuit with grounded guard ring 7.8 resetting timer1 using a ccp trigger output if the ccp1 module is configured in compare mode to generate a ?special event trigger? signal (ccp1m3:ccp1m0 = 1011 ), the signal will reset timer1 and start an a/d conversion (if the a/d module is enabled). timer1 must be configured for either timer or synchro- nized counter mode to take advantage of this feature. if timer1 is running in asynchronous counter mode, this reset operation may not work. in the event that a write to timer1 coincides with a special event trigger from ccp1, the write will take precedence. in this mode of operation, the ccpr1h:ccpr1l register pair effectively becomes the period register for timer1. osc type freq c1 c2 lp 32 khz 33 pf 33 pf note 1: microchip suggests this value as a starting point in validating the oscillator circuit. 2: higher capacitance increases the stability of the oscillator but also increases the start-up time. 3: since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropriate values of external components. 4: capacitor values are for design guidance only. pic16f818/819 t1osi t1oso c2 33 pf c1 33 pf xtal 32.768 khz note: see the notes with table 7-1 for additional information about capacitor selection. osc1 v ss osc2 rb7 rb6 rb5
? 2003 microchip technology inc. preliminary ds39598d-page 61 pic16f818/819 7.9 resetting timer1 register pair (tmr1h, tmr1l) tmr1h and tmr1l registers are not reset to 00h on a por or any other reset, except by the ccp1 special event triggers. t1con register is reset to 00h on a power-on reset or a brown-out reset, which shuts off the timer and leaves a 1:1 prescale. in all other resets, the register is unaffected. 7.10 timer1 prescaler the prescaler counter is cleared on writes to the tmr1h or tmr1l registers. 7.11 using timer1 as a real-time clock adding an external lp oscillator to timer1 (such as the one described in section 7.6 ?timer1 oscillator? ), gives users the option to include rtc functionality to their applications. this is accomplished with an inex- pensive watch crystal to provide an accurate time base, and several lines of application code to calculate the time. when operating in sleep mode and using a battery or supercapacitor as a power source, it can completely eliminate the need for a separate rtc device and battery backup. the application code routine, rtcisr , shown in example 7-3, demonstrates a simple method to increment a counter at one-second intervals using an interrupt service routine. incrementing the tmr1 reg- ister pair to overflow, triggers the interrupt and calls the routine which increments the seconds counter by one; additional counters for minutes and hours are incremented as the previous counter overflow. since the register pair is 16 bits wide, counting up to overflow the register directly from a 32.768 khz clock would take 2 seconds. to force the overflow at the required one-second intervals, it is necessary to pre- load it; the simplest method is to set the msbit of tmr1h with a bsf instruction. note that the tmr1l register is never preloaded or altered; doing so may introduce cumulative error over many cycles. for this method to be accurate, timer1 must operate in asynchronous mode and the timer1 overflow interrupt must be enabled (pie1<0> = 1 ) as shown in the routine, rtcinit . the timer1 oscillator must also be enabled and running at all times.
pic16f818/819 ds39598d-page 62 preliminary ? 2003 microchip technology inc. example 7-3: implementing a real-time clock using a timer1 interrupt service table 7-2: registers associated with timer1 as a timer/counter rtcinit banksel tmr1h movlw 0x80 ; preload tmr1 register pair movwf tmr1h ; for 1 second overflow clrf tmr1l movlw b?00001111? ; configure for external clock, movwf t1con ; asynchronous operation, external oscillator clrf secs ; initialize timekeeping registers clrf mins movlw .12 movwf hours banksel pie1 bsf pie1, tmr1ie ; enable timer1 interrupt return rtcisr banksel tmr1h bsf tmr1h, 7 ; preload for 1 sec overflow bcf pir1, tmr1if ; clear interrupt flag incf secs, f ; increment seconds movf secs, w sublw .60 btfss status, z ; 60 seconds elapsed? return ; no, done clrf seconds ; clear seconds incf mins, f ; increment minutes movf mins, w sublw .60 btfss status, z ; 60 seconds elapsed? return ; no, done clrf mins ; clear minutes incf hours, f ; increment hours movf hours, w sublw .24 btfss status, z ; 24 hours elapsed? return ; no, done clrf hours ; clear hours return ; done address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh,8bh, 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ? adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ? adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 0eh tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 0fh tmr1h holding register for the most significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 10h t1con ? ? t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on --00 0000 --uu uuuu legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?. shaded cells are not used by the timer1 module.
? 2003 microchip technology inc. preliminary ds39598d-page 63 pic16f818/819 8.0 timer2 module timer2 is an 8-bit timer with a prescaler and a postscaler. it can be used as the pwm time base for the pwm mode of the ccp1 module. the tmr2 register is readable and writable and is cleared on any device reset. the input clock (f osc /4) has a prescale option of 1:1, 1:4 or 1:16, selected by control bits, t2ckps1:t2ckps0 (t2con<1:0>). the timer2 module has an 8-bit period register, pr2. timer2 increments from 00h until it matches pr2 and then resets to 00h on the next increment cycle. pr2 is a readable and writable register. the pr2 register is initialized to ffh upon reset. the match output of tmr2 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a tmr2 interrupt (latched in flag bit, tmr2if (pir1<1>)). timer2 can be shut-off by clearing control bit, tmr2on (t2con<2>), to minimize power consumption. register 8-1 shows the timer2 control register. additional information on timer modules is available in the picmicro ? mid-range mcu family reference manual (ds33023). 8.1 timer2 prescaler and postscaler the prescaler and postscaler counters are cleared when any of the following occurs: a write to the tmr2 register a write to the t2con register any device reset (power-on reset, mclr , wdt reset or brown-out reset) tmr2 is not cleared when t2con is written. 8.2 output of tmr2 the output of tmr2 (before the postscaler) is fed to the synchronous serial port module which optionally uses it to generate a shift clock. figure 8-1: timer2 block diagram comparator tmr2 sets flag tmr2 reg output (1) reset postscaler prescaler pr2 reg 2 f osc /4 1:1 1:16 1:1, 1:4, 1:16 eq 4 bit tmr2if note 1: tmr2 register output can be software selected by the ssp module as a baud clock. to
pic16f818/819 ds39598d-page 64 preliminary ? 2003 microchip technology inc. register 8-1: t2con: timer2 control regist er (address 12h) table 8-1: registers associated with timer2 as a timer/counter u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 bit 7 bit 0 bit 7 unimplemented: read as ? 0 ? bit 6-3 toutps3:toutps0: timer2 output postscale select bits 0000 = 1:1 postscale 0001 = 1:2 postscale 0010 = 1:3 postscale 1111 = 1:16 postscale bit 2 tmr2on: timer2 on bit 1 = timer2 is on 0 = timer2 is off bit 1-0 t2ckps1:t2ckps0: timer2 clock prescale select bits 00 = prescaler is 1 01 = prescaler is 4 1x = prescaler is 16 legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh, 8bh, 10bh, 18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ? adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ? adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 11h tmr2 timer2 module register 0000 0000 0000 0000 12h t2con ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 92h pr2 timer2 period register 1111 1111 1111 1111 legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?. shaded cells are not used by the timer2 module.
? 2003 microchip technology inc. preliminary ds39598d-page 65 pic16f818/819 9.0 capture/compare/pwm (ccp) module the capture/compare/pwm (ccp) module contains a 16-bit register that can operate as a: 16-bit capture register 16-bit compare register pwm master/slave duty cycle register table 9-1 shows the timer resources of the ccp module modes. capture/compare/pwm register 1 (ccpr1) is com- prised of two 8-bit registers: ccpr1l (low byte) and ccpr1h (high byte). the ccp1con register controls the operation of ccp1. the special event trigger is generated by a compare match which will reset timer1 and start an a/d conversion (if the a/d module is enabled). the ccp module?s input/output pin (ccp1) can be configured as rb2 or rb3. this selection is set in bit 12 (ccpmx) of the configuration word register. additional information on the ccp module is available in the picmicro ? mid-range mcu family reference manual (ds33023) and in application note an594, ? using the ccp module(s)? (ds00594). table 9-1: ccp mode ? timer resource register 9-1: ccp1con: capture/compare/pwm control register 1 (address 17h) ccp mode timer resource capture compare pwm timer1 timer1 timer2 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 ? ? ccp1x ccp1y ccp1m3 ccp1m2 ccp1m1 ccp1m0 bit 7 bit 0 bit 7-6 unimplemented: read as ? 0 ? bit 5-4 ccp1x:ccp1y: pwm least significant bits capture mode: unused. compare mode: unused. pwm mode: these bits are the two lsbs of the pwm duty cycle. the eight msbs are found in ccprxl. bit 3-0 ccp1m3:ccp1m0: ccp1 mode select bits 0000 = capture/compare/pwm disabled (resets ccp1 module) 0100 = capture mode, every falling edge 0101 = capture mode, every rising edge 0110 = capture mode, every 4th rising edge 0111 = capture mode, every 16th rising edge 1000 = compare mode, set output on match (ccp1if bit is set) 1001 = compare mode, clear output on match (ccp1if bit is set) 1010 = compare mode, generate software interrupt on match (ccp1if bit is set, ccp1 pin is unaffected) 1011 = compare mode, trigger special event (ccp1if bit is set, ccp1 pin is unaffected); ccp1 resets tmr1 and starts an a/d conversion (if a/d module is enabled) 11xx =pwm mode legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
pic16f818/819 ds39598d-page 66 preliminary ? 2003 microchip technology inc. 9.1 capture mode in capture mode, ccpr1h:ccpr1l captures the 16-bit value of the tmr1 register when an event occurs on ccp1 pin. an event is defined as: every falling edge every rising edge every 4th rising edge every 16th rising edge an event is selected by control bits, ccp1m3:ccp1m0 (ccp1con<3:0>). when a capture is made, the inter- rupt request flag bit, ccp1if (pir1<2>), is set. it must be cleared in software. if another capture occurs before the value in register ccpr1 is read, the old captured value is overwritten by the new captured value. 9.1.1 ccp pin configuration in capture mode, the ccp1 pin should be configured as an input by setting the trisb bit. figure 9-1: capture mode operation block diagram 9.1.2 timer1 mode selection timer1 must be running in timer mode or synchro- nized counter mode for the ccp module to use the capture feature. in asynchronous counter mode, the capture operation may not work. 9.1.3 software interrupt when the capture mode is changed, a false capture interrupt may be generated. the user should keep bit, ccp1ie (pie1<2>), clear to avoid false interrupts and should clear the flag bit, ccp1if, following any such change in operating mode. 9.1.4 ccp prescaler there are four prescaler settings specified by bits ccp1m3:ccp1m0. whenever the ccp module is turned off, or the ccp module is not in capture mode, the prescaler counter is cleared. this means that any reset will clear the prescaler counter. switching from one capture prescaler to another may generate an interrupt. also, the prescaler counter will not be cleared, therefore, the first capture may be from a non-zero prescaler. example 9-1 shows the recommended method for switching between capture prescalers. this example also clears the prescaler counter and will not generate the ?false? interrupt. example 9-1: changing between capture prescalers note 1: if the ccp1 pin is configured as an output, a write to the port can cause a capture condition. 2: the trisb bit (2 or 3) is dependent upon the setting of configuration bit 12 (ccpmx). ccpr1h ccpr1l tmr1h tmr1l set flag bit ccp1if (pir1<2>) capture enable q?s ccp1con<3:0> ccp1 pin prescaler 1, 4, 16 and edge detect clrf ccp1con ;turn ccp module off movlw new_capt_ps ;load the w reg with ;the new prescaler ;move value and ccp on movwf ccp1con ;load ccp1con with this ;value
? 2003 microchip technology inc. preliminary ds39598d-page 67 pic16f818/819 9.2 compare mode in compare mode, the 16-bit ccpr1 register value is constantly compared against the tmr1 register pair value. when a match occurs, the ccp1 pin is: driven high driven low remains unchanged the action on the pin is based on the value of control bits, ccp1m3:ccp1m0 (ccp1con<3:0>). at the same time, interrupt flag bit ccp1if is set. figure 9-2: compare mode operation block diagram 9.2.1 ccp pin configuration the user must configure the ccp1 pin as an output by clearing the trisb bit. 9.2.2 timer1 mode selection timer1 must be running in timer mode or synchro- nized counter mode if the ccp module is using the compare feature. in asynchronous counter mode, the compare operation may not work. 9.2.3 software interrupt mode when generate software interrupt is chosen, the ccp1 pin is not affected. only a ccp interrupt is generated (if enabled). 9.2.4 special event trigger in this mode, an internal hardware trigger is generated that may be used to initiate an action. the special event trigger output of ccp1 resets the tmr1 register pair and starts an a/d conversion (if the a/d module is enabled). this allows the ccpr1 regis- ter to effectively be a 16-bit programmable period register for timer1. table 9-2: registers associated with capture, compare and timer1 ccpr1h ccpr1l tmr1h tmr1l comparator qs r output logic special event trigger set flag bit ccp1if (pir1<2>) match ccp1 pin trisb ccp1con<3:0> mode select output enable special event trigger will: reset timer1 but not set interrupt flag bit, tmr1if (pir1<0>) set go/done bit (adcon0<2>) which starts an a/d conversion note 1: clearing the ccp1con register will force the ccp1 compare output latch to the default low level. this is not the data latch. 2: the trisb bit (2 or 3) is dependent upon the setting of configuration bit 12 (ccpmx). note: the special event trigger from the ccp1 module will not set interrupt flag bit, tmr1if (pir1<0>). address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh,8bh 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ? adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ? adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 86h trisb portb data direction register 1111 1111 1111 1111 0eh tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 0fh tmr1h holding register for the most significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu 10h t1con ? ? t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on --00 0000 --uu uuuu 15h ccpr1l capture/compare/pwm register 1 (lsb) xxxx xxxx uuuu uuuu 16h ccpr1h capture/compare/pwm register 1 (msb) xxxx xxxx uuuu uuuu 17h ccp1con ? ? ccp1x ccp1y ccp1m3 ccp1m2 ccp1m1 ccp1m0 --00 0000 --00 0000 legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?. shaded cells are not us ed by capture and timer1.
pic16f818/819 ds39598d-page 68 preliminary ? 2003 microchip technology inc. 9.3 pwm mode in pulse width modulation (pwm) mode, the ccp1 pin produces up to a 10-bit resolution pwm output. since the ccp1 pin is multiplexed with the portb data latch, the trisb bit must be cleared to make the ccp1 pin an output. figure 9-3 shows a simplified block diagram of the ccp module in pwm mode. for a step by step procedure on how to set up the ccp module for pwm operation, see section 9.3.3 ?setup for pwm operation? . figure 9-3: simplified pwm block diagram a pwm output (figure 9-4) has a time base (period) and a time that the output stays high (duty cycle). the frequency of the pwm is the inverse of the period (1/period). figure 9-4: pwm output 9.3.1 pwm period the pwm period is specified by writing to the pr2 register. the pwm period can be calculated using the following formula. equation 9-1: pwm frequency is defined as 1/[pwm period]. when tmr2 is equal to pr2, the following three events occur on the next increment cycle: tmr2 is cleared the ccp1 pin is set (exception: if pwm duty cycle = 0%, the ccp1 pin will not be set) the pwm duty cycle is latched from ccpr1l into ccpr1h 9.3.2 pwm duty cycle the pwm duty cycle is specified by writing to the ccpr1l register and to the ccp1con<5:4> bits. up to 10-bit resolution is available. the ccpr1l contains the eight msbs and the ccp1con<5:4> contains the two lsbs. this 10-bit value is represented by ccpr1l:ccp1con<5:4>. the following equation is used to calculate the pwm duty cycle in time. equation 9-2: ccpr1l and ccp1con<5:4> can be written to at any time but the duty cycle value is not latched into ccpr1h until after a match between pr2 and tmr2 occurs (i.e., the period is complete). in pwm mode, ccpr1h is a read-only register. the ccpr1h register and a 2-bit internal latch are used to double-buffer the pwm duty cycle. this double-buffering is essential for glitchless pwm operation. when the ccpr1h and 2-bit latch match tmr2, concatenated with an internal 2-bit q clock or 2 bits of the tmr2 prescaler, the ccp1 pin is cleared. note: clearing the ccp1con register will force the ccp1 pwm output latch to the default low level. this is not the portb i/o data latch. ccpr1l ccpr1h (slave) comparator tmr2 comparator pr2 (note 1) r q s duty cycle registers ccp1con<5:4> clear timer, ccp1 pin and latch d.c. trisb ccp1 pin note 1: 8-bit timer is concatenated with 2-bit internal q clock or 2 bits of the prescaler to create 10-bit time base. period duty cycle tmr2 = pr2 tmr2 = duty cycle tmr2 = pr2 note: the timer2 postscaler (see section 8.0 ?timer2 module? ) is not used in the determination of the pwm frequency. the postscaler could be used to have a servo update rate at a different frequency than the pwm output. pwm period = [(pr2) + 1] ? 4 t osc (tmr2 prescale value) pwm duty cycle = (ccpr1l:ccp1con<5:4>) t osc (tmr2 prescale value)
? 2003 microchip technology inc. preliminary ds39598d-page 69 pic16f818/819 the maximum pwm resolution (bits) for a given pwm frequency is given by the following formula. equation 9-3: 9.3.3 setup for pwm operation the following steps should be taken when configuring the ccp module for pwm operation: 1. set the pwm period by writing to the pr2 register. 2. set the pwm duty cycle by writing to the ccpr1l register and ccp1con<5:4> bits. 3. make the ccp1 pin an output by clearing the trisb bit. 4. set the tmr2 prescale value and enable timer2 by writing to t2con. 5. configure the ccp1 module for pwm operation. table 9-3: example pwm frequencies and resolutions at 20 mhz table 9-4: registers associated with pwm and timer2 note: if the pwm duty cycle value is longer than the pwm period, the ccp1 pin will not be cleared. log ( f pwm log(2) f osc ) bits = resolution note: the trisb bit (2 or 3) is dependant upon the setting of configuration bit 12 (ccpmx). pwm frequency 1.22 khz 4.88 khz 19.53 khz 78.12 khz 156.3 khz 208.3 khz timer prescaler (1, 4, 16) 16 4 1 1 1 1 pr2 value 0xff 0xff 0xff 0x3f 0x1f 0x17 maximum resolution (bits) 10 10 10 8 7 5.5 address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh,8bh 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ? adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ? adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 86h trisb portb data direction register 1111 1111 1111 1111 11h tmr2 timer2 module register 0000 0000 0000 0000 92h pr2 timer2 module period register 1111 1111 1111 1111 12h t2con ? toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 15h ccpr1l capture/compare/pwm register 1 (lsb) xxxx xxxx uuuu uuuu 16h ccpr1h capture/compare/pwm register 1 (msb) xxxx xxxx uuuu uuuu 17h ccp1con ? ? ccp1x ccp1y ccp1m3 ccp1m2 ccp1m1 ccp1m0 --00 0000 --00 0000 legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?. shaded cells are not used by pwm and timer2.
