Problems using Dev.ser with TL16C550B UART

QNX Newsgroups (Archives) comp.os.qnx
1

Hi, I have build a prototype board using a TL16C550B UART that is connected
to a Pentium CPU via a PC104 connector.

The BIOS of the PC detect the UART at the right place and the Dev32.ser too.

The problem is when i’m trying to do redirection to the serial port i.e (ls

/dev/ser1) only 1 caracter is send and this is a random caracter.

If I access the port through direct I/O access i.e ( outp(0x3F8, ‘A’); ) it
works fine.


any hint ?


thanks in advance


Simon Bilodeau
HTRC Paper Technologies Inc.
email : simon.bilodeau@htrc.com

2

You may have flow control on that port. Check your stty </dev/ser1 and look
for things like +ohflow +ihflow +lkhflow. These will cause Dev.ser to use
hardware handshaking, in the which, if the receiving device does not raise
or lower clear to send, etc, then you may very well see such behavior.

This seems consitant as your outp(0x3f8, ‘A’) does not care about flow
control.

Try this at the shell prompt
stty -ohflow -ihflow -lkhflow </dev/ser1

…and see what happens. Also you might see something call +ohpaged or
something like that, turn that one off too…

Hope this helps
Kevin
Simon Bilodeau <sbilodo@videotron.ca> wrote in message
news:1Clp5.1083$Tr3.34678@wagner.videotron.net…

Hi, I have build a prototype board using a TL16C550B UART that is
connected
to a Pentium CPU via a PC104 connector.

The BIOS of the PC detect the UART at the right place and the Dev32.ser
too.

The problem is when i’m trying to do redirection to the serial port i.e
(ls
/dev/ser1) only 1 caracter is send and this is a random caracter.

If I access the port through direct I/O access i.e ( outp(0x3F8, ‘A’); )
it
works fine.


any hint ?


thanks in advance


Simon Bilodeau
HTRC Paper Technologies Inc.
email : > simon.bilodeau@htrc.com

3

Try using qtalk to test the port
qtalk -m /dev/ser1

Also try starting the port in raw mode with no flow control
Dev.ser -E -F 3f8,3 &

-Paul


Simon Bilodeau <sbilodo@videotron.ca> wrote in message
news:1Clp5.1083$Tr3.34678@wagner.videotron.net…

Hi, I have build a prototype board using a TL16C550B UART that is
connected
to a Pentium CPU via a PC104 connector.

The BIOS of the PC detect the UART at the right place and the Dev32.ser
too.

The problem is when i’m trying to do redirection to the serial port i.e
(ls
/dev/ser1) only 1 caracter is send and this is a random caracter.

If I access the port through direct I/O access i.e ( outp(0x3F8, ‘A’); )
it
works fine.


any hint ?


thanks in advance


Simon Bilodeau
HTRC Paper Technologies Inc.
email : > simon.bilodeau@htrc.com

4

I finally find my problem …


thanks for your help guys!

Simon



Simon Bilodeau <sbilodo@videotron.ca> wrote in message
news:1Clp5.1083$Tr3.34678@wagner.videotron.net…

Hi, I have build a prototype board using a TL16C550B UART that is
connected
to a Pentium CPU via a PC104 connector.

The BIOS of the PC detect the UART at the right place and the Dev32.ser
too.

The problem is when i’m trying to do redirection to the serial port i.e
(ls
/dev/ser1) only 1 caracter is send and this is a random caracter.

If I access the port through direct I/O access i.e ( outp(0x3F8, ‘A’); )
it
works fine.


any hint ?


thanks in advance


Simon Bilodeau
HTRC Paper Technologies Inc.
email : > simon.bilodeau@htrc.com