启动程序.asm

该源码与书本配套

	ORG	00H
	MOV	SP,#60H
START:	JB	P3.0,$
	JB	P3.1,REV
	ANL	P1,#11110000B
FOR:	CLR	P1.3
	SETB	P1.0
	SETB	P1.1
	ACALL	SPEED
	CLR	P1.0
	SETB	P1.1
	SETB	P1.2
	ACALL	SPEED
	CLR	P1.1
	SETB	P1.2
	SETB	P1.3
	ACALL	SPEED
	CLR	P1.2
	SETB	P1.3
	SETB	P1.0
	ACALL	SPEED
	AJMP	START
REV:	CLR	P1.0
	SETB	P1.3
	ACALL	SPEED
	CLR	P1.3
	SETB	P1.2
	ACALL	SPEED
	CLR	P1.2
	SETB	P1.1
	ACALL	SPEED
	CLR	P1.1
	SETB	P1.0
	ACALL	SPEED
	AJMP	START
SPEED:	MOV	A,P2
	ANL	A,#0FH
	MOV	R7,A
X2:	MOV	R6,#20H
X1:	MOV	R5,#90H
	DJNZ	R5,$
	DJNZ	R6,X1
	DJNZ	R7,X2
	RET
	END