On 3/13/06, Matthew Percival <matthew@xxxxxxxxx> wrote:
> G'Day,
>
> > The problem is an issue of the serial port being in "cooked" mode -
> > the driver doesn't deliver the characters in the buttern until either
> > a carriage return or a line feed (I forget which one) is received.
> > There is a way to put the driver into "raw" mode, which delivers every
> > single character immediately. However, I don't have any example code
> > in front of me, and the only example code that I have is in C. I can
> > forward you the example code a little later today, if you are
> > intereseted. I'm surry there's a way to do it via command-line/script,
> > I just don't know it off the top of my head.
>
> That seems to fit the behaviour I have noticed. If you could send me
> that C code, it would be useful. I am working with Lua, so more than
> likely whatever needs to be done is not possible in the language, but
> with example C code I could add the functionality. At the very least,
> it would help me to understand what needs to be done.
>
Basic skeleton code as follows:
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
long BAUD = B115200;
long DATABITS = CS8;
long STOPBITS = 0;
long PARITYON = 0;
long PARITY = 0;
int keyenceCommFD;
struct termios oldtio, newtio;
pid_t myPid;
int makeSerportRaw(void)
{
keyenceCommFD = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NONBLOCK);
if (keyenceCommFD < 0)
{
return EXIT_FAILURE;
}
myPid = getpid();
newtio.c_iflag = IGNPAR;
newtio.c_oflag = 0;
newtio.c_cflag = BAUD | DATABITS | STOPBITS | PARITYON | PARITY |
CLOCAL | CREAD;
newtio.c_cc[VMIN] = 1;
newtio.c_cc[VTIME] = 0;
tcgetattr(keyenceCommFD, &oldtio);
fcntl(keyenceCommFD, F_SETOWN, myPid);
fcntl(keyenceCommFD, F_SETFL, FASYNC);
tcsetattr(keyenceCommFD, TCSANOW, &newtio);
return EXIT_SUCCESS;
}
int restoreSerport(void)
{
tcsetattr(keyenceCommFD, TCSANOW, &oldtio);
return EXIT_SUCCESS;
}
The important thing in the code is that the newtio.c_lflag does NOT
contain ICANON. You can get more info about all the termios-related
flags via man termios.
HTH-
James
> Thanks,
>
> Matthew
>
>
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