4 Jun
2008
4 Jun
'08
8:05 p.m.
Charles wrote:
OK, so how close am I?
What you described is fairly close to how the IBM CGA adapter generated
composite video.
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).
Eric