rs232.asm

计算机串口通信程序

           ORG      0000H;
           LJMP     MAIN ;
           ORG      0023H;
           LJMP     RII;
           org      0030h
RII:       PUSH     PSW;
           PUSH     ACC;
           clr      es;
           JNB      RI,$
           CLR      RI;
           MOV      A,SBUF;
           MOV      SBUF,A;
           jnb      ti,$;
           clr      ti;
           MOV      B,A;
           ANL      A,#0F0H;
           SWAP     A;
           MOV      DPTR,#SZ;
           MOVC     A,@A+DPTR;
           MOV      P1,A;
           MOV      A,B;
           ANL      A,#0FH;
           MOVC     A,@A+DPTR;
           MOV      P2,A;

           POP      ACC;
           POP      PSW;
           SETB     ES;
           RETI
SZ:        DB   0C0H,0CFH,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H,88H，83H，0C6H,0A1H,86H,8EH;(共阳)



MAIN:      MOV      TMOD,#20H;
           MOV      TH1,#0F3H;
           MOV      TL1,#0F3H;
           SETB     TR1;
           MOV      PCON,#00H;
           MOV      SCON,#50H;
           clr      ET1;
           SETB     EA;
           clr      es;

           MOV      A,#00H;
NEXT:      mov      sbuf,a;
           JNB      TI,$;
           CLR      TI;
           INC      A;
           CJNE     A,#00H,NEXT;
           SETB     ES;
           jmp      $
           END