timer.asm

汇编语言

	ORG	0000H
RESET:	AJMP	MAIN
	ORG	000BH
	AJMP	IT0P
	ORG	0100H
MAIN:	MOV	SP,#60H
	MOV	TMOD,#20H
	ACALL	PT0MO
HERE:	AJMP	HERE	;等待中断
PT0MO:	MOV	TL0,#0CH	;T0置初值
	MOV	TH0,#0F0H
	SETB	TR0	;启动T0
	SETB	ET0	;允许T0中断
	SETB	EA	;CPU开中断
	RET
IT0P:	MOV	TL0,#0CH	;T0置初值
	MOV	TH0,#0F0H
	CPL	P1.0	;取反P1.0
	RETI
	END