NES 2.0 Mapper 521

NES 2.0 Mapper 521 is used for 장두진 바둑교실: 입문편, commonly known as Korean Igo. Its UNIF board name is DREAMTECH01, without prefix.

Banks

• CPU $8000-$BFFF: 16 KiB switchable PRG-ROM bank
• CPU $C000-$FFFF: 16 KiB fixed PRG-ROM bank (last bank in ROM file)
• PPU $0000-$1FFF: 8 KiB of unbanked CHR-RAM.

Mirroring is hard-wired.

Since the fixed PRG-ROM bank comes from a separate PRG-ROM chip, the ROM file can have a non-power-of-two size.

Bank Register ($5020, write)

Mask: $5030
D~[.... BBBB]
        ++++- PRG A18..14 when CPU A14=0

Note that writes to $5030 are ignored.

See also

PCB images and circuit diagram