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From: pgd@bbt.se (P.Garbha)
Newsgroups: comp.unix.xenix.sco
Subject: Re: Using COM3 under SCO XENIX
Message-ID: <1990Sep20.074757.1140@bbt.se>
Date: 20 Sep 90 07:47:57 GMT
References: <3446@dftsrv.gsfc.nasa.gov>
Organization: .
Lines: 30

In article <3446@dftsrv.gsfc.nasa.gov> spiesman@amarna.gsfc.nasa.gov writes:
>I have added a mouse to my i386 XENIX system. I put it on
>the COM2 serial port. I find that my I/O board cannot
>be configured for COM1 and COM2 use; only a COM2/COM3
>or COM1/COM4 combination. 

I have successfully used COM1,COM2,COM3 and COM4 at the same time in
a Xenix system.

In the file /usr/sys/io/sioconf.c you have two lines:

{0,IBM_BOARD,  1,4,0,  (sd)0x3f8,0,                 0,MCRBIT3}, /*ibm COM1*/
{1,IBM_BOARD,  1,3,8,  (sd)0x2f8,0,                 0,MCRBIT3}, /*ibm COM2*/

They define the IRQ and i/o addresses for COM1 and COM2
Add the following two lines:

{2,IBM_BOARD,  1,4,0,  (sd)?????,0,                 0,MCRBIT3}, /*ibm COM3*/
{3,IBM_BOARD,  1,3,8,  (sd)?????,0,                 0,MCRBIT3}, /*ibm COM4*/
                 ^ IRQ     ^ i/o port address
                       
Replacing the question marks with your respective i/o port address.
You have to have different IRQ addresses on all your port. At least I
never got it to work with sharing IRQ addressess, but I think that
Xenix is supposed to be able to handle that, if the hardware can.
You can have all 4 lines in your sioconf.c, but only ports with
different IRQ can be installed at the same time.

Now, if you can get your mouse to work, is a completely different
thing.