[a1369209993]

The 6502 can only address 64K, so I'd assume 32K of ROM at 8000-FFFF with 128 (not 100) bytes of RAM mapped at both 80-FF (zero page) and 180-1FF (for the stack) and 128 MMIO bytes at 00-7F. It depends on how much they've modified the base 6502 design, though; the above is for "not at all".

[vardump]

In such an integrated design 6502 can address exactly as much as you want/need it to.

Just implement bank switching for top 32 kB of address space. 256 banks (= one 8-bit register) * 32 kB = 8 MB. Need more? Add another bank switch register and you got up to 2 GB.