Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!rpi!batcomputer!cornell!vax5.cit.cornell.edu!hh2x
From: hh2x@vax5.cit.cornell.edu (Aaron Peromsik)
Newsgroups: comp.sys.cbm
Subject: Re: Wanna use a PC Keyboard with your C-64?
Message-ID: <1991Apr21.211259.4176@vax5.cit.cornell.edu>
Date: 22 Apr 91 01:12:58 GMT
References: <1991Apr16.035008.5667@spool.cs.wisc.edu>
Distribution: comp
Organization: CIT, Cornell University
Lines: 76

In article <1991Apr16.035008.5667@spool.cs.wisc.edu>,
kolstad@jomby.cs.wisc.edu (Joel Kolstad) writes: 
> From: kolstad@jomby.cs.wisc.edu (Joel Kolstad)
> Newsgroups: comp.sys.cbm
> Subject: Wanna use a PC keyboard with your C-64?
> References: 
> Sender: 
> Followup-To: 
> Distribution: world
> Organization: U of Wisconsin CS Dept
> Keywords: 
> 
> Well, after becoming very frustrated with my always dirty, rarely working
> very well original Commodore 64 keyboard, I decided to built myself an
> IBM PC to Commodore 64 keyboard interface.
> 
> I finished this little hack this past weekend, and am now happily typing
> on a Bondwell PC-XT keyboard going through my circuit to a C-64 (this
> was about the cheapest PC keyboard I could find... $25 from Lesko's, in
> Wisconsin...).
> 
> The circuit is quite simple... just two chips: An Intel 8748 microcontroller
> (yes, ancient, I know) and a (New! :-) ) Dallas Semiconductor's 8x8 Cross
> Point switch.  (What's rather ironic, here, is that many PC keyboards,
> including this one from Bondwell, use 8x48s themselves! :-) )
> 
> The 8748 just watches the PC keyboard's scan codes, and figures out what to tell
> the 8x8 Cross Point switch to do -- that is, what keys to "fake" on the
> Commodore 64 keyboard.
> 
> I think I did a decent job on the tiny program that runs the 8748... Caps lock
> is supported, Num lock is supported, shifted PC keys function like their 64
> counterparts should, hitting arrow keys on the PC keyboard automatically
> adds shifts when needed, etc.  Overall, pretty much transparent to the user.
> The only place wher there are a few quirks is in "non-standard" characters
> such as vertical bars, tildes, etc.  I tried to map this characters into
> the most standard C-64 keys I could, but by their natur of being non-
> standard keys, how perfect the translation is depends on what the program
> is looking for. :-) Also, sending "impossible" key combinations (like,
> hitting Shift-2 (@) and U and the same time on the PC keyboard) won't
> produce useful results.  But I wouldn't expect it too...
> 
> Personally, my C-64 and its assorted hardware lives in a big metal box, so it
> was no problem to stick in another board.  But for people who would want to 
> keep their original cases, it'd probably be possible to just drill a hole
> for the keyboard connnector in the case, anad keep the circuit board inside.
> Since this thing uses a crosspoint switch, a simple passthru lets both the
> C-64 and PC keyboard work at once -- now there's where we could see
> some productivity!  But more importantly, this means you can still use the
> C-64 keyboard when there isn't a PC keyboard plugged in.
> 
> Sound useful?  Good!  Since I doubt I could ever generate enough interest
> in this to make any money, I'm releasing it as more or less "public domain
> hardware."  If anybody wants a schematic or more information, you can
> mail me at my below e-mail address.  Sorry to say that I can only provide
> HPGL or Epson printer dump outputs.  If you want the code for the 8748,
> you can have Intel Hex format, or UUencoded binary.
> 
> I'd appreciate it if anyone sending for schematics and/or 8748 listings
> keep the things off of FTP sites, and such, for awhile -- I might just
> try to sell this to some magazine. :-)  All of you who want more
> information, then, are my close personal friends and beta testers. :-)
> 
> That's about it.  I hope someone out there finds this as useful as I have --
> I _love_ my new keyboard!
> 
> ---Joel Kolstad
> kolstad@jomby.cs.wisc.edu

Anyone wanna do this for the 128 (not D)
and a 101-key extended IBM keyboard? I'd be
impressed.

Aaron Peromsik
hh2x@crnlvax5.bitnet
hh2x@vax5.cit.cornell.edu