p13_2.asm

来自「单片机原理与应用实例教程 单片机原理与应用实例教程」· 汇编 代码 · 共 66 行

		COL1 EQU P2.2
		COL2 EQU P2.1
		COL3 EQU P2.0
		ROW1 EQU P2.5
		ROW2 EQU P2.6
		ROW3 EQU P2.7
		LED7 EQU P1
		
		ORG 0000H
		LJMP MAIN
		ORG	0003H
		LJMP INT_0
		ORG 4100H
TAB:	DB 40h, 4FH, 24H, 30H, 19H
		DB 12H, 02H, 78H, 00H, 10H

MAIN:	MOV DPTR, #TAB
		SETB EX0
		SETB IT0
		SETB EA
		MOV LED7, #0FFH
				
LOOP:	CLR ROW1
		CLR ROW2
		CLR ROW3
		SETB COL1
		SETB COL2
		SETB COL3
		AJMP LOOP

INT_0:	CLR EX0
		MOV R0, #0H
		MOV R1, #0H
		MOV A, #11011111B
SCAN:	MOV P2, #0FFH
		MOV P2, A
		JB COL1, J_COL2
		MOV R0, #1
		AJMP KEYDN
J_COL2:	JB COL2, J_COL3
		MOV R0, #2
		AJMP KEYDN
J_COL3:	JB COL3, NEXT
		MOV R0, #3
		AJMP KEYDN
NEXT:	INC R1
		INC R1
		INC R1
		RL A
		CJNE R1, #9, SCAN
		AJMP RETURN
KEYDN:	MOV A, R1
		ADD A, R0
		MOVC A, @A+DPTR
		MOV LED7, A
RETURN: ACALL DELAY 
		SETB EX0
		RETI

DELAY:	MOV R6, #0FFH
DL1:	MOV R7, #0FH
DL2:	DJNZ R7, DL2
		DJNZ R6, DL1
		RET

		END