[Coco] RGB to XGA (Bruce Borer)

[Andrew Ayers]

Bruce,

I'm not sure what you mean by "256 colours (3,3,2)", in relation to 
video from the CoCo 3...?

The CoCo 3 doesn't generate 256 colors; to be clear, the "256-color" 
"mode" is an artifact color system; the colors are generated by how the 
four-color gray-scale is displayed by the limited-bandwidth of the NTSC 
composite video system (much like four colors in PMODE 4 are displayed 
on an NTSC composite video system, when only black and white are being 
actually used).

I'm just confused in wondering if you understood what I was saying, or 
you've implemented something else, or I am misunderstanding what you are 
meaning by "256 colours" in your response?

Andrew L. Ayers
Glendale, Arizona
phoenixgarage.org
github.com/andrew-ayers

On 12/31/25 7:28 PM, Bruce Borer wrote:
> Hi Andrew,
>      I got 225 lines working on my converter.
> I now supports 32, 40 and 80 characters per line,
> 192, 200 and 225 lines and
> 256 colours (3,3,2).
>     The new version of firmware needs to be uploaded to GitHub,
> probably this week.  I also want to demonstrate on UTUBE.
> 
> Bruce P. Borer