Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!rochester!rutgers!att!mtuxo!mtgzz!drutx!druhi!dlm
From: dlm@druhi.ATT.COM (Dan Moore)
Newsgroups: comp.sys.atari.8bit
Subject: Re: Atari 800XL Parallel Bus Documentation
Message-ID: <3885@druhi.ATT.COM>
Date: 6 Feb 89 17:05:38 GMT
References: <1270016@hpclkms.HP.COM>
Organization: AT&T, Denver, CO
Lines: 25

in article <1270016@hpclkms.HP.COM>, ken@hpclkms.HP.COM (Kenneth Sumrall) says:
> A few years back either Analog or Antic published a four part series on
> interfacing to the parallel port on the XL.  It doesn't mention the XE
> parallel port, but it does present a full details for building an RS-232
> port that runs over the parallel port, including hardware, and software
> drivers.  I don't remember the issues, but if you need to know, I have them
> at home and can look it up for you.

	The articles did *not* describe the parallel expansion bus on
the XL.  They described the bus in the 1090 expansion box which has
several differences (buffers, power, a couple of new signals).  You can
use the information to figure out what is actually on the expansion bus
just don't expect it to be a 100% match.  The software driver information
applies to both the expansion bus and to the 1090 bus.

	I don't think Atari ever "officially" released any info on the
expansion bus.  There was a very nice manual written up on the XL (OS,
hardware, etc) but it died about the time Jack bought Atari. 


				Dan Moore
				AT&T Bell Labs
				Denver
				dlm@druhi.ATT.COM
				dlm@druwy.ATT.COM