zy8279.asm

利用8279实现键盘键值显示功能

        ORG 0000H
        LJMP MAIN
        ORG 0013H
        LJMP INT1P
MAIN:   MOV SP,#60H
        SETB EX1
        NOP     
        MOV DPTR,#5FFFH
        MOV A,#0DCH
        MOVX @DPTR,A
LP:     MOVX A,@DPTR
        JB ACC.7,LP
        MOV A,#00H
        MOVX @DPTR,A
        MOV A,#34H
        MOVX @DPTR,A
        CLR IT1
        NOP
        SETB EA
        NOP
        MOV R0,#39H
        MOV R7,#06H
LLP:    MOV @R0,#00H
        INC R0
        DJNZ R7,LLP
QC10:   LCALL DSY
        LJMP QC10
INT1P:  PUSH ACC
        PUSH DPH
        PUSH DPL
        MOV A,#40H
        MOV DPTR,#5FFFH
        MOVX @DPTR,A
        MOV DPTR,#5EFFH
        MOVX A,@DPTR
        MOV 39H,A       
        LCALL DSY
        POP DPL
        POP DPH
        POP ACC
        RETI
DSY:    MOV R2,#06H
        MOV A,#92H
        MOV DPTR,#5FFFH
        MOVX @DPTR,A
        MOV R0,#39H
TY11:   MOV A,@R0
        MOV DPTR,#TABL
        MOVC A,@A+DPTR
        MOV DPTR,#5EFFH
        MOVX @DPTR,A
        INC R0
        DJNZ R2,TY11
        RET
TABL:   DB 0C0H,0F9H,0A4H,0B0H,99H
        DB 92H,82H,0F8H,80H,90H,88H
        DB 83H,0C6H,0A1H,86H,8EH,8CH
        DB 0C1H,89H,0C7H,0BFH,91H       
        DB 00H,0FFH
        END