NES 2.0 Mapper 535

NES 2.0 Mapper 535 is used for Whirlwind Manu's cartridge conversion (cartrige code LH53) of the Famicom Disk System Game 謎の村雨城 (Nazo no Murasamejō). Its UNIF board name is UNL-LH53.

Banks

• CPU $6000-$7FFF: 8 KiB switchable PRG-ROM bank
• CPU $8000-$FFFF: 32 KiB fixed PRG-ROM bank #3, except where overlaid by PRG-RAM
• CPU $B800-$D7FF: 8 KiB fixed PRG-RAM bank
• PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM

Registers

IRQ register ($E000-$EFFF, write)

Mask: probably $F000

D~7654 3210
  ---------
  .... ..E.
         +-- 1= Enable counting

Writing to this register acknowledges a pending IRQ, and resets the counter to zero. When counting is enabled, the counter increases on every M2 cycle; upon reaching a value of 7560, an IRQ is generated (according to FCEUX source code).

PRG bank register ($F000-$FFFF, write)

Mask: probably $F000

Sets the 8 KiB PRG-ROM bank at CPU $6000-$7FFF.

Notes

• The conversion retains all writes to the FDS sound channel registers, so an emulator could provide the expansion sound channel even though the original Whirlwind Manu cartridge did not.
• Game progress cannot be saved.