From: Torsten Duwe (duwe@informatik.uni-erlangen.de)
Subject: public S3 design (Was: Free software and ... Diamond products)
Organization: CSD., University of Erlangen, Germany
Date: Tue, 29 Sep 1992 21:10:12 GMT
Keywords: Diamond, free-software, S3, VGA, SVGA

(I'm changing the subject because this thread has been straying far from the
original topic) 

hasty@netcom.com (Amancio Hasty Jr) writes:

[...]
>My end-goal is to acquire an affordable high end graphics svga
>which we can program and that the board can be  purchased and supported.
>Ideally, the card should cost below  $200 (US) mark.
[...]
>In dealing with both Diamond and Orchid, we have run into
>a stumbling block as far as the ability to set the dotted clock 
shouldn't that be: 'DOT Clock' (the frequency that clocks the dots) ?
I'm not shure - my english isn't that good so forgive me if I'm wrong but
with a dotted clock I'd associate something like a Swatch(tm:)
>values in the S3 boards due to the use of custom clock synthetizers.
>Both Diamond and Orchid, so far are not releasing the information
>required to set the dotted clock values. In order to use
>the higher resolutions available with svga monitors and to
>increase the performance of graphics operations, the functionality
>to set the dotted clock values is required.

Doesn't performance depend solely on the main (bus/memory/whatever) clock ?
... would be a bad thing if drawing speed was closely coupled to the pixel
clock. 

[...]
-------------------------------------------------------------
>The S3 set is a combination of an 8514/A and SVGA chipset.
>Basically, all the control functions needed to set the
>S3 are provided in the form of  VGA registers. All enhanced
>graphics functions such as bitblt follow very closely the
>IBM 8514/A register convention.
-------------------------------------------------------------
^ this can't be emphasized enough !! (in fact 'C911 enhanced 
regs and functions are a subset of the 8514/A, but the missing parts
shouldn't hurt too much)

IS ANYBODY WORKING ON A PORT OF X.8514 TO THE 86C911 ? PLEASE send me mail
because I AM. (part-time at least :-|  - totally screwed up last week 'cuz I
downloaded (probably) incompatible parts [mit/server/..., x.8514, Xfree86])

[...]
>(2) The S3 was designed with local bus in mind, and there are
>    existing VESA local bus implementations as well as for other
>    local bus implemantations.

In my opinion local bus is unnecessary if you have an 'intelligent' SVGA to
give complex commands to. Only memory to screen bitblt is an issue but that
should be solved using more video RAM - hope the '928 is able to address more
than 1 Meg.

[...]
>(4) S3 corportation provides a software development kit
Yup! They're very DOS-infected but nice people.

[...]

>Thank you for support,
>Amancio Hasty

I'd suggest to use a programmable clock generator !-)   >:^)   >:^]   >:^) 
Siemens for instance provides a PLL to lock a VCO to quartz accuracy - the
chip's called TBB 200 or so - and the programming info is freely available.
You may know of better/faster/cheaper chips but if you don't this might be
something to start with.

Currently not in need of a SVGA but very interested...

	Torsten
-- 
 Torsten Duwe      duwe@informatik.uni-erlangen.de |       Solaris 2.0 ???
 Friedrich-Alexander-Universitt Erlangen-Nrnberg |
 Informatik IV (Betriebssyteme, verteilte Systeme) |       please wait ...