10-3-1.asm

书籍8051入门篇

;10-3-1.ASM
$MOD51
	ORG	0000H		; PROGRAM START POINT			(1)
	LJMP	START		; GOTO MAIN PROGRAM			(2)
	ORG	000BH		;  TIMER0 INTERRUPT POINT		(3)
	LJMP	T0_ISR		; GOTO TIMER0 INTERRUPT PROGRAM 	(4)
;
	ORG	0030H		; MAIN PROGRAM				(5)
START:	SETB	P1.0		; INITIALIZE P1.0 = 1			(6)
	MOV	TMOD,#11H	; TIMER0 = MODE1			(7)
	MOV	TH0,#0DBH	; (65536-9217) / 256			(8)
	MOV	TL0,#0FFH	; (65536-9217) % 256			(9)
	CLR	TF0		; CLEAR TF0 FLAG			(10)
	SETB	TR0		; START TIMER0				(11)
	SETB	ET0		; ENABLE TIMER0 INTERRUPT	   	(12)
	SETB	EA		; START INTERRUPT			(13)
LOOP:	SJMP	LOOP		; MAIN PROGRAM END			(14)
;
T0_ISR:	CPL	P1.0		; CPL P1.0				(15)
	CLR	TF0		; CLEAR TF0 FLAG			(16)
	MOV	TH0,#0DBH	; (65536-9217) / 256			(17)
	MOV	TL0,#0FFH	; (65536-9217) % 256			(18)
	RETI			; RETURN FROM INTERRUPT			(19)
	END