pic16f818/819 ds39598d-page 70 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 71 pic16f818/819 10.0 synchronous serial port (ssp) module 10.1 ssp module overview the synchronous serial port (ssp) module is a serial interface useful for communicating with other periph- eral or microcontroller devices. these peripheral devices may be serial eeproms, shift registers, display drivers, a/d converters, etc. the ssp module can operate in one of two modes: serial peripheral interface (spi) inter-integrated circuit (i 2 c) an overview of i 2 c operations and additional informa- tion on the ssp module can be found in the picmicro ? mid-range mcu family reference manual (ds33023). refer to application note an578, ?use of the ssp module in the i 2 c multi-master environment? (ds00578). 10.2 spi mode this section contains register definitions and operational characteristics of the spi module. spi mode allows 8 bits of data to be synchronously transmitted and received simultaneously. to accomplish communication, typically three pins are used: serial data out (sdo) rb2/sdo/ccp1 serial data in (sdi) rb1/sdi/sda serial clock (sck) rb4/sck/scl additionally, a fourth pin may be used when in a slave mode of operation: slave select (ss ) rb5/ss when initializing the spi, several options need to be specified. this is done by programming the appropriate control bits in the sspcon register (sspcon<5:0>) and the sspstat register (sspstat<7:6>). these control bits allow the following to be specified: master mode (sck is the clock output) slave mode (sck is the clock input) clock polarity (idle state of sck) clock edge (output data on rising/falling edge of sck) clock rate (master mode only) slave select mode (slave mode only)
pic16f818/819 ds39598d-page 72 preliminary ? 2003 microchip technology inc. register 10-1: sspstat: synchronous serial port stat us register (address 94h) r/w-0 r/w-0 r-0 r-0 r-0 r-0 r-0 r-0 smp cke d/a psr/w ua bf bit 7 bit 0 bit 7 smp: spi data input sample phase bit spi master mode: 1 = input data sampled at end of data output time 0 = input data sampled at middle of data output time (microwire) spi slave mode: this bit must be cleared when spi is used in slave mode. i 2 c mode: this bit must be maintained clear. bit 6 cke: spi clock edge select bit spi mode, ckp = 0 : 1 = data transmitted on rising edge of sck (microwire alternate) 0 = data transmitted on falling edge of sck spi mode, ckp = 1 : 1 = data transmitted on falling edge of sck (microwire alternate) 0 = data transmitted on rising edge of sck i 2 c mode: this bit must be maintained clear. bit 5 d/a : data/address bit (i 2 c mode only) in i 2 c slave mode: 1 = indicates that the last byte received was data 0 = indicates that the last byte received was address bit 4 p: stop bit (1) (i 2 c mode only) 1 = indicates that a stop bit has been detected last 0 = stop bit was not detected last bit 3 s: start bit (1) (i 2 c mode only) 1 = indicates that a start bit has been detected last (this bit is ? 0 ? on reset) 0 = start bit was not detected last bit 2 r/w : read/write information bit (i 2 c mode only) holds the r/w bit information following the last address match and is only valid from address match to the next start bit, stop bit or ack bit. 1 =read 0 = write bit 1 ua: update address bit (10-bit i 2 c mode only) 1 = indicates that the user needs to update the address in the sspadd register 0 = address does not need to be updated bit 0 bf: buffer full status bit receive (spi and i 2 c modes): 1 = receive complete, sspbuf is full 0 = receive not complete, sspbuf is empty transmit (in i 2 c mode only): 1 = transmit in progress, sspbuf is full (8 bits) 0 = transmit complete, sspbuf is empty note 1: this bit is cleared when the ssp module is disabled (i.e., the sspen bit is cleared). legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
? 2003 microchip technology inc. preliminary ds39598d-page 73 pic16f818/819 register 10-2: sspcon: synchronous serial port control register 1 (address 14h) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 bit 7 bit 0 bit 7 wcol: write collision detect bit 1 = an attempt to write the sspbuf register failed because the ssp module is busy (must be cleared in software) 0 = no collision bit 6 sspov: receive overflow indicator bit in spi mode: 1 = a new byte is received while the sspbuf register is still holding the previous data. in case of overflow, the data in sspsr is lost. overflow can only occur in slave mode. the user must read the sspbuf, even if only transmitting data, to avoid setting overflow. in master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the sspbuf register. 0 = no overflow in i 2 c mode: 1 = a byte is received while the sspbuf register is still holding the previous byte. sspov is a ?don?t care? in transmit mode. sspov must be cleared in software in either mode. 0 = no overflow bit 5 sspen: synchronous serial port enable bit (1) in spi mode: 1 = enables serial port and configures sck, sdo and sdi as serial port pins 0 = disables serial port and configures these pins as i/o port pins in i 2 c mode : 1 = enables the serial port and configures the sda and scl pins as serial port pins 0 = disables serial port and configures these pins as i/o port pins note 1: in both modes, when enabled, these pins must be properly configured as input or output. bit 4 ckp: clock polarity select bit in spi mode: 1 = transmit happens on falling edge, receive on rising edge. idle state for clock is a high level. 0 = transmit happens on rising edge, receive on falling edge. idle state for clock is a low level. in i 2 c slave mode: sck release control. 1 = enable clock 0 = holds clock low (clock stretch). (used to ensure data setup time.) bit 3-0 sspm<3:0>: synchronous serial port mode select bits 0000 = spi master mode, clock = osc/4 0001 = spi master mode, clock = osc/16 0010 = spi master mode, clock = osc/64 0011 = spi master mode, clock = tmr2 output/2 0100 = spi slave mode, clock = sck pin. ss pin control enabled. 0101 = spi slave mode, clock = sck pin. ss pin control disabled. ss can be used as i/o pin. 0110 =i 2 c slave mode, 7-bit address 0111 =i 2 c slave mode, 10-bit address 1011 =i 2 c firmware controlled master mode (slave idle) 1110 =i 2 c slave mode, 7-bit address with start and stop bit interrupts enabled 1111 =i 2 c slave mode, 10-bit address with start and stop bit interrupts enabled 1000, 1001, 1010, 1100, 1101 = reserved legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
pic16f818/819 ds39598d-page 74 preliminary ? 2003 microchip technology inc. figure 10-1: ssp block diagram (spi mode) to enable the serial port, ssp enable bit, sspen (sspcon<5>), must be set. to reset or reconfigure spi mode, clear bit sspen, reinitialize the sspcon register and then set bit sspen. this configures the sdi, sdo, sck and ss pins as serial port pins. for the pins to behave as the serial port function, they must have their data direction bits (in the trisb register) appropriately programmed. that is: sdi must have trisb<1> set sdo must have trisb<2> cleared sck (master mode) must have trisb<4> cleared sck (slave mode) must have trisb<4> set ss must have trisb<5> set table 10-1: registers associated with spi operation read write internal data bus rb1/sdi/sda rb2/sdo/ rb5/ss rb4/sck/ sspsr reg sspbuf reg sspm3:sspm0 bit0 shift clock ss control enable edge select clock select tmr2 output t cy prescaler 4, 16, 64 trisb<4> 2 edge select 2 4 scl ccp1 note 1: when the spi is in slave mode with ss pin control enabled (sspcon<3:0> = 0100 ), the spi module will reset if the ss pin is set to v dd . 2: if the spi is used in slave mode with cke = 1 , then the ss pin control must be enabled. 3: when the spi is in slave mode with ss pin control enabled (sspcon<3:0> = 0100 ), the state of ss pin can affect the state read back from the trisb<5> bit. the peripheral oe signal from the ssp mod- ule into portb controls the state that is read back from the trisb<5> bit. if read- modify-write instructions, such as bsf are performed on the trisb register while the ss pin is high, this will cause the trisb<5> bit to be set, thus disabling the sdo output. address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh,8bh 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ? adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ? adie ? ?sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 86h trisb portb data direction register 1111 1111 1111 1111 13h sspbuf synchronous serial port receive buffer/transmit register xxxx xxxx uuuu uuuu 14h sspcon wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 0000 0000 94h sspstat smp cke d/a p s r/w ua bf 0000 0000 0000 0000 legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?. shaded cells are not used by the ssp in spi mode.
? 2003 microchip technology inc. preliminary ds39598d-page 75 pic16f818/819 figure 10-2: spi mode timing, master mode figure 10-3: spi mode timing (slave mode with cke = 0 ) figure 10-4: spi mode timing (slave mode with cke = 1 ) sck (ckp = 0 , sdi (smp = 0 ) sspif bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 sdi (smp = 1 ) sck (ckp = 0 , sck (ckp = 1 , sck (ckp = 1 , sdo bit 7 bit 7 bit 0 bit 0 cke = 0 ) cke = 1 ) cke = 0 ) cke = 1 ) sck (ckp = 0 ) sdi (smp = 0 ) sspif bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 sck (ckp = 1 ) sdo bit 7 bit 0 ss (optional) sck (ckp = 0 ) sdi (smp = 0 ) sspif bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 sck (ckp = 1 ) sdo bit 7 bit 0 ss
pic16f818/819 ds39598d-page 76 preliminary ? 2003 microchip technology inc. 10.3 ssp i 2 c mode operation the ssp module in i 2 c mode fully implements all slave functions, except general call support and provides interrupts on start and stop bits in hardware to facilitate firmware implementations of the master functions. the ssp module implements the standard mode specifications, as well as 7-bit and 10-bit addressing. two pins are used for data transfer. these are the rb4/sck/scl pin, which is the clock (scl) and the rb1/sdi/sda pin, which is the data (sda). the user must configure these pins as inputs or outputs through the trisb<4,1> bits. the ssp module functions are enabled by setting ssp enable bit, sspen (sspcon<5>). figure 10-5: ssp block diagram (i 2 c mode) the ssp module has five registers for i 2 c operation: ssp control register (sspcon) ssp status register (sspstat) serial receive/transmit buffer (sspbuf) ssp shift register (sspsr) ? not directly accessible ssp address register (sspadd) the sspcon register allows control of the i 2 c opera- tion. four mode selection bits (sspcon<3:0>) allow one of the following i 2 c modes to be selected: i 2 c slave mode (7-bit address) i 2 c slave mode (10-bit address) i 2 c slave mode (7-bit address) with start and stop bit interrupts enabled to support firmware master mode i 2 c slave mode (10-bit address) with start and stop bit interrupts enabled to support firmware master mode i 2 c firmware controlled master mode with start and stop bit interrupts enabled, slave is idle selection of any i 2 c mode, with the sspen bit set, forces the scl and sda pins to be open-drain, pro- vided these pins are programmed to inputs by setting the appropriate trisb bits. pull-up resistors must be provided externally to the scl and sda pins for proper operation of the i 2 c module. additional information on ssp i 2 c operation may be found in the picmicro ? mid-range mcu family reference manual (ds33023). 10.3.1 slave mode in slave mode, the scl and sda pins must be config- ured as inputs (trisb<4,1> set). the ssp module will override the input state with the output data when required (slave-transmitter). when an address is matched, or the data transfer after an address match is received, the hardware automati- cally will generate the acknowledge (ack ) pulse and then load the sspbuf register with the received value currently in the sspsr register. either or both of the following conditions will cause the ssp module not to give this ack pulse: a) the buffer full bit, bf (sspstat<0>), was set before the transfer was received. b) the overflow bit, sspov (sspcon<6>), was set before the transfer was received. in this case, the sspsr register value is not loaded into the sspbuf but bit, sspif (pir1<3>), is set. table 10-2 shows what happens when a data transfer byte is received, given the status of bits bf and sspov. the shaded cells show the condition where user software did not properly clear the overflow condi- tion. flag bit bf is cleared by reading the sspbuf register while bit sspov is cleared through software. the scl clock input must have a minimum high and low for proper operation. the high and low times of the i 2 c specification, as well as the requirement of the ssp module, are shown in timing parameter #100 and parameter #101. read write sspsr reg match detect sspadd reg start and stop bit detect sspbuf reg internal data bus addr match set, reset s, p bits (sspstat reg ) rb4/sck/scl rb1/ shift clock msb sdi/ lsb sda
? 2003 microchip technology inc. preliminary ds39598d-page 77 pic16f818/819 10.3.1.1 addressing once the ssp module has been enabled, it waits for a start condition to occur. following the start condition, the eight bits are shifted into the sspsr register. all incoming bits are sampled with the rising edge of the clock (scl) line. the value of register sspsr<7:1> is compared to the value of the sspadd register. the address is compared on the falling edge of the eighth clock (scl) pulse. if the addresses match and the bf and sspov bits are clear, the following events occur: a) the sspsr register value is loaded into the sspbuf register. b) the buffer full bit, bf, is set. c) an ack pulse is generated. d) ssp interrupt flag bit, sspif (pir1<3>), is set (interrupt is generated if enabled) ? on the falling edge of the ninth scl pulse. in 10-bit address mode, two address bytes need to be received by the slave device. the five most significant bits (msbs) of the first address byte specify if this is a 10-bit address. bit r/w (sspstat<2>) must specify a write so the slave device will receive the second address byte. for a 10-bit address, the first byte would equal ? 1111 0 a9 a8 0 ?, where a9 and a8 are the two msbs of the address. the sequence of events for 10-bit address is as follows, with steps 7-9 for slave-transmitter: 1. receive first (high) byte of address (bits sspif, bf and bit ua (sspstat<1>) are set). 2. update the sspadd register with second (low) byte of address (clears bit ua and releases the scl line). 3. read the sspbuf register (clears bit bf) and clear flag bit, sspif. 4. receive second (low) byte of address (bits sspif, bf and ua are set). 5. update the sspadd register with the first (high) byte of address, if match releases scl line, this will clear bit ua. 6. read the sspbuf register (clears bit bf) and clear flag bit, sspif. 7. receive repeated start condition. 8. receive first (high) byte of address (bits sspif and bf are set). 9. read the sspbuf register (clears bit bf) and clear flag bit, sspif. 10.3.1.2 reception when the r/w bit of the address byte is clear and an address match occurs, the r/w bit of the sspstat register is cleared. the received address is loaded into the sspbuf register. when the address byte overflow condition exists, then a no acknowledge (ack ) pulse is given. an overflow condition is indicated if either bit, bf (sspstat<0>), is set or bit, sspov (sspcon<6>), is set. an ssp interrupt is generated for each data transfer byte. flag bit, sspif (pir1<3>), must be cleared in software. the sspstat register is used to determine the status of the byte. 10.3.1.3 transmission when the r/w bit of the incoming address byte is set and an address match occurs, the r/w bit of the sspstat register is set. the received address is loaded into the sspbuf register. the ack pulse will be sent on the ninth bit and pin rb4/sck/scl is held low. the transmit data must be loaded into the sspbuf register which also loads the sspsr register. then pin rb4/sck/scl should be enabled by setting bit, ckp (sspcon<4>). the master device must mon- itor the scl pin prior to asserting another clock pulse. the slave devices may be holding off the master device by stretching the clock. the eight data bits are shifted out on the falling edge of the scl input. this ensures that the sda signal is valid during the scl high time (figure 10-7). an ssp interrupt is generated for each data transfer byte. flag bit sspif must be cleared in software and the sspstat register is used to determine the status of the byte. flag bit sspif is set on the falling edge of the ninth clock pulse. as a slave-transmitter, the ack pulse from the master- receiver is latched on the rising edge of the ninth scl input pulse. if the sda line was high (not ack ), then the data transfer is complete. when the ack is latched by the slave device, the slave logic is reset (resets sspstat register) and the slave device then monitors for another occurrence of the start bit. if the sda line was low (ack ), the transmit data must be loaded into the sspbuf register which also loads the sspsr register. then pin rb4/sck/scl should be enabled by setting bit, ckp.
pic16f818/819 ds39598d-page 78 preliminary ? 2003 microchip technology inc. table 10-2: data transfer received byte actions figure 10-6: i 2 c waveforms for reception (7-bit address) figure 10-7: i 2 c waveforms for transmission (7-bit address) status bits as data transfer is received sspsr sspbuf generate ack pulse set bit sspif (ssp interrupt occurs if enabled) bf sspov 00 yes yes yes 10 no no yes 11 no no yes 0 1 no no yes note 1: shaded cells show the conditions where the user software did not properly clear the overflow condition. p 9 8 7 6 5 d0 d1 d2 d3 d4 d5 d6 d7 s a7 a6 a5 a4 a3 a2 a1 sda scl 12 3 4 5 6 7 8 9 12 3 4 56 7 89 123 4 bus master terminates transfer bit sspov is set because the sspbuf register is still full cleared in software sspbuf register is read ack receiving data receiving data d0 d1 d2 d3 d4 d5 d6 d7 ack r/w = 0 receiving address sspif (pir1<3>) bf (sspstat<0>) sspov (sspcon<6>) ack ack is not sent sda scl sspif (pir1<3>) bf (sspstat<0>) ckp (sspcon<4>) a7 a6 a5 a4 a3 a2 a1 ack d7 d6 d5 d4 d3 d2 d1 d0 ack transmitting data r/w = 1 receiving address 123456789 123456789 p cleared in software sspbuf is written in software from ssp interrupt service routine set bit after writing to sspbuf s data is sampled scl held low while cpu responds to sspif (the sspbuf must be written to before the ckp bit can be set)
? 2003 microchip technology inc. preliminary ds39598d-page 79 pic16f818/819 10.3.2 master mode operation master mode operation is supported in firmware using interrupt generation on the detection of the start and stop conditions. the stop (p) and start (s) bits are cleared from a reset or when the ssp module is dis- abled. the stop (p) and start (s) bits will toggle based on the start and stop conditions. control of the i 2 c bus may be taken when the p bit is set or the bus is idle and both the s and p bits are clear. in master mode operation, the scl and sda lines are manipulated in firmware by clearing the corresponding trisb<4,1> bit(s). the output level is always low, irre- spective of the value(s) in portb<4,1>. so when transmitting data, a ? 1 ? data bit must have the trisb<1> bit set (input) and a ? 0 ? data bit must have the trisb<1> bit cleared (output). the same scenario is true for the scl line with the trisb<4> bit. pull-up resistors must be provided externally to the scl and sda pins for proper operation of the i 2 c module. the following events will cause the ssp interrupt flag bit, sspif, to be set (ssp interrupt if enabled): start condition stop condition data transfer byte transmitted/received master mode operation can be done with either the slave mode idle (sspm3:sspm0 = 1011 ) or with the slave mode active. when both master mode operation and slave modes are used, the software needs to differentiate the source(s) of the interrupt. for more information on master mode operation, see an554, ?software implementation of i 2 c bus master? (ds00554). 10.3.3 multi-master mode operation in multi-master mode operation, the interrupt genera- tion on the detection of the start and stop conditions allows the determination of when the bus is free. the stop (p) and start (s) bits are cleared from a reset or when the ssp module is disabled. the stop (p) and start (s) bits will toggle based on the start and stop conditions. control of the i 2 c bus may be taken when bit p (sspstat<4>) is set or the bus is idle and both the s and p bits clear. when the bus is busy, enabling the ssp interrupt will generate the interrupt when the stop condition occurs. in multi-master mode operation, the sda line must be monitored to see if the signal level is the expected out- put level. this check only needs to be done when a high level is output. if a high level is expected and a low level is present, the device needs to release the sda and scl lines (set trisb<4,1>). there are two stages where this arbitration can be lost: address transfer data transfer when the slave logic is enabled, the slave device con- tinues to receive. if arbitration was lost during the address transfer stage, communication to the device may be in progress. if addressed, an ack pulse will be generated. if arbitration was lost during the data trans- fer stage, the device will need to retransfer the data at a later time. for more information on multi-master mode operation, see an578, ?use of the ssp module in the i 2 c multi-master environment? (ds00578). table 10-3: registers associated with i 2 c operation address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh, 8bh, 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ? adif ? ?sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ? adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 13h sspbuf synchronous serial port receive buffer/transmit register xxxx xxxx uuuu uuuu 93h sspadd synchronous serial port (i 2 c mode) address register 0000 0000 0000 0000 14h sspcon wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 0000 0000 94h sspstat smp (1) cke (1) d/a psr/w ua bf 0000 0000 0000 0000 86h trisb portb data direction register 1111 1111 1111 1111 legend: x = unknown, u = unchanged, - = unimplemented locations read as ? 0 ?. shaded cells are not used by ssp module in spi mode. note 1: maintain these bits clear in i 2 c mode.
pic16f818/819 ds39598d-page 80 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 81 pic16f818/819 11.0 analog-to-digital converter (a/d) module the analog-to-digital (a/d) converter module has five inputs for 18/20 pin devices. the conversion of an analog input signal results in a corresponding 10-bit digital number. the a/d module has a high and low-voltage reference input that is software selectable to some combination of v dd , v ss , ra2 or ra3. the a/d converter has a unique feature of being able to operate while the device is in sleep mode. to oper- ate in sleep, the a/d conversion clock must be derived from the a/d?s internal rc oscillator. the a/d module has four registers: a/d result high register (adresh) a/d result low register (adresl) a/d control register 0 (adcon0) a/d control register 1 (adcon1) the adcon0 register, shown in register 11-1, controls the operation of the a/d module. the adcon1 register, shown in register 11-2, configures the functions of the port pins. the port pins can be configured as analog inputs (ra3 can also be a voltage reference) or a digital i/o. additional information on using the a/d module can be found in the picmicro ? mid-range mcu family reference manual (ds33023). register 11-1: adcon0: a/d control register 0 (address 1fh) r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 u-0 r/w-0 adcs1 adcs0 chs2 chs1 chs0 go/done ?adon bit 7 bit 0 bit 7-6 adcs1:adcs0: a/d conversion clock select bits if adsc2 = 0 : 00 = f osc /2 01 = f osc /8 10 = f osc /32 11 = f rc (clock derived from the internal a/d module rc oscillator) if adsc2 = 1 : 00 = f osc /4 01 = f osc /16 10 = f osc /64 11 = f rc (clock derived from the internal a/d module rc oscillator) bit 5-3 chs2:chs0: analog channel select bits 000 = channel 0 (ra0/an0) 001 = channel 1 (ra1/an1) 010 = channel 2 (ra2/an2) 011 = channel 3 (ra3/an3) 100 = channel 4 (ra4/an4) bit 2 go/done : a/d conversion status bit if adon = 1 : 1 = a/d conversion in progress (setting this bit starts the a/d conversion) 0 = a/d conversion not in progress (this bit is automatically cleared by hardware when the a/d conversion is complete) bit 1 unimplemented: read as ? 0 ? bit 0 adon: a/d on bit 1 = a/d converter module is operating 0 = a/d converter module is shut-off and consumes no operating current legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown
pic16f818/819 ds39598d-page 82 preliminary ? 2003 microchip technology inc. register 11-2: adcon1: a/d control register 1 (address 9fh) r/w-0 r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 adfm adcs2 ? ? pcfg3 pcfg2 pcfg1 pcfg0 bit 7 bit 0 bit 7 adfm: a/d result format select bit 1 = right justified, 6 most significant bits of adresh are read as ? 0 ? 0 = left justified, 6 least significant bits of adresl are read as ? 0 ? bit 6 adcs2: a/d clock divide by 2 select bit 1 = a/d clock source is divided by 2 when system clock is used 0 = disabled bit 5-4 unimplemented: read as ? 0 ? bit 3-0 pcfg<3:0>: a/d port configuration control bits a = analog input d = digital i/o c/r = number of analog input channels/number of a/d voltage references legend: r = readable bit w = writable bit u = unimplemented bit, read as ?0? - n = value at por ?1? = bit is set ?0? = bit is cleared x = bit is unknown pcfg an4 an3 an2 an1 an0 v ref +v ref -c/r 0000 aa aaaav dd av ss 5/0 0001 av ref+ aaaan3av ss 4/1 0010 aa aaaav dd av ss 5/0 0011 av ref+ aaaan3av ss 4/1 0100 da daaav dd av ss 3/0 0101 dv ref+ daaan3av ss 2/1 011x dd dddav dd av ss 0/0 1000 av ref+ v ref- aaan3an2 3/2 1001 aa aaaav dd av ss 5/0 1010 av ref+ aaaan3av ss 4/1 1011 av ref+ v ref- aaan3an2 3/2 1100 av ref+ v ref- aaan3an2 3/2 1101 dv ref+ v ref- aaan3an2 2/2 1110 dd ddaav dd av ss 1/0 1111 dv ref+ v ref- daan3an2 1/2
? 2003 microchip technology inc. preliminary ds39598d-page 83 pic16f818/819 the adresh:adresl registers contain the result of the a/d conversion. when the a/d conversion is complete, the result is loaded into the a/d result register pair, the go/done bit (adcon0<2>) is cleared and a/d interrupt flag bit, adif, is set. the block diagram of the a/d module is shown in figure 11-1. after the a/d module has been configured as desired, the selected channel must be acquired before the con- version is started. the analog input channels must have their corresponding tris bits selected as inputs. to determine sample time, see section 11.1 ?a/d acquisition requirements? . after this sample time has elapsed, the a/d conversion can be started. these steps should be followed for doing an a/d conversion: 1. configure the a/d module: configure analog pins/voltage reference and digital i/o (adcon1) select a/d input channel (adcon0) select a/d conversion clock (adcon0) turn on a/d module (adcon0) 2. configure a/d interrupt (if desired): clear adif bit set adie bit set gie bit 3. wait the required acquisition time. 4. start conversion: set go/done bit (adcon0) 5. wait for a/d conversion to complete by either: polling for the go/done bit to be cleared (with interrupts disabled); or waiting for the a/d interrupt 6. read a/d result register pair (adresh:adresl), clear bit adif if required. 7. for next conversion, go to step 1 or step 2 as required. the a/d conversion time per bit is defined as t ad . a minimum wait of 2 t ad is required before the next acquisition starts. figure 11-1: a/d block diagram (input voltage) v in v ref + (reference voltage) av dd pcfg<3:0> chs<3:0> ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 011 010 001 000 a/d converter v ref - (reference voltage) av ss pcfg<3:0> ra4/an4 100
pic16f818/819 ds39598d-page 84 preliminary ? 2003 microchip technology inc. 11.1 a/d acquisition requirements for the a/d converter to meet its specified accuracy, the charge holding capacitor (c hold ) must be allowed to fully charge to the input channel voltage level. the analog input model is shown in figure 11-2. the source impedance (r s ) and the internal sampling switch (r ss ) impedance directly affect the time required to charge the capacitor c hold . the sampling switch (r ss ) impedance varies over the device voltage (v dd ), see figure 11-2. the maximum recommended imped- ance for analog sources is 2.5 k ? . as the impedance is decreased, the acquisition time may be decreased. after the analog input channel is selected (changed), this acquisition must be done before the conversion can be started. to calculate the minimum acquisition time, equation 11-1 may be used. this equation assumes that 1/2 lsb error is used (1024 steps for the a/d). the 1/2 lsb error is the maximum error allowed for the a/d to meet its specified resolution. to calculate the minimum acquisition time, t acq , see the picmicro ? mid-range mcu family reference manual (ds33023). equation 11-1: acquisition time figure 11-2: analog input model t acq t c t acq = = = = = = = = amplifier settling time + hold capacitor charging time + temperature coefficient t amp + t c + t coff 2 s + t c + [(temperature -25 c)(0.05 s/c)] c hold (r ic + r ss + r s ) in(1/2047) -120 pf (1 k ? + 7 k ? + 10 k ? ) in(0.0004885) 16.47 s 2 s + 16.47 s + [(50c ? 25 c)(0.05 s/ c) 19.72 s note 1: the reference voltage (v ref ) has no effect on the equation since it cancels itself out. 2: the charge holding capacitor (c hold ) is not discharged after each conversion. 3: the maximum recommended impedance for analog sources is 10 k ? . this is required to meet the pin leakage specification. 4: after a conversion has completed, a 2.0 t ad delay must complete before acquisition can begin again. during this time, the holding capacitor is not connected to the selected a/d input channel. c pin va rs anx 5 pf v dd v t = 0.6v v t = 0.6v i leakage r ic 1k sampling switch ss r ss c hold = dac capacitance v ss 6v sampling switch 5v 4v 3v 2v 567891011 (k ? ) v dd = 51.2 pf 500 na legend: c pin v t i leakage r ic ss c hold = input capacitance = threshold voltage = leakage current at the pin due to = interconnect resistance = sampling switch = sample/hold capacitance (from dac) various junctions
? 2003 microchip technology inc. preliminary ds39598d-page 85 pic16f818/819 11.2 selecting the a/d conversion clock the a/d conversion time per bit is defined as t ad . the a/d conversion requires 9.0 t ad per 8-bit conversion. the source of the a/d conversion clock is software selectable. the seven possible options for t ad are: 2t osc 4t osc 8t osc 16t osc 32t osc 64t osc internal a/d module rc oscillator (2-6 s) for correct a/d conversions, the a/d conversion clock (t ad ) must be selected to ensure a minimum t ad time as small as possible, but no less than 1.6 s and not greater than 6.4 s. table 11-1 shows the resultant t ad times derived from the device operating frequencies and the a/d clock source selected. 11.3 configuring analog port pins the adcon1 and trisa registers control the opera- tion of the a/d port pins. the port pins that are desired as analog inputs must have their corresponding tris bits set (input). if the tris bit is cleared (output), the digital output level (v oh or v ol ) will be converted. the a/d operation is independent of the state of the chs<2:0> bits and the tris bits. table 11-1: t ad vs. maximum device operating frequencies (standard devices (f)) note 1: when reading the port register, all pins configured as analog input channels will read as cleared (a low level). pins config- ured as digital inputs will convert an analog input. analog levels on a digitally configured input will not affect the conversion accuracy. 2: analog levels on any pin that is defined as a digital input (including the an4:an0 pins) may cause the input buffer to consume current out of the device specification. ad clock source (t ad ) maximum device frequency operation adcs<2> adcs<1:0> 2 t osc 000 1.25 mhz 4 t osc 100 2.5 mhz 8 t osc 001 5 mhz 16 t osc 101 10 mhz 32 t osc 010 20 mhz 64 t osc 110 20 mhz rc (1,2,3) x11 (note 1) note 1: the rc source has a typical t ad time of 4 s but can vary between 2-6 s. 2: when the device frequencies are greater than 1 mhz, the rc a/d conversion clock source is only recommended for sleep operation. 3: for extended voltage devices (lf), please refer to section 15.0 ?electrical characteristics? .
