[Coco] Coco proto board

[Mark McDougall]

jdaggett at gate.net wrote:

> This was discussed a while back and the community then was split between 
> using discrete logic versus CPLD for address decoding. A part of the 
> community sees a CPLD as fixed address range and somewhat inflexible. 

The idea of using a CPLD is so the decoding *isn't* fixed!

I was thinking of offering a few standard options, such as 16/32KB ROM, 
various I/O decoded at $FF40-FF5F.

Right now I was looking at a 44-pin device, but that leaves very little - 
perhaps too little - options IMHO. After routing data, 8-bit GPIO bus, CTS#, 
SCS#, NMI#, R/W# plus a ROM_CS# & READ#, there's only a few pins left over 
for *internal* address decoding and _no_ external address decoding (no 
generation of ext CS lines)...

I'll have to think more about this...

Regards,

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