[Coco] Example basic code for screen grid

[Darren A]

On Fri, Feb 24, 2012 at 12:43 AM, mike del yea wrote:
>
> ...
>
> I'd use the text screen rather than a semigraphics screen because the coco
> 3 can't use the semigraphics screen.
>

By semigraphics screen, I meant the text screen.  Any byte value
greater than 127 poked into the text screen uses the semigraphics4
mode.  And yes, this does work on a CoCo 3.

The screen addresses range from 1024 to 1535.  Poke values of 128 for
black or 207 for white.  You can also construct larger "graphic"
strings with CHR$ and/or STRING$ and print them to the screen much
faster.

Darren