1.asm

51单片机的按键程序

			ORG		00H
	START: 	MOV		R4,#00H
	L1:	  	MOV 	R3,#0F7H 
			MOV		R1,#00H
	L2:		MOV		A,R3
			MOV 	P3,A
			MOV		A,P3
			MOV		R4,A
			SETB	C
			MOV		R5,#04H
	L3:		RLC		A
			JNC		KEY
			INC		R1
			DJNZ	R5,L3
			MOV		A,R3
			SETB	C
			RRC		A
			MOV		R3,A
			JC		L2
			JMP		L1
	KEY:	ACALL	DELAY
	D1:		MOV		A,P3
			XRL		A,R4
			JZ		D1
			MOV		A,R1
			ACALL	DISP
			JMP		L1
	DISP:	MOV		DPTR,#TABLE
			MOVC	A,@A+DPTR
			MOV		P0,A
			RET
	DELAY:	MOV		R7,#60
			MOV		R6,#248
	DLY1:	DJNZ	R6,$
			DJNZ	R7,DLY1
			RET
	TABLE:	DB		0C0H,0F9H,0A4H,0B0H
			DB		99H,92H,82H,0F8H
			DB		80H,90H,88H,83H
			DB		0C6H,0A1H,86H,8EH
			END