small_mcu.asm

本代码用汇编语言实现最常用的单片机最小系统的程序

ORG      0000H
         LJMP  MAIN
ORG      0013H
         LJMP  INTT1
ORG      0030H
MAIN:
         LCALL DELAY
         SETB  EX1
         SETB  EA
         MOV   SP,#60H
         MOV   DPTR,#3FFDH    ;      ()
         MOV   A,#0D1H
         MOVX  @DPTR,A

KK:      MOVX  A,@DPTR
         JB    ACC.7,KK

         MOV   A,#34H
         MOVX  @DPTR,A
         MOV   A,#0A0H
         MOVX  @DPTR,A  ;消隐 P141
         MOV   A,#10H
         MOVX  @DPTR,A
         MOV   A,#90H
         MOVX  @DPTR,A
         MOV   A,#40H
         MOVX  @DPTR,A

         MOV   DPTR,#3FFDH
         MOV   A,#90H
         MOVX  @DPTR,A

         MOV   DPTR,#3FFCH    ;     ()
         MOV   A,#0F3H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A
         MOV   A,#00H
         MOVX  @DPTR,A

         SJMP  $              ;     ()

ORG      0100H
INTT1:
         CLR   EX1
         CLR   EA
         PUSH  PSW
         MOV   DPTR,#3FFDH     ;    ()
         MOV   A,#40H
         MOVX  @DPTR,A
         MOV   DPTR,#3FFCH     ;    ()
         MOVX  A,@DPTR
         ANL   A,#3FH
         MOV   R6,A
         ANL   A,#07H
         MOV   B,#04H
         MUL   AB
         MOV   R5,A
         MOV   A,R6
         ANL   A,#38H
         MOV   B,#08H
         DIV   AB
         ADD   A,R5
         MOV   40H,A
         MOV   R7,40H



PP:      LCALL KEYCODE

PRI:
         POP   PSW
         SETB  EX1
         SETB  EA

         RETI







KEYCODE: MOV  4FH,4EH
         MOV  4EH,4DH
         MOV  4DH,4CH
         MOV  4CH,4BH
         MOV  4BH,4AH
         MOV  4AH,49H
         MOV  49H,48H   ;    ()
         MOV  47H,46H
         MOV  46H,45H
         MOV  45H,44H
         MOV  44H,43H
         MOV  43H,42H
         MOV  42H,41H
         MOV  41H,40H

         MOV   A,40H
         MOV   DPTR,#TABLE


         MOVC  A,@A+DPTR
         MOV   48H,A
         ACALL DIR

         RET

DIR:     MOV   DPTR,#3FFDH
         MOV   A,#90H
         MOVX  @DPTR,A
         MOV   R7,#08H
         MOV   R0,#48H
LOOP:
         MOV   A,@R0
         MOV   DPTR,#3FFCH
         MOVX  @DPTR,A
         INC   R0
         DJNZ  R7,LOOP
         RET

TABLE:   DB    3FH,06H,5BH,4FH
         DB    66H,6DH,7DH,07H
         DB    7fH,6FH,77H,7CH
         DB    39H,5EH,79H,71H
         DB    40H,00H



DELAY:
         MOV   R7,#0FAH
FF:      MOV   R6,#0FAH
AFAF:    DJNZ  R6,AFAF
         DJNZ  R7,FF
         RET

END