[Coladam] CV Ultimate SD Cart on ADAM
atarimax at gmail.com
Wed Jul 14 02:03:36 CEST 2010
(1) The cartridge ROM space can be switched in and out of the ADAM 64K
> address space. It occupies the upper 32K, which also is where the ADAM
> EOS operating system code lives. There is no way that I know of to make
> the cartridge slot be the entire 64K of Z80 address space.
> (2) If your SD cart has some simple way to select RAM in banks (e.g.,
> send a select value out some I/O port), then additional cart RAM could
> be accessed, but again it would be in a 32K snapshot mapped to the upper
> 32K of Z80 address space. Existing memory expanders (for right internal
> slot) are accessed in this way.
Thanks for the reply! I'm guessing that memory expansion cards have access
to the signals for port in/out I/O, so I would not be able to emulate a
traditional memory expansion as the cartridge port only has read strobes for
the rom area.
I'm encouraged that the whole cartridge can be mapped directly into the ADAM
memory space. It should be possible for any game or program to access the
onboard CPU or RAM the same way the Colecovision does then.
In fact it should be much easier for code running on the ADAM, as the
cartridge is unavailable while the CPU is busy and the Colecovision has wait
for the I/O to complete before it can continue to execute code from the ROM
area. With the ADAM I/O operations could be pended and code could continue
to run without interruption from other areas of RAM.
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