| | ; COUNT.ASM |
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| | ; Copyright (c) 2002, TundraWare Inc. |
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| | ; |
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| | ; Loosely based on David Tait's LED 'WALK.ASM' Test Program |
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| | ; Uses same hardware setup but counts in binary, flashing at |
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| | ; full count. |
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| | |
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| | ;;; Generally speaking, UPPER-CASE symbols in the code below are |
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| | ;;; defined in the standard MPLAB include file. My code is in |
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| | ;;; lower-case. |
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| | list p=16F84A |
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| | #include <P16F84A.INC> |
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| | |
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| | errorlevel -302 ;suppress bank selection messages |
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| | __config 3ff5h ;xt osc, watchdog |
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| | __idlocs 1234 |
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| | |
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| | ;;; Device Constants |
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| | |
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| | pre1 equ 08h ; prescaler constants |
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| | pre2 equ 09h |
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| | pre4 equ 0ah |
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| | pre8 equ 0bh |
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| | pre16 equ 0ch |
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| | pre32 equ 0dh |
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| | pre64 equ 0eh |
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| | pre128 equ 0fh |
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| | ;;; Program Constants |
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| | |
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| | blinkcnt equ 05h ; number of times to blink |
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| | bcount equ 0dh ; register to hold blink count |
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| | maxcnt equ 0fh ; maximum count to display |
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| | preblink equ pre32 ; prescaler value for blinking |
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| | precount equ pre16 ; prescaler value for counting |
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| | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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| | |
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| | ;;; |
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| | ; Main program logic |
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| | ;;; |
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| | |
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| | begin call portb_w ; setup PORTB for writing |
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| | movlw precount ; set prescaler for slow disply |
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| | call wdt_pre |
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| | movlw maxcnt ; number of counts |
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| | clrf PORTB ; all leds off |
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| | count sleep ; display current count for a while |
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| | incf PORTB,F ; next value to display |
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| | movf PORTB,W ; see if we're displaying 'maxcnt' |
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| | andlw 0fh ; mask hi nibble - no LEDs there |
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| | xorlw maxcnt ; subtract 'maxcnt' from w |
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| | btfss STATUS,Z |
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| | goto count ; nope, continue counting |
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| | call blink |
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| | goto begin |
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| | ;;; End of main logic |
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| | |
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| | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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| | |
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| | ;;; |
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| | ; Supporting Subroutines |
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| | ;;; |
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| | ;;; |
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| | ; Set PORTB To Write |
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| | ; Returns with Bank 0 selected |
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| | ;;; |
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| | portb_w bsf STATUS,RP0 ; select register bank 1 |
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| | clrf TRISB ; set PORTB to all outputs |
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| | bcf STATUS,RP0 ; select register bank 0 |
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| | return |
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| | ;;; End of 'portb_w' |
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| | ;;; |
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| | ; Set the WDT Prescaler |
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| | ; Value required must be passed in w |
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| | ; Returns with Bank 0 selected |
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| | ;;; |
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| | wdt_pre bsf STATUS,RP0 ; select register bank 1 |
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| | movwf OPTION_REG |
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| | bcf STATUS,RP0 ; bank0 so PORTB is addressable |
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| | return |
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| | ;;; End of 'wdt_pre' |
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| | ;;; |
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| | ; Blink The Lights |
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| | ;;; |
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| | blink movlw preblink ; set prescaler for fast blink |
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| | call wdt_pre |
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| | movlw blinkcnt ; number of times to blink |
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| | movwf bcount |
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| | bcycle sleep ; display on from caller |
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| | clrf PORTB ; display off |
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| | sleep |
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| | decfsz bcount,F ; if zero, we've done 'blinkcnt' repetitions |
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| | goto again ; we're not done yet |
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| | return ; all done |
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| | again movlw maxcnt ; blink again - display on |
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| | movwf PORTB |
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| | goto bcycle |
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| | ;;; End of 'blink' |
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| | ;;; |
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| | ; EEPROM Contents |
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| | ;;; |
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| | org 2100h |
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| | ; |
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| | DE "$Id: count.asm,v 1.9 2002/03/10 15:43:56 tundra Exp tundra $" |
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| | END |
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