smith 
#include <stdio.h> // Standard input/output definitions
#include <string.h> // String function definitions
#include <unistd.h> // UNIX standard function definitions
#include <fcntl.h> // File control definitions
#include <errno.h> // Error number definitions
#include <termios.h> // POSIX terminal control definitions
int open_port(void)
{
int fd; // File descriptor for the port
fd = open("/dev/ttyS0", O_RDWR | O_NONBLOCK);
if (fd == -1)
{
fprintf(stderr, "open_port: Unable to open /dev/ttyS0
%s\n",strerror(errno));
// exit(EXIT_FAILURE);
}
return (fd);
}
int main(void){
int fd = 0; // File descriptor
struct termios options; // Terminal options
char *a="Sushant ME";
//a = malloc(100);
fd = open_port(); // Open tty device for RD and WR
printf("fd =%d\n",fd);
fcntl(fd, F_SETFL); // Configure port reading
tcgetattr(fd, &options); // Get the current options for the port
cfsetispeed(&options, B19200); // Set the baud rates to 19200
cfsetospeed(&options, B19200);
printf("1:\n");
options.c_cflag |= (CLOCAL | CREAD); // Enable the receiver and set
local mode
options.c_cflag &= ~PARENB; // No parity bit
options.c_cflag &= ~CSTOPB; // 1 stop bit
options.c_cflag &= ~CSIZE; // Mask data size
options.c_cflag |= CS8; // Select 8 data bits
//options.c_cflag &= CRTSCTS; // Disable hardware flow
control //
options.c_lflag &= ~(ICANON | ECHO | ISIG);
tcsetattr(fd, TCSANOW, &options);
int rd,wr;
while(1)
{
wr = write(fd,a,10);
if(wr <0)
{
perror("Write:");
}
memset(a,'\0',sizeof(a));
rd = read(fd,a,10);
if(rd <0)
{
perror("Read:");
}
printf("a= %s\n",a);
}
close(fd);
return 0;
}