INES Mapper 063

iNES Mapper 063 is used for NTDEC's "Powerful 250-in-1" multicart (PCB ID TH2291-3) and its pirate-of-a-pirate equivalent, the "Hello Kitty 255-in-1" (PCB ID CH-011) multicart. The address-latch-based bankswitching hardware supports only NROM-128 and NROM-256 games. CHR data is stored in 8 KiB of unbanked CHR-RAM that can be write-protected.

Address latch ($8000-$FFFF, write)

A~FEDC BA98 7654 3210
  -------------------
  1... .CBB BBBB BbPM
        ||| |||| |||+- Select nametable mirroring type
        ||| |||| |||    0: Vertical
        ||| |||| |||    1: Horizontal
        ||| |||| ||+-- Select PRG banking mode
        ||| |||| ||     0: NROM-128, CPU A14 replaced with b
        ||| |||| ||     1: NROM-256, CPU A14 unmodified
        |++-++++-++--- Select 16 KiB PRG-ROM bank (A14..A21)
        +------------- Select CHR-RAM write-protection
                        0: Disabled, CHR-RAM writable
                        1: Enabled, CHR-RAM write-protected

For the menu code to correctly detect the number of games, selecting unpopulated PRG-ROM banks must result in open bus rather than wrapped addresses.