Re: [ts-7000] TS-7800 COM2 port won't transmit until program has ended

[walter marvin <>]

Try doing a flush after the write.

--- On Mon, 1/17/11, tommessum <> wrote:

From: tommessum <>
Subject: [ts-7000] TS-7800 COM2 port won't transmit until program has ended
To:
Date: Monday, January 17, 2011, 11:29 AM

 

In a nutshell I have: at the start:

fd = open("/dev/ttyS1", O_RDWR | O_NOCTTY); (1) (2)

followed by:

tcgetattr(fd,&oldtio);
newtio.c_cflag = B115200 | CRTSCTS | CS8 | CLOCAL | CREAD ;
newtio.c_iflag = 0;
newtio.c_oflag = 0;
newtio.c_lflag = 0;
newtio.c_cc[VMIN] = 1;
newtio.c_cc[VTIME] = 0;
tcsetattr(fd, TCSANOW, &newtio);

then later on, to write some data:
write(fd,"hello\r\n",7); (3)

The problem is that data doesn't get sent to the UART until the program is terminated. The "write" must be buffering the output data obviously. But I can't figure a way of forcing a flush after the "write".

There must be some simple obvious explanation, but I can't figure out why! Any ideas?

Thanks!

NB:

(1) Also have tried including "O_NDELAY O_NONBLOCK"

(2) Also have tried including "fcntl(fd, F_SETFL, O_NONBLOCK)"

(3) Also tried adding fsync(fd), fflush(NULL) after write()

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