*BSD News Article 14532


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Newsgroups: comp.os.386bsd.questions
Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!spool.mu.edu!torn!nott!cunews!roger!ebx
From: ebx@scs.carleton.ca (edmond bo xiao)
Subject: Re: COM ports?
Message-ID: <1993Apr15.185109.4338@cunews.carleton.ca>
Sender: news@cunews.carleton.ca (News Administrator)
Reply-To: ebx@scs.carleton.ca
Organization: School of Computer Scince, Carleton University, Ottawa, Canada
References: <1993Apr14.182343.1130@88open.org>
Date: Thu, 15 Apr 1993 18:51:09 GMT
Lines: 40

In article 1130@88open.org, ferg@88open.org (John Ferguson) writes:
> Why are only com1 and com2 available?  I need to access com3, as well.

The basic bariar is that com1 and com3 share a common interrupt, so do 
com2 and com4. You have a choice of choosing either one from each pair, 
but not both. If you HAVE TO use com3 or com4, you should rebuild the 
kernel. Of course, after some modifications to the source.

Since I don't have the space for the source , the following is quoted 
from a pervious post by dean@deanstoy.wa.com in this group.

Here is a real brief explaination of how to add a com port to 386BSD.

Step 1) Address your card appropriately.  The standard COM4 setup uses
the same interupt as COM2.  The com driver does not currently handle
this.  Therefore make sure that all the com ports that you are going
to use are assigned to different I/O ports and interupts.

Step 2) Edit /sys/i386/isa/isa.h and add a line that looks like
#define COM_x 0x...

Step 3) Add a line to your config file in /sys/i386/conf/... which
calls out the new port and interupt.

Step 4) config, make depend, make, install, boot

Thats all there is to it.  If you need examples send me email at home
where my 386bsd system is and I will try to put something together
with a little more detail.

---
- Edmond B. Xiao		Play low from both hands!
- School of Comp. Sci.
- Carleton University	ab107@freenet.carleton.ca
- Ottawa, ON K1S 5B6	ebx@scs.carleton.ca	   (613)788-4340(O)