[Coco] CoCo/FPGA board (was Multi-Processor 6809 Computer System)

[Frank Swygert]

Date: Fri, 03 May 2013 09:03:45 +1000 From: Mark McDougall 
<msmcdoug at iinet.net.au> Subject: Re: [Coco] Multi-Processor 6809 
Computer System On 2/05/2013 3:11 AM, Brian Blake wrote:

> And I would certainly agree with this. Gary's CoCo-X is a perfect example of
> the above - along with unwanted drama...

As I've mentioned before, it is going to be difficult to design a Coco
replacement and even get anywhere near breaking even in the long run. It
will have to be a labour of love for someone...

FWIW I'm currently designing a custom FPGA board for my own purposes -
primarily for the prototyping of a specific emulation not related to Coco -
but also to be used for "play" over the next 5 years or so - it is
ridiculously over-engineered! With that in mind, the design does include
expansion capabilities, and I've specifically been thinking about the Coco
along the way. The base board, along with a relatively simple 2-layer
expansion PCB, should have everything that you could possibly want on a
Coco-X, and much more.

The board itself will cost way, way more than any Coco enthusiast could
possibly justify spending (it's not for sale anyway) but I was intending to
port both my own Coco1/2 and Gary's Coco3FPGA designs to it, and 'showcase'
the possibilities in a video. I think in these types of cases, a picture (or
video) is worth a thousand words, and it might just be enough to get people
enthused again. And of course the future possibility exists to down-scale
the design specifically for a Coco-X application.
=========================================================

Could a CoCo replacement FPGA board be designed that wouldn't be too expensive? Rather than the cartridge port itself a BUFFERED dual header would work. Since it's buffered a short ribbon cable could be used to connect cartridges or anything else, and a Y cable would work. Keep the PIAs and such, but would need VGA video with Drivewire built in, and would be nice to have a floppy emulator with SD card, and a PS-2 or USB keyboard port. If you want a CoCo keyboard make the USB adapter like Chris Hawks did.

The GIME could be a second FPGA (or would one large one with both the 6809 and GIME be more cost effective?).

I think CoCo3 software compatibility is a must, but if you drop a lot of the older CoCo2 stuff, like what uses semi-graphics modes and other seldom used features, it should be okay. You can only have so much backward compatibility! Even the CC3 lost a few CC1/2 programs.

-- 
Frank Swygert
Editor - American Motors Cars Magazine
www.amc-mag.com