INES Mapper 153
iNES Mapper 153 is used for a Bandai FCG board with an LZ93D50 ASIC and 8192 bytes of battery-backed WRAM. These 8192 bytes must be denoted as PRG-NVRAM in the NES 2.0 header using byte value $70. Only one game, Famicom Jump II: Saikyou no 7-nin, uses this mapper.
- CPU $6000-$7FFF: 8 KiB battery-backed WRAM
- CPU $8000-$BFFF: 16 KiB switchable PRG-ROM bank
- CPU $C000-$FFFF: 16 KiB PRG ROM bank, fixed to the last bank
- PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM
Outer PRG-ROM Bank Select ($8000-$8003 write)
Mask: $800F 7 bit 0 ---- ---- xxxx xxxP | +-- Select 256 KiB outer PRG-ROM bank at CPU $8000-$FFFF
- The same value must be written to all four registers, or the outer PRG-ROM bank would be switched as the PPU is rendering.
- Because the ASIC's PA12 and PA13 inputs are grounded, only registers $8000-$8003 instead of $8000-$8007 are relevant.
- No CHR banking is available.
Inner PRG-ROM Bank Select ($8008 write)
Nametable Mirroring Type Select ($8009 write)
IRQ Control ($800A write)
IRQ Latch ($800B-$800C write)
These four registers function the same way as on INES Mapper 016, submapper 5.
PRG-RAM Control ($800D write)
Mask: $800F 7 bit 0 ---- ---- ..E. .... | +-------- PRG-RAM Chip Enable (1=Enable)
When booting with WRAM filled with zeroes, Famicom Jump II will freeze with a black screen. Simply soft-resetting the console will then always run the game properly unless WRAM is zeroed out again.