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From: connery@bnrmtv.UUCP (Glenn Connery)
Newsgroups: net.micro.pc
Subject: Re: 8259 PIC
Message-ID: <323@bnrmtv.UUCP>
Date: Tue, 15-Apr-86 17:18:56 EST
Article-I.D.: bnrmtv.323
Posted: Tue Apr 15 17:18:56 1986
Date-Received: Fri, 18-Apr-86 08:24:37 EST
References: <84@uscvax.UUCP>
Distribution: net
Organization: Bell Northern Research, Mtn. View, CA
Lines: 35

> "One can send a EOI to 8259 PIC by writing a 20H into port 20H."
> 
> Where can I get more detail on this?
> I have looked through the followings with no success:
> 
>    1) IBM PC TECH REF MANUAL
>    2) IBM AT TECH REF MANUAL
>    3) Norton's "Programmers Guide.."
>    4) Dan Rollins' "IBM PC 8088 Assembler Prog."
>    5) David Bradley's "Assembly Language Programming for the IBM PC"
> 
> The only place I found any reference to this was in Bradley's book
> and that was very brief. And by looking at other peoples code and seeing 
> that they all write a 20H to port 20H at the end of their interrupt handling 
> routines.
> 
> Is there anything else to know about port 20H? Can anyone direct me
> (exact pointers please) to find a little detail about this and related 
> subjects.
> 
> Thanxs, 
> nadji
>                               ARPA:     nadji%usc-cse@csnet-relay.arpa
>                               CSNET:    nadji@usc-cse.csnet

Basically, you will have to get the Intel documents for the part.  I have
a very old copy of "The 8086 Family User's Manual" which describes this quite
well.  The only other book I've seen that really discusses this in any
detail is "Interfacing to the IBM Personal Computer" by Lewis C.
Eggebrecht, published by Howard W. Sams & Co., Inc.  The latter is not
bad actually...
-- 

Glenn Connery, Bell Northern Research, Mountain View, CA
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