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