89C51单片机9个按键的行列式键盘输入电路

若行线为P1.0～P1.2，列线为P1.5～P1.7，试画出只有9个按键的行列式键盘输入电路，并编写按键扫描程序

 

图片1

KEY: MOV P1,#11100000B

MOV A,P1

CPL A

ANL A,#111000000B

JZ GORET

KEY1: JB P1.5,KEY2

MOV 30H,#00H

KEY2: JB P1.6,KEY3

MOV 30H,#01H

KEY3: JB P1.7,GORET

MOV 31H,#02H

KEY4: MOV P1,#00000111B

MOV A,P1

CPL A

ANL A,#00000111B

JZ GORET

JB P1.0,KEY5

MOV A,30H

KEY5: JB P1.1,KEY6

MOV A,#3

ADD A,30H

KEY6: JB P1.2,GORET

MOV A,#6

ADD A,30H

KEY7: ADD A,#4

MOV DPTR,#TAB

JMP @A+DPTR

TAB: LCALL WORK0

RET

LCALL WORK1

RET

LCALL WORK2

RET

LCALL WORK3

RET

LCALL WORK4

RET

LCALL WORK5

RET

LCALL WORK6

RET

LCALL WORK7

RET

LCALL WORK8

GORET: RET