Undocumented Tseng-4000 video mode

Article View: comp.os.msdos.programmer

Article #739

Back to comp.os.msdos.programmer Previous Next

#739

From: Ralf.Brown
Date: Wed, 15 Apr 1992 02:40

19 lines
1489 bytes

I stumbled across the following undocumented video mode on my Boca Super
X VGA, which is a Tseng ET4000 chipset with 1M RAM, a Sierra HiColor
DAC, and the Tseng ET4000 BIOS version 3.00.

Mode 3Dh (which can also be set with "VMODE 3D", an undocumented switch)
sets a 1280x1024 graphics mode with 16 colors and 128x64 text (using an
8x16 character cell).  Not bad for a card which advertises itself as
capable of a top resolution of 1024x768.  Unfortunately, the BIOS text
support is buggy in this mode, only scrolling the top third of the
screen and clearing the top 3/4 on a "CLS".

FRACTINT worked just fine after I hacked the appropriate data table
into the card's VESA driver, which luckily comes with source code.

-- 
{backbone}!cs.cmu.edu!ralf  ARPA: RALF@CS.CMU.EDU  FIDO: Ralf Brown 1:129/26.1
BITnet: RALF%CS.CMU.EDU@CARNEGIE   AT&Tnet: (412)268-3053 (school)   FAX: ask
DISCLAIMER?  Did   |  Hansen's Library Axiom: The closest library doesn't
I claim something? |                          have the material you need.

Technical Details

Message-ID: <29eb978a@ralf>

Path: arc1-ca.pugleaf.net!sparky!uunet!wupost!udel!rochester!cantaloupe.srv.cs.cmu.edu!ralf

Show Full Headers

Complete Article Headers

Newsgroups: comp.os.msdos.programmer
Path: arc1-ca.pugleaf.net!sparky!uunet!wupost!udel!rochester!cantaloupe.srv.cs.cmu.edu!ralf
From: Ralf.Brown@B.GP.CS.CMU.EDU
Subject: Undocumented Tseng-4000 video mode
Message-ID: <29eb978a@ralf>
Date: Wed, 15 Apr 92 02:40:10 GMT
Organization: Carnegie Mellon University School of Computer Science
Nntp-Posting-Host: b.gp.cs.cmu.edu
Summary: mode 3Dh = 1280x1024x16
Originator: ralf@B.GP.CS.CMU.EDU
Lines: 19