atmega8and74hc164controlledprogram.asm

在AVRStudio下用ATmega8控制四只串联的74HC164,实现电子钟程序

              .include "m8def.inc"
              .org      $00   
               rjmp     main
              .org     $20
main:          ldi      r16,high(ramend)
               out      sph,r16
               ldi      r16,low(ramend) 
               out      spl,r16
               sbi      ddrb,0
               sbi      ddrb,4
               sbi      ddrb,5 
               sbi      portb,0   ;pb0数码管的数据线
               sbi      portb,4   ;pb4数码管的时钟线
               sbi      portb,5   ;pb5数码管的小数点
               ldi      r16,0
               call     shumaguan
               ldi      r16,0
               call     shumaguan
               ldi      r16,0
               call     shumaguan
               ldi      r16,0
               call     shumaguan
               clr      r22
               out      tcnt0,r22
               out      timsk,r22
               out      tifr,r22
               ldi      r16,5
               out      tccr0,r16
               clr      r23     ;秒
               clr      r24  
               clr      r25     ;分                                       
loop:          in       r16,tifr
               sbrs     r16,0
               rjmp     loop
               ldi      r16,1
               out      tifr,r16
               inc      r24
               cpi      r24,14
               brlo     loop
               clr      r24
               inc      r23              
               cpi      r23,60
               brlo     loop1
               clr      r23
               inc      r25
               cpi      r25,60
               brlo     loop1
               clr      r25
loop1:         mov      r27,r23
               call     shijinzhi
               mov      r27,r25
               call     shijinzhi
               rjmp     loop               
;****************************************************************  
shumaguan:     wdr
               ldi      r17,8
               ldi      r31,4
               mov      r30,r16
               lpm      r16,z
shumg1:        sbi      portb,0
               rol      r16
               brcs     shumg2
               cbi      portb,0
shumg2:        cbi      portb,4    ;pb4数码管的时钟线
               sbi      portb,4
               dec      r17 
               cpi      r17,1
               brsh     shumg1 
               wdr
               ret   
;**************************************************************************
shijinzhi:     wdr
               clr      r26
shi0:          cpi      r27,10
               brlo     shi1
               subi     r27,10 
               inc      r26
               rjmp     shi0  
shi1:          mov      r16,r27
               call     shumaguan
               mov      r16,r26
               call     shumaguan
               ret
;;***************************************************************************
.org    $200 ;数码管显示对应值
        .db  $ee,$28,$cd,$6d,$2b,$67,$e7,$2c,$ef,$6f,$00,$00