[Coco] The Definitive Post on the CC-Five ;)

[Fedor Steeman]

Hi all,

On 28/01/07, Mark McDougall <msmcdoug at iinet.net.au> wrote:
> The only way I see is to realise the CC-Five as a specification.
> However, I also believe that this specification *must* be written by a
> person or persons who:> (a) have hardware experience, or better yet, FPGA
experience
> (b) understand the Coco, or more specifically the GIME.
>
> Of course, the whole point is to have collaboration by the coco community
on
> the design. Everyone gets to add their $0.02, but unless someone with the
> experience I've outlined takes charge of the specification, IMHO it'll
> remain unattainable and end up going nowhere.

I quite agree that the hardware experts pulling the shots here. My line of
thinking was simply to start with a more abstract design of the hardware,
including constraints, that can easily be implemented as software (i.e. a
realistic emulator). That way, people like me (with only a basic
understanding of hardware) can contribute to a project like this as well.
Also, we could try out some neat ideas and already start developing software
for the CC5...

But of course, I wouldn't want to slow down any momentum towards a direct
hardware implementation that seems to picking up now...

Fundamentally, there's no need to tie the CPU or any other clock to the
> video. In fact, that's an annoying constraint. Designed properly, the CPU
> can be clocked independently of the video and even the system bus.
>
> Graphics. Yes, obviously we enhance the graphics. But we don't alter the
> fundamental operation of the GIME. Or we design a new chip from scratch
> which can look (to software) like a GIME. I don't know enough about the
> GIME
> myself to comment further.
>
And don't forget, 32MB of 16.7 million colour display memory is pretty
> useless when you're trying to shift data around with a 0.89MHz 6809 (to
> take
> an extreme). We need to be realistic, and not try to design a 6809-powered
> PC.


How about a HD63484 graphics chip? Or something similar? Surely we can buy
up a lot of them at some legacy IC vendor? And surely such a chip is
powerful and versatile enough to emulate a GIME+? Or do we want an all-FPGA
solution?

All the best,

Fedor