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From: jdeitch@pnet01.cts.com (Jim Deitch)
Newsgroups: comp.os.minix
Subject: Re: minix '286 patches (problem)
Message-ID: <4233@crash.cts.com>
Date: 21 May 89 17:36:46 GMT
Sender: news@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 24

> Unfortunately, Bruce's rs232 io doesn't work for me yet (it didn't work 
> before the pmode diffs, either).  Specifically, when using term to talk to
> my external modem, I can see that it is sending chars just fine, and the
> modem is echoing chars back.  But term never sees the echoed chars; it
> hangs on the first read from the tty port.  Anyone seen a similar problem?

What type UART are you using?  I have seen this problem under other O/S's when
using a 16450 or 16550.  The easiest thing to try is put :
  echo " " > /dev/tty1
  echo " " > /dev/tty2
in your etc/rc file.  It seems to "jump start" the UARTS.  If you are using
the 16550 then you might want to add a line at the end of rs232.c that 

outputs to port 3FA (for port 1) or 2FA (port 2) a 0xC7.  This sets up the
built in FIFO for an interupt level of 14 bytes.  Speeds things up a bit.  As
a matter of fact, you should include these outputs anyway, because these ports
are unwritable on 8250's and 16450's so they will just ignore it.  This is
what cleared up the problem on my end.

Jim

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