Are you running this code as root, or a regular user ?
On Fri, Jul 8, 2016 at 7:03 AM, <[email protected]> wrote:
> Hello,
>
> I'm have connected some device on one of the UART peripherals of the
> BeagleBone Black, and now I would like to be able to somehow detect if
> there's a "BREAK" sequence present (with some kind of Linux signaling
> method).
>
> I have tried with this code:
>
> #include <errno.h>
> #include <fcntl.h>
> #include <string.h>
> #include <termios.h>
> #include <unistd.h>
> #include <stdio.h>
> #include <signal.h>
>
>
> #define error_message printf
>
>
> int set_interface_attribs (int fd, int speed, int parity) {
> struct termios tty;
>
> memset (&tty, 0, sizeof tty);
>
> if (tcgetattr (fd, &tty) != 0) {
> error_message ("error %d from tcgetattr", errno);
> return -1;
> }
>
>
> cfsetospeed (&tty, speed);
> cfsetispeed (&tty, speed);
>
>
> tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; // 8-bit chars
> tty.c_iflag &= IGNBRK; // disable break processing
> tty.c_lflag = 0; // no signaling chars, no echo,
> // no canonical processing
> tty.c_oflag = 0; // no remapping, no delays
> tty.c_cc[VMIN] = 0; // read doesn't block
> tty.c_cc[VTIME] = 5; // 0.5 seconds read timeout
>
>
> tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl
>
>
> tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
> // enable reading
> tty.c_cflag &= ~(PARENB | PARODD); // shut off parity
> tty.c_cflag |= parity;
> tty.c_cflag &= ~CSTOPB;
> tty.c_cflag &= ~CRTSCTS;
> //tty.c_iflag = ~BRKINT | ~INPCK;
>
>
> if (tcsetattr (fd, TCSANOW, &tty) != 0) {
> error_message ("error %d from tcsetattr", errno);
> return -1;
> }
> return 0;
> }
>
> void breakHandler(int signo) {
> printf("\n\nCATCHED!!!\n\n");
> }
>
>
> int main() {
>
>
> char *portname = "/dev/ttyO5";
>
>
> int fd = open (portname, O_NOCTTY);
>
> if (fd < 0) {
> error_message ("error %d opening %s: %s", errno, portname, strerror (
> errno));
> return;
> }
>
>
> set_interface_attribs (fd, B19200, 0); // set speed to 192,000 bps, 8n1
> (no parity)
>
> char buf [100];
>
>
> if (signal(SIGINT, breakHandler) == SIG_ERR) {
> printf("\n\nCan't catch SIGINT!\n\n");
> }
>
>
> fcntl(fd, F_SETOWN, getpid());
>
>
> struct sigaction saio; /* definition of signal action */
>
> saio.sa_handler = breakHandler;
> saio.sa_flags = 0;
> saio.sa_restorer = NULL;
>
> sigaction(SIGINT, &saio, NULL);
>
>
> while(1) {
> int n = read (fd, buf, sizeof buf); // read up to 100 characters if
> ready to read
> usleep ((95 + 25) * 100);
> printf("\n I read:\n");
>
>
> int i;
>
> for(i = 0; i < n; i++) {
> printf("%#08x ", buf[i]);
> }
>
>
> printf("\nError: %s\n", strerror(errno));
> }
>
> return 0;
> }
>
> But it seems that it's not working, the signal is only triggered when I
> press CTRL+C on my keyboard.
>
> What should be the problem?
>
> Thanks.
>
> --
> For more options, visit http://beagleboard.org/discuss
> ---
> You received this message because you are subscribed to the Google Groups
> "BeagleBoard" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/beagleboard/13566592-486b-4c62-8c2c-82220ce660f3%40googlegroups.com
> <https://groups.google.com/d/msgid/beagleboard/13566592-486b-4c62-8c2c-82220ce660f3%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
> For more options, visit https://groups.google.com/d/optout.
>
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/CALHSORrOc5TdtSByX1jmbog_Q3jrBS0ffyENfeXGM0VioENeSw%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
