PC/Apple/etc. Cards Worth Keeping/Storing
Jim Leonard
trixter at oldskool.org
Fri Apr 29 22:36:27 CDT 2005
Tony Duell wrote:
>>Well, nothing that probably already hasn't been stated before -- I know the
>>specifications of the Motorola 6845 and how it works, and I know that the tech
>>ref documents each CRTC register, etc... what I'm looking for is stuff that
>>probably isn't in the tech ref, like "what are the invalid settings for each
>>register", etc as implemented on the CGA.
>
> That is not in the techref :-(. It doesn't even tell you how to get the
> 160*200 16 colour mode...
Considering that the 160x200 composite color mode was actually documented, that
stinks!
> What, I suspect, you need to do is look at the schematics. Those are in
> the techref, the board consists of a 6845, 16K DRAMs and a lot of TTL.
> There's nothing custom (unlike the gate array in the PCjr), so it should
> be possible to figure it all out.
Okay, looking at MC6845 specs right now...
> Be warned that, of course, clone cards may not support such tricks.
That's their problem :-) I have a true blue CGA card, so that's what I'm going
to hammer on.
Thanks for checking for me!
--
Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/
Want to help an ambitious games project? http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
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