8-10-3.asm

书籍8051入门篇

;8-10-3.ASM
BUFFER		DATA	20H
TEST_BIT	BIT	20H.4
$MOD51
		ORG	0000H		
		MOV	BUFFER,#00H
		MOV	P1,#0FFH	;LED全部OFF
		MOV	SP,#60H
CHECK:		INC	BUFFER
		JNB	TEST_BIT,ONES	;TEST_BIT?
		ACALL	ALL_ON		;CALL继续往下做
		SJMP	CHECK
ONES:		ACALL	ONLY_ONE	;CALL继续往下做
		SJMP	CHECK
ONLY_ONE:				;TEST_BIT=0
		CLR	P1.0		;1 LED ON
		ACALL	DELAY		;延迟
		SETB	P1.0		;1 LED OFF
		ACALL	DELAY
		RET
;
;TEST_BIT=1
ALL_ON:		MOV	P1,#00H		;ALL LEDS TURN ON
		ACALL	DELAY
		MOV	P1,#0FFH	;ALL LEDS TURN OFF
		ACALL	DELAY
		RET
DELAY:		MOV	R0,#00H
DLY1:		MOV	R1,#00H
		DJNZ	R1,$
		DJNZ	R0,DLY1
		RET
		END