s12-3.asm

51单片机程序教程

	ORG 0000H
	LJMP MAIN
	ORG 030H
MAIN:	MOV 30H,#20
	MOV 31H,#60
	MOV TMOD,#10H
	MOV TH1,#3CH
	MOV TL1,#0B0H
	MOV IE,#00H
	SETB TR1
LOOP:	JBC TF1,LOOP1
       	AJMP LOOP
LOOP1:	MOV TH1,# 3CH 
	MOV TL1,#0B0H
	DJNZ 30H,LOOP
	MOV 30H,#20
	DJNZ 31H,LOOP
	MOV 31H,#60
	CPL P1.0
	AJMP LOOP
	END