[Coco] How does the cartridge port work, anyway?

[Allen Huffman]

On Feb 15, 2013, at 4:05 AM, Phill Harvey-Smith <afra at ramoth.org.uk> wrote:
> The other way that this can happen of course is if the cartridge has it's own address decoding and holds the "device select disable" line low it can pretty much override the internal memory decoding.
> 
> This could for example be used to map an external ROM / RAM into the
> area that the basic roms normally occupy.

How big of an area could a cartridge map in this way? Did anything do that?

		-- Allen