pwmdeng.asm

8051汇编语言对灯泡的PWM控制的实验

deng	bit	p1.7
time1	data	3ah
time2	data	3bh
	org	00h
	ajmp	start
	org	40h
start:	mov	time1,#00h
	mov	time2,#171
loop1:	
	inc	time1
	dec	time2
	mov	a,time1
	cjne	a,#170,next1
	ajmp	next2
next1:	setb	deng
	mov	r1,time1	
	call	delay
	clr	deng
	mov	r1,time2
	call	delay
	ajmp	loop1
next2:	SETB	DENG
	CALL	DELAY
	CALL	DELAY
;	CALL	DELAY
;	CALL	DELAY
	mov	time1,#200
	mov	time2,#00h
loop2:	setb	deng
	dec	time1
	inc	time2
	mov	a,time1
	jz	next3
	mov	r1,time1
	call	delay
	clr	deng
	mov	r1,time2
	call	delay
	ajmp	loop2
next3:	CLR	DENG
	mov	r1,#255
	call	delay
	mov	r1,#255
	call	delay
	CALL	DELAY
	CALL	DELAY
	AJMP	START
DELAY:	MOV	R2,#2
DE1:	MOV	R3,#35
	DJNZ	R3,$
	DJNZ	R2,DE1
	DJNZ	R1,DELAY
	RET
	END