Path: utzoo!utgpu!watmath!clyde!att!whuts!jmbj
From: jmbj@whuts.att.com (BITTMAN)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Looking for AT Bus Technical Reference.
Summary: AT bus hardware reference
Keywords: AT BUS
Message-ID: <5050@whuts.att.com>
Date: 15 Nov 88 17:21:24 GMT
Organization: AT&T Bell Laboratories
Lines: 40

> >good technical reference for the AT bus.
> 
> Oh, wouldn't we _ALL_! (Well, a lot of us anyway...)
> 
> >					   I'd really like to have something
> >which describes both the "official" bus, as well as "ill behaved", but popular
> >versions of the bus.  The reference should include detailed timing
> >specifications and bus protocols.
> 
> In my short search all I could find was "English language" descriptions of
> the various functions, but nothing with timing diagrams or even timing
> relationships between/among the various signals.
> 
> Please let us know if you find a good hardware reference manual.
> 

Byte had an article on interfacing to the IBM PC bus, which is VERY
similar to the AT bus: add 8-data lines, 8-int lines, 4-addr lines...

The issue was the IBM-Special Edition from last year (1987).  The 
article included timing, even some schematics for a peripheral
board, etc.  The article may talk about the AT, I don't remember.
DMA is not mentioned, but I've heard that it's really not that
great an idea anyway.

If you need more help, let me know, I can send you
a short piece of assembly code which demonstrates how to use
hardware interrupts from a peripheral board.  If you need even more 
help I can send the schematics....

Another good reference is the Intel Data Book, the bus is basically
just an extension of the Processor.  About 3 years ago, when I was
first designing this board, the ONLY reference which I could find
that addressed the issue of hardware interrupts was a book
by Sam's, but I forget the title...

I hope this mish-mash of information is helpful to all the IBM-PC
hardware hackers out there...

Jim Bittman, whuts!jmbj