NES 2.0 Mapper 515

iNES 2.0 Mapper 515 is used for Family Noraebang, a Korean karaoke cartridge that uses UNROM-style CHR banking, has provisions for an expansion cartridge, an ADC for Microphone input, and a clone of the Yamaha YM2413 chip for expansion audio.

Banks

• CPU $8000-$BFFF: 16 KB switchable PRG ROM bank
• CPU $C000-$FFFF: 16 KB PRG ROM bank, fixed to the last bank

PRG-ROM bankswitching

Mask $E00F:
  W 8000: [RBBB BBBB] - R:0-select external ROM; 1-select internal ROM; B-select bank at $8000-$BFFF
                        $C000-$FFFF is always last bank of internal ROM

The board does not seem to suffer from bus conflicts. The existing ROM images are arranged similarly to INES Mapper 188: The last 1 MiB of PRG-ROM are the main cartridge, the first (total PRG-ROM size minus 1 MiB) are the expansion cartridge.

Expansion sound

Mask: $E003:
  W 6000: YM2413 index
  W 6001: YM2413 data

Note that the board does not allow the 2A03 audio to be mixed with the YM2413 output.

Microphone input

Mask: $E003:
   R 6003: [D... ....] - SPI (ADC) data
Mask not yet known:
   W C002: [S... ....] - SPI (ADC) chip select
   W C003: [K... ....] - SPI clock / ADC conversion clock

See also

http://forums.nesdev.org/viewtopic.php?f=9&t=16124