NES 2.0 Mapper 353
From Nesdev wiki
NES 2.0 Mapper 353 is used for the 92 Super Mario Family multicart, consisting of an MMC3 clone ASIC together with a PAL. The PCB code is 81-03-05-C.
Outer Bank Register ($8080-$E080)
Mask: Unknown, but must be more than just $8080. A~FEDC BA98 7654 3210 ------------------- 1OO. .... 1... .... ++----------------- Select 256 KiB outer PRG-ROM bank (PRG A18-19) and 128 KiB outer CHR-ROM bank (CHR A17-18) Power-up value: $00
- In addition to the setting the outer PRG-ROM and CHR-ROM bank, the outer bank register also modifies other aspects:
- Outer bank 0: Uses CHR A17 instead of the MMC3's Mirroring register, similar to INES Mapper 118.
- Outer bank 2: The outer PRG-ROM bank size is just 128 KiB, with CHR A17 serving as PRG A17 instead. Additionally, if CHR A17 is high, 8 KiB of unbanked CHR-RAM are used instead of CHR-ROM.
- Outer bank 3: If CHR A17 is low, PRG A17 is replaced with CPU A14, so that CPU $8000-$BFFF are taken from the first and CPU $C000-$FFF are taken from the second 128 KiB half.
- The conversion of Bio Miracle Bokutte Upa on that multicart retains all writes to the FDS sound channel registers, so an emulator could provide the expansion sound channel even though the original multicart did not.
- The conversion of Super Mario Bros. 2 (J) is incomplete and will fail to work after World 4-4.
- Resetting the console always returns to the main menu (outer bank register reset to $0) due to a circuit detecting interruptions in the M2 signal.