Nintendo made a crapload of boards using discrete chips to perform a mapper function.
 The Boards: NES-AMROM - Max. 128K PRG (Bus conflicts), 8K VRAM. NES-ANROM - Max. 128K PRG (No bus conflicts), 8K VRAM. NES-AOROM - Max. 256K PRG (Bus conflicts), 8K VRAM. NES-BNROM - Max. 128K PRG (Bus conflicts), 8K VRAM. NES-CNROM - Max. 32K PRG (Bus conflicts), Max. 32K CHR. NES-CPROM - Max. 32K PRG (Bus conflicts), 16K VRAM. NES-NROM-128 - 16K PRG, 8K CHR. NES-NROM-256 - 32K PRG, 8K CHR. NES-RROM-128 - 16K PRG, 8K CHR (Early). NES-UNROM - Max. 128K PRG (Bus conflicts), 8K VRAM. NES-UOROM - Max. 256K PRG (Bus conflicts), 8K VRAM.
I need the following boards:  |