pic16f818/819 ds39598d-page 86 preliminary ? 2003 microchip technology inc. 11.4 a/d conversions clearing the go/done bit during a conversion will abort the current conversion. the a/d result register pair will not be updated with the partially completed a/d conversion sample. that is, the adresh:adresl registers will continue to contain the value of the last completed conversion (or the last value written to the adresh:adresl registers). after the a/d conversion is aborted, a 2-t ad wait is required before the next acquisition is started. after this 2-t ad wait, acquisition on the selected channel is automatically started. the go/done bit can then be set to start the conversion. in figure 11-3, after the go bit is set, the first time segment has a minimum of t cy and a maximum of t ad . 11.4.1 a/d result registers the adresh:adresl register pair is the location where the 10-bit a/d result is loaded at the completion of the a/d conversion. this register pair is 16 bits wide. the a/d module gives the flexibility to left or right justify the 10-bit result in the 16-bit result register. the a/d format select bit (adfm) controls this justification. figure 11-4 shows the operation of the a/d result justification. the extra bits are loaded with ? 0 ?s. when an a/d result will not overwrite these locations (a/d dis- able), these registers may be used as two general purpose 8-bit registers. figure 11-3: a/d conversion t ad cycles figure 11-4: a/d result justification note: the go/done bit should not be set in the same instruction that turns on the a/d. t ad 1 t ad 2 t ad 3 t ad 4 t ad 5 t ad 6 t ad 7 t ad 8 t ad 9 set go bit holding capacitor is disconnected from analog input (typically 100 ns) b9 b8 b7 b6 b5 b4 b3 b2 t ad 10 t ad 11 b1 b0 t cy to t ad conversion starts adres is loaded, go bit is cleared, adif bit is set, holding capacitor is connected to analog input 10-bit result adresh adresl 0000 00 adfm = 0 0 2 1 0 7 7 10-bit result adresh adresl 10-bit result 0000 00 7 0 7 6 5 0 adfm = 1 right justified left justified
? 2003 microchip technology inc. preliminary ds39598d-page 87 pic16f818/819 11.5 a/d operation during sleep the a/d module can operate during sleep mode. this requires that the a/d clock source be set to rc (adcs1:adcs0 = 11 ). when the rc clock source is selected, the a/d module waits one instruction cycle before starting the conversion. this allows the sleep instruction to be executed which eliminates all digital switching noise from the conversion. when the conver- sion is completed, the go/done bit will be cleared and the result loaded into the adres register. if the a/d interrupt is enabled, the device will wake-up from sleep. if the a/d interrupt is not enabled, the a/d module will then be turned off, although the adon bit will remain set. when the a/d clock source is another clock option (not rc), a sleep instruction will cause the present conver- sion to be aborted and the a/d module to be turned off, though the adon bit will remain set. turning off the a/d places the a/d module in its lowest current consumption state. 11.6 effects of a reset a device reset forces all registers to their reset state. the a/d module is disabled and any conversion in progress is aborted. all a/ d input pins are configured as analog inputs. the value that is in the adresh:adresl registers is not modified for a power-on reset. the adresh:adresl registers will contain unknown data after a power-on reset. 11.7 use of the ccp trigger an a/d conversion can be started by the ?special event trigger? of the ccp module. this requires that the ccp1m3:ccp1m0 bits (ccp1con<3:0>) be programmed as ? 1011 ? and that the a/d module is enabled (adon bit is set). when the trigger occurs, the go/done bit will be set, starting the a/d conversion and the timer1 counter will be reset to zero. timer1 is reset to automatically repeat the a/d acquisition period with minimal software overhead (moving the adresh:adresl to the desired location). the appro- priate analog input channel must be selected and the minimum acquisition done before the ?special event trigger? sets the go/done bit (starts a conversion). if the a/d module is not enabled (adon is cleared), then the ?special event trigger? will be ignored by the a/d module but will still reset the timer1 counter. table 11-2: registers/bits associated with a/d note: for the a/d module to operate in sleep, the a/d clock source must be set to rc (adcs1:adcs0 = 11 ). to perform an a/d conversion in sleep, ensure the sleep instruction immediately follows the instruction that sets the go/done bit. address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets 0bh,8bh 10bh,18bh intcon gie peie tmr0ie inte rbie tmr0if intf rbif 0000 000x 0000 000u 0ch pir1 ?adif ? ? sspif ccp1if tmr2if tmr1if -0-- 0000 -0-- 0000 8ch pie1 ?adie ? ? sspie ccp1ie tmr2ie tmr1ie -0-- 0000 -0-- 0000 1eh adresh a/d result register high byte xxxx xxxx uuuu uuuu 9eh adresl a/d result register low byte xxxx xxxx uuuu uuuu 1fh adcon0 adcs1 adcs0 chs2 chs1 chs0 go/done ?adon 0000 00-0 0000 00-0 9fh adcon1 adfm adcs2 ? ? pcfg3 pcfg2 pcfg1 pcfg0 00-- 0000 00-- 0000 05h porta ra7 ra6 ra5 ra4 ra3 ra2 ra1 ra0 xxx0 0000 uuu0 0000 85h trisa trisa7 trisa6 trisa5 porta data direction register 1111 1111 1111 1111 legend: x = unknown, u = unchanged, - = unimplemented, read as ? 0 ?. shaded cells are not used for a/d conversion.
pic16f818/819 ds39598d-page 88 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 89 pic16f818/819 12.0 special features of the cpu these devices have a host of features intended to maximize system reliability, minimize cost through elimination of external components, provide power saving operating modes and offer code protection: reset - power-on reset (por) - power-up timer (pwrt) - oscillator start-up timer (ost) - brown-out reset (bor) interrupts watchdog timer (wdt) sleep code protection id locations in-circuit serial programming there are two timers that offer necessary delays on power-up. one is the oscillator start-up timer (ost), intended to keep the chip in reset until the crystal oscil- lator is stable. the other is the power-up timer (pwrt) which provides a fixed delay of 72 ms (nominal) on power-up only. it is designed to keep the part in reset while the power supply stabilizes and is enabled or disabled using a configuration bit. with these two timers on-chip, most applications need no external reset circuitry. sleep mode is designed to offer a very low current power-down mode. the user can wake-up from sleep through external reset, watchdog timer wake-up or through an interrupt. several oscillator options are also made available to allow the part to fit the application. the rc oscillator option saves system cost while the lp crystal option saves power. configuration bits are used to select the desired oscillator mode. additional information on special features is available in the picmicro ? mid-range mcu family reference manual (ds33023). 12.1 configuration bits the configuration bits can be programmed (read as ? 0 ?), or left unprogrammed (read as ? 1 ?), to select vari- ous device configurations. these bits are mapped in program memory location 2007h. the user will note that address 2007h is beyond the user program memory space which can be accessed only during programming.
pic16f818/819 ds39598d-page 90 preliminary ? 2003 microchip technology inc. register 12-1: configurat ion word (address 2007h) (1) r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 cp ccpmx debug wrt1 wrt0 cpd lvp boren mclre f osc 2pwrten wdten f osc 1f osc 0 bit 13 bit 0 bit 13 cp: flash program memory code protection bit 1 = code protection off 0 = all memory locations code-protected bit 12 ccpmx: ccp1 pin selection bit 1 = ccp1 function on rb2 0 = ccp1 function on rb3 bit 11 debug: in-circuit debugger mode bit 1 = in-circuit debugger disabled, rb6 and rb7 are general purpose i/o pins 0 = in-circuit debugger enabled, rb6 and rb7 are dedicated to the debugger bit 10-9 wrt1:wrt0: flash program memory write enable bits for pic16f818: 11 = write protection off 10 = 000h to 01ff write-protected, 0200 to 03ff may be modified by eecon control 01 = 000h to 03ff write-protected for pic16f819: 11 = write protection off 10 = 0000h to 01ffh write-protected, 0200h to 07ffh may be modified by eecon control 01 = 0000h to 03ffh write-protected, 0400h to 07ffh may be modified by eecon control 00 = 0000h to 05ffh write-protected, 0600h to 07ffh may be modified by eecon control bit 8 cpd: data ee memory code protection bit 1 = code protection off 0 = data ee memory locations code-protected bit 7 lvp: low-voltage programming enable bit 1 = rb3/pgm pin has pgm function, low-voltage programming enabled 0 = rb3/pgm pin has digital i/o function, hv on mclr must be used for programming bit 6 boren: brown-out reset enable bit 1 = bor enabled 0 = bor disabled bit 5 mclre: ra5/mclr pin function select bit 1 = ra5/mclr pin function is mclr 0 = ra5/mclr pin function is digital i/o, mclr internally tied to v dd bit 3 pwrten : power-up timer enable bit 1 = pwrt disabled 0 = pwrt enabled bit 2 wdten: watchdog timer enable bit 1 = wdt enabled 0 = wdt disabled bit 4, 1-0 f osc 2:f osc 0: oscillator selection bits 111 = extrc oscillator; clko function on ra6/osc2/clko pin 110 = extrc oscillator; port i/o function on ra6/osc2/clko pin 101 = intrc oscillator; clko function on ra6/osc2/clko pin and port i/o function on ra7/osc1/clki pin 100 = intrc oscillator; port i/o function on both ra6/osc2/clko pin and ra7/osc1/clki pin 011 = extclk; port i/o function on ra6/osc2/clko pin 010 = hs oscillator 001 = xt oscillator 000 = lp oscillator note 1: the erased (unprogrammed) value of the configuration word is 3fffh. legend: r = readable bit p = programmable bit u = unimplemented bit, read as ?1? - n = value when device is unprogrammed u = unchanged from programmed state
? 2003 microchip technology inc. preliminary ds39598d-page 91 pic16f818/819 12.2 reset the pic16f818/819 differentiates between various kinds of reset: power-on reset (por) mclr reset during normal operation mclr reset during sleep wdt reset during normal operation wdt wake-up during sleep brown-out reset (bor) some registers are not affected in any reset condition. their status is unknown on por and unchanged in any other reset. most other registers are reset to a ?reset state? on power-on reset (por), on the mclr and wdt reset, on mclr reset during sleep, and brown- out reset (bor). they are not affected by a wdt wake-up which is viewed as the resumption of normal operation. the to and pd bits are set or cleared differ- ently in different reset situations as indicated in table 12-3. these bits are used in software to deter- mine the nature of the reset. upon a por, bor or wake-up from sleep, the cpu requires approximately 5-10 s to become ready for code execution. this delay runs in parallel with any other timers. see table 12-4 for a full description of reset states of all registers. a simplified block diagram of the on-chip reset circuit is shown in figure 12-1. figure 12-1: simplified block diagram of on-chip reset circuit s r q external reset mclr v dd osc1 wdt module v dd rise detect ost/pwrt intrc wdt time-out power-on reset ost 10-bit ripple counter pwrt chip_reset 10-bit ripple counter reset enable ost enable pwrt sleep brown-out reset boren 31.25 khz
pic16f818/819 ds39598d-page 92 preliminary ? 2003 microchip technology inc. 12.3 mclr pic16f818/819 device has a noise filter in the mclr reset path. the filter will detect and ignore small pulses. it should be noted that a wdt reset does not drive mclr pin low. the behavior of the esd protection on the mclr pin has been altered from previous devices of this family. voltages applied to the pin that exceed its specification can result in both mclr and excessive current beyond the device specification during the esd event. for this reason, microchip recommends that the mclr pin no longer be tied directly to v dd . the use of an rc network, as shown in figure 12-2, is suggested. the ra5/mclr pin can be configured for mclr (default) or as an i/o pin (ra5). this is configured through the mclre bit in the configuration register. figure 12-2: recommended mclr circuit 12.4 power-on reset (por) a power-on reset pulse is generated on-chip when v dd rise is detected (in the range of 1.2v-1.7v). to take advantage of the por, tie the mclr pin to v dd as described in section 12.3 ?mclr ?. a maximum rise time for v dd is specified. see section 15.0 ?electrical characteristics? for details. when the device starts normal operation (exits the reset condition), device operating parameters (volt- age, frequency, temperature,...) must be met to ensure operation. if these conditions are not met, the device must be held in reset until the operating conditions are met. for more information, see application note an607, ?power-up trouble shooting? (ds00607). 12.5 power-up timer (pwrt) the power-up timer (pwrt) of the pic16f818/819 is a counter that uses the intrc oscillator as the clock input. this yields a count of 72 ms. while the pwrt is counting, the device is held in reset. the power-up time delay depends on the intrc and will vary from chip-to-chip due to temperature and process variation. see dc parameter #33 for details. the pwrt is enabled by clearing configuration bit, pwrten . 12.6 oscillator start-up timer (ost) the oscillator start-up timer (ost) provides 1024 oscillator cycles (from osc1 input) delay after the pwrt delay is over (if enabled). this helps to ensure that the crystal oscillator or resonator has started and stabilized. the ost time-out is invoked only for xt, lp and hs modes and only on power-on reset or wake-up from sleep. 12.7 brown-out reset (bor) the configuration bit, boren, can enable or disable the brown-out reset circuit. if v dd falls below v bor (parameter #d005, about 4v) for longer than t bor (parameter #35, about 100 s), the brown-out situation will reset the device. if v dd falls below v bor for less than t bor , a reset may not occur. once the brown-out occurs, the device will remain in brown-out reset until v dd rises above v bor . the power-up timer (if enabled) will keep the device in reset for t pwrt (parameter #33, about 72 ms). if v dd should fall below v bor during t pwrt , the brown-out reset process will restart when v dd rises above v bor with the power-up timer reset. unlike previous pic16 devices, the pwrt is no longer automatically enabled when the brown-out reset circuit is enabled. the pwrten and boren configuration bits are independent of each other. 12.8 time-out sequence on power-up, the time-out sequence is as follows: the pwrt delay starts (if enabled) when a por occurs. then, ost starts counting 1024 oscillator cycles when pwrt ends (lp, xt, hs). when the ost ends, the device comes out of reset. if mclr is kept low long enough, all delays will expire. bringing mclr high will begin execution immediately. this is useful for testing purposes or to synchronize more than one pic16f818/819 device operating in parallel. table 12-3 shows the reset conditions for the status, pcon and pc registers, while table 12-4 shows the reset conditions for all the registers. c1 0.1 f r1 1 k ? (or greater) (optional, not critical) v dd mclr pic16f818/819
? 2003 microchip technology inc. preliminary ds39598d-page 93 pic16f818/819 12.9 power control/status register (pcon) the power control/status register, pcon, has two bits to indicate the type of reset that last occurred. bit 0 is brown-out reset status bit, bor . bit bor is unknown on a power-on reset. it must then be set by the user and checked on subsequent resets to see if bit bor cleared, indicating a brown-out reset occurred. when the brown-out reset is disabled, the state of the bor bit is unpredictable. bit 1 is power-on reset status bit, por . it is cleared on a power-on reset and unaffected otherwise. the user must set this bit following a power-on reset. table 12-1: time-out in various situations table 12-2: status bits and their significance table 12-3: reset condition for special registers oscillator configuration power-up brown-out reset wake-up from sleep pwrte = 0 pwrte = 1 pwrte = 0 pwrte = 1 xt, hs, lp t pwrt + 1024 t osc 1024 t osc t pwrt + 1024 t osc 1024 t osc 1024 t osc extrc, extclk, intrc t pwrt 5-10 s (1) t pwrt 5-10 s (1) 5-10 s (1) note 1: cpu start-up is always invoked on por, bor and wake-up from sleep. por bor to pd 0x11 power-on reset 0x0x illegal, to is set on por 0xx0 illegal, pd is set on por 1011 brown-out reset 1101 wdt reset 1100 wdt wake-up 11uu mclr reset during normal operation 1110 mclr reset during sleep or interrupt wake-up from sleep legend: u = unchanged, x = unknown condition program counter status register pcon register power-on reset 000h 0001 1xxx ---- --0x mclr reset during normal operation 000h 000u uuuu ---- --uu mclr reset during sleep 000h 0001 0uuu ---- --uu wdt reset 000h 0000 1uuu ---- --uu wdt wake-up pc + 1 uuu0 0uuu ---- --uu brown-out reset 000h 0001 1uuu ---- --u0 interrupt wake-up from sleep pc + 1 (1) uuu1 0uuu ---- --uu legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ? note 1: when the wake-up is due to an interrupt and the gie bit is set, the pc is loaded with the interrupt vector (0004h).
pic16f818/819 ds39598d-page 94 preliminary ? 2003 microchip technology inc. table 12-4: initialization conditions for all registers register power-on reset, brown-out reset mclr reset, wdt reset wake-up via wdt or interrupt w xxxx xxxx uuuu uuuu uuuu uuuu indf n/a n/a n/a tmr0 xxxx xxxx uuuu uuuu uuuu uuuu pcl 0000h 0000h pc + 1 (2) status 0001 1xxx 000q quuu (3) uuuq quuu (3) fsr xxxx xxxx uuuu uuuu uuuu uuuu porta xxx0 0000 uuu0 0000 uuuu uuuu portb xxxx xxxx uuuu uuuu uuuu uuuu pclath ---0 0000 ---0 0000 ---u uuuu intcon 0000 000x 0000 000u uuuu uuuu (1) pir1 -0-- 0000 -0-- 0000 -u-- uuuu (1) pir2 ---0 ---- ---0 ---- ---u ---- (1) tmr1l xxxx xxxx uuuu uuuu uuuu uuuu tmr1h xxxx xxxx uuuu uuuu uuuu uuuu t1con --00 0000 --uu uuuu --uu uuuu tmr2 0000 0000 0000 0000 uuuu uuuu t2con -000 0000 -000 0000 -uuu uuuu sspbuf xxxx xxxx uuuu uuuu uuuu uuuu sspcon 0000 0000 0000 0000 uuuu uuuu ccpr1l xxxx xxxx uuuu uuuu uuuu uuuu ccpr1h xxxx xxxx uuuu uuuu uuuu uuuu ccp1con --00 0000 --00 0000 --uu uuuu adresh xxxx xxxx uuuu uuuu uuuu uuuu adcon0 0000 00-0 0000 00-0 uuuu uu-u option 1111 1111 1111 1111 uuuu uuuu trisa 1111 1111 1111 1111 uuuu uuuu trisb 1111 1111 1111 1111 uuuu uuuu pie1 -0-- 0000 -0-- 0000 -u-- uuuu pie2 ---0 ---- ---0 ---- ---u ---- pcon ---- --qq ---- --uu ---- --uu osccon -000 -0-- -000 -0-- -uuu -u-- osctune --00 0000 --00 0000 --uu uuuu pr2 1111 1111 1111 1111 1111 1111 sspadd 0000 0000 0000 0000 uuuu uuuu sspstat 0000 0000 0000 0000 uuuu uuuu adresl xxxx xxxx uuuu uuuu uuuu uuuu adcon1 00-- 0000 00-- 0000 uu-- uuuu eedata xxxx xxxx uuuu uuuu uuuu uuuu eeadr xxxx xxxx uuuu uuuu uuuu uuuu eedath --xx xxxx --uu uuuu --uu uuuu eeadrh ---- -xxx ---- -uuu ---- -uuu eecon1 x--x x000 u--x u000 u--u uuuu eecon2 ---- ---- ---- ---- ---- ---- legend: u = unchanged, x = unknown, - = unimplemented bit, read as ? 0 ?, q = value depends on condition, r = reserved maintain clear note 1: one or more bits in intcon, pir1 and pr2 will be affected (to cause wake-up). 2: when the wake-up is due to an interrupt and the gie bit is set, the pc is loaded with the interrupt vector (0004h). 3: see table 12-3 for reset value for specific conditions.
