$A130FF address range is special
in that the
/TIME signal on the cartridge slot is asserted
whenever the 68000 accesses it (simplifying the wiring for extra
on-cartridge hardware). However it's a limited range, so we want to make
sure to avoid stepping on each other.
Pier Solar uses the
for its custom mapper and EEPROM access. It wouldn't be recommended to
put anything there that you want to be usable across multiple games.
$A130E8 is being eyed for potential standarization on