12 Nov
2007
12 Nov
'07
7:22 p.m.
On Nov 7, 2007 5:53 PM, Jim Leonard <trixter at oldskool.org> wrote:
Unfortunately both the converters.tv units ignore the
"intensity" pin of
CGA, which means that only 8 of the 16 colors can be displayed from an
IBM CGA card. :-( This is the bit (pun intended) missing from all
converters I've come across, unfortunately.
I forgot about that. Many (if not all) of these boards are actually
converting analog signal levels rather than digital. The most common
use of these boards is vintage video games, which were often analog
RGB at CGA (i.e. video) scan rates. You can usually recover the
intensity bit with a small preconditioner board. If you are using
multiple sources on one of these boards you are going to want to
precondition the signal levels anyway rather than having to fiddle
with the gain every time you change sources. A quad line driver, some
resistors and capacitors should do the trick if you want quality. If
you want simple (no power supply required) and are willing to live
with some imprecision in color output you can skip the line driver .
http://www.softwolves.pp.se/cbm/maskinvara/scart.en.html
Eric