MOV	DPTR,#4003H
		MOV	A,#55H		
AGAIN:	MOV	DPTR,#4000H	
		MOVX	@DPTR,A		
		INC	DPTR			
		MOVX	@DPTR,A		
		INC	DPTR			
		MOVX	@DPTR,A		
		CPL	A			
		ACALL DELAY		
		SJMP AGAIN