? 2003 microchip technology inc. preliminary ds39598d-page 95 pic16f818/819 figure 12-3: time-out sequence on power-up (mclr tied to v dd through pull-up resistor) figure 12-4: time-out sequence on power-up (mclr tied to v dd through rc network): case 1 figure 12-5: time-out sequence on power-up (mclr tied to v dd through rc network): case 2 t pwrt t ost v dd mclr internal por pwrt time-out ost time-out internal reset t pwrt t ost v dd mclr internal por pwrt time-out ost time-out internal reset v dd mclr internal por pwrt time-out ost time-out internal reset t pwrt t ost
pic16f818/819 ds39598d-page 96 preliminary ? 2003 microchip technology inc. figure 12-6: slow rise time (mclr tied to v dd through rc network) 12.10 interrupts the pic16f818/819 has up to nine sources of inter- rupt. the interrupt control register (intcon) records individual interrupt requests in flag bits. it also has individual and global interrupt enable bits. a global interrupt enable bit, gie (intcon<7>), enables (if set) all unmasked interrupts or disables (if cleared) all interrupts. when bit gie is enabled and an interrupt?s flag bit and mask bit are set, the interrupt will vector immediately. individual interrupts can be disabled through their corresponding enable bits in various registers. individual interrupt bits are set regardless of the status of the gie bit. the gie bit is cleared on reset. the ?return from interrupt? instruction, retfie , exits the interrupt routine, as well as sets the gie bit, which re-enables interrupts. the rb0/int pin interrupt, the rb port change interrupt and the tmr0 overflow interrupt flags are contained in the intcon register. the peripheral interrupt flags are contained in the special function register, pir1. the corresponding interrupt enable bits are contained in special function register, pie1 and the peripheral interrupt enable bit is contained in special function register, intcon. when an interrupt is serviced, the gie bit is cleared to disable any further interrupt, the return address is pushed onto the stack and the pc is loaded with 0004h. once in the interrupt service routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. the interrupt flag bit(s) must be cleared in software before re-enabling interrupts to avoid recursive interrupts. for external interrupt events, such as the int pin or portb change interrupt, the interrupt latency will be three or four instruction cycles. the exact latency depends on when the interrupt event occurs, relative to the current q cycle. the latency is the same for one or two-cycle instructions. individual interrupt flag bits are set regardless of the status of their corresponding mask bit, peie bit or the gie bit. figure 12-7: interrupt logic v dd mclr internal por pwrt time-out ost time-out internal reset 0v 1v 5v t pwrt t ost note: individual interrupt flag bits are set regardless of the status of their corresponding mask bit or the gie bit. adif adie sspif sspie ccp1if ccp1ie tmr2if tmr2ie tmr1if tmr1ie tmr0if tmr0ie intf inte rbif rbie gie peie wake-up (if in sleep mode) interrupt to cpu eeif eeie
? 2003 microchip technology inc. preliminary ds39598d-page 97 pic16f818/819 12.10.1 int interrupt external interrupt on the rb0/int pin is edge triggered, either rising if bit intedg (option<6>) is set, or fall- ing if the intedg bit is clear. when a valid edge appears on the rb0/int pin, flag bit, intf (intcon<1>), is set. this interrupt can be disabled by clearing enable bit, inte (intcon<4>). flag bit intf must be cleared in software in the interrupt service routine before re-enabling this interrupt. the int inter- rupt can wake-up the processor from sleep if bit inte was set prior to going into sleep. the status of global interrupt enable bit, gie decides whether or not the processor branches to the interrupt vector following wake-up. see section 12.13 ?power-down mode (sleep)? for details on sleep mode. 12.10.2 tmr0 interrupt an overflow (ffh 00h) in the tmr0 register will set flag bit, tmr0if (intcon<2>). the interrupt can be enabled/disabled by setting/clearing enable bit, tmr0ie (intcon<5>) (see section 6.0 ?timer0 module? ). 12.10.3 portb intcon change an input change on portb<7:4> sets flag bit, rbif (intcon<0>). the interrupt can be enabled/disabled by setting/clearing enable bit, rbie (intcon<4>). see section 3.2 ?eecon1 and eecon2 registers? . 12.11 context saving during interrupts during an interrupt, only the return pc value is saved on the stack. typically, users may wish to save key reg- isters during an interrupt (i.e., w, status registers). this will have to be implemented in software as shown in example 12-1. for pic16f818 devices, the upper 64 bytes of each bank are common. temporary holding registers, w_temp and status_temp, should be placed here. these 64 locations do not require banking and therefore, make it easier for context save and restore. for pic16f819 devices, the upper 16 bytes of each bank are common. example 12-1: saving status and w registers in ram movwf w_temp ;copy w to temp register swapf status,w ;swap status to be saved into w clrf status ;bank 0, regardless of current bank, clears irp,rp1,rp0 movwf status_temp ;save status to bank zero status_temp register : :(isr) ;insert user code here : swapf status_temp,w ;swap status_temp register into w ;(sets bank to original state) movwf status ;move w into status register swapf w_temp,f ;swap w_temp swapf w_temp,w ;swap w_temp into w
pic16f818/819 ds39598d-page 98 preliminary ? 2003 microchip technology inc. 12.12 watchdog timer (wdt) for pic16f818/819 devices, the wdt is driven by the intrc oscillator. when the wdt is enabled, the intrc (31.25 khz) oscillator is enabled. the nominal wdt period is 16 ms and has the same accuracy as the intrc oscillator. during normal operation, a wdt time-out generates a device reset (watchdog timer reset). if the device is in sleep mode, a wdt time-out causes the device to wake-up and continue with normal operation (watchdog timer wake-up). the to bit in the status register will be cleared upon a watchdog timer time-out. the wdt can be permanently disabled by clearing con- figuration bit, wdten (see section 12.1 ?configuration bits? ). wdt time-out period values may be found in section 15.0 ?electrical characteristics? under parameter #31. values for the wdt prescaler (actually a postscaler but shared with the timer0 prescaler) may be assigned using the option register. figure 12-8: watchdog timer block diagram table 12-5: summary of watchdog timer registers note 1: the clrwdt and sleep instructions clear the wdt and the postscaler if assigned to the wdt and prevent it from timing out and generating a device reset condition. 2: when a clrwdt instruction is executed and the prescaler is assigned to the wdt, the prescaler count will be cleared but the prescaler assignment is not changed. from tmr0 clock source (figure 6-1) to tmr0 (figure 6-1) postscaler intrc wdt enable bit 0 1 m u x psa 8 - to - 1 mux ps2:ps0 0 1 mux psa wdt time-out note: psa and ps2:ps0 are bits in the option register. 8 31.25 khz address name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 81h,181h option rbpu intedg t0cs t0se psa ps2 ps1 ps0 2007h configuration bits lvp boren mvclre f osc 2 pwrten wdten f osc 1 f osc 0 legend: shaded cells are not used by the watchdog timer. note 1: see register 12-1 for operation of these bits.
? 2003 microchip technology inc. preliminary ds39598d-page 99 pic16f818/819 12.13 power-down mode (sleep) power-down mode is entered by executing a sleep instruction. if enabled, the watchdog timer will be cleared but keeps running, the pd bit (status<3>) is cleared, the to (status<4>) bit is set and the oscillator driver is turned off. the i/o ports maintain the status they had before the sleep instruction was executed (driving high, low or high-impedance). for lowest current consumption in this mode, place all i/o pins at either v dd or v ss , ensure no external cir- cuitry is drawing current from the i/o pin, power-down the a/d and disable external clocks. pull all i/o pins that are high-impedance inputs, high or low externally, to avoid switching currents caused by floating inputs. the t0cki input should also be at v dd or v ss for low- est current consumption. the contribution from on-chip pull-ups on portb should also be considered. the mclr pin must be at a logic high level (v ihmc ). 12.13.1 wake-up from sleep the device can wake-up from sleep through one of the following events: 1. external reset input on mclr pin. 2. watchdog timer wake-up (if wdt was enabled). 3. interrupt from int pin, rb port change or a peripheral interrupt. external mclr reset will cause a device reset. all other events are considered a continuation of program execution and cause a ?wake-up?. the to and pd bits in the status register can be used to determine the cause of the device reset. the pd bit, which is set on power-up, is cleared when sleep is invoked. the to bit is cleared if a wdt time-out occurred and caused wake-up. the following peripheral interrupts can wake the device from sleep: 1. tmr1 interrupt. timer1 must be operating as an asynchronous counter. 2. ccp capture mode interrupt. 3. special event trigger (timer1 in asynchronous mode using an external clock). 4. ssp (start/stop) bit detect interrupt. 5. ssp transmit or receive in slave mode (spi/i 2 c). 6. a/d conversion (when a/d clock source is rc). 7. eeprom write operation completion. other peripherals cannot generate interrupts since during sleep, no on-chip clocks are present. when the sleep instruction is being executed, the next instruction (pc + 1) is prefetched. for the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). wake-up occurs regardless of the state of the gie bit. if the gie bit is clear (disabled), the device continues execution at the instruction after the sleep instruction. if the gie bit is set (enabled), the device executes the instruction after the sleep instruction and then branches to the interrupt address (0004h). in cases where the execu- tion of the instruction following sleep is not desirable, the user should have a nop after the sleep instruction. 12.13.2 wake-up using interrupts when global interrupts are disabled (gie cleared) and any interrupt source has both its interrupt enable bit and interrupt flag bit set, one of the following will occur: if the interrupt occurs before the execution of a sleep instruction, the sleep instruction will complete as a nop . therefore, the wdt and wdt postscaler will not be cleared, the to bit will not be set and pd bit will not be cleared. if the interrupt occurs during or after the execution of a sleep instruction, the device will immediately wake-up from sleep. the sleep instruction will be completely executed before the wake-up. therefore, the wdt and wdt postscaler will be cleared, the to bit will be set and the pd bit will be cleared. even if the flag bits were checked before executing a sleep instruction, it may be possible for flag bits to become set before the sleep instruction completes. to determine whether a sleep instruction executed, test the pd bit. if the pd bit is set, the sleep instruction was executed as a nop . to ensure that the wdt is cleared, a clrwdt instruction should be executed before a sleep instruction.
pic16f818/819 ds39598d-page 100 preliminary ? 2003 microchip technology inc. figure 12-9: wake-up from sleep through interrupt 12.14 in-circuit debugger when the debug bit in the configuration word is programmed to a ? 0 ?, the in-circuit debugger functional- ity is enabled. this function allows simple debugging functions when used with mplab ? icd. when the microcontroller has this feature enabled, some of the resources are not available for general use. table 12-6 shows which features are consumed by the background debugger. table 12-6: debugger resources to use the in-circuit debugger function of the micro- controller, the design must implement in-circuit serial programming connections to mclr /v pp , v dd , gnd, rb7 and rb6. this will interface to the in-circuit debugger module available from microchip or one of the third party development tool companies. 12.15 program verification/code protection if the code protection bit(s) have not been programmed, the on-chip program memory can be read out for verification purposes. 12.16 id locations four memory locations (2000h-2003h) are designated as id locations, where the user can store checksum or other code identification numbers. these locations are not accessible during normal execution but are readable and writable during program/verify. it is recommended that only the four least significant bits of the id location are used. q1 q2 q3 q4 q1 q2 q3 q4 q1 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 clko (4) int pin intf flag (intcon<1>) gie bit (intcon<7>) instruction flow pc instruction fetched instruction executed pc pc+1 pc+2 inst(pc) = sleep inst(pc ? 1) inst(pc + 1) sleep processor in sleep interrupt latency (note 2) inst(pc + 2) inst(pc + 1) inst(0004h) inst(0005h) inst(0004h) dummy cycle pc + 2 0004h 0005h dummy cycle t ost (2) pc+2 note 1: xt, hs or lp oscillator mode assumed. 2: t ost = 1024 t osc (drawing not to scale). this delay will not be there for rc oscillator mode. 3: gie = 1 assumed. in this case, after wake-up, th e processor jumps to the interrupt routine. if gie = 0 , execution will continue in-line. 4: clko is not available in these oscillator modes but shown here for timing reference. i/o pins rb6, rb7 stack 1 level program memory address 0000h must be nop last 100h words data memory 0x070 (0x0f0, 0x170, 0x1f0) 0x1eb-0x1ef
? 2003 microchip technology inc. preliminary ds39598d-page 101 pic16f818/819 12.17 in-circuit serial programming pic16f818/819 microcontrollers can be serially pro- grammed while in the end application circuit. this is simply done with two lines for clock and data and three other lines for power, ground and the programming voltage (see figure 12-10 for an example). this allows customers to manufacture boards with unprogrammed devices and then program the microcontroller just before shipping the product. this also allows the most recent firmware or a custom firmware to be programmed. for more information on serial programming, please refer to the pic16f818/819 flash memory programming specification (ds39603). figure 12-10: typical in-circuit serial programming connection 12.18 low-voltage icsp programming the lvp bit of the configuration word register enables low-voltage icsp programming. this mode allows the microcontroller to be programmed via icsp using a v dd source in the operating voltage range. this only means that v pp does not have to be brought to v ihh but can instead be left at the normal operating voltage. in this mode, the rb3/pgm pin is dedicated to the programming function and ceases to be a general purpose i/o pin. if low-voltage programming mode is not used, the lvp bit can be programmed to a ? 0 ? and rb3/pgm becomes a digital i/o pin. however, the lvp bit may only be pro- grammed when programming mode is entered with v ihh on mclr . the lvp bit can only be changed when using high voltage on mclr . it should be noted that once the lvp bit is programmed to ? 0 ?, only the high-voltage programming mode is available and only this mode can be used to program the device. when using low-voltage icsp, the part must be sup- plied at 4.5v to 5.5v if a bulk erase will be executed. this includes reprogramming of the code-protect bits from an on state to an off state. for all other cases of low-voltage icsp, the part may be programmed at the normal oper- ating voltage. this means calibration values, unique user ids or user code can be reprogrammed or added. the following lvp steps assume the lvp bit is set in the configuration register. 1. apply v dd to the v dd pin. 2. drive mclr low. 3. apply v dd to the rb3/pgm pin. 4. apply v dd to the mclr pin. 5. follow with the associated programming steps. external connector signals to normal connections to n o r m a l connections pic16f818/819 v dd v ss mclr /v pp rb6 rb7 +5v 0v v pp clk data i/o v dd * * * * * isolation devices (as required). ? rb3 only used in lvp mode. rb3 ? rb3/pgm note 1: the high-voltage programming mode is always available, regardless of the state of the lvp bit, by applying v ihh to the mclr pin. 2: while in low-voltage icsp mode (lvp = 1 ), the rb3 pin can no longer be used as a general purpose i/o pin. 3: when using low-voltage icsp program- ming (lvp) and the pull-ups on portb are enabled, bit 3 in the trisb register must be cleared to disable the pull-up on rb3 and ensure the proper operation of the device. 4: rb3 should not be allowed to float if lvp is enabled. an external pull-down device should be used to default the device to normal operating mode. if rb3 floats high, the pic16f818/819 device will enter programming mode. 5: lvp mode is enabled by default on all devices shipped from microchip. it can be disabled by clearing the lvp bit in the configuration register. 6: disabling lvp will provide maximum compatibility to other pic16cxxx devices.
pic16f818/819 ds39598d-page 102 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 103 pic16f818/819 13.0 instruction set summary the pic16 instruction set is highly orthogonal and is comprised of three basic categories: byte-oriented operations bit-oriented operations literal and control operations each pic16 instruction is a 14-bit word divided into an opcode, which specifies the instruction type and one or more operands, which further specify the operation of the instruction. the formats for each of the categories are presented in figure 13-1, while the various opcode fields are summarized in table 13-1. table 13-2 lists the instructions recognized by the mpasm tm assembler. a complete description of each instruction is also available in the picmicro ? mid-range mcu family reference manual (ds33023). for byte-oriented instructions, ?f? represents a file register designator and ?d? represents a destination designator. the file register designator specifies which file register is to be used by the instruction. the destination designator specifies where the result of the operation is to be placed. if ?d? is zero, the result is placed in the w register. if ?d? is one, the result is placed in the file register specified in the instruction. for bit-oriented instructions, ?b? represents a bit field designator, which selects the bit affected by the opera- tion, while ?f? represents the address of the file in which the bit is located. for literal and control operations, ?k? represents an eight or eleven-bit constant or literal value one instruction cycle consists of four oscillator periods. for an oscillator frequency of 4 mhz, this gives a nor- mal instruction execution time of 1 s. all instructions are executed within a single instruction cycle, unless a conditional test is true, or the program counter is changed as a result of an instruction. when this occurs, the execution takes two instruction cycles, with the second cycle executed as a nop . all instruction examples use the format ? 0xhh ? to repre- sent a hexadecimal number, where ? h ? signifies a hexadecimal digit. 13.1 read-modify-write operations any instruction that specifies a file register as part of the instruction performs a read-modify-write (r-m-w) operation. the register is read, the data is modified and the result is stored according to either the instruction or the destination designator ?d?. a read operation is per- formed on a register even if the instruction writes to that register. for example, a ? clrf portb ? instruction will read portb, clear all the data bits, then write the result back to portb. this example would have the unin- tended result that the condition that sets the rbif flag would be cleared. table 13-1: opcode field descriptions figure 13-1: general format for instructions note: to maintain upward compatibility with future pic16f818/819 products, do not use the option and tris instructions. field description f register file address (0x00 to 0x7f) w working register (accumulator) b bit address within an 8-bit file register k literal field, constant data or label x don?t care location (= 0 or 1 ). the assembler will generate code with x = 0 . it is the recommended form of use for compatibility with all microchip software tools. d destination select; d = 0 : store result in w, d = 1: store result in file register f. default is d = 1. pc program counter to time-out bit pd power-down bit byte-oriented file register operations 13 8 7 6 0 d = 0 for destination w opcode d f (file #) d = 1 for destination f f = 7-bit file register address bit-oriented file register operations 13 10 9 7 6 0 opcode b (bit #) f (file #) b = 3-bit bit address f = 7-bit file register address literal and control operations 13 8 7 0 opcode k (literal) k = 8-bit immediate value 13 11 10 0 opcode k (literal) k = 11-bit immediate value general call and goto instructions only
pic16f818/819 ds39598d-page 104 preliminary ? 2003 microchip technology inc. table 13-2: pic16f818/819 instruction set mnemonic, operands description cycles 14-bit opcode status affected notes msb lsb byte-oriented file register operations addwf andwf clrf clrw comf decf decfsz incf incfsz iorwf movf movwf nop rlf rrf subwf swapf xorwf f, d f, d f - f, d f, d f, d f, d f, d f, d f, d f - f, d f, d f, d f, d f, d add w and f and w with f clear f clear w complement f decrement f decrement f, skip if 0 increment f increment f, skip if 0 inclusive or w with f move f move w to f no operation rotate left f through carry rotate right f through carry subtract w from f swap nibbles in f exclusive or w with f 1 1 1 1 1 1 1 (2) 1 1 (2) 1 1 1 1 1 1 1 1 1 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0111 0101 0001 0001 1001 0011 1011 1010 1111 0100 1000 0000 0000 1101 1100 0010 1110 0110 dfff dfff lfff 0xxx dfff dfff dfff dfff dfff dfff dfff lfff 0xx0 dfff dfff dfff dfff dfff ffff ffff ffff xxxx ffff ffff ffff ffff ffff ffff ffff ffff 0000 ffff ffff ffff ffff ffff c, dc, z z z z z z z z z c c c, dc, z z 1, 2 1, 2 2 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 bit-oriented file register operations bcf bsf btfsc btfss f, b f, b f, b f, b bit clear f bit set f bit test f, skip if clear bit test f, skip if set 1 1 1 (2) 1 (2) 01 01 01 01 00bb 01bb 10bb 11bb bfff bfff bfff bfff ffff ffff ffff ffff 1, 2 1, 2 3 3 literal and control operations addlw andlw call clrwdt goto iorlw movlw retfie retlw return sleep sublw xorlw k k k - k k k - k - - k k add literal and w and literal with w call subroutine clear watchdog timer go to address inclusive or literal with w move literal to w return from interrupt return with literal in w return from subroutine go into standby mode subtract w from literal exclusive or literal with w 1 1 2 1 2 1 1 2 2 2 1 1 1 11 11 10 00 10 11 11 00 11 00 00 11 11 111x 1001 0kkk 0000 1kkk 1000 00xx 0000 01xx 0000 0000 110x 1010 kkkk kkkk kkkk 0110 kkkk kkkk kkkk 0000 kkkk 0000 0110 kkkk kkkk kkkk kkkk kkkk 0100 kkkk kkkk kkkk 1001 kkkk 1000 0011 kkkk kkkk c, dc, z z to , pd z to , pd c, dc, z z note 1: when an i/o register is modified as a function of itself ( e.g., movf portb, 1 ), the value used will be that value present on the pins themselves. for example, if the data latch is ? 1 ? for a pin configured as input and is driven low by an external device, the data will be written back with a ? 0 ?. 2: if this instruction is executed on the tm r0 register (and where applicable, d = 1 ), the prescaler will be cleared if assigned to the timer0 module. 3: if the program counter (pc) is modified or a conditional te st is true, the instruction requires two cycles. the second cycle is executed as a nop . note: additional information on the mid-range instruction set is available in the picmicro ? mid-range mcu family reference manual (ds33023).
? 2003 microchip technology inc. preliminary ds39598d-page 105 pic16f818/819 13.2 instruction descriptions addlw add literal and w syntax: [ label ] addlw k operands: 0 k 255 operation: (w) + k (w) status affected: c, dc, z description: the contents of the w register are added to the eight-bit literal ?k? and the result is placed in the w register. addwf add w and f syntax: [ label ] addwf f,d operands: 0 f 127 d [0,1] operation: (w) + (f) (destination) status affected: c, dc, z description: add the contents of the w register with register ?f?. if ?d? = 0 , the result is stored in the w register. if ?d? = 1 , the result is stored back in register ?f?. andlw and literal with w syntax: [ label ] andlw k operands: 0 k 255 operation: (w) .and. (k) (w) status affected: z description: the contents of w register are and?ed with the eight-bit literal ?k?. the result is placed in the w register. andwf and w with f syntax: [ label ] andwf f,d operands: 0 f 127 d [0,1] operation: (w) .and. (f) (destination) status affected: z description: and the w register with register ?f?. if ?d? = 0 , the result is stored in the w register. if ?d? = 1 , the result is stored back in register ?f?. bcf bit clear f syntax: [ label ] bcf f,b operands: 0 f 127 0 b 7 operation: 0 (f) status affected: none description: bit ?b? in register ?f? is cleared. bsf bit set f syntax: [ label ] bsf f,b operands: 0 f 127 0 b 7 operation: 1 (f) status affected: none description: bit ?b? in register ?f? is set.
pic16f818/819 ds39598d-page 106 preliminary ? 2003 microchip technology inc. btfss bit test f, skip if set syntax: [ label ] btfss f,b operands: 0 f 127 0 b < 7 operation: skip if (f) = 1 status affected: none description: if bit ?b? in register ?f? = 0 , the next instruction is executed. if bit ?b? = 1 , then the next instruction is discarded and a nop is executed instead, making this a 2 t cy instruction. btfsc bit test, skip if clear syntax: [ label ] btfsc f,b operands: 0 f 127 0 b 7 operation: skip if (f) = 0 status affected: none description: if bit ?b? in register ?f? = 1 , the next instruction is executed. if bit ?b? in register ?f? = 0 , the next instruction is discarded and a nop is executed instead, making this a 2 t cy instruction. call call subroutine syntax: [ label ] call k operands: 0 k 2047 operation: (pc) + 1 tos, k pc<10:0>, (pclath<4:3>) pc<12:11> status affected: none description: call subroutine. first, return address (pc+1) is pushed onto the stack. the eleven-bit immediate address is loaded into pc bits<10:0>. the upper bits of the pc are loaded from pclath. call is a two-cycle instruction. clrf clear f syntax: [ label ] clrf f operands: 0 f 127 operation: 00h (f) 1 z status affected: z description: the contents of register ?f? are cleared and the z bit is set. clrw clear w syntax: [ label ] clrw operands: none operation: 00h (w) 1 z status affected: z description: w register is cleared. zero bit (z) is set. clrwdt clear watchdog timer syntax: [ label ] clrwdt operands: none operation: 00h wdt 0 wdt prescaler, 1 to 1 pd status affected: to , pd description: clrwdt instruction resets the watchdog timer. it also resets the prescaler of the wdt. status bits to and pd are set.
