Hi,
I am having problems in writing a simple serial communication code in linux. I want to send single charector on the serial port which my hardware will receive and execute.
Here is the code.
**************************************************************************************************** ********
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#define BAUDRATE B9600
#define MODEMDEVICE "/dev/ttyS0"
#define _POSIX_SOURCE 1 /* POSIX compliant source */
#define FALSE 0
#define TRUE 1
volatile int STOP=FALSE;
main()
{
int fd,c, res;
struct termios oldtio,newtio;
char buf[255];
fd = open(MODEMDEVICE, O_RDWR | O_NDELAY );
if (fd <0) {perror(MODEMDEVICE); exit(-1); }
tcgetattr(fd,&oldtio); /* save current port settings */
bzero(&newtio, sizeof(newtio));
newtio.c_cflag = BAUDRATE | CRTSCTS | CS8 | CLOCAL | CREAD;
newtio.c_iflag = IGNPAR;
newtio.c_oflag = OPOST;
/* set input mode (non-canonical, no echo,...) */
newtio.c_lflag = 0;
cfsetispeed(&newtio, B9600);
cfsetospeed(&newtio, B9600);
newtio.c_cc[VTIME] = 0; /* inter-character timer unused */
newtio.c_cc[VMIN] = 0; /* blocking read until 5 chars received */
tcsetattr(fd,TCSANOW,&newtio);
printf("1\n"); // This is to test where the code has reached.
tcflow(fd, TCOON );
tcflush(fd, TCIFLUSH);
tcflush(fd, TCOFLUSH);
printf("2\n");
strcpy(buf,"82345\n") ;
printf("3\n");
write(fd,buf,1);
tcdrain(fd);
printf("Work done\n");
// I never got to see "work done" in the output. The terminal would hang . If I removed write(fd,buf,1) then work done would print but then my main purpose of the program is lost. It even worked for write(1,buf,1) . So I guess the problem is with write(fd,buf,1)
tcsetattr(fd,TCSANOW,&oldtio);
}
**************************************************************************************************** ***
I had one more observation. When I tried to open proc folder it would not open.
Please suggest. Am I missing in some configuration for the output.
I am using ret hat ver 5.0 its a pentium processor. The hyper-terminal is working in windows very well.
Regards,
Suraj Swami,
suraj.g.swami@gmail.com
