NES 2.0 Mapper 432

NES 2.0 Mapper 432 denotes a series of MMC3-based Realtec multicart circuit boards.

• Submapper 0: Realtec 8043, 8086, 8090, GN-30C PCB
• Submapper 1: Realtec 8023 PCB
• Submapper 2: Realtec 8085 PCB
• Submapper 3: Realtec 8145 PCB

Solder Pad Enable Register ($6000-$7FFE, even)

Mask: $E001

D~7654 3210
  ---------
  .... ...S
          +- 1=Replace PRG-ROM with solder pad value
               in the CPU $8000-$FFFF address range

Outer Bank Register ($6001-$7FFF, odd)

Mask: $E001

D~7654 3210
  ---------
  pNQP CmMb
  |||| |||+- PRG/CHR A17 if M=1
  |||| ||+-- PRG A17 mode
  |||| ||     0: from MMC3 (256 KiB inner bank)
  |||| ||     1: from b (128 KiB inner bank)
  |||| |+--- CHR A17 mode
  |||| |      0: from MMC3 (256 KiB inner bank)
  |||| |      1: from b (128 KiB inner bank)
  |||| +---- CHR A18
  |||+------ PRG A18
  ||+------- Submapper-specific functionality
  ||         Submapper 0: PRG+CHR A19
  ||         Submapper 1: Read solder pad
  ||         Submapper 2: NROM-256 mode
  ||         Submapper 3: 512 KiB MMC3 CHR mode (like INES Mapper 197 Submapper 2)
  |+-------- NROM-128 mode (1=enabled)
  +--------- Submapper 0/1: NROM-256 mode
             Submapper 2/3: Lock Outer Bank register

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. NROM-128 mode forces the MMC3 clone's CPU A14 input low, causing MMC3 register 6 to select both the bank at $8000 and $C000, and register 7 to select both the bank at $A000 and $E000.

MMC3-compatible registers ($8000-$FFFF)

Mask: $E001

See MMC3.