? 2003 microchip technology inc. preliminary ds39598d-page 107 pic16f818/819 comf complement f syntax: [ label ] comf f,d operands: 0 f 127 d [0,1] operation: (f) (destination) status affected: z description: the contents of register ?f? are complemented. if ?d? = 0 , the result is stored in w. if ?d? = 1 , the result is stored back in register ?f?. decf decrement f syntax: [ label ] decf f,d operands: 0 f 127 d [0,1] operation: (f) - 1 (destination) status affected: z description: decrement register ?f?. if ?d? = 0 , the result is stored in the w regis- ter. if ?d? = 1 , the result is stored back in register ?f?. decfsz decrement f, skip if 0 syntax: [ label ] decfsz f,d operands: 0 f 127 d [0,1] operation: (f) - 1 (destination); skip if result = 0 status affected: none description: the contents of register ?f? are decremented. if ?d? = 0 , the result is placed in the w register. if ?d? = 1 , the result is placed back in register ?f?. if the result is ? 1 ?, the next instruc- tion is executed. if the result is ? 0 ?, then a nop is executed instead, making it a 2 t cy instruction. goto unconditional branch syntax: [ label ] goto k operands: 0 k 2047 operation: k pc<10:0> pclath<4:3> pc<12:11> status affected: none description: goto is an unconditional branch. the eleven-bit immediate value is loaded into pc bits<10:0>. the upper bits of pc are loaded from pclath<4:3>. goto is a two-cycle instruction. incf increment f syntax: [ label ] incf f,d operands: 0 f 127 d [0,1] operation: (f) + 1 (destination) status affected: z description: the contents of register ?f? are incremented. if ?d? = 0 , the result is placed in the w register. if ?d? = 1 , the result is placed back in register ?f?. incfsz increment f, skip if 0 syntax: [ label ] incfsz f,d operands: 0 f 127 d [0,1] operation: (f) + 1 (destination), skip if result = 0 status affected: none description: the contents of register ?f? are incremented. if ?d? = 0 , the result is placed in the w register. if ?d? = 1 , the result is placed back in register ?f?. if the result is ? 1 ?, the next instruc- tion is executed. if the result is ? 0 ?, a nop is executed instead, mak- ing it a 2 t cy instruction.
pic16f818/819 ds39598d-page 108 preliminary ? 2003 microchip technology inc. iorlw inclusive or literal with w syntax: [ label ] iorlw k operands: 0 k 255 operation: (w) .or. k (w) status affected: z description: the contents of the w register are or?d with the eight-bit literal ?k?. the result is placed in the w register. iorwf inclusive or w with f syntax: [ label ] iorwf f,d operands: 0 f 127 d [0,1] operation: (w) .or. (f) (destination) status affected: z description: inclusive or the w register with register ?f?. if ?d? = 0 , the result is placed in the w register. if ?d? = 1 , the result is placed back in register ?f?. movf move f syntax: [ label ] movf f,d operands: 0 f 127 d [0,1] operation: (f) (destination) status affected: z description: the contents of register ?f? are moved to a destination dependant upon the status of ?d?. if ?d? = 0 , the destination is w register. if ?d? = 1 , the destination is file regis- ter ?f? itself. ?d? = 1 is useful to test a file register, since status flag z is affected. movlw move literal to w syntax: [ label ] movlw k operands: 0 k 255 operation: k (w) status affected: none description: the eight-bit literal ?k? is loaded into w register. the don?t cares will assemble as ? 0 ?s. movwf move w to f syntax: [ label ] movwf f operands: 0 f 127 operation: (w) (f) status affected: none description: move data from w register to register ?f?. nop no operation syntax: [ label ] nop operands: none operation: no operation status affected: none description: no operation.
? 2003 microchip technology inc. preliminary ds39598d-page 109 pic16f818/819 retfie return from interrupt syntax: [ label ] retfie operands: none operation: tos pc, 1 gie status affected: none retlw return with literal in w syntax: [ label ] retlw k operands: 0 k 255 operation: k (w); tos pc status affected: none description: the w register is loaded with the eight-bit literal ?k?. the program counter is loaded from the top of the stack (the return address). this is a two-cycle instruction. return return from subroutine syntax: [ label ] return operands: none operation: tos pc status affected: none description: return from subroutine. the stack is poped and the top of the stack (tos) is loaded into the program counter. this is a two-cycle instruction. rlf rotate left f through carry syntax: [ label ] rlf f,d operands: 0 f 127 d [0,1] operation: see description below status affected: c description: the contents of register ?f? are rotated one bit to the left through the carry flag. if ?d? = 0 , the result is placed in the w register. if ?d? = 1 , the result is stored back in register ?f?. rrf rotate right f through carry syntax: [ label ] rrf f,d operands: 0 f 127 d [0,1] operation: see description below status affected: c description: the contents of register ?f? are rotated one bit to the right through the carry flag. if ?d? = 0 , the result is placed in the w register. if ?d? = 1 , the result is placed back in register ?f?. sleep syntax: [ label ]sleep operands: none operation: 00h wdt, 0 wdt prescaler, 1 to , 0 pd status affected: to , pd description: the power-down status bit, pd , is cleared. time-out status bit, to , is set. watchdog timer and its prescaler are cleared. the processor is put into sleep mode with the oscillator stopped. register f c register f c
pic16f818/819 ds39598d-page 110 preliminary ? 2003 microchip technology inc. sublw subtract w from literal syntax: [ label ] sublw k operands: 0 k 255 operation: k - (w) ( w) status affected: c, dc, z description: the w register is subtracted (2?s complement method) from the eight-bit literal ?k?. the result is placed in the w register. subwf subtract w from f syntax: [ label ] subwf f,d operands: 0 f 127 d [0,1] operation: (f) - (w) ( destination) status affected: c, dc, z description: subtract (2?s complement method) w register from register ?f?. if ?d? = 0 , the result is stored in the w register. if ?d? = 1 , the result is stored back in register ?f?. swapf swap nibbles in f syntax: [ label ] swapf f,d operands: 0 f 127 d [0,1] operation: (f<3:0>) (destination<7:4>), (f<7:4>) (destination<3:0>) status affected: none description: the upper and lower nibbles of register ?f? are exchanged. if ?d? = 0 , the result is placed in w register. if ?d? = 1 , the result is placed in register ?f?. xorlw exclusive or literal with w syntax: [ label ]xorlw k operands: 0 k 255 operation: (w) .xor. k ( w) status affected: z description: the contents of the w register are xor?ed with the eight-bit literal ?k?. the result is placed in the w register. xorwf exclusive or w with f syntax: [ label ] xorwf f,d operands: 0 f 127 d [0,1] operation: (w) .xor. (f) ( destination) status affected: z description: exclusive or the contents of the w register with register ?f?. if ?d? = 0 , the result is stored in the w register. if ?d? = 1 , the result is stored back in register ?f?.
? 2003 microchip technology inc. preliminary ds39598d-page111 pic16f818/819 14.0 development support the picmicro ? microcontrollers are supported with a full range of hardware and software development tools: integrated development environment - mplab ? ide software assemblers/compilers/linkers - mpasm tm assembler - mplab c17 and mplab c18 c compilers -mplink tm object linker/ mplib tm object librarian - mplab c30 c compiler - mplab asm30 assembler/linker/library simulators - mplab sim software simulator - mplab dspic30 software simulator emulators - mplab ice 2000 in-circuit emulator - mplab ice 4000 in-circuit emulator in-circuit debugger - mplab icd 2 device programmers -pro mate ? ii universal device programmer - picstart ? plus development programmer low-cost demonstration boards - picdem tm 1 demonstration board - picdem.net tm demonstration board - picdem 2 plus demonstration board - picdem 3 demonstration board - picdem 4 demonstration board - picdem 17 demonstration board - picdem 18r demonstration board - picdem lin demonstration board - picdem usb demonstration board evaluation kits -k ee l oq ? - picdem msc -microid ? -can - powersmart ? -analog 14.1 mplab integrated development environment software the mplab ide software brings an ease of software development previously unseen in the 8/16-bit micro- controller market. the mplab ide is a windows ? based application that contains: an interface to debugging tools - simulator - programmer (sold separately) - emulator (sold separately) - in-circuit debugger (sold separately) a full-featured editor with color coded context a multiple project manager customizable data windows with direct edit of contents high-level source code debugging mouse over variable inspection extensive on-line help the mplab ide allows you to: edit your source files (either assembly or c) one touch assemble (or compile) and download to picmicro emulator and simulator tools (automatically updates all project information) debug using: - source files (assembly or c) - absolute listing file (mixed assembly and c) - machine code mplab ide supports multiple debugging tools in a single development paradigm, from the cost effective simulators, through low-cost in-circuit debuggers, to full-featured emulators. this eliminates the learning curve when upgrading to tools with increasing flexibility and power. 14.2 mpasm assembler the mpasm assembler is a full-featured, universal macro assembler for all picmicro mcus. the mpasm assembler generates relocatable object files for the mplink object linker, intel ? standard hex files, map files to detail memory usage and symbol ref- erence, absolute lst files that contain source lines and generated machine code and coff files for debugging. the mpasm assembler features include: integration into mplab ide projects user defined macros to streamline assembly code conditional assembly for multi-purpose source files directives that allow complete control over the assembly process
pic16f818/819 ds39598d-page 112 preliminary ? 2003 microchip technology inc. 14.3 mplab c17 and mplab c18 c compilers the mplab c17 and mplab c18 code development systems are complete ansi c compilers for microchip?s pic17cxxx and pic18cxxx family of microcontrollers. these compilers provide powerful integration capabilities, superior code optimization and ease of use not found with other compilers. for easy source level debugging, the compilers provide symbol information that is optimized to the mplab ide debugger. 14.4 mplink object linker/ mplib object librarian the mplink object linker combines relocatable objects created by the mpasm assembler and the mplab c17 and mplab c18 c compilers. it can link relocatable objects from precompiled libraries, using directives from a linker script. the mplib object librarian manages the creation and modification of library files of precompiled code. when a routine from a library is called from a source file, only the modules that contain that routine will be linked in with the application. this allows large libraries to be used efficiently in many different applications. the object linker/library features include: efficient linking of single libraries instead of many smaller files enhanced code maintainability by grouping related modules together flexible creation of libraries with easy module listing, replacement, deletion and extraction 14.5 mplab c30 c compiler the mplab c30 c compiler is a full-featured, ansi compliant, optimizing compiler that translates standard ansi c programs into dspic30f assembly language source. the compiler also supports many command- line options and language extensions to take full advantage of the dspic30f device hardware capabili- ties and afford fine control of the compiler code generator. mplab c30 is distributed with a complete ansi c standard library. all library functions have been vali- dated and conform to the ansi c library standard. the library includes functions for string manipulation, dynamic memory allocation, data conversion, time- keeping and math functions (trigonometric, exponential and hyperbolic). the compiler provides symbolic information for high-level source debugging with the mplab ide. 14.6 mplab asm30 assembler, linker and librarian mplab asm30 assembler produces relocatable machine code from symbolic assembly language for dspic30f devices. mplab c30 compiler uses the assembler to produce it?s object file. the assembler generates relocatable object files that can then be archived or linked with other relocatable object files and archives to create an executable file. notable features of the assembler include: support for the entire dspic30f instruction set support for fixed-point and floating-point data command line interface rich directive set flexible macro language mplab ide compatibility 14.7 mplab sim software simulator the mplab sim software simulator allows code devel- opment in a pc hosted environment by simulating the picmicro series microcontrollers on an instruction level. on any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any pin. the execu- tion can be performed in single-step, execute until break or trace mode. the mplab sim simulator fully supports symbolic debugging using the mplab c17 and mplab c18 c compilers, as well as the mpasm assembler. the software simulator offers the flexibility to develop and debug code outside of the laboratory environment, making it an excellent, economical software development tool. 14.8 mplab sim30 software simulator the mplab sim30 software simulator allows code development in a pc hosted environment by simulating the dspic30f series microcontrollers on an instruction level. on any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any of the pins. the mplab sim30 simulator fully supports symbolic debugging using the mplab c30 c compiler and mplab asm30 assembler. the simulator runs in either a command line mode for automated tasks, or from mplab ide. this high-speed simulator is designed to debug, analyze and optimize time intensive dsp routines.
? 2003 microchip technology inc. preliminary ds39598d-page113 pic16f818/819 14.9 mplab ice 2000 high-performance universal in-circuit emulator the mplab ice 2000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for picmicro microcontrollers. software control of the mplab ice 2000 in-circuit emulator is advanced by the mplab integrated development environment, which allows editing, building, downloading and source debugging from a single environment. the mplab ice 2000 is a full-featured emulator sys- tem with enhanced trace, trigger and data monitoring features. interchangeable processor modules allow the system to be easily reconfigured for emulation of differ- ent processors. the universal architecture of the mplab ice in-circuit emulator allows expansion to support new picmicro microcontrollers. the mplab ice 2000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. the pc platform and microsoft ? windows 32-bit operating system were chosen to best make these features available in a simple, unified application. 14.10 mplab ice 4000 high-performance universal in-circuit emulator the mplab ice 4000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for high- end picmicro microcontrollers. software control of the mplab ice in-circuit emulator is provided by the mplab integrated development environment, which allows editing, building, downloading and source debugging from a single environment. the mplab icd 4000 is a premium emulator system, providing the features of mplab ice 2000, but with increased emulation memory and high-speed perfor- mance for dspic30f and pic18xxxx devices. its advanced emulator features include complex triggering and timing, up to 2 mb of emulation memory and the ability to view variables in real-time. the mplab ice 4000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. the pc platform and microsoft windows 32-bit operating system were chosen to best make these features available in a simple, unified application. 14.11 mplab icd 2 in-circuit debugger microchip?s in-circuit debugger, mplab icd 2, is a powerful, low-cost, run-time development tool, connecting to the host pc via an rs-232 or high-speed usb interface. this tool is based on the flash picmicro mcus and can be used to develop for these and other picmicro microcontrollers. the mplab icd 2 utilizes the in-circuit debugging capability built into the flash devices. this feature, along with microchip?s in-circuit serial programming tm (icsp tm ) protocol, offers cost effective in-circuit flash debugging from the graphical user interface of the mplab inte- grated development environment. this enables a designer to develop and debug source code by setting breakpoints, single-stepping and watching variables, cpu status and peripheral registers. running at full speed enables testing hardware and applications in real-time. mplab icd 2 also serves as a development programmer for selected picmicro devices. 14.12 pro mate ii universal device programmer the pro mate ii is a universal, ce compliant device programmer with programmable voltage verification at v ddmin and v ddmax for maximum reliability. it features an lcd display for instructions and error messages and a modular detachable socket assembly to support various package types. in stand-alone mode, the pro mate ii device programmer can read, verify and program picmicro devices without a pc connection. it can also set code protection in this mode. 14.13 picstart plus development programmer the picstart plus development programmer is an easy-to-use, low-cost, prototype programmer. it con- nects to the pc via a com (rs-232) port. mplab integrated development environment software makes using the programmer simple and efficient. the picstart plus development programmer supports most picmicro devices up to 40 pins. larger pin count devices, such as the pic16c92x and pic17c76x, may be supported with an adapter socket. the picstart plus development programmer is ce compliant.
pic16f818/819 ds39598d-page 114 preliminary ? 2003 microchip technology inc. 14.14 picdem 1 picmicro demonstration board the picdem 1 demonstration board demonstrates the capabilities of the pic16c5x (pic16c54 to pic16c58a), pic16c61, pic16c62x, pic16c71, pic16c8x, pic17c42, pic17c43 and pic17c44. all necessary hardware and software is included to run basic demo programs. the sample microcontrollers provided with the picdem 1 demonstration board can be programmed with a pro mate ii device program- mer or a picstart plus development programmer. the picdem 1 demonstration board can be connected to the mplab ice in-circuit emulator for testing. a prototype area extends the circuitry for additional appli- cation components. features include an rs-232 interface, a potentiometer for simulated analog input, push button switches and eight leds. 14.15 picdem.net internet/ethernet demonstration board the picdem.net demonstration board is an internet/ ethernet demonstration board using the pic18f452 microcontroller and tcp/ip firmware. the board supports any 40-pin dip device that conforms to the standard pinout used by the pic16f877 or pic18c452. this kit features a user friendly tcp/ip stack, web server with html, a 24l256 serial eeprom for xmodem download to web pages into serial eeprom, icsp/mplab icd 2 interface con- nector, an ethernet interface, rs-232 interface and a 16 x 2 lcd display. also included is the book and cd-rom ?tcp/ip lean, web servers for embedded systems,? by jeremy bentham 14.16 picdem 2 plus demonstration board the picdem 2 plus demonstration board supports many 18, 28 and 40-pin microcontrollers, including pic16f87x and pic18fxx2 devices. all the neces- sary hardware and software is included to run the dem- onstration programs. the sample microcontrollers provided with the picdem 2 demonstration board can be programmed with a pro mate ii device program- mer, picstart plus development programmer, or mplab icd 2 with a universal programmer adapter. the mplab icd 2 and mplab ice in-circuit emulators may also be used with the picdem 2 demonstration board to test firmware. a prototype area extends the circuitry for additional application components. some of the features include an rs-232 interface, a 2 x 16 lcd display, a piezo speaker, an on-board temperature sensor, four leds and sample pic18f452 and pic16f877 flash microcontrollers. 14.17 picdem 3 pic16c92x demonstration board the picdem 3 demonstration board supports the pic16c923 and pic16c924 in the plcc package. all the necessary hardware and software is included to run the demonstration programs. 14.18 picdem 4 8/14/18-pin demonstration board the picdem 4 can be used to demonstrate the capa- bilities of the 8, 14 and 18-pin pic16xxxx and pic18xxxx mcus, including the pic16f818/819, pic16f87/88, pic16f62xa and the pic18f1320 fam- ily of microcontrollers. picdem 4 is intended to show- case the many features of these low pin count parts, including lin and motor control using eccp. special provisions are made for low-power operation with the supercapacitor circuit and jumpers allow on-board hardware to be disabled to eliminate current draw in this mode. included on the demo board are provisions for crystal, rc or canned oscillator modes, a five volt regulator for use with a nine volt wall adapter or battery, db-9 rs-232 interface, icd connector for program- ming via icsp and development with mplab icd 2, 2x16 liquid crystal display, pcb footprints for h-bridge motor driver, lin transceiver and eeprom. also included are: header for expansion, eight leds, four potentiometers, three push buttons and a prototyping area. included with the kit is a pic16f627a and a pic18f1320. tutorial firmware is included along with the user?s guide. 14.19 picdem 17 demonstration board the picdem 17 demonstration board is an evaluation board that demonstrates the capabilities of several microchip microcontrollers, including pic17c752, pic17c756a, pic17c762 and pic17c766. a pro- grammed sample is included. the pro mate ii device programmer, or the picstart plus development pro- grammer, can be used to reprogram the device for user tailored application development. the picdem 17 demonstration board supports program download and execution from external on-board flash memory. a generous prototype area is available for user hardware expansion.
? 2003 microchip technology inc. preliminary ds39598d-page115 pic16f818/819 14.20 picdem 18r pic18c601/801 demonstration board the picdem 18r demonstration board serves to assist development of the pic18c601/801 family of microchip microcontrollers. it provides hardware implementation of both 8-bit multiplexed/demultiplexed and 16-bit memory modes. the board includes 2 mb external flash memory and 128 kb sram memory, as well as serial eeprom, allowing access to the wide range of memory types supported by the pic18c601/801. 14.21 picdem lin pic16c43x demonstration board the powerful lin hardware and software kit includes a series of boards and three picmicro microcontrollers. the small footprint pic16c432 and pic16c433 are used as slaves in the lin communication and feature on-board lin transceivers. a pic16f874 flash microcontroller serves as the master. all three micro- controllers are programmed with firmware to provide lin bus communication. 14.22 pickit tm 1 flash starter kit a complete ?development system in a box?, the pickit flash starter kit includes a convenient multi-section board for programming, evaluation and development of 8/14-pin flash pic ? microcontrollers. powered via usb, the board operates under a simple windows gui. the pickit 1 starter kit includes the user's guide (on cd rom), pickit 1 tutorial software and code for vari- ous applications. also included are mplab ? ide (inte- grated development environment) software, software and hardware ?tips 'n tricks for 8-pin flash pic ? microcontrollers? handbook and a usb interface cable. supports all current 8/14-pin flash pic microcontrollers, as well as many future planned devices. 14.23 picdem usb pic16c7x5 demonstration board the picdem usb demonstration board shows off the capabilities of the pic16c745 and pic16c765 usb microcontrollers. this board provides the basis for future usb products. 14.24 evaluation and programming tools in addition to the picdem series of circuits, microchip has a line of evaluation kits and demonstration software for these products. k ee l oq evaluation and programming tools for microchip?s hcs secure data products can developers kit for automotive network applications analog design boards and filter design software powersmart battery charging evaluation/ calibration kits irda ? development kit microid development and rflab tm development software seeval ? designer kit for memory evaluation and endurance calculations picdem msc demo boards for switching mode power supply, high-power ir driver, delta sigma adc and flow rate sensor check the microchip web page and the latest product line card for the complete list of demonstration and evaluation kits.
pic16f818/819 ds39598d-page 116 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 117 pic16f818/819 15.0 electrical characteristics absolute maximum ratings ? ambient temperature under bias................................................................................................. ........... -55c to +125c storage temperature ............................................................................................................ .................. -65c to +150c voltage on any pin with respect to v ss (except v dd and m clr ) ................................................... -0.3v to (v dd + 0.3v) voltage on v dd with respect to v ss ............................................................................................................ -0.3 to +7.5v voltage on mclr with respect to v ss (note 2) .............................................................................................-0.3 to +14v total power dissipation (note 1) ............................................................................................................................... ...1w maximum current out of v ss pin ........................................................................................................................... 200 ma maximum current into v dd pin ........................................................................................................................... ...200 ma input clamp current, i ik (v i < 0 or v i > v dd ) ..................................................................................................................... 20 ma output clamp current, i ok (v o < 0 or v o > v dd ) ............................................................................................................. 20 ma maximum output current sunk by any i/o pin..................................................................................... .....................25 ma maximum output current sourced by any i/o pin .................................................................................. ..................25 ma maximum current sunk by porta ........................................................................................................................10 0 ma maximum current sourced by porta............................................................................................... ....................100 ma maximum current sunk by portb........................................................................................................................10 0 ma maximum current sourced by portb ............................................................................................... ...................100 ma note 1: power dissipation is calculated as follows: pdis = v dd x {i dd ? i oh } + {(v dd ? v oh ) x i oh } + (v o l x i ol ) 2: voltage spikes at the mclr pin may cause latch-up. a series resistor of greater than 1 k ? should be used to pull mclr to v dd , rather than tying the pin directly to v dd . ? notice: stresses above those listed under ?absolute maximum ratings? may cause permanent damage to the device. this is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. exposure to maximum rating conditions for extended periods may affect device reliability.
pic16f818/819 ds39598d-page 118 preliminary ? 2003 microchip technology inc. figure 15-1: pic16f818/819 voltage-frequency graph figure 15-2: pic16lf818/819 voltage-frequency graph frequency voltage 6.0v 5.5v 4.5v 4.0v 2.0v 20 mhz 5.0v 3.5v 3.0v 2.5v 16 mhz frequency voltage 6.0v 5.5v 4.5v 4.0v 2.0v 5.0v 3.5v 3.0v 2.5v f max = (12 mhz/v) (v ddappmin ? 2.5v) + 4 mhz note 1: v ddappmin is the minimum voltage of the picmicro ? device in the application. 4 mhz 10 mhz note 2: f max has a maximum frequency of 10 mhz.
