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From: glenn@cs.utexas.edu (Glenn G. Lai)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: ProDesigner II and its color-lookup-table chip
Message-ID: <18820@cs.utexas.edu>
Date: 29 Mar 91 15:57:36 GMT
Organization: UTexas CS Dept, Austin, Texas
Lines: 20

I have an application that requires setting the entire color lookup table.
However, I couldn't set the rgb values of color 0 to anything other than
(0,0,0) (or a low-value triple) and get a proper image.  It seems that the
intensity of the card's rgb output is reduced by color 0's rgb values.  For
example, if color 0 is (65535,0,0), then the red component of the image is
completely filtered out; if it's (65535,65535,0), then both red and green
are gone. 

The ProDesigner II uses a 478 D/A to store the color lookup table.  I called
Orchid tech support for the second time and, as was the first time, the first
person got confused when I got technical and the second person said that he
couldn't provide me with any information to anything I asked, including how I
could find out anything about the 478.  (I'm curious as to if this really meant
he was also ignorant.) 

Do I need to write more values into the 478, or is there no solution to yhid? 


Glenn
glenn@cs.utexas.edu