[Coco] [Color Computer] Opinion time
jdaggett at gate.net
jdaggett at gate.net
Sat Apr 1 18:25:27 EST 2006
On 1 Apr 2006 at 12:52, George's Coco Address wrote:
> I wonder why that is.
> What experience did you have with this?
> I thought RGB is pretty much standardized.
> George
RGB for the PC is standardize. The problem is the Coco is not PC RGB compatible.
Most LCD monitors on the market today are EGA/VGA/SVGA/XVGA resolution
compatible. IF the monitor by some weird chance supports Composite video input
then maybe it will work with the Coco3. The Coco3 is hodge podge signal to some
extent. CGA standard originally supported two colors, not 16. CGA max resoltion is
640x200. EGA max resoution is 640x350.
Secondly the Coco3 outputs positive sync that is TTL levels. The RGB signal is 1.2
Volts P-P. Mondern VGA monitors require 0.7V P-P for the analog signal. EGA
monitors require Horizontal pulse positive and vertical pulse negative. VGA
monitors require both sync pulses negative.
Modern LCD monitors will not directly accept the COCO signal. Very few monitors
made today support 15.7KHz horizontal sync which is what the Coco is.
james
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