[Coco] Coco ProtoType Board

[Phill Harvey-Smith]

Mike Pepe wrote:
> Hi James,
> 
>> 2) some form of flexible address decoding included along with 
>> buffering. It is still unclear as to whether just the Coco 3 I/O range 
>> be flexible or also the range from $C000 to $FFDF also be included. 
> 
> I think the PLD would be nice, but overkill.

I dunno, if you feed all the important signals into it, data, address, 
R/W, Q,E, SCS/P2, CART/FIRQ, and bring any spare pins on the PLD to 
headers, then the PLD becomes very usefull for all sorts of other things 
besides decoding.

For example you can bury latches in there, or use it to generate intel 
style /RD and /WR signals etc.

With this sort of setup, things like an IDE controller could be 
implemented completely in the PLD for example.

Disadvantage is to take advantage of this you have to have some knoledge 
of PLD programming, and you would need the programming hardware, and 
software, however most of the common CPLD manufacturers supply the 
software for free, also for most a simple paralell port programming 
cable can be knocked up for a small cost, as it's often just a couple of 
resistors and an LS/HC buffer :)

Cheers,

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.