classic computer/game machine color video generation
eric at brouhaha.com
Wed Jun 4 19:05:11 CDT 2008
> OK, so how close am I?
What you described is fairly close to how the IBM CGA adapter generated
For the chroma signal, rather than a shift register, they used three
flip-flops clocked in such a manner as to produce six color phases
(three phases and their 180 degree opposites). Three bits of the
pixel value drive an 8:1 multiplexer to select one of these colors,
or black or white (mux inputs tied to logic 0 or 1).
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