This is a timer circuit which measures time in hours, minutes, seconds, and toggles two controls. The code is provided here"as is" as an example of PIC macro assembler code and is here for anyone wishing to make use of it for their own projects.
This code here was part of a project which required time events to happen at approximately 6 hours and 25 minutes apart, and to happen only once. As you can see, the code shown here is rather simple, does not make use of the watch dog timer, or do anything else after reaching "done", but it can serve as a code example for anyone interested in asm code for the pic10 or pic12 type chips.
If you are wondering what sort of circuit would make use of such a program, think of devices that require run-once timing, such as drains, gas or air vents, or anything that requires a slow sequence of power control events to happen where timing is NOT critical. This circuit can be improved by syncing to some external event (for example, sprinkler control using sun setting as an event), or using a crystal or 60Hz/50Hz power-line for timing. Basically, potential ideas can be plentiful for those who are curious and interested.
...and Good Luck with your project. I'd also be interested to hear about it.
You can download 6-Hour A/B-Timer, or you can copy and paste the code shown below into your ASM code editor.
title 'Simple A/B timer by Jose Da Silva, 1999mar01' radix dec list P=12C508 list C=120,T=on #include <P12C508.INC> __fuses _MCLRE_OFF&_CP_OFF&_WDT_OFF&_IntRC_OSC __idlocs h'9904' ;date code 1999, March w equ 0 f equ 1 org 8 ;start of ram area hours res 1 mins res 1 secs res 4 ;--------------------------------------------------------------- ; ; pic12c508 ; +5v--|1 8|--gnd ; gp5<-|2 7|->gp0 (A)__/^^^^^^^^^\____ ; gp4<-|3 6|->gp1 (B)_________/^^^^^\_ ; gp3->|4 5|->gp2 ; ;*************************************************************** ;Time Down Macro ;This macro counts down hours,minutes,seconds ;before continuing to next step ;enter: hours,minutes,seconds ;exit : ? TmeDwnM macro v1,v2,v3 movlw v1+1 ;store hours to go movwf hours movlw v2+1 ;store minutes to go movwf mins movlw v3+1 ;store seconds to go movwf secs call CntDwn ;loop until everthing at zero endm ;*************************************************************** ;Program start vector location org 0 Start movlw 07fh movwf OSCCAL movlw b'11011111' ;set options register option clrf GPIO ;set-up outputs movlw b'00001000' ;..GPIO3 always an input tris GPIO ;--------------------------------------------------------------- ;Flip outputs according to specs movlw b'00000001' ;set bit A and wait 6 hours movwf GPIO TmeDwnM 6,0,0 movlw b'00000011' ;set bits AB and wait 25 minutes movwf GPIO TmeDwnM 0,25,0 movlw b'00000010' ;set bit B and wait 25 minutes movwf GPIO TmeDwnM 0,25,0 movlw b'00000000' ;turn everthing off movwf GPIO Done goto Done ;loop forever or until reset ;*************************************************************** ;Count Down Subroutine ;Slightly longer than required, but good enough for this project CntDwn movlw 244 ;setup 1 second loop movwf secs+1 CntDwn0 movlw 0 movwf secs+2 CntDwn1 movlw 4 ;loop for 1 second movwf secs+3 CntDwn2 decfsz secs+3,f goto CntDwn2 decfsz secs+2,f goto CntDwn1 decfsz secs+1,f goto CntDwn0 CntDwnS decfsz secs,f ;count down seconds left goto CntDwn movlw 60 ;setup for another 60 seconds movwf secs decfsz mins,f ;count down minutes left goto CntDwn movlw 60 ;setup for another 60 minutes movwf mins decfsz hours,f ;count down hours left goto CntDwn return ;*************************************************************** dt "Copyright Jose Da Silva 1999mar01 Vancouver BC" ;*************************************************************** org 01ffh osc_set movlw 07fh ;load osc calibration value end |
If you find this code (or sections of this code) useful for yourself, or a project, I will appreciate a little credit for providing it here for your use/project (for example, in your source code comments, or even a web link back to this web page is great if you have a project that uses it that you want to show/demonstrate). Thanks.
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