Article View: comp.os.msdos.programmer
Article #4470Request for assistance programming VGA
From: Jim Blakey RG8U
Date: Thu, 31 Jan 1991 21:44
Date: Thu, 31 Jan 1991 21:44
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A friend of mine and I are attempting to program VGA adapters
to display WEFAX images in 800x600x256 (or higher). We have the
hardware pretty well squared away, but we're having some trouble
with programming the VGA adapter on the bare metal. (There are
rather stringent time constraints present - this beast is seriously
interrupt driven). Are there any source-code examples of how to
manipulate the VGA registers for the higher modes? Has anyone
actually suceeded in figuring the VGA card out by reverse engineering?
Our main interest is in Trident chipset-derived cards, but info for
other ones may prove helpful as well. Modes that require less than 64K
(ie 320x200x256) work as expected. Our color register setup routines work,
as well as the sum to grayscale command. We've tried INT 10H to put the card
in the proper mode, but any and all attempts to jam data in the video RAM
for modes that require more than 64K have resulted in seemingly random results.
Any information will be greatly appreciated, thank you in advance.
--
David E. Tiller davet@tsdiag.ccur.com | Concurrent Computer Corp.
FAX: 201-870-5952 Ph: (201) 870-4119 (w) | 2 Crescent Place, M/S 117
UUCP: ucbvax!rutgers!petsd!tsdiag!davet | Oceanport NJ, 07757
ICBM: 40 16' 52" N 73 59' 00" W | N2KAU @ NN2Z
and...
--
Jim Blakey jimb@tsdiag.ccur.com
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!elroy.jpl.nasa.gov!sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!masscomp!ocpt!tsdiag!jimb From: jimb@tsdiag.ccur.com (Jim Blakey RG8U) Newsgroups: comp.os.msdos.programmer,comp.sys.ibm.pc.misc Subject: Request for assistance programming VGA Keywords: VGA, graphics, pain, gnashing_of_teeth etc Message-ID: <1435@tsdiag.ccur.com> Date: 31 Jan 91 21:44:23 GMT Organization: CONCURRENT,ENG. SERVICES,OCEANPORT NJ Lines: 25