? 2003 microchip technology inc. preliminary ds39598d-page 119 pic16f818/819 15.1 dc characteristics: supply voltage pic16f818/819 (industrial) pic16lf818/819 (industrial) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. symbol characteristic min typ max units conditions v dd supply voltage d001 pic16lf818/819 2.0 ? 5.5 v hs, xt, rc and lp oscillator mode d001 pic16f818/819 4.0 ? 5.5 v d002 v dr ram data retention voltage (1) 1.5 ? ? v d003 v por v dd start voltage to ensure internal power-on reset signal ? ? 0.7 v see section 12.4 ?power-on reset (por)? , for details d004 s vdd v dd rise rate to ensure internal power-on reset signal 0.05 ? ? v/ms see section 12.4 ?power-on reset (por)? , for details v bor brown-out reset voltage d005 pic16lf818/819 3.65 ? 4.35 v d005 pic16f818/819 3.65 ? 4.35 v f max = 14 mhz (2) legend: shading of rows is to assist in readability of the table. note 1: this is the limit to which v dd can be lowered in sleep mode, or duri ng a device reset, without losing ram data. 2: when bor is enabled, the device will operate correctly until the v bor voltage trip point is reached.
pic16f818/819 ds39598d-page 120 preliminary ? 2003 microchip technology inc. 15.2 dc characteristics: power-down and supply current pic16f818/819 (industrial) pic16lf818/819 (industrial) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions power-down current (i pd ) (1) pic16lf818/819 0.1 0.4 a -40c v dd = 2.0v 0.1 0.4 a +25c 0.4 1.5 a +85c pic16lf818/819 0.3 0.5 a -40c v dd = 3.0v 0.3 0.5 a +25c 0.7 1.7 a +85c all devices 0.6 1.0 a -40c v dd = 5.0v 0.6 1.0 a +25c 1.2 5.0 a +85c legend: shading of rows is to assist in readability of the table. note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt enabled/disabled as specified. 3: for rc oscillator configurations, current through r ext is not included. the current through the resistor can be estimated by the formula ir = v dd /2r ext (ma) with r ext in k ? .
? 2003 microchip technology inc. preliminary ds39598d-page 121 pic16f818/819 supply current (i dd ) (2,3) pic16lf818/819 9 20 a -40c v dd = 2.0v f osc = 32 kh z (lp oscillator) 715 a +25c 715 a +85c pic16lf818/819 16 30 a -40c v dd = 3.0v 14 25 a +25c 14 25 a +85c all devices 32 40 a -40c v dd = 5.0v 26 35 a +25c 26 35 a +85c pic16lf818/819 72 95 a -40c v dd = 2.0v f osc = 1 mh z (rc oscillator) (3) 76 90 a +25c 76 90 a +85c pic16lf818/819 138 175 a -40c v dd = 3.0v 136 170 a +25c 136 170 a +85c all devices 310 380 a -40c v dd = 5.0v 290 360 a +25c 280 360 a +85c pic16lf818/819 270 315 a -40c v dd = 2.0v f osc = 4 mhz (rc oscillator) (3) 280 310 a +25c 285 310 a +85c pic16lf818/819 460 610 a -40c v dd = 3.0v 450 600 a +25c 450 600 a +85c all devices 900 1060 a -40c v dd = 5.0v 890 1050 a +25c 890 1050 a +85c 15.2 dc characteristics: power-down and supply current pic16f818/819 (industrial) pic16lf818/819 (industrial) (continued) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions legend: shading of rows is to assist in readability of the table. note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt enabled/disabled as specified. 3: for rc oscillator configurations, current through r ext is not included. the current through the resistor can be estimated by the formula ir = v dd /2r ext (ma) with r ext in k ? .
pic16f818/819 ds39598d-page 122 preliminary ? 2003 microchip technology inc. supply current (i dd ) (2,3) all devices 1.8 2.3 ma -40c v dd = 4.0v f osc = 20 mh z (hs oscillator) 1.6 2.2 ma +25c 1.3 2.2 ma +85c all devices 3.0 4.2 ma -40c v dd = 5.0v 2.5 4.0 ma +25c 2.5 4.0 ma +85c 15.2 dc characteristics: power-down and supply current pic16f818/819 (industrial) pic16lf818/819 (industrial) (continued) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions legend: shading of rows is to assist in readability of the table. note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt enabled/disabled as specified. 3: for rc oscillator configurations, current through r ext is not included. the current through the resistor can be estimated by the formula ir = v dd /2r ext (ma) with r ext in k ? .
? 2003 microchip technology inc. preliminary ds39598d-page 123 pic16f818/819 supply current (i dd ) (2,3) pic16lf818/819 8 20 a -40c v dd = 2.0v f osc = 31.25 khz ( rc_run mode, internal rc oscillator) 715 a +25c 715 a +85c pic16lf818/819 16 30 a -40c v dd = 3.0v 14 25 a +25c 14 25 a +85c all devices 32 40 a -40c v dd = 5.0v 29 35 a +25c 29 35 a +85c pic16lf818/819 132 160 a -40c v dd = 2.0v f osc = 1 mhz ( rc_run mode, internal rc oscillator) 126 155 a +25c 126 155 a +85c pic16lf818/819 260 310 a -40c v dd = 3.0v 230 300 a +25c 230 300 a +85c all devices 560 690 a -40c v dd = 5.0v 500 650 a +25c 500 650 a +85c pic16lf818/819 310 420 a -40c v dd = 2.0v f osc = 4 mhz ( rc_run mode, internal rc oscillator) 300 410 a +25c 300 410 a +85c pic16lf818/819 550 650 a -40c v dd = 3.0v 530 620 a +25c 530 620 a +85c all devices 1.2 1.5 ma -40c v dd = 5.0v 1.1 1.4 ma +25c 1.1 1.4 ma +85c 15.2 dc characteristics: power-down and supply current pic16f818/819 (industrial) pic16lf818/819 (industrial) (continued) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions legend: shading of rows is to assist in readability of the table. note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt enabled/disabled as specified. 3: for rc oscillator configurations, current through r ext is not included. the current through the resistor can be estimated by the formula ir = v dd /2r ext (ma) with r ext in k ? .
pic16f818/819 ds39598d-page 124 preliminary ? 2003 microchip technology inc. supply current (i dd ) (2,3) pic16lf818/819 .950 1.3 ma -40c v dd = 3.0v f osc = 8 mhz ( rc_run mode, internal rc oscillator) .930 1.2 ma +25c .930 1.2 ma +85c all devices 1.8 3.0 ma -40c v dd = 5.0v 1.7 2.8 ma +25c 1.7 2.8 ma +85c 15.2 dc characteristics: power-down and supply current pic16f818/819 (industrial) pic16lf818/819 (industrial) (continued) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions legend: shading of rows is to assist in readability of the table. note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt enabled/disabled as specified. 3: for rc oscillator configurations, current through r ext is not included. the current through the resistor can be estimated by the formula ir = v dd /2r ext (ma) with r ext in k ? .
? 2003 microchip technology inc. preliminary ds39598d-page 125 pic16f818/819 module differential currents ( ? i wdt , ? i bor , ? i lvd , ? i oscb , ? i ad ) d022 ( ? i wdt ) watchdog timer 1.5 3.8 a -40c v dd = 2.0v 2.2 3.8 a +25c 2.7 4.0 a +85c 2.3 4.6 a -40c v dd = 3.0v 2.7 4.6 a +25c 3.1 4.8 a +85c 3.0 10.0 a -40c v dd = 5.0v 3.3 10.0 a +25c 3.9 13.0 a +85c d022a ( ? i bor ) brown-out reset 40 60 a-40 c to +85 cv dd = 5.0v d025 ( ? i oscb ) timer1 oscillator 1.7 2.3 a -40c v dd = 2.0v 32 khz on timer1 1.8 2.3 a +25c 2.0 2.3 a +85c 2.2 3.8 a -40c v dd = 3.0v 2.6 3.8 a +25c 2.9 3.8 a +85c 3.0 6.0 a -40c v dd = 5.0v 3.2 6.0 a +25c 3.4 7.0 a +85c d026 ( ? i ad ) a/d converter 0.001 2.0 a-40 c to +85 cv dd = 2.0v a/d on, not converting 0.001 2.0 a-40 c to +85 cv dd = 3.0v 0.003 2.0 a-40 c to +85 cv dd = 5.0v 15.2 dc characteristics: power-down and supply current pic16f818/819 (industrial) pic16lf818/819 (industrial) (continued) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device typ max units conditions legend: shading of rows is to assist in readability of the table. note 1: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in high-impedance state and tied to v dd or v ss and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, etc.). 2: the supply current is mainly a function of operating voltage, frequency and mode. other factors, such as i/o pin loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail-to-ra il; all i/o pins tri-stated, pulled to v dd ; mclr = v dd ; wdt enabled/disabled as specified. 3: for rc oscillator configurations, current through r ext is not included. the current through the resistor can be estimated by the formula ir = v dd /2r ext (ma) with r ext in k ? .
pic16f818/819 ds39598d-page 126 preliminary ? 2003 microchip technology inc. 15.3 dc characteristics: internal rc accuracy pic16f818/819 (industrial) pic16lf818/819 (industrial) pic16lf818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial pic16f818/819 (industrial) standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. device min typ max units conditions intosc accuracy @ freq = 8 mhz, 4 mhz, 2 mhz, 1 mhz, 500 khz, 250 khz, 125 khz (1) pic16lf818/819 -2 1 2 % +25c v dd = 2.7-3.3v -5 ? 5 % -10c to +85c v dd = 2.7-3.3v -10 ? 10 % -40c to +85c v dd = 2.7-3.3v pic16f818/819 -2 1 2 % +25c v dd = 4.5-5.5v -5 ? 5 % -10c to +85c v dd = 4.5-5.5v -10 ? 10 % -40c to +85c v dd = 4.5-5.5v intrc accuracy @ freq = 31 khz (2) pic16lf818/819 26.562 ? 35.938 khz -40c to +85c v dd = 2.7-3.3v pic16f818/819 26.562 ? 35.938 khz -40c to +85c v dd = 4.5-5.5v legend: shading of rows is to assist in readability of the table. note 1: frequency calibrated at 25c. osctune register can be used to compensate for temperature drift. 2: intrc frequency after calibration.
? 2003 microchip technology inc. preliminary ds39598d-page 127 pic16f818/819 15.4 dc characteristics: pic16f818/819 (industrial, extended) pic16lf818/819 (industrial) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended operating voltage v dd range as described in section 15.1 ?dc characteristics: supply voltage ?. param no. sym characteristic min typ? max units conditions v il input low voltage i/o ports: d030 with ttl buffer v ss ? 0.15 v dd v for entire v dd range d030a v ss ?0.8v v4.5v v dd 5.5v d031 with schmitt trigger buffer v ss ? 0.2 v dd v d032 mclr , osc1 (in rc mode) v ss ? 0.2 v dd v (note 1) d033 osc1 (in xt and lp mode) v ss ?0.3v v osc1 (in hs mode) v ss ? 0.3 v dd v ports rb1 and rb4: d034 with schmitt trigger buffer v ss ? 0.3 v dd v for entire v dd range v ih input high voltage i/o ports: d040 with ttl buffer 2.0 ? v dd v4.5v v dd 5.5v d040a 0.25 v dd + 0.8v ?v dd v for entire v dd range d041 with schmitt trigger buffer 0.8 v dd ?v dd v for entire v dd range d042 mclr 0.8 v dd ?v dd v d042a osc1 (in xt and lp mode) 1.6v ? v dd v osc1 (in hs mode) 0.7 v dd ?v dd v d043 osc1 (in rc mode) 0.9 v dd ?v dd v (note 1) ports rb1 and rb4: d044 with schmitt trigger buffer 0.7 v dd ?v dd v for entire v dd range d070 i purb portb weak pull-up current 50 250 400 av dd = 5v, v pin = v ss i il input leakage current (notes 2, 3) d060 i/o ports ? ? 1 avss v pin v dd , pin at high-impedance d061 mclr ??5 avss v pin v dd d063 osc1 ? ? 5 avss v pin v dd , xt, hs and lp osc configuration * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: in rc oscillator configuration, the osc1/clki pin is a schmitt trigger input. it is not recommended that the pic16f818/819 be driven with external clock in rc mode. 2: the leakage current on the mclr pin is strongly dependent on the applied voltage level. the specified levels represent normal operating conditions. higher leakage cu rrent may be measured at different input voltages. 3: negative current is defined as current sourced by the pin.
pic16f818/819 ds39598d-page 128 preliminary ? 2003 microchip technology inc. v ol output low voltage d080 i/o ports ? ? 0.6 v i ol = 8.5 ma, v dd = 4.5v, -40 c to +125 c d083 osc2/clko (rc osc config) ? ? 0.6 v i ol = 1.6 ma, v dd = 4.5v, -40 c to +125 c v oh output high voltage d090 i/o ports (note 3) v dd ? 0.7 ? ? v i oh = -3.0 ma, v dd = 4.5v, -40 c to +125 c d092 osc2/clko (rc osc config) v dd ? 0.7 ? ? v i oh = -1.3 ma, v dd = 4.5v, -40 c to +125 c capacitive loading specs on output pins d100 c osc2 osc2 pin ? ? 15 pf in xt, hs and lp modes when external clock is used to drive osc1 d101 c io all i/o pins and osc2 (in rc mode) ??50pf d102 c b scl, sda in i 2 c mode ? ? 400 pf data eeprom memory d120 e d endurance 100k 10k 1m 100k ? ? e/w e/w -40c to +85c +85c to +125c d121 v drw v dd for read/write v min ? 5.5 v using eecon to read/write, v min = min. operating voltage d122 t dew erase/write cycle time ? 4 8 ms program flash memory d130 e p endurance 10k 1k 100k 10k ? ? e/w e/w -40c to +85c +85c to +125c d131 v pr v dd for read v min ?5.5 v d132a v dd for erase/write v min ? 5.5 v using eecon to read/write, v min = min. operating voltage d133 t pe erase cycle time ? 2 4 ms d134 t pw write cycle time ? 2 4 ms 15.4 dc characteristics: pic16f818/819 (industrial, extended) pic16lf818/819 (industrial) (continued) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended operating voltage v dd range as described in section 15.1 ?dc characteristics: supply voltage ?. param no. sym characteristic min typ? max units conditions * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: in rc oscillator configuration, the osc1/clki pin is a schmitt trigger input. it is not recommended that the pic16f818/819 be driven with external clock in rc mode. 2: the leakage current on the mclr pin is strongly dependent on the applied voltage level. the specified levels represent normal operating conditions. higher leakage cu rrent may be measured at different input voltages. 3: negative current is defined as current sourced by the pin.
? 2003 microchip technology inc. preliminary ds39598d-page 129 pic16f818/819 15.5 timing parameter symbology the timing parameter symbols have been created using one of the following formats: figure 15-3: load conditions 1. tpps2pps 3. t cc : st (i 2 c specifications only) 2. tpps 4. ts (i 2 c specifications only) t f frequency t time lowercase letters (pp) and their meanings: pp cc ccp1 osc osc1 ck clko rd rd cs cs rw rd or wr di sdi sc sck do sdo ss ss dt data in t0 t0cki io i/o port t1 t1cki mc mclr wr wr uppercase letters and their meanings: s ffall pperiod hhigh rrise i invalid (high-impedance) v valid l low z hi-impedance i 2 c only aa output access high high buf bus free low low t cc : st (i 2 c specifications only) cc hd hold su setup st dat data input hold sto stop condition sta start condition v dd /2 c l r l pin pin v ss v ss c l r l = 464 ? c l = 50 pf for all pins except osc2, but including portd and porte outputs as ports 15 pf for osc2 output load condition 1 load condition 2
pic16f818/819 ds39598d-page 130 preliminary ? 2003 microchip technology inc. figure 15-4: external clock timing osc1 clko q4 q1 q2 q3 q4 q1 1 2 3 3 4 4 table 15-1: external clock timing requirements param no. sym characteristic min typ? max units conditions f osc external clki frequency (note 1) dc ? 1 mhz xt and rc osc mode dc ? 20 mhz hs osc mode dc ? 32 khz lp osc mode oscillator frequency (note 1) dc ? 4 mhz rc osc mode 0.1 ? 4 mhz xt osc mode 4 5 ? ? 20 200 mhz khz hs osc mode lp osc mode 1t osc external clki period (note 1) 1000 ? ? ns xt and rc osc mode 50 ? ? ns hs osc mode 5 ? ? ms lp osc mode oscillator period (note 1) 250 ? ? ns rc osc mode 250 ? 10,000 ns xt osc mode 50 ? 250 ns hs osc mode 5 ? ? ms lp osc mode 2t cy instruction cycle time (note 1) 200 t cy dc ns t cy = 4/f osc 3t os l, t os h external clock in (osc1) high or low time 500 ? ? ns xt oscillator 2.5 ? ? ms lp oscillator 15 ? ? ns hs oscillator 4t os r, t os f external clock in (osc1) rise or fall time ? ? 25 ns xt oscillator ? ? 50 ns lp oscillator ? ? 15 ns hs oscillator ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. note 1: instruction cycle period (t cy ) equals four times the input oscillator time base period. all specified values are based on characterization data for that particular oscillator type under standard operating conditions, with the device executing code. exceeding these specified limits may result in an unstable oscillator opera- tion and/or higher than expected current consumption. all devices are tested to operate at ?min.? values with an external clock applied to the osc1/clki pin. when an external clock input is used, the ?max.? cycle time limit is ?dc? (no clock) for all devices.
? 2003 microchip technology inc. preliminary ds39598d-page 131 pic16f818/819 figure 15-5: clko and i/o timing table 15-2: clko and i/o timing requirements note: refer to figure 15-3 for load conditions. osc1 clko i/o pin (input) i/o pin (output) q4 q1 q2 q3 10 13 14 17 20, 21 19 18 15 11 12 16 old value new value param no. symbol characteristic min typ? max units conditions 10* t os h2 ck losc1 to clko ? 75 200 ns (note 1) 11* t os h2 ck hosc1 to clko ? 75 200 ns (note 1) 12* t ck r clko rise time ? 35 100 ns (note 1) 13* t ck f clko fall time ? 35 100 ns (note 1) 14* t ck l2 io vclko to port out valid ? ? 0.5 t cy + 20 ns (note 1) 15* t io v2 ck h port in valid before clko t osc + 200 ? ? ns (note 1) 16* t ck h2 io i port in hold after clko 0??ns (note 1) 17* t os h2 io vosc1 (q1 cycle) to port out valid ? 100 255 ns 18* t os h2 io iosc1 (q2 cycle) to port input invalid (i/o in hold time) pic16 f 818/819 100 ? ? ns pic16 lf 818/819 200 ? ? ns 19* t io v2 os h port input valid to osc1 (i/o in setup time) 0 ? ? ns 20* t io r port output rise time pic16 f 818/819 ? 10 40 ns pic16 lf 818/819 ? ? 145 ns 21* t io f port output fall time pic16 f 818/819 ? 10 40 ns pic16 lf 818/819 ? ? 145 ns 22??* t inp int pin high or low time t cy ??ns 23??* t rbp rb7:rb4 change int high or low time t cy ??ns * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. ?? these parameters are asynchronous events, not related to any internal clock edges. note 1: measurements are taken in rc mode, where clko output is 4 x t osc .
pic16f818/819 ds39598d-page 132 preliminary ? 2003 microchip technology inc. figure 15-6: reset, watchdog timer, oscillator start-up timer and power-up timer timing figure 15-7: brown-out reset timing table 15-3: reset, watchdog timer, oscillator start-up timer, power-up timer and brown-out reset requirements v dd mclr internal por pwrt time-out osc time-out internal reset watchdog timer reset 33 32 30 31 34 i/o pins 34 note: refer to figure 15-3 for load conditions. v dd v bor 35 param no. symbol characteristic min typ? max units conditions 30 t mc lmclr pulse width (low) 2 ? ? sv dd = 5v, -40c to +85c 31* t wdt watchdog timer time-out period (no prescaler) tbd 16 tbd ms v dd = 5v, -40c to +85c 32 t ost oscillation start-up timer period ? 1024 t osc ??t osc = osc1 period 33* t pwrt power-up timer period tbd 72 tbd ms v dd = 5v, -40c to +85c 34 t ioz i/o high-impedance from mclr low or watchdog timer reset ??2.1 s 35 t bor brown-out reset pulse width 100 ? ? sv dd v bor (d005) * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise st ated. these parameters are fo r design guidance only and are not tested.
