p18_1.asm

单片机原理与应用实例教程 单片机原理与应用实例教程

			ORG	0000H
			LJMP	MAIN
			ORG	3000H
MAIN: 		MOV	SP,#60H
			MOV	P0,#0FFH
			MOV	P1,#0FEH
			MOV	P2,#0FFH
			MOV	P3,#0FFH

LOOP:		JB		P3.2, $ 

			ACALL	DELAY
			

			JB		P3.2, LOOP	
			
			ACALL	SOUND
			AJMP	LOOP

DELAY:		MOV	R4, #28		;延时子程序
DL:			MOV	R5, #88
			DJNZ	R5, $
			DJNZ	R4, DL
			RET

SOUND:		MOV	R7, #228		;音效延时子程序
SDL1:		CPL		P0.0
			MOV	R6, #0FFH
SDL0:		DJNZ	R6, SDL0
			DJNZ	R7, SDL1
			RET	

			END