[Coco] Super Cartridge

[Arthur Flexser]

Yes, bank switching was used for some cartridges.  I saw an
interesting version of one of these where someone had cleverly adapted
a CoCo 1/2 bank-switching game that used four banks to run from disk
on a CoCo 3.  He replaced the bank switching with CoCo 3 MMU switching
and turned the cartridge code into a segmented binary file where some
segments were a single byte loaded into an MMU register address to
cause the following segment (resident in a particular bank in the
cartridge version) to be directly loaded into the appropriate MMU
memory block.  Neat!

Art

On Wed, Jan 16, 2013 at 4:46 PM, john dumas <JohnDumas at austin.rr.com> wrote:
> On 1/16/2013 3:16 PM, Luis Antoniosi (CoCoDemus) wrote:
>>
>> I/O ports are at FF00 - FFFF.
>>
>> A bank switching register ? Pretty much like the superIDE banks ?
>
> I have never seen a 32k coco cart, but bank switching sounds
> like the most likely way to "see" 32K thru a smaller address space hole...
>
> Bank switching ROM programs get interesting. If you have
> some scratch RAM, you can copy some small code there
> to switch banks while you "are somewhere else".
> Without RAM, you essentially have to saw off the limb
> you are sitting on. Best saw off the limb correctly and
> be fast on your feet to jump elsewhere!!!
> (Or BRANCH if you can stand the pun.)
>
> In the Day, we saw quite a bit of very creative ways to
> stuff more code in a very limited address space.
> Hardware to detect a read of a certain address and thus
> change an address bit was not uncommon - think SAM
> chip............
>
> cheers,
> johnd
>
>
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