[Coco] [Color Computer] Re: Coco flash cartridge

[James Diffendaffer]

Well, I *was* going to post how I would do this but I think you have
it well in hand.  I drew up a circuit to do this but with a fixed size
ROM window and it didn't look that difficult or expensive to me... but
then I never built the thing to find out if it worked.  I have do have
a tube of FLASH memory somewhere around here though.

Not resetting the bank switch on reset is a must if it's to be used as
a multi-cart since you have to reset some games to get them to work in
the proper colors.  However, you may want to add a place on the board
where you can reset the cart from a button on it.  Perhaps it could
reset the entire system.

On the Atari, people have converted non-cartridge games to work on
multi-carts so you can load them up quicker.  It would be cool to see
that done with a bunch of the CoCo classics.  With up to 128 games on
some of the Atari ones... very neat!

The fancier multi-carts attach to a PC through a USB so you can change
the contents from your PC at any time.  I think a high speed serial
driver would work just fine from a menu option on the device.
Being able to select between playing a game, adding a game or running
a DriveWire like program would make it a perfect option for many
people and it should cost much less than an IDE/FLASH board due to the
reduced size and parts count.

--- In ColorComputer at yahoogroups.com, "James Diffendaffer"
><jdiffendaffer at ...> wrote:
>>
>> Mark, if you remove the dipswitch and add a latch that can be written
>> to on the computer the flash cart can be used as a multicart with a
>> menu to select the game you want to play.  This has been done on the
>> Atari's, Vectrex and several other systems.
>> 
>> It could also be used to write programs that take more memory than can
>> be addressed on the cart interface since you can page through the
>> cart's memory from software.
>>
>
>I started a new design this morning. You can load a 1/2/4MByte flash
for up
>to 256x 16KB images, or 128x 32KB images. Bank-switching is done via
>software, as is selecting 16/32KB. There is an external jumper to
_disable_
>autostart. There is no (E)EPROM support on this one.
>
>The RESET# signal _won't_ reset the bank switch, so you can select an
image
>and then hard-reset to auto-run the cartridge.
>
>It might even turn out _cheaper_ than my previous design...
>
>Regards, 
>
>
>-- 
>
>| Mark McDougall | "Electrical Engineers do it