[Coco] Coco flash cartridge

[Mark McDougall]

Steve Bjork wrote:

> When you tell port $FF90 on a CoCo 3 that ROM mapping is 32k external 
> (except for vectors), the CTS decodes for $8000-$FFEF.

Ah, yes, of course, I forgot about the GIME control...

FWIW I swapped the 7404 (inverter) to 7400 (NAND). Unfortunately, by my 
reckoning I need 4 NAND gates (well, 3 plus an inverter) to implement a 
16/32KB switch... and I've only got 3 left. And routing A14 will be a PITA...

In any case, if my back-of-a-napkin calcs are right...

A14_ROM <= (size NAND BANK0) NAND (NOT SIZE NAND A14)

Regards,

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