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From: alan@hal.larc.nasa.gov (alan dare)
Newsgroups: comp.sys.sgi
Subject: tty problems
Message-ID: <1991May1.144614.5582@news.larc.nasa.gov>
Date: 1 May 91 14:46:14 GMT
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Distribution: usa
Organization: NASA Langley Research Center, Hampton, VA  USA
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Originator: alan@hal.larc.nasa.gov


I having a problem using the tty ports to input data at 19200 baud on
my 310 VGX.  I've connected an Ascension Technology head tracker to ttyd2. The
port is set up as follows:

	port_setup.c_line = LDISC0;
        port_setup.c_iflag = IGNBRK | IGNPAR;
        port_setup.c_oflag = 0;
        port_setup.c_cflag = B9600 | CS8 | CLOCAL | CREAD;
        port_setup.c_lflag = 0;
        status = ioctl(fd, TCSETA, &port_setup);


	I read the port with "read(fd, &buffer, 12)" because i'm expecting
a record to contain 12 bytes. The problem is sometimes it works...and sometimes it doesn't. It may read 5, 10, 20 or 50 records and then hang. A rep from
Ascension Technology thinks the driver may not be an interrupt driven
driver thus missing some data and some how hanging. I've not been able to
find any documentation describing the driver behind ttyd2. Does anyone know?
Has anyone out there used a device to input binary data at 19200 baud
on the tty ports with success or know what the problem might be?

Thanks...
-- 

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