NES 2.0 Mapper 345
NES 2.0 Mapper 345 is used for the New Star 6-in-1 Game Cartridge multicart. Unusually, it combines MMC3 and AxROM games. Its UNIF board name is BMC-L6IN1. CHR data comes from 8 KiB of MMC3-banked CHR-RAM.
Mask: $E000
D~7654 3210
---------
OOMS mmPP
|||| ||++- Select 32 KiB inner PRG-ROM bank in AxROM mode
|||| ++--- Select PRG-ROM banking mode (0=AxROM, 1-3=MMC3)
|||+------ Select 1 KiB CIRAM bank in one-screen mirroring mode
||+------- Select nametable mirroring type
|| 0: from MMC3
|| 1: one-screen mirroring
++-------- Select 128 KiB outer PRG-ROM bank in either mode
As it uses the MMC3 clones’s WRAM interface, writing to the Outer Bank register requires enabling and not write-protecting WRAM in the MMC’s $A001 register.
Mask: $E001
See MMC3.