ORG  0000H
		AJMP 0030H

		ORG 0003H
		AJMP SS

		ORG 0030H
START:	MOV P2,#0F0H
		MOV TCON,#01H
		MOV IE,#81H
		AJMP $

SS:		
		MOV A,#0F0H
		MOV P2,A		;置p2口為輸入狀態
		MOV A,P2
		JNB ACC.4,K0 	;檢測0號鍵是否按下
		JNB ACC.5,K1	;檢測1號鍵是否按下
		JNB ACC.6,K2
		AJMP SS
		
K0:		MOV P2,#0F1H				
	   	MOV 20H,#0FFH
	  	MOV P1,20H
		MOV R7,#03
LOP:	MOV A,#0FEH
PP1:	MOV R4,#08H
LOOP0:	MOV P0,A
	   	RL  A
	   	ACALL DD
		DJNZ R4,LOOP0
		
		MOV A,#7FH
		MOV R4,#08
PP2:	MOV P0,A
		RR 	A
		ACALL DD
		DJNZ R4,PP2
		DJNZ R7,LOP
	   	AJMP RRD

	
K1:		MOV P2,#0F2H
	   	MOV 20H,#00H
	   	MOV P0,20H
		MOV R7,#03
LP:		MOV A,#01H		
		MOV R4,#08H
LOOP1:	MOV P1,A
	   	RL  A
	   	ACALL DD
		DJNZ R4,LOOP1
		DJNZ R7,LP
	   	AJMP RRD
		
K2:		MOV P2,#0F3H
		MOV R7,#01	
LP1:	MOV R5,#08
		MOV 20H,#01H
LOOP3:	MOV A,20H
        MOV P1,A
		RL A
		MOV 20H,A
		MOV R6,#08
		MOV A,#0FEH
LOOP2:	MOV P0,A
		RL A
		LCALL DDD
		DJNZ R6,LOOP2
		MOV A,#0FFH
		MOV P0,A
		DJNZ R5,LOOP3
		DJNZ R7,LP1
RRD:	RETI

DD:		MOV R0,#04
DD1:	MOV R1,#0FFH
DD2:	DJNZ R1,DD2
		DJNZ R0,DD1
		RET

DDD:	MOV R2,#01
D1:		MOV R3,#20
D2:		DJNZ R3,D2
		DJNZ R2,D1
		RET
 
		END