[Coco] [OT] Atari 8-bit video card

[billg999 at cs.uofs.edu]

> Bill,
>
> I think the main challenge is that the GIME is such a monolithic chip.  It
> does video, but it also handles the DRAM, generates the clocks, and does
> peripheral decoding.  You'd need to be able to have your cartridge be able
> to take over those portions of the graphics memory and registers, but you
> wouldn't be able to shove the GIME out of the way to do it.  Even an
> software-incompatible option would have a lot of challenges, but I suppose
> could be possible.  For example, the Gameduino is a VGA output sprite
> graphics system that is FPGA-based, and it interacts with the main CPU via
> a simple serial interface.  It gets away with that because there isn't a
> significant amount of graphics storage.
>
> That's my quick take.

I wasn't thinking of replacing the built-in graphics in the COCO.
The GIME and all that could remain.  I was just wondering about
something that would allow much greater graphics generation driven
by the COCO.  Think of it in terms of the Speech/Sound or the Music
cartridges.  They don't remove or replace the ability of the COCO
to do SOUND 24,64 but give a much greater capability if you want
to program to it.

bill