CLR	P2.3			
		MOV	TMOD,#01		
HERE:		MOV	TL0,#0		
		MOV	TH0,#0		
		SETB	P2.3			
		SETB	TR0			
AGAIN:	JNB	TF0,AGAIN		
		CLR	TR0			
		CLR	TF0			
		CLR	P2.3