键盘扫描汇编程序

文章摘要： mov r0,#8 ajmp scanendrow21: cjne a,#0ddh,row22 mov r0,#9 acall delay20ms ajmp scanend row22: cjne a,#0bdh,row23 mov r0,#10 acall delay20ms ajmp scanendrow23: mov r0,#11 acall delay20ms ajmp scanendrow3:

键盘扫描汇编程序,标签：嵌入式系统开发,嵌入式开发,http://www.88dzw.com
         mov r0,#8
         ajmp scanend
row21:   cjne a,#0ddh,row22
         mov r0,#9
         acall delay20ms
         ajmp scanend       
row22:   cjne a,#0bdh,row23
         mov r0,#10
         acall delay20ms
         ajmp scanend
row23:   mov r0,#11
         acall delay20ms
         ajmp scanend

row3:   mov key,#0fbh
        mov a,key
        cjne a,#0fbh,row3scan
        ajmp row4
row3scan:cjne a,#0ebh,row31
         mov r0,#4
         acall delay20ms
         ajmp scanend
row31:   cjne a,#0dbh,row32
         mov r0,#5
         acall delay20ms
         ajmp scanend       
row32:   cjne a,#0bbh,row33
         mov r0,#6
         acall delay20ms
         ajmp scanend
row33:   mov r0,#7
         acall delay20ms
         ajmp scanend

row4:    mov key,#0f7h
         mov a,key
         cjne a,#0e7h,row41
         mov r0,#0
         acall delay20ms
         ajmp scanend
row41:   cjne a,#0d7h,row42
         mov r0,#1
         acall delay20ms
         ajmp scanend       
row42:   cjne a,#0b7h,row43
         mov r0,#2
         acall delay20ms
         ajmp scanend
row43:   mov r0,#3
         acall delay20ms
         ajmp scanend

scanend:ret

;判断是否松开
keyoff:  mov key,#0fh
         mov a,key
         cjne a,#0fh,keyret
         sjmp keyoff
keyret:  acall delay20ms
         ret

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