按键识别和数码管显示 8255芯片
CLEAR: MOV DX,MY8255_B MOV AL,00H OUT DX,AL
RET
DIS: PUSH AX
MOV SI,3000H MOV DL,0DFH MOV AL,DL
AGAIN: PUSH DX
MOV DX,MY8255_A OUT DX,AL MOV AL,[SI]
MOV BX,OFFSET DTABLE
AND AX,00FFH ADD BX,AX MOV AL,[BX]
MOV DX,MY8255_B
OUT DX,AL CALL DALLY INC SI
POP DX MOV AL,DL
TEST AL,01H
JZ OUT1
ROR AL,1 MOV DL,AL JMP AGAIN
OUT1: POP AX
RET