Untitled

#include <stdio.h>
#include <termios.h>
#include <fcntl.h>
#include <string.h>

int main()
{
  int fd;
  struct termios options;
  int n;
  char buff[15]="";

  /* Open Port */
  fd = open("/dev/ttySAC1", O_RDWR | O_NOCTTY | O_NDELAY);  /* <--- YOUR PORT */


  if(fd == -1) {
                  printf("ERROR Open Serial Port!");
                }


  /* Serial Configuration */
  tcgetattr(fd, &options);   // Get Current Config
  cfsetispeed(&options, B9600); // Set Baud Rate
  cfsetospeed(&options, B9600);
  options.c_cflag = (options.c_cflag & ~CSIZE) | CS8;
  options.c_iflag =  IGNBRK;
  options.c_lflag = 0;
  options.c_oflag = 0;
  options.c_cflag |= CLOCAL | CREAD;
  options.c_cc[VMIN] = 1;
  options.c_cc[VTIME] = 5;
  options.c_iflag &= ~(IXON|IXOFF|IXANY);
  options.c_cflag &= ~(PARENB | PARODD);

  /* Save The Configure */
  tcsetattr(fd, TCSANOW, &options);

  /* Flush the input (read) buffer */
tcflush(fd,TCIOFLUSH);
printf ("\ntest point 1\n");
write(fd,"R",4);
printf ("\ntest point 2\n");
 /* Flush the input (read) buffer */
printf ("\ntest point 3\n");
tcflush(fd,TCIOFLUSH);
printf ("\ntest point 4\n");
write(fd,"S",4);
usleep(50);
printf ("\ntest point 5\n");
read(fd,buff,10);   // Read Data From Serial Port
printf ("\ntest point 6\n : %s : \n",buff);   // Print Out

close(fd); // Close Port
  return 0; // End Program
}