neh@rci.dk (Niels Erik Holm) (04/25/91)
====================================== 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 --------------------------------------------------------------------------- Every day, once a day, give yourself a present. Don't plan it, don't wait for it, just... let it happen. Could be a new shirt at the men's store, a catnap in your office chair, or two cups of good, hot, black coffee. (Dale Cooper in Twin Peaks). ---------------------------------------------------------------------------
rkl@cbnewsh.att.com (kevin.laux) (04/26/91)
In article <1991Apr25.111900.4948@rci.dk>, neh@rci.dk (Niels Erik Holm) writes: > 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: [code deleted] > 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 ?? Command A7h is Disable Mouse Interface; A8h is Enable Mouse Interface. -- ________________________________________________________________________________ R. Kevin Laux Email: rkl1@hound.att.com AT&T Bell Labs Voice: (908) 949-1160 Holmdel, NJ 07733 Fax: (908) 949-0959
markh@csd4.csd.uwm.edu (Mark William Hopkins) (04/27/91)
In article <1991Apr25.111900.4948@rci.dk> neh@rci.dk (Niels Erik Holm) writes: > 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 They're not used for AT's. But if they match the PS/2 functions then they mean: A7: Disable auxilliary device. A8: Enable auxilliary device. If the system's keyboard controller's incompatible, it could accidentally mean A7: Enable PC keyboard mode. A8: Disable PC keyboard mode. or who knows what.