Article View: comp.sys.ibm.pc.misc
Article #3605Loosing characters when using 80286 protected mode
From: Rick Hoover
Date: Mon, 01 Oct 1990 14:42
Date: Mon, 01 Oct 1990 14:42
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2143 bytes
Hi notes users,
I've got an older AT clone (1987) with AMI BIOS and keyboard controller on
an Everex motherboard labeled as a Joy Systems computer. However, it
appears to not be 100% compatible with software that switches in and out
of protected mode. This incompatibility causes my system to loose characters
typed at the keyboard when my system switches out of protected mode. I have
seen this behavior with OS/2, Windows 3.0 running in standard mode, and disk
caching software which uses extended memory in the AT. If I carefully set
up my system so it doesn't switch in and out of protected mode, I have
no problems with the keyboard.
One thing I am fairly certain of, it is not the system BIOS since I have tried
using Phoenix BIOS in place of the AMI BIOS without resolving the problem.
Therefore, I suspect it is the AMI keyboard controller (an 8042?) which is
introducing the imcompatibility. Is it possible that the keyboard controller
has a firmware bug in it which causes the system to not see the scan codes
coming from the keyboard while the system is resetting when returning
to real mode from protected mode? If any one has seen this problem or
knows of a solution to it, please drop me an E-Mail message. I will post
any working solution on notes when I find it.
Thanks,
Rick Hoover | ######## / ########
Development Engineer | ####### / #######
Boise Division | ###### /_ __ ###### H E W L E T T
Boise, ID | ##### / / / / #####
| ##### / / /__/ #####
Email:rick@hpbsla.hp.com | ###### / ###### P A C K A R D
| ####### / #######
| ########/ ########
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!hplabs!hpcc05!hpdmd48!rick From: rick@hpdmd48.boi.hp.com (Rick Hoover) Newsgroups: comp.sys.ibm.pc.misc Subject: Loosing characters when using 80286 protected mode Message-ID: <14950006@hpdmd48.boi.hp.com> Date: 1 Oct 90 14:42:15 GMT Organization: Hewlett Packard - Boise, ID Lines: 32