h8255-1.asm

可编程并行接口８２５５Ａ完成的交通灯实验 用８２５５Ａ的Ｂ端口和Ｃ端口控制１２个ＬＥＤ的亮和灭（输出为０则亮

CODE SEGMENT
ASSUME CS:CODE
IOCONPT EQU 0073H
IOCPT	EQU 0072H
IOBPT	EQU 0071H
CONTPORT EQU 00DFH
DATAPORT EQU 00DEH
DATA1	 EQU 0500H
START:	JMP IOLED
IOLED:	CALL FORMAT
	CALL LEDDISP
	MOV AL,89H
	MOV DX,IOCONPT
	OUT DX,AL
	NOP
	NOP
	NOP
IOLED1: MOV DX,IOCPT
	IN AL,DX
	MOV DX,IOBPT
	OUT DX,AL
	MOV CX,0FFFFH
DELAY:	LOOP DELAY
	JMP IOLED1

LEDDISP:MOV AL,90H
	MOV DX,CONTPORT
	OUT DX,AL
	MOV BYTE PTR DS:[0600H],00
LED1:	CMP BYTE PTR DS:[0600H],07H
	JA  LED2
	MOV BL,DS:[0600H]
	MOV BH,0H
	MOV AL,CS:[BX+DATA1]
	MOV DX,DATAPORT
	OUT DX,AL
	ADD BYTE PTR DS:[0600H],01H
	JNZ LED1
LED2:	RET
FORMAT: MOV BX,0
	MOV WORD PTR DS:[BX+0500H],4006H
	ADD BX,2
	MOV WORD PTR DS:[BX+0500H],4040H
	ADD BX,2
	MOV WORD PTR DS:[BX+0500H],6D6DH
	ADD BX,2
	MOV WORD PTR DS:[BX+0500H],7F5BH
	RET
CODE ENDS
END  START