单片机和pc机串口通讯实例.asm

单片机和PC机串口通讯实例说明 首先打开串口调试程序并按要求设置。启动51板后

             ORG 0000H
             MOV SP,#050H
             AJMP MAIN







MAIN:

             MOV 030H,#0BFH
             MOV 031H,#086H
             MOV 032H,#0DBH
             MOV 033H,#0CFH
             MOV 034H,#0E6H
             MOV 035H,#0EDH
             MOV 036H,#0FDH
             MOV 037H,#0A7H
             MOV 038H,#0FFH
             MOV 039H,#0EFH
             MOV P1,#0FFH
             MOV P0,#00H

             CLR P2.2
             MOV SCON,#50H
             MOV TMOD,#20H
             MOV PCON,#00H
             MOV TH1,#0FAH
             MOV TL1,#0FAH
             SETB TR1
             AJMP TXD
      TORXD: AJMP RXD


TXD:
             SETB P1.7
             CLR P1.5
             JNB P1.4,TORXD
             SETB P1.5



CLR5:        CLR P1.5
             JNB P1.1,S1
             JNB P1.2,S4
             JNB P1.3,S7

             SETB P1.5

CLR6:        CLR P1.6
             JNB P1.1,S2
             JNB P1.2,S5
             JNB P1.3,S8

             SETB P1.6
CLR7:        CLR P1.7
             JNB P1.1,S3
             JNB P1.2,S6
             JNB P1.3,S9

             SETB P1.7
             AJMP RTI
        S1:  MOV 021H,#086H
             MOV 022H,#01H
             AJMP GOON
        S2:  MOV 021H,#0DBH
             MOV 022H,#02H
             AJMP GOON
        S3:  MOV 021H,#0CFH
             MOV 022H,#03H
             AJMP GOON
        S4:  MOV 021H,#0E6H
             MOV 022H,#04H
             AJMP GOON
        S5:  MOV 021H,#0EDH
             MOV 022H,#05H
             AJMP GOON
        S6:  MOV 021H,#0FDH
             MOV 022H,#06H
             AJMP GOON
        S7:  MOV 021H,#0A7H
             MOV 022H,#07H
             AJMP GOON
        S8:  MOV 021H,#0FFH
             MOV 022H,#08H
             AJMP GOON
        S9:  MOV 021H,#0EFH
             MOV 022H,#09H
   GOON:     SETB P1.5
             SETB P1.6
             SETB P1.7
         DD:
             MOV A,022H
             MOV SBUF,A
           QQ:  JNB TI,Q
             CLR TI
              AJMP RTI
            Q:
             MOV P2,#040H
             MOV P0,021H
             AJMP QQ
       RTI:
             MOV P2,#040H
             MOV P0,021H




             AJMP TXD

      TOTXD: AJMP TXD
RXD:        SETB P1.5
             CLR P1.7
             JNB P1.4,TOTXD
             SETB P1.7


             SETB REN
             MOV A,SBUF
             JNB RI,RRI
             CLR RI

             MOV B,#64H
             DIV AB
             ADD A,#30H
             MOV 040H,A
             MOV A,B
             MOV B,#0AH
             DIV AB
             ADD A,#30H
             MOV 041H,A
             MOV A,B
             ADD A,#30H
             MOV 042H,A

          RRI:
             MOV P2,#040H
             MOV R0,042H
             MOV P0,@R0
             ACALL DELAY

             MOV P2,#020H
             MOV R0,041H
             MOV P0,@R0
             ACALL DELAY

             MOV P2,#010H
             MOV R0,040H
             MOV P0,@R0
             ACALL DELAY
             AJMP RXD



DELAY:       MOV R6,#0FFH
      DE:    ACALL DELAY1
             DJNZ R6,DE
             RET

DELAY1:      MOV R7,#05H
        DE1: DJNZ R7,DE1
             RET


             END