+------------------------------+ | 72-in-1 225 | +------------------------------+ +---------------------------------------------+ | The 72-in-1 pirate cart uses this mapper. | +---------------------------------------------+ +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |A15|A14|A13|A12|A11|A10|A09|A08|A07|A06|A05|A04|A03|A02|A01|A00| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1 | X | M | S | P | P | P | P | P | H | C | C | C | C | C | C | +---+---+-+-+-+-+-+-+---+---+---+-+-+-+-+-+-+---+---+---+---+-+-+ | | | | | | | | | +---------------+ | +-------------------+ | | | | | | | | | + Select 8K VROM bank at PPU | | | | $0000 | | | | | | | +---- Select upper half (1) or | | | lower half (0) of 32K PRG | | | page. This half is mirrored | | | both to $8000 and $C000. | | | No effect if page size is set | | | to 32K. | | | | | +------------------------ Select PRG page (size and | | location determined by lines | | A06 and A12) | | | +---------------------------- Select PRG page size. 0 - 32K, | 1 - 16K. If the size is 16K, | it's mirrored at both $8000 | and $A000. Whether the top | or bottom half of the 32K | chunk is used depends on the | condition of A06. | +-------------------------------- Mirroring select 0 - Vertical mirroring 1 - Horizontal mirroring Notes: - This mapper is interesting in that the address written, rather than the value, controls the switching. A15-A00 is simply the address written in binary notation. For example, writing to $A3C7 (1010001111000111 in binary) would select horizontal mirroring, 32K PRG bank #7, and 8K CHR bank #7. Note that only writes to $8000 and above are valid. - Vertical mirroring is probably set at powerup. - At reset, the first 32K ROM bank is swapped into $8000, and the first 8K VROM bank is swapped into PPU $0000. - Thanks to Mark Knibbs for hacking this mapper. ****************************************************************************