HALF DUPLEX COMMUNICATION USING RS-232 IN C (CHARACTER PASSING)

HALF DUPLEX COMMUNICATION USING RS-232 IN C (CHARACTER         PASSING)

CHARACTER TRANSMITTER -RECEIVER

#include<stdio.h>

#include<conio.h>

#include<bios.h>

#include<process.h>

#define COM2 1

#define COM1ADDR 0x2F8

#define DATA_READY 0x100

#define TRANS_READY 0x2000

main()

{

        char ch,ch1;

         int status,choice;

        char setting,baud = 0xe0,parity = 0x08,data = 0x04,stop = 0x03;

        setting = baud | parity | data | stop;

        clrscr();

        bioscom(0,setting,COM2);

        while(1)

        {

                  clrscr();

                  printf("\n           SERIAL COMMUNICATION USING RS-232 PROTOCOLS\n");

                  printf(" 1: Char Transsmission...\t  2:Exit....\n");

                  printf("\n                       Enter Choice :\n");

                  scanf("%d",&ch);

                  switch(choice)

                  {

                           

                            case 1:

                            do

                           {

                                     ch=getch();

                                     if(ch==0x0d)

                                     printf("\n");

                                     printf("%c",ch);

                                     output(0x3f8,ch);

                            }

                            while(ch!=0x1b);

                            break;

                            case 2:exit(0);

                  }

        }

                  printf("\n 1: Char Receive...\t  2:Exit....\n");

                  printf("\n                       Enter Choice :\n");

                  scanf("%d",&ch1);

                  switch(choice)

                  {

                           

                            case 1:

                           do

                           {

                                     status=bioscom(3,0,COM2);

                                     if(status & DATA_READY)

                                     {

                                                          ch1 = inport(0x2F8);

                                               if(ch1==0x0d)

                                               printf("\n");

                                               if(ch1==0x1b)

                                               break;

                                              printf(" %c",ch1);

                                     }

                            }

                            while(ch1!=0x1d);

                           break;

                            case 2: exit(0);

                  }

        }