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From: neh@rci.dk (Niels Erik Holm)
Newsgroups: comp.sys.ibm.pc.programmer,comp.sys.ibm.pc.hardware,comp.sys.ibm.pc.misc
Subject: Keyboard controller
Keywords: PC, keyboard,keyboard controller
Message-ID: <1991Apr25.111900.4948@rci.dk>
Date: 25 Apr 91 11:19:00 GMT
Organization: RC International, Copenhagen, Denmark
Lines: 41

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Unknown keyboard controller commands
======================================

I write this article because of some problems, I've experienced on our
IBM AT clones. The problem was detected when we used the "IBM PC Network
Adapter II", and the corresponding network programs. When a particular
program was loaded, the computer would reboot.

After some trouble the problem was located to a piece of code, which
put some commands to the keyboard controller. The piece of code was
something like:

	mov	al,0A7h		; Unknown code ????
	out	64h,al
	mov	al,0ADh		; Disable keyboard
	out	64h,al

and

	mov	al,0A8h		; Unknown code ????
	out	64h,al
	mov	al,0AEh		; Enable keyboard
	out	64h,al

The unknown commands A7h and A8h are unknown to me, and they are not listed
in my IBM AT Reference book. Is there anybody who knows what they are
intended for ??

Best regards

Niels Erik Holm
RC International
Denmark
Mail address: neh@rci.dk
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