[Coco] Coco ProtoType Board

[Mike Pepe]

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.

It really depends on how much granularity everyone wants. My guess is 
that an 8 or 16 byte block would probably be sufficient. That could be 
done with a 74x133, some inverters, and a jumper block to set the X 
digit in $FFXY. The 13th input could be the E clock to gate the signal.

If more granularity is needed, a 74x85 or 74x688 could do. It would only 
require 2 chips, and if you're going to use SMT they would be extremely 
small. (though I'm oldschool and prefer through-hole on this)


-Mike