? 2003 microchip technology inc. preliminary ds39598d-page 133 pic16f818/819 figure 15-8: timer0 and timer1 external clock timings table 15-4: timer0 and timer1 external clock requirements param no. symbol characteristic min typ? max units conditions 40* t t 0h t0cki high pulse width no prescaler 0.5 t cy + 20 ? ? ns must also meet parameter 42 with prescaler 10 ? ? ns 41* t t 0l t0cki low pulse width no prescaler 0.5 t cy + 20 ? ? ns must also meet parameter 42 with prescaler 10 ? ? ns 42* t t 0p t0cki period no prescaler t cy + 40 ??ns with prescaler greater of: 20 or t cy + 40 n ? ? ns n = prescale value (2, 4, ..., 256) 45* t t 1h t1cki high time synchronous, prescaler = 1 0.5 t cy + 20 ? ? ns must also meet parameter 47 synchronous, prescaler = 2,4,8 pic16 f 818/819 15 ? ? ns pic16 lf 818/819 25 ? ? ns asynchronous pic16 f 818/819 30 ? ? ns pic16 lf 818/819 50 ? ? ns 46* t t 1l t1cki low time synchronous, prescaler = 1 0.5 t cy + 20 ? ? ns must also meet parameter 47 synchronous, prescaler = 2,4,8 pic16 f 818/819 15 ? ? ns pic16 lf 818/819 25 ? ? ns asynchronous pic16 f 818/819 30 ? ? ns pic16 lf 818/819 50 ? ? ns 47* t t 1p t1cki input period synchronous pic16 f 818/819 greater of: 30 or t cy + 40 n ? ? ns n = prescale value (1, 2, 4, 8) pic16 lf 818/819 greater of: 50 or t cy + 40 n n = prescale value (1, 2, 4, 8) asynchronous pic16 f 818/819 60 ? ? ns pic16 lf 818/819 100 ? ? ns f t 1 timer1 oscillator input frequency range (oscillator enabled by setting bit t1oscen) dc ? 32.768 khz 48 tckez tmr 1 delay from external clock edge to timer increment 2 t osc ?7 t osc ? * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested. note: refer to figure 15-3 for load conditions. 46 47 45 48 41 42 40 ra4/t0cki rb6/t1oso/t1cki tmr0 or tmr1
pic16f818/819 ds39598d-page 134 preliminary ? 2003 microchip technology inc. figure 15-9: capture/compare/pwm timings (ccp1) table 15-5: capture/compare/pwm requirements (ccp1) note: refer to figure 15-3 for load conditions. ccp1 (capture mode) 50 51 52 53 54 ccp1 (compare or pwm mode) param no. symbol characteristic min typ? max units conditions 50* t cc l ccp1 input low time no prescaler 0.5 t cy + 20 ? ? ns pic16 f 818/819 10 ? ? ns with prescaler pic16 lf 818/819 20 ? ? ns 51* t cc h ccp1 input high time no prescaler 0.5 t cy + 20 ? ? ns pic16 f 818/819 10 ? ? ns with prescaler pic16 lf 818/819 20 ? ? ns 52* t cc p ccp1 input period 3 t cy + 40 n ? ? ns n = prescale value (1,4 or 16) 53* t cc r ccp1 output rise time pic16 f 818/819 ? 10 25 ns pic16 lf 818/819 ? 25 50 ns 54* t cc f ccp1 output fall time pic16 f 818/819 ? 10 25 ns pic16 lf 818/819 ? 25 45 ns * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stated. these parameters are for design guidance only and are not tested.
? 2003 microchip technology inc. preliminary ds39598d-page 135 pic16f818/819 figure 15-10: spi master mode timing (cke = 0 , smp = 0 ) figure 15-11: spi master mode timing (cke = 1 , smp = 1 ) ss sck (ckp = 0 ) sck (ckp = 1 ) sdo sdi 70 71 72 73 74 75, 76 78 79 80 79 78 msb lsb bit 6 - - - - - -1 msb in lsb in bit 6 - - - -1 note: refer to figure 15-3 for load conditions. ss sck (ckp = 0 ) sck (ckp = 1 ) sdo sdi 81 71 72 74 75, 76 78 80 msb 79 73 msb in bit 6 - - - - - -1 lsb in bit 6 - - - -1 lsb note: refer to figure 15-3 for load conditions.
pic16f818/819 ds39598d-page 136 preliminary ? 2003 microchip technology inc. figure 15-12: spi slave mode timing (cke = 0 ) figure 15-13: spi slave mode timing (cke = 1 ) ss sck (ckp = 0 ) sck (ckp = 1 ) sdo sdi 70 71 72 73 74 75, 76 77 78 79 80 79 78 sdi msb lsb bit 6 - - - - - -1 msb in bit 6 - - - -1 lsb in 83 note: refer to figure 15-3 for load conditions. ss sck (ckp = 0 ) sck (ckp = 1 ) sdo sdi 70 71 72 82 sdi 74 75, 76 msb bit 6 - - - - - -1 lsb 77 msb in bit 6 - - - -1 lsb in 80 83 note: refer to figure 15-3 for load conditions.
? 2003 microchip technology inc. preliminary ds39598d-page 137 pic16f818/819 table 15-6: spi mode requirements figure 15-14: i 2 c bus start/stop bits timing param no. symbol characteristic min typ? max units conditions 70* t ss l2 sc h, t ss l2 sc l ss to sck or sck input t cy ?? ns 71* t sc h sck input high time (slave mode) t cy + 20 ? ? ns 72* t sc l sck input low time (slave mode) t cy + 20 ? ? ns 73* t di v2 sc h, t di v2 sc l setup time of sdi data input to sck edge 100 ? ? ns 74* t sc h2 di l, t sc l2 di l hold time of sdi data input to sck edge 100 ? ? ns 75* t do r sdo data output rise time pic16 f 818/819 pic16 lf 818/819 ? ? 10 25 25 50 ns ns 76* t do f sdo data output fall time ? 10 25 ns 77* t ss h2 do zss to sdo output high-impedance 10 ? 50 ns 78* t sc r sck output rise time (master mode) pic16 f 818/819 pic16 lf 818/819 ? ? 10 25 25 50 ns ns 79* t sc f sck output fall time (master mode) ? 10 25 ns 80* t sc h2 do v, t sc l2 do v sdo data output valid after sck edge pic16 f 818/819 pic16 lf 818/819 ? ? ? ? 50 145 ns ns 81* t do v2 sc h, t do v2 sc l sdo data output setup to sck edge t cy ?? ns 82* t ss l2 do v sdo data output valid after ss edge ? ? 50 ns 83* t sc h2 ss h, t sc l2 ss h ss after sck edge 1.5 t cy + 40 ? ? ns * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise st ated. these parameters are for design guidance only and are not tested. note : refer to figure 15-3 for load conditions. 91 92 93 scl sda start condition stop condition 90
pic16f818/819 ds39598d-page 138 preliminary ? 2003 microchip technology inc. table 15-7: i 2 c bus start/stop bits requirements figure 15-15: i 2 c bus data timing param no. symbol characteristic min typ max units conditions 90* t su : sta start condition 100 khz mode 4700 ? ? ns only relevant for repeated start condition setup time 400 khz mode 600 ? ? 91* t hd : sta start condition 100 khz mode 4000 ? ? ns after this period, the first clock pulse is generated hold time 400 khz mode 600 ? ? 92* t su : sto stop condition 100 khz mode 4700 ? ? ns setup time 400 khz mode 600 ? ? 93 t hd : sto stop condition 100 khz mode 4000 ? ? ns hold time 400 khz mode 600 ? ? * these parameters are characterized but not tested. note: refer to figure 15-3 for load conditions. 90 91 92 100 101 103 106 107 109 109 110 102 scl sda in sda out
? 2003 microchip technology inc. preliminary ds39598d-page 139 pic16f818/819 table 15-8: i 2 c bus data requirements param. no. symbol characteristic min max units conditions 100* t high clock high time 100 khz mode 4.0 ? s 400 khz mode 0.6 ? s ssp module 1.5 t cy ? 101* t low clock low time 100 khz mode 4.7 ? s 400 khz mode 1.3 ? s ssp module 1.5 t cy ? 102* t r sda and scl rise time 100 khz mode ? 1000 ns 400 khz mode 20 + 0.1 c b 300 ns c b is specified to be from 10-400 pf 103* t f sda and scl fall time 100 khz mode ? 300 ns 400 khz mode 20 + 0.1 c b 300 ns c b is specified to be from 10-400 pf 90* t su : sta start condition setup time 100 khz mode 4.7 ? s only relevant for repeated start condition 400 khz mode 0.6 ? s 91* t hd : sta start condition hold time 100 khz mode 4.0 ? s after this period, the first clock pulse is generated 400 khz mode 0.6 ? s 106* t hd : dat data input hold time 100 khz mode 0 ? ns 400 khz mode 0 0.9 s 107* t su : dat data input setup time 100 khz mode 250 ? ns (note 2) 400 khz mode 100 ? ns 92* t su : sto stop condition setup time 100 khz mode 4.7 ? s 400 khz mode 0.6 ? s 109* t aa output valid from clock 100 khz mode ? 3500 ns (note 1) 400 khz mode ? ? ns 110* t buf bus free time 100 khz mode 4.7 ? s time the bus must be free before a new transmission can start 400 khz mode 1.3 ? s c b bus capacitive loading ? 400 pf * these parameters are characterized but not tested. note 1: as a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (min. 300 ns) of the falling edge of scl to avoid unintended generation of start or stop conditions. 2: a fast mode (400 khz) i 2 c bus device can be used in a standard mode (100 khz) i 2 c bus system but the requirement, t su : dat 250 ns, must then be met. this will automatically be the case if the device does not stretch the low period of the scl signal. if such a device does stretch the low period of the scl signal, it must output the next data bit to the sda line t r max. + t su : dat = 1000 + 250 = 1250 ns (according to the standard mode i 2 c bus specification), before the scl line is released.
pic16f818/819 ds39598d-page 140 preliminary ? 2003 microchip technology inc. table 15-9: a/d converter characteristics:pic16f818/819 (industrial, extended) pic16lf818/819 (industrial) param no. sym characteristic min typ? max units conditions a01 n r resolution ? ? 10 bits bit v ref = v dd = 5.12v, v ss v ain v ref a03 e il integral linearity error ? ? < 1 lsb v ref = v dd = 5.12v, v ss v ain v ref a04 e dl differential linearity error ? ? < 1 lsb v ref = v dd = 5.12v, v ss v ain v ref a06 e off offset error ? ? < 2 lsb v ref = v dd = 5.12v, v ss v ain v ref a07 e gn gain error ? ? < 1 lsb v ref = v dd = 5.12v, v ss v ain v ref a10 ? monotonicity (3) ? guaranteed ? ? v ss v ain v ref a20 v ref reference voltage 2.5 2.2 ? ? v dd + 0.3 v dd + 0.3 v v -40c to +85c 0c to +85c a21 v ref + reference voltage high av dd ? 2.5v av dd + 0.3v v a22 v ref - reference voltage low av ss ? 0.3v v ref + ? 2.0v v a25 v ain analog input voltage v ss ? 0.3v ? v ref + 0.3v v a30 z ain recommended impedance of analog voltage source ??2.5k ? (note 4) a50 i ref v ref input current (note 2) ? ? ? ? 5 500 a a during v ain acquisition. based on differential of v hold to v ain to charge c hold , see section 11.1 ?a/d acquisition requirements? . during a/d conversion cycle. * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise st ated. these parameters are for design guidance only and are not tested. note 1: when a/d is off, it will not consume any current other than minor leakage current. the powe r-down current spec includes any such leakage from the a/d module. 2: v ref current is from ra3 pin or v dd pin, whichever is selected as reference input. 3: the a/d conversion result never dec reases with an increase in the input voltage and has no missing codes. 4: the maximum allowed impedance for analog voltage source is 10 k ? . this requires higher acquisition times.
? 2003 microchip technology inc. preliminary ds39598d-page 141 pic16f818/819 figure 15-16: a/d conversion timing table 15-10: a/d conversion requirements 131 130 132 bsf adcon0, go q4 a/d clk a/d data adres adif go sample old_data sampling stopped done new_data (t osc /2) (1) 987 210 note 1: if the a/d clock source is selected as rc, a time of t cy is added before the a/d clock starts. this allows the sleep instruction to be executed. 1 t cy . . . . . . param no. sym characteristic min typ? max units conditions 130 t ad a/d clock period pic16 f 818/819 1.6 ? ? st osc based, v ref 3.0v pic16 lf 818/819 3.0 ? ? st osc based, v ref 2.0v pic16 f 818/819 2.0 4.0 6.0 s a/d rc mode pic16 lf 818/819 3.0 6.0 9.0 s a/d rc mode 131 t cnv conversion time (not including s/h time) (note 1) ?12t ad 132 t acq acquisition time (note 2) 10* 40 ? ? ? s s the minimum time is the amplifier settling time. this may be used if the ?new? input voltage has not changed by more than 1 lsb (i.e., 20.0 mv @ 5.12v) from the last sampled voltage (as stated on c hold ). 134 t go q4 to a/d clock start ? t osc /2 ? ? if the a/d clock source is selected as rc, a time of t cy is added before the a/d clock starts. this allows the sleep instruction to be executed. * these parameters are characterized but not tested. ? data in ?typ? column is at 5v, 25c unless otherwise stat ed. these parameters are for design guidance only and are not tested. this specification ensured by design. note 1: adres register may be read on the following t cy cycle. 2: see section 11.1 ?a/d acquisition requirements? for minimum conditions.
pic16f818/819 ds39598d-page 142 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 143 pic16f818/819 16.0 dc and ac characteristics graphs and tables no graphs and tables are available at this time.
pic16f818/819 ds39598d-page 144 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 145 pic16f818/819 17.0 packaging information 17.1 package marking information 18-lead pdip xxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxx yywwnnn example pic16f818-i/p 0310017 18-lead soic xxxxxxxxxxxx xxxxxxxxxxxx xxxxxxxxxxxx yywwnnn example pic16f818-04 /so 0310017 20-lead ssop xxxxxxxxxxx xxxxxxxxxxx yywwnnn example pic16f818- 20/ss 0310017 28-lead qfn xxxxxxxx xxxxxxxx yywwnnn example 16f818- i/ml 0310017 legend: xx...x customer specific information* y year code (last digit of calendar year) yy year code (last 2 digits of calendar year) ww week code (week of january 1 is week ?01?) nnn alphanumeric traceability code note : in the event the full microchip part number cannot be marked on one line, it will be carried over to the next line thus limiting the number of available characters for customer specific information. * standard picmicro device marking consists of microchip part number, year code, week code, and traceability code. for picmicro device marking beyond this, certain price adders apply. please check with your microchip sales office. for qtp devices, any special marking adders are included in qtp price.
pic16f818/819 ds39598d-page 146 preliminary ? 2003 microchip technology inc. 18-lead plastic dual in-line (p) ? 300 mil (pdip) 15 10 5 15 10 5 mold draft angle bottom 15 10 5 15 10 5 mold draft angle top 10.92 9.40 7.87 .430 .370 .310 eb overall row spacing 0.56 0.46 0.36 .022 .018 .014 b lower lead width 1.78 1.46 1.14 .070 .058 .045 b1 upper lead width 0.38 0.29 0.20 .015 .012 .008 c lead thickness 3.43 3.30 3.18 .135 .130 .125 l tip to seating plane 22.99 22.80 22.61 .905 .898 .890 d overall length 6.60 6.35 6.10 .260 .250 .240 e1 molded package width 8.26 7.94 7.62 .325 .313 .300 e shoulder to shoulder width 0.38 .015 a1 base to seating plane 3.68 3.30 2.92 .145 .130 .115 a2 molded package thickness 4.32 3.94 3.56 .170 .155 .140 a top to seating plane 2.54 .100 p pitch 18 18 n number of pins max nom min max nom min dimension limits millimeters inches* units 1 2 d n e1 c eb e p a2 l b1 b a a1 * controlling parameter notes: dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010? (0.254mm) per side. jedec equivalent: ms-001 drawing no. c04-007 significant characteristic
? 2003 microchip technology inc. preliminary ds39598d-page 147 pic16f818/819 18-lead plastic small outline (so) ? wide, 300 mil (soic) foot angle 048048 15 12 0 15 12 0 mold draft angle bottom 15 12 0 15 12 0 mold draft angle top 0.51 0.42 0.36 .020 .017 .014 b lead width 0.30 0.27 0.23 .012 .011 .009 c lead thickness 1.27 0.84 0.41 .050 .033 .016 l foot length 0.74 0.50 0.25 .029 .020 .010 h chamfer distance 11.73 11.53 11.33 .462 .454 .446 d overall length 7.59 7.49 7.39 .299 .295 .291 e1 molded package width 10.67 10.34 10.01 .420 .407 .394 e overall width 0.30 0.20 0.10 .012 .008 .004 a1 standoff 2.39 2.31 2.24 .094 .091 .088 a2 molded package thickness 2.64 2.50 2.36 .104 .099 .093 a overall height 1.27 .050 p pitch 18 18 n number of pins max nom min max nom min dimension limits millimeters inches* units l c h 45 1 2 d p n b e1 e a2 a1 a * controlling parameter notes: dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010? (0.254mm) per side. jedec equivalent: ms-013 drawing no. c04-051 significant characteristic
pic16f818/819 ds39598d-page 148 preliminary ? 2003 microchip technology inc. 20-lead plastic shrink small outline (ss) ? 209 mil, 5.30 mm (ssop) 10 5 0 10 5 0 mold draft angle bottom 10 5 0 10 5 0 mold draft angle top 0.38 0.32 0.25 .015 .013 .010 b lead width 203.20 101.60 0.00 8 4 0 foot angle 0.25 0.18 0.10 .010 .007 .004 c lead thickness 0.94 0.75 0.56 .037 .030 .022 l foot length 7.34 7.20 7.06 .289 .284 .278 d overall length 5.38 5.25 5.11 .212 .207 .201 e1 molded package width 8.18 7.85 7.59 .322 .309 .299 e overall width 0.25 0.15 0.05 .010 .006 .002 a1 standoff 1.83 1.73 1.63 .072 .068 .064 a2 molded package thickness 1.98 1.85 1.73 .078 .073 .068 a overall height 0.65 .026 p pitch 20 20 n number of pins max nom min max nom min dimension limits millimeters inches* units 2 1 d p n b e e1 l c a2 a a1 * controlling parameter notes: dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010? (0.254mm) per side. jedec equivalent: mo-150 drawing no. c04-072 significant characteristic
? 2003 microchip technology inc. preliminary ds39598d-page 149 pic16f818/819 28-lead plastic quad flat no lead package (ml) 6x6 mm body, punch singulated (qfn) lead width *controlling parameter drawing no. c04-114 notes: mold draft angle top dimensions d and e1 do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010" (0.254mm) per side. b .009 12 .011 .014 0.23 12 0.28 0.35 pitch number of pins overall width standoff molded package length overall length molded package width molded package thickness overall height max units dimension limits a2 a1 e1 d d1 e n p a .026 .236 bsc .000 .226 bsc inches .026 bsc min 28 nom max 0.65 .031 .002 0.00 6.00 bsc 5.75 bsc millimeters* .039 min 28 0.65 bsc nom 0.80 0.05 1.00 .008 ref base thickness a3 0.20 ref jedec equivalent: mmo-220 0.85 .033 .0004 0.01 .236 bsc .226 bsc 6.00 bsc 5.75 bsc lead length tie bar width l .020 .024 .030 0.50 0.60 0.75 r .005 .007 .010 0.13 0.17 0.23 tie bar length q .012 .016 .026 0.30 0.40 0.65 chamfer ch .009 .017 .024 0.24 0.42 0.60 e2 d2 exposed pad width exposed pad length .140 .146 .152 3.55 3.70 3.85 .140 .146 .152 3.55 3.70 3.85 d e e1 n 1 2 d1 a a2 exposed metal pads bottom view top view q l r p a1 a3 ch x 45 b d2 e2
pic16f818/819 ds39598d-page 150 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 151 pic16f818/819 appendix a: revision history revision a (may 2002) original version of this data sheet. revision b (august 2002) added intrc section. pwrt and bor are indepen- dent of each other. revised program memory text and code routine. added qfn package. modified portb diagrams. revision c (november 2002) added various new feature descriptions. added inter- nal rc oscillator specifications. added low-power timer1 specifications and rtc application example. revision d (november 2003) updated ircf bit modification information and changed the intosc stabilization delay from 1 ms to 4 ms in section 4.0 ?oscillator configurations? . updated section 12.17 ?in-circuit serial programming? to clarify lvp programming. in section 15.0 ?electrical characteristics? , the dc characteristics ( section 15.2 and section 15.3 ) have been updated to include the typ, min and max values and table 15-1 ?external clock timing requirements? has been updated. appendix b: devi ce differences the differences between the devices in this data sheet are listed in table b-1. table b-1: differences between the pic16f818 and pic16f819 features pic16f818 pic16f819 flash program memory (14-bit words) 1k 2k data memory (bytes) 128 256 eeprom data memory (bytes) 128 256
pic16f818/819 ds39598d-page 152 preliminary ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 153 pic16f818/819 index a a/d acquisition requirements .......................................... 84 adif bit ...................................................................... 83 analog-to-digital converter ........................................ 81 associated registers ................................................. 87 calculating acquisition time ...................................... 84 configuring analog port pins ..................................... 85 configuring the interrupt ............................................ 83 configuring the module .............................................. 83 conversion clock ....................................................... 85 conversions ............................................................... 86 converter characteristics ........................................ 140 delays ........................................................................ 84 effects of a reset ....................................................... 87 go/done bit ............................................................. 83 internal sampling switch (rss) impedance ............... 84 operation during sleep ............................................. 87 result registers ......................................................... 86 source impedance ..................................................... 84 time delays ............................................................... 84 use of the ccp trigger .............................................. 87 absolute maximum ratings ............................................. 117 ack .................................................................................... 77 adcon0 register .............................................................. 81 adcon1 register .............................................................. 81 adresh register ........................................................ 13 , 81 adresh, adresl register pair ...................................... 83 adresl register ........................................................ 14 , 81 application notes an556 (implementing a table read) ........................ 23 an578 (use of the ssp module in the i 2 c multi-master environment) ........................... 71 an607 (power-up trouble shooting) ......................... 92 assembler mpasm assembler .................................................. 111 b bf bit ................................................................................. 76 block diagrams a/d ............................................................................. 83 analog input model .................................................... 84 capture mode operation ........................................... 66 compare mode operation ......................................... 67 in-circuit serial programming connections ............. 101 interrupt logic ............................................................ 96 on-chip reset circuit ................................................ 91 pic16f818/819 ............................................................ 6 pwm .......................................................................... 68 ra0/an0:ra1/an1 pins ............................................ 40 ra2/an2/v ref - pin .................................................... 40 ra3/an3/v ref + pin ................................................... 40 ra4/an4/t0cki pin ................................................... 40 ra5/mclr /v pp pin ................................................... 41 ra6/osc2/clko pin ................................................ 41 ra7/osc1/clki pin .................................................. 42 rb0 pin ...................................................................... 45 rb1 pin ...................................................................... 46 rb2 pin ...................................................................... 47 rb3 pin ...................................................................... 48 rb4 pin ...................................................................... 49 rb5 pin ...................................................................... 50 rb6 pin ...................................................................... 51 rb7 pin ..................................................................... 52 recommended mclr circuit .................................... 92 ssp in i 2 c mode ........................................................ 76 ssp in spi mode ....................................................... 74 system clock ............................................................. 38 timer0/wdt prescaler .............................................. 53 timer1 ....................................................................... 58 timer2 ....................................................................... 63 watchdog timer (wdt) ............................................. 98 bor. see brown-out reset. brown-out reset (bor) .............................. 89 , 91 , 92 , 93 , 94 c c compilers mplab c17 ............................................................. 112 mplab c18 ............................................................. 112 mplab c30 ............................................................. 112 capture/compare/pwm (ccp) ......................................... 65 capture mode ............................................................ 66 ccp prescaler ................................................... 66 software interrupt .............................................. 66 timer1 mode selection ...................................... 66 capture, compare and timer1 associated registers ......................................... 67 ccp timer resources ............................................... 65 ccp1if ...................................................................... 66 ccpr1 ...................................................................... 66 ccpr1h:ccpr1l ..................................................... 66 compare mode .......................................................... 67 ccp pin configuration ...................................... 67 software interrupt mode .................................... 67 special event trigger ........................................ 67 special trigger output of ccp1 ........................ 67 timer1 mode selection ...................................... 67 pwm and timer2 associated registers ......................................... 69 pwm mode ................................................................ 68 pwm, example frequencies/resolutions ................. 69 ccp1m0 bit ....................................................................... 65 ccp1m1 bit ....................................................................... 65 ccp1m2 bit ....................................................................... 65 ccp1m3 bit ....................................................................... 65 ccp1x bit .......................................................................... 65 ccp1y bit .......................................................................... 65 ccpr1h register .............................................................. 65 ccpr1l register .............................................................. 65 code examples changing between capture prescalers ..................... 66 changing prescaler assignment from timer0 to wdt .................................................. 55 changing prescaler assignment from wdt to timer0 .................................................. 55 clearing ram using indirect addressing .................. 23 erasing a flash program memory row ..................... 29 implementing a real-time clock using a timer1 interrupt service .................................... 62 initializing porta ...................................................... 39 reading a 16-bit free running timer ....................... 59 reading data eeprom ............................................ 27 reading flash program memory ............................... 28 saving status and w registers in ram .................... 97 writing a 16-bit free running timer .......................... 59 writing to data eeprom .......................................... 27 writing to flash program memory ............................. 31
pic16f818/819 ds39598d-page 154 ? 2003 microchip technology inc. code protection ......................................................... 89 , 100 computed goto ............................................................... 23 configuration bits ............................................................... 89 crystal oscillator and ceramic resonators ....................... 33 d data eeprom memory ..................................................... 25 associated registers ................................................. 32 eeadr register ........................................................ 25 eeadrh register ...................................................... 25 eecon1 register ...................................................... 25 eecon2 register ...................................................... 25 eedata register ...................................................... 25 eedath register ...................................................... 25 operation during code-protect .................................. 32 protection against spurious writes ............................ 32 reading ...................................................................... 27 write complete flag (eeif bit) .................................. 25 writing ........................................................................ 27 data memory special function registers ........................................ 13 dc and ac characteristics graphs and tables ................................................... 143 dc characteristics internal rc accuracy ............................................... 126 pic16f818/819, pic16lf818/819 ........................... 127 power-down and supply current ............................. 120 supply voltage ......................................................... 119 demonstration boards picdem 1 ................................................................ 114 picdem 17 .............................................................. 114 picdem 18r pic18c601/801 ................................. 115 picdem 2 plus ........................................................ 114 picdem 3 pic16c92x ............................................ 114 picdem 4 ................................................................ 114 picdem lin pic16c43x ......................................... 115 picdem usb pic16c7x5 ....................................... 115 picdem.net internet/ethernet ................................. 114 development support ...................................................... 111 device differences ........................................................... 151 device overview .................................................................. 5 direct addressing ............................................................... 24 e eeadr register ................................................................ 25 eeadrh register .............................................................. 25 eecon1 register .............................................................. 25 eecon2 register .............................................................. 25 eedata register .............................................................. 25 eedath register .............................................................. 25 electrical characteristics .................................................. 117 endurance ............................................................................ 1 errata ................................................................................... 3 evaluation and programming tools ................................. 115 external clock input ........................................................... 34 external interrupt input (rb0/int). see interrupt sources. f flash program memory ...................................................... 25 associated registers ................................................. 32 eeadr register ........................................................ 25 eeadrh register ...................................................... 25 eecon1 register ...................................................... 25 eecon2 register ...................................................... 25 eedata register ...................................................... 25 eedath register ...................................................... 25 erasing ....................................................................... 28 reading ..................................................................... 28 writing ........................................................................ 30 fsr register .................................................... 13 , 14 , 15 , 23 i i/o ports ............................................................................. 39 porta ...................................................................... 39 portb ...................................................................... 43 trisb register .......................................................... 43 i 2 c addressing ................................................................. 77 associated registers ................................................. 79 master mode operation ............................................. 79 mode .......................................................................... 76 mode selection .......................................................... 76 multi-master mode operation .................................... 79 reception ................................................................... 77 scl and sda pins .................................................... 76 slave mode ................................................................ 76 transmission ............................................................. 77 id locations ..................................................................... 100 in-circuit debugger .......................................................... 100 in-circuit serial programming (icsp) .............................. 101 indf register .........................................................14 , 15 , 23 indirect addressing .......................................................23 , 24 instruction format ............................................................ 103 instruction set .................................................................. 103 addlw .................................................................... 105 addwf .................................................................... 105 andlw .................................................................... 105 andwf .................................................................... 105 bcf .......................................................................... 105 bsf .......................................................................... 105 btfsc ..................................................................... 106 btfss ..................................................................... 106 call ........................................................................ 106 clrf ....................................................................... 106 clrw ...................................................................... 106 clrwdt ................................................................. 106 comf ...................................................................... 107 decf ....................................................................... 107 decfsz .................................................................. 107 descriptions ............................................................. 105 goto ...................................................................... 107 incf ........................................................................ 107 incfsz .................................................................... 107 iorlw ..................................................................... 108 iorwf ..................................................................... 108 movf ...................................................................... 108 movlw ................................................................... 108 movwf ................................................................... 108 nop ......................................................................... 108 read-modify-write operations ................................ 103 retfie .................................................................... 109 retlw .................................................................... 109 return .................................................................. 109 rlf .......................................................................... 109 rrf ......................................................................... 109 sleep ........................................................................ 109 sublw .................................................................... 110 subwf .................................................................... 110 summary table ....................................................... 104 swapf .................................................................... 110 xorlw .................................................................... 110 xorwf ................................................................... 110
