atmega8and74hc164controllcd1602program.asm

用AVRStudio3.56编写的ATmega8控制74HC164驱动LCD1602的汇编程序

            .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      ddrc,1
            cbi      portc,1     ;pc1为液晶的数据/指令线(RS)
            sbi      ddrb,3
            sbi      portb,3     ;pb3为74hc164的数据线(A,B)
            sbi      ddrb,2
            sbi      portb,2     ;pb2为74hc164的时钟线(CLK)
            sbi      ddrc,2
            cbi      portc,2     ;pc2为液晶的片选线,高电平有效(E)
            ldi      r18,0
loop:       ldi      r31,4
            mov      r30,r18
            lpm      r16,z
            call     yiwei
            call     delay1
            inc      r18
            cpi      r18,6
            brlo     loop
            ldi      r16,$80
            call     yiwei
            call     delay1
            sbi      portc,1
            ldi      r16,$33 
            call     yiwei  
            call     delay1
            ldi      r16,$34 
            call     yiwei 
            call     delay1
            ldi      r16,$35
            call     yiwei
            call     delay1
wait:       rjmp     wait  
;************************************************          
yiwei:      ldi      r17,8
yiwei0:     sbi      portb,3
            rol      r16         ;r16为要移位的数
            brcs     yiwei1
            cbi      portb,3      
yiwei1:     cbi      portb,2
            sbi      portb,2     ;时钟线置1,送出数据
            dec      r17
            cpi      r17,1
            brsh     yiwei0
          ;  sbi      portc,2    ;液晶片选置1,给液晶送入数据
          ;  cbi      portc,2
            sbi      portc,2    ;液晶片选置1,给液晶送入数据
            cbi      portc,2
            ret  
;*******************************************            
delay1:     ldi      r16,20
del1:       ldi      r17,255
del2:       dec      r17
            cpi      r17,1
            brsh     del2
            dec      r16
            cpi      r16,1
            brsh     del1
            ret  
;***********************************************************************
.org    $200 ;液晶初始化的值
        .db  $01,$03,$06,$0f,$14,$3c