INES Mapper 195

iNES Mapper 195 describes Waixing's FS303 board, which has an MMC3 clone and a GAL that can dynamically change which CHR banks are mapped to RAM.

The game writes, via the PPU, to specific CHR banks in order to select both which and how many CHR banks are mapped to RAM instead of ROM.

Writes to CHR ROM in multiples of 1 KiB:

CHRB~[1Z.D L.L.]
      || | |  |
      |+-|-+--+--------------- Select first bank and size of CHR RAM:
      || |                      $80 = $28-$2B
      || |                      $82 = $00-$03
      || |                      $88 = $4C-$4F
      || |                      $8A = $64-$67
      || |                      $C0 = $46-$47
      || |                      $C2 = $7C-$7D
      || |                      $C8 = $0A-$0B
      || |                      $CA = only CHR ROM
      || +-------------------- If 1, ignore above and always enable CHR ROM / disable CHR RAM
      |+---------------------- Number of banks of CHR RAM, 0=4KiB, 1=2KiB
      +----------------------- Must be 1 

The following games are known to use this mapper: Waixing's pirate ports of Columbus - Ougon no Yoake, Captain Tsubasa Vol 2, Sugoro Quest, and Crystalis.

Mappers 252 and 253, also used for Waixing's localizations, are similar but use a VRC4.

See also: NewRisingSun's findings