9-9-1.asm

书籍8051入门篇

;9-9-1.ASM
$MOD51
START:	MOV	TMOD,#21H	; TIMER1=MODE1		(1)
	MOV	TH1,#0FDH	; 9600b/s		(2)
	SETB	TR1		; START  TIMER1		(3)
	MOV	SCON,#50H	; SERIAL MODE1, UART ENABLE
	SETB	P1.0		; P1.0=1
LOOP:	CLR	TI		; CLEAR TI
	MOV	A,#31H		; OUTPUT DATA=31H
	CPL	P1.0		; CPL P1.0
	MOV	SBUF,A		; SEND 31H
WAIT:	JNB	TI,WAIT		; WAIT FOR OUTPUT OK
	CPL	P1.0		; CPL P1.0
	ACALL	DELAY		; CALL DELAY
	SJMP	LOOP		; SEND 31H AGAIN
DELAY:	MOV	R0,#00H		; DELAY FOR A WHILE
	DJNZ	R0,$	
	RET
	END