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From: cliffhanger@cup.portal.com (Cliff C Heyer)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: DMA references
Message-ID: <40301@cup.portal.com>
Date: 19 Mar 91 03:05:31 GMT
References: <103130@unix.cis.pitt.edu>
Organization: The Portal System (TM)
Lines: 21

Needed: DMA Hardware I/O Port Command Documentation.

I've written an MS-D0S program that uses a data disk (a disk with
no file structure on it that is written with bytes direct to the
AT task registers). I want to add DMA so the software can be doing
other things rather than polling I/0 ports to transfer words.

I need documentation about how to use the DMA controller. I have a list 
of the ports from the Phoenix BIOS book, but it has no info on the commands.
I suppose I could disassemble my BIOS (which I have ended up doing 
in the past after failing to find documentation).

This documentation should have the ports and the commands to put in the
ports to make it work, as well as the interrupts used by the DMA chip
to communicate DMA completion.

I did a computer search on it and came up with a Dr Dobbs article Jan
1990. I don't know if this is worth heading to the library.

Please mail, I'll post.
Thanx, Cliff.