BSF	TRISB,2	
	CLRF	TRISD		
AGAIN	BTFSS	PORTB,2	
	BRA	OVER		
	MOVLW	A'Y'		
	MOVWF	PORTD		
	GOTO	AGAIN		
OVER	MOVLW	A'N'		
	MOVWF	PORTD		
	GOTO	AGAIN