Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!bridge2!jarthur!nntp-server.caltech.edu!madler
From: madler@nntp-server.caltech.edu (Mark Adler)
Newsgroups: comp.sys.next
Subject: Re: Color station specs
Message-ID: <1991Apr24.175501.3489@nntp-server.caltech.edu>
Date: 24 Apr 91 17:55:01 GMT
References: <1991Apr24.122116.25517@slate.mines.colorado.edu>
Organization: California Institute of Technology, Pasadena
Lines: 16

In article <1991Apr24.122116.25517@slate.mines.colorado.edu> mfriedel@slate.mines.colorado.edu (Friedel Michael) writes:
>>The RAMDAC receives four bits from the VRAMs for each color (red, green, and 
>>blue).  These four bits address a color palette RAM inside the RAMDAC, 
>>selecting an eight bit DAC value.  The color palette is set by the window 
>            ^^^^^^^^^^^^^^^
>meaning that 256 shades of gray are posssible.

Doesn't sound that way to me.  I interpret what John Graves had to say
as there being three look up tables, each with a four bit address and
an eight bit output.  Thus, at any one time, you are still limited to
sixteen shades of true gray.  To be able to display 256 shades of gray,
you would need a 4Kx24 ram in the RAMDAC, which it doesn't sound like
it has.

Mark Adler
madler@pooh.caltech.edu