[Coco] The X9

[Mark McDougall]

Chuck Youse wrote:

> Alright, folks, so I've been pondering the FPGA-based "Coco 4".  The
> goal is to have a more modern 6809/GIME-compatible system that can run
> NitrOS-9 and still provide hacking fun.
	(snip)
> Any comments?  Any interest? 

Your post infers that you're already familiar with earlier discussions on 
this very topic on this mailing list - yes? There's a wealth of proposals 
and ideas from a number of us in the group, so not quite sure what you want 
us to add without re-iterating what's already been said?!?

Since the discussions, Gary Becker has released an operational Coco 3 FPGA 
design based on John Kent's 6809 core. IIRC he has an "overclocking" mode. 
Note that I could never get his design working on my own hardware. YMMV.

IMHO, I'd be adding peripherals inside the FPGA as far as possible. Maximum 
flexibility and minimum cost. Note that ethernet MAC, IDE controller and 
multiple UART cores, as you mention in your "two other things" thread, are 
all easily implemented on-chip (I've had plenty experience will all 3) with 
a few simple external support chips such as PHY and serial line drivers. And 
extended video modes are reasonably trivial - the problem is software 
support and squeezing enough grunt out of the 6809 to do anything useful 
with a few MB of pixels...

Aside from that - interested? - yes, very! Time to do anything about it atm? 
Unfortunately, no. I'm guilty of having *way* too many irons in the fire to 
the point where I don't even know what to work on anymore. :(

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"