MOV	P2,#0FFH	
K1:	MOV	P1,#0	
  	MOV	A,P2        
    	ANL	A,#00001111B 	
    	CJNE	A,#00001111B,K1	
K2:	ACALL	DELAY        	
   	MOV	A,P2        	
  	ANL	A,#00001111B    	
   	CJNE	A,#00001111B,OVER	
  	SJMP	K2          	
OVER:	ACALL	DELAY         	
   	MOV	A,P2          	
   	ANL	A,#00001111B  	
    	CJNE	A,#00001111B,OVER1	
   	SJMP	K2            	
OVER1:	MOV	P1,#11111110B  	
   	MOV	A,P2          	
    	ANL	A,#00001111B   	
   	CJNE	A,#00001111B,ROW_0	
   	MOV	P1,#11111101B  	
    	MOV	A,P2          	
   	ANL	A,#00001111B   	
    	CJNE	A,#00001111B,ROW_1	
  	MOV	P1,#11111011B  	
   	MOV	A,P2          	
   	ANL	A,#00001111B  	
   	CJNE	A,#00001111B,ROW_2	
   	MOV	P1,#11110111B 	
    	MOV	A,P2         	
   	ANL	A,#00001111B  	
    	CJNE	A,#00001111B,ROW_3	
    	LJMP	K2        	
          
ROW_0:	MOV	DPTR,#KCODE0    	
ROW_1:	MOV	DPTR,#KCODE1    	
    	SJMP	FIND           	
ROW_2:	MOV	DPTR,#KCODE2    	
    	SJMP	FIND           	
ROW_3:	MOV	DPTR,#KCODE3     	
FIND:	RRC	A            	
   	JNC	MATCH        	
  	INC	DPTR       	
    	SJMP	FIND          	
MATCH:	CLR	A             	
   	MOVC	A,@A+DPTR     	
	MOV	P0,A	
    	LJMP	K1
   	ORG	300H
KCODE0:	DB	'0','1','2','3'          
KCODE1:	DB	'4','5','6','7'          
KCODE2:	DB	'8','9','A','B'          
KCODE3:	DB	'C','D','E','F'          
      END