? 2003 microchip technology inc. preliminary ds39598d-page 155 pic16f818/819 int interrupt (rb0/int). see interrupt sources. intcon register ............................................................... 15 gie bit ........................................................................ 18 inte bit ...................................................................... 18 intf bit ...................................................................... 18 rbif bit ...................................................................... 18 tmr0ie bit ................................................................. 18 internal oscillator block ..................................................... 35 intrc modes ............................................................ 35 interrupt sources .......................................................... 89 , 96 rb0/int pin, external ................................................ 97 tmr0 overflow .......................................................... 97 interrupts rb7:rb4 port change ............................................... 43 synchronous serial port interrupt .............................. 20 interrupts, context saving during ...................................... 97 interrupts, enable bits global interrupt enable (gie bit) ............................... 96 interrupt-on-change (rb7:rb4) enable (rbie bit) ........................................................... 97 rb0/int enable (inte bit) ........................................ 18 tmr0 overflow enable (tmr0ie bit) ........................ 18 interrupts, enable bits global interrupt enable (gie bit) ............................... 18 interrupts, flag bits interrupt-on-change (rb7:rb4) flag (rbif bit) ..................................................... 18 , 97 rb0/int flag (intf bit) ............................................. 18 tmr0 overflow flag (tmr0if bit) ............................. 97 intrc modes adjustment ................................................................. 36 l loading of pc .................................................................... 23 low-voltage icsp programming ..................................... 101 m master clear (mclr ) mclr reset, normal operation .....................91 , 93 , 94 mclr reset, sleep ........................................91 , 93 , 94 operation and esd protection ................................... 92 memory organization ........................................................... 9 data memory ............................................................. 10 program memory ......................................................... 9 mplab asm30 assembler, linker, librarian .................. 112 mplab icd 2 in-circuit debugger ................................... 113 mplab ice 2000 high performance universal in-circuit emulator ................................................... 113 mplab ice 4000 high performance universal in-circuit emulator ................................................... 113 mplab integrated development environment software .............................................. 111 mplink object linker/mplib object librarian ............... 112 o opcode field descriptions ............................................... 103 option register .................................................................. 15 intedg bit ................................................................ 17 ps2:ps0 bits ............................................................. 17 psa bit ....................................................................... 17 rbpu bit .................................................................... 17 t0cs bit ..................................................................... 17 t0se bit ..................................................................... 17 oscillator configuration ..................................................... 33 ecio .......................................................................... 33 extclk ..................................................................... 93 extrc ...................................................................... 93 hs .........................................................................33 , 93 intio1 ....................................................................... 33 intio2 ....................................................................... 33 intrc ........................................................................ 93 lp .........................................................................33 , 93 rc ........................................................................33 , 35 rcio .......................................................................... 33 xt .........................................................................33 , 93 oscillator control register ................................................. 37 modifying ircf bits ................................................... 37 clock transition sequence ................................ 37 oscillator start-up timer (ost) ....................................89 , 92 oscillator, wdt .................................................................. 98 p packaging information ..................................................... 145 marking .................................................................... 145 pcfg0 bit .......................................................................... 82 pcfg1 bit .......................................................................... 82 pcfg2 bit .......................................................................... 82 pcfg3 bit .......................................................................... 82 pcl register .................................................... 13 , 14 , 15 , 23 pclath register ............................................. 13 , 14 , 15 , 23 pcon register .................................................................. 93 por bit ...................................................................... 22 pickit 1 flash starter kit ................................................. 115 picstart plus development programmer .................... 113 pinout descriptions pic16f818/819 ........................................................... 7 pointer, fsr ...................................................................... 23 pop ................................................................................... 23 por. see power-on reset. porta ................................................................................ 7 associated register summary .................................. 39 porta register ................................................................ 13 portb ................................................................................ 8 associated register summary .................................. 44 pull-up enable (rbpu bit) ......................................... 17 rb0/int edge select (intedg bit) .......................... 17 rb0/int pin, external ................................................ 97 rb7:rb4 interrupt-on-change .................................. 97 rb7:rb4 interrupt-on-change enable (rbie bit) ........................................................... 97 rb7:rb4 interrupt-on-change flag (rbif bit) ......................................................18 , 97 portb register ...........................................................13 , 15 postscaler, wdt assignment (psa bit) ................................................ 17 rate select (ps2:ps0 bits) ....................................... 17 power-down mode. see sleep. power-on reset (por) ............................... 89 , 91 , 92 , 93 , 94 por status (por bit) ............................................... 22 power control (pcon) register ................................ 93 power-down (pd bit) ................................................. 91 time-out (to bit) ..................................................16 , 91 power-up timer (pwrt) ..............................................89 , 92 pr2 register ..................................................................... 63 prescaler, timer0 assignment (psa bit) ................................................ 17 rate select (ps2:ps0 bits) ....................................... 17
pic16f818/819 ds39598d-page 156 ? 2003 microchip technology inc. pro mate ii universal device programmer ................... 113 program counter reset conditions ........................................................ 93 program memory interrupt vector ............................................................ 9 map and stack pic16f818 ........................................................... 9 pic16f819 ........................................................... 9 reset vector ................................................................ 9 program verification ......................................................... 100 push ................................................................................. 23 r r/w bit ............................................................................... 77 ra0/an0 pin ........................................................................ 7 ra1/an1 pin ........................................................................ 7 ra2/an2/v ref - pin .............................................................. 7 ra3/an3/v ref + pin ............................................................. 7 ra4/an4/t0cki pin ............................................................. 7 ra5/mclr /v pp pin .............................................................. 7 ra6/osc2/clko pin .......................................................... 7 ra7/osc1/clki pin ............................................................ 7 rb0/int pin ......................................................................... 8 rb1/sdi/sda pin ................................................................. 8 rb2/sdo/ccp1 pin ............................................................. 8 rb3/ccp1/pgm pin ............................................................ 8 rb4/sck/scl pin ................................................................ 8 rb5/ss pin .......................................................................... 8 rb6/t1oso/t1cki/pgc pin ............................................... 8 rb7/t1osi/pgd pin ............................................................ 8 rbif bit .............................................................................. 43 rcio oscillator .................................................................. 35 receive overflow indicator bit, sspov ............................. 73 register file ....................................................................... 10 register file map pic16f818 ................................................................. 11 pic16f819 ................................................................. 12 registers adcon0 (a/d control 0) ........................................... 81 adcon1 (a/d control 1) ........................................... 82 ccp1con (capture/compare/pwm control 1) ........ 65 configuration word .................................................... 90 eecon1 (data eeprom access control 1) ............. 26 initialization conditions (table) ................................... 94 intcon (interrupt control) ........................................ 18 option ......................................................................... 17 option_reg ............................................................ 54 osccon (oscillator control) .................................... 38 osctune (oscillator tuning) ................................... 36 pcon (power control) ............................................... 22 pie1 (peripheral interrupt enable 1) .......................... 19 pie2 (peripheral interrupt enable 2) .......................... 21 pir1 (peripheral interrupt flag 1) .............................. 20 pir2 (peripheral interrupt flag 2) .............................. 21 sspcon (synchronous serial port control 1) .......... 73 sspstat (synchronous serial port status) ............. 72 status ......................................................................... 16 t1con (timer1 control) ............................................ 57 t2con (timer2 control) ............................................ 64 reset ............................................................................89 , 91 brown-out reset (bor). see brown-out reset (bor). mclr reset. see mclr . power-on reset (por). see power-on reset (por). reset conditions for all registers ............................. 94 reset conditions for pcon register ........................ 93 reset conditions for program counter ...................... 93 reset conditions for status register ......................... 93 wdt reset. see watchdog timer (wdt). revision history ............................................................... 151 rp0 bit ............................................................................... 10 rp1 bit ............................................................................... 10 s sales and support ........................................................... 161 scl .................................................................................... 76 slave mode scl ............................................................................ 76 sda ........................................................................... 76 sleep .......................................................................89 , 91 , 99 software simulator (mplab sim) .................................... 112 software simulator (mplab sim30) ................................ 112 special event trigger ......................................................... 87 special features of the cpu ............................................. 89 special function register summary .................................. 13 special function registers ................................................ 13 spi associated registers ................................................. 74 serial clock ................................................................ 71 serial data in ............................................................. 71 serial data out .......................................................... 71 slave select ............................................................... 71 ssp ack ........................................................................... 76 i 2 c i 2 c operation ..................................................... 76 sspadd register .............................................................. 14 sspif ................................................................................ 20 sspov .............................................................................. 73 sspov bit ......................................................................... 76 sspstat register ............................................................ 14 stack .................................................................................. 23 overflows ................................................................... 23 underflow ................................................................... 23 status register .............................................................13 , 15 dc bit ........................................................................ 16 irp bit ........................................................................ 16 pd bit ......................................................................... 91 to bit ....................................................................16 , 91 z bit ........................................................................... 16 synchronous serial port (ssp) .......................................... 71 overview .................................................................... 71 spi mode ................................................................... 71 synchronous serial port interrupt ...................................... 20
? 2003 microchip technology inc. preliminary ds39598d-page 157 pic16f818/819 t t1ckps0 bit ...................................................................... 57 t1ckps1 bit ...................................................................... 57 t1oscen bit ..................................................................... 57 t1sync bit ........................................................................ 57 t2ckps0 bit ...................................................................... 64 t2ckps1 bit ...................................................................... 64 t ad ..................................................................................... 85 time-out sequence ............................................................ 92 timer0 ................................................................................ 53 associated registers ................................................. 55 clock source edge select (t0se bit) ........................ 17 clock source select (t0cs bit) ................................. 17 external clock ............................................................ 54 interrupt ...................................................................... 53 operation ................................................................... 53 overflow enable (tmr0ie bit) ................................... 18 overflow flag (tmr0if bit) ....................................... 97 overflow interrupt ...................................................... 97 prescaler .................................................................... 54 t0cki ......................................................................... 54 timer1 ................................................................................ 57 associated registers ................................................. 62 capacitor selection .................................................... 60 counter operation ..................................................... 58 operation ................................................................... 57 operation in asynchronous counter mode ................ 59 operation in synchronized counter mode ................. 58 operation in timer mode ........................................... 58 oscillator .................................................................... 60 oscillator layout considerations ............................... 60 prescaler .................................................................... 61 resetting timer1 register pair .................................. 61 resetting timer1 using a ccp trigger output .......... 60 tmr1h ....................................................................... 59 tmr1l ....................................................................... 59 use as a real-time clock ......................................... 61 timer2 ................................................................................ 63 associated registers ................................................. 64 output ........................................................................ 63 postscaler .................................................................. 63 prescaler .................................................................... 63 prescaler and postscaler ........................................... 63 timing diagrams a/d conversion ........................................................ 141 brown-out reset ...................................................... 132 capture/compare/pwm (ccp1) .............................. 134 clko and i/o .......................................................... 131 external clock .......................................................... 130 i 2 c bus data ............................................................ 138 i 2 c bus start/stop bits ............................................. 137 i 2 c reception (7-bit address) .................................... 78 i 2 c transmission (7-bit address) ............................... 78 pwm output .............................................................. 68 reset, watchdog timer, oscillator start-up timer and power-up timer .............................. 132 slow rise time (mclr tied to v dd through rc network) ........................................ 96 spi master mode ....................................................... 75 spi master mode (cke = 0, smp = 0) .................... 135 spi master mode (cke = 1, smp = 1) .................... 135 spi slave mode (cke = 0) .................................75 , 136 spi slave mode (cke = 1) .................................75 , 136 time-out sequence on power-up (mclr tied to v dd through pull-up resistor) .............. 95 time-out sequence on power-up (mclr tied to v dd through rc network): case 1 ....... 95 time-out sequence on power-up (mclr tied to v dd through rc network): case 2 ....... 95 timer0 and timer1 external clock .......................... 133 timer1 incrementing edge ........................................ 58 wake-up from sleep through interrupt .................... 100 timing parameter symbology ......................................... 129 timing requirements external clock .......................................................... 130 tmr0 register ................................................................... 15 tmr1cs bit ....................................................................... 57 tmr1h register ................................................................ 13 tmr1l register ................................................................. 13 tmr1on bit ...................................................................... 57 tmr2 register ................................................................... 13 tmr2on bit ...................................................................... 64 toutps0 bit ..................................................................... 64 toutps1 bit ..................................................................... 64 toutps2 bit ..................................................................... 64 toutps3 bit ..................................................................... 64 trisa register .............................................................14 , 39 trisb register .............................................................14 , 15 v v dd pin ................................................................................ 8 v ss pin ................................................................................ 8 w wake-up from sleep .....................................................89 , 99 interrupts ..............................................................93 , 94 mclr reset .............................................................. 94 wdt reset ................................................................ 94 wake-up using interrupts .................................................. 99 watchdog timer (wdt) ................................................89 , 98 associated registers ................................................. 98 enable (wdten bit) .................................................. 98 intrc oscillator ........................................................ 98 postscaler. see postscaler, wdt. programming considerations .................................... 98 time-out period ......................................................... 98 wdt reset, normal operation ....................... 91 , 93 , 94 wdt reset, sleep ................................................91 , 94 wdt wake-up ........................................................... 93 wcol ................................................................................ 73 write collision detect bit, wcol ...................................... 73 www, on-line support ...................................................... 3
pic16f818/819 ds39598d-page 158 ? 2003 microchip technology inc. notes:
? 2003 microchip technology inc. preliminary ds39598d-page 159 pic16f818/819 on-line support microchip provides on-line support on the microchip world wide web site. the web site is used by microchip as a means to make files and information easily available to customers. to view the site, the user must have access to the internet and a web browser, such as netscape ? or microsoft ? internet explorer. files are also available for ftp download from our ftp site. connecting to the microchip internet web site the microchip web site is available at the following url: www.microchip.com the file transfer site is available by using an ftp service to connect to: ftp://ftp.microchip.com the web site and file transfer site provide a variety of services. users may download files for the latest development tools, data sheets, application notes, user's guides, articles and sample programs. a vari- ety of microchip specific business information is also available, including listings of microchip sales offices, distributors and factory representatives. other data available for consideration is: latest microchip press releases technical support section with frequently asked questions design tips device errata job postings microchip consultant program member listing links to other useful web sites related to microchip products conferences for products, development systems, technical information and more listing of seminars and events systems information and upgrade hot line the systems information and upgrade line provides system users a listing of the latest versions of all of microchip's development systems software products. plus, this line provides information on how customers can receive the most current upgrade kits. the hot line numbers are: 1-800-755-2345 for u.s. and most of canada, and 1-480-792-7302 for the rest of the world. 042003
pic16f818/819 ds39598d-page 160 preliminary ? 2003 microchip technology inc. reader response it is our intention to provide you with the best documentation possible to ensure successful use of your microchip prod- uct. if you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please fax your comments to the technical publications manager at (480) 792-4150. please list the following information, and use this outline to provide us with your comments about this document. to : technical publications manager re: reader response total pages sent ________ from: name company address city / state / zip / country telephone: (_______) _________ - _________ application (optional): would you like a reply? y n device: literature number: questions: fax: (______) _________ - _________ ds39598d pic16f818/819 1. what are the best features of this document? 2. how does this document meet your hardware and software development needs? 3. do you find the organization of this document easy to follow? if not, why? 4. what additions to the document do you think would enhance the structure and subject? 5. what deletions from the document could be made without affecting the overall usefulness? 6. is there any incorrect or misleading information (what and where)? 7. how would you improve this document?
? 2003 microchip technology inc. preliminary ds39598d-page 161 pic16f818/819 pic16f818/819 product identification system to order or obtain information, e.g. , on pricing or delivery, refer to the factory or the listed sales office. part no. x /xx xxx pattern package temperature range device device pic16f818: standard v dd range pic16f818t: (tape and reel) pic16lf818: extended v dd range temperature range - = 0c to +70c i = -40c to +85c package p = pdip so = soic ss = ssop ml = qfn pattern qtp, sqtp, rom code (factory specified) or special requirements. blank for otp and windowed devices. examples: a) pic16f818-i/p = industrial temp., pdip package, extended v dd limits. b) pic16f818-i/so = industrial temp., soic package, normal v dd limits. note 1: f = cmos flash lf = low-power cmos flash 2: t = in tape and reel ? soic, ssop packages only.
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