ORG	000H

	CALL	BAUDRATE
	
	MOV	R0,#25
	MOV	DPTR,#TABLE
NEXT:
	MOV	A,#0
	MOVC	A,@A+DPTR
	CLR 	TI    			;Clear TI.
	MOV	SBUF,A
	MOV	P2,099H
	JNB	TI,$			;Pause until the TI bit is set.

	INC	DPTR
	DJNZ	R0,NEXT
	
	CALL	BAUDRATE
		
	MOV	R2,#25
	MOV	DPTR,#RESPONSE
NEXT1:
	JNB 	RI,$  			;Wait for 8051 to set the RI flag.
	MOV 	A,SBUF			;Read the character from the serial port.
	CLR	RI
	MOV 	R0,A
	MOV	A,#0
	MOVC	A,@A+DPTR
	XRL	A,R0
	JNZ	FAILED
	DJNZ	R2,NEXT1
	MOV	P2,#0
	JMP	$

FAILED:
	MOV	P2,#01100110B
	JMP	$

;===================================baudrate==========================================
BAUDRATE:

	MOV	SCON,#50H		; receive enable, 8-BIT, 1 STOP BIT.
	MOV	TMOD,#21H		; timer 1 in 8-bit auto reload.
	MOV	TH1,#-3			; baud rate 9600.
	SETB	TR1			; Start Timer 1
	ANL	PCON, #01111111B	; SMOD = 0
	RET
;======================================================================================

;==============================
; DELAY 0.5S
;==============================
DELAY:
	MOV	R5,#5
DL2:
	MOV	R6,#200
DL1:
	MOV	R7,#249
	DJNZ	R7,$
	DJNZ	R6,DL1
	DJNZ	R5,DL2
	RET

;==============================
TABLE:	
	DB	7EH,00H,00H,00H,01H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,01H	

RESPONSE:	
	DB	7EH,00H,00H,00H,01H,00H,00H,00H,01H,00H,00H,00H,03H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,00H,05H
	END