NES 2.0 Mapper 521: Difference between revisions

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=Banks=
=Banks=
*CPU $8000-$BFFF: 16 KiB switchable PRG-ROM bank, selected via latch at $5000-$5FFF
*CPU $8000-$BFFF: 16 KiB switchable PRG-ROM bank
*CPU $C000-$FFFF: 16 KiB fixed PRG-ROM bank #8
*CPU $C000-$FFFF: 16 KiB fixed PRG-ROM bank (last bank in ROM file)
*PPU $0000-$1FFF: 8 KiB of unbanked CHR-RAM.
*PPU $0000-$1FFF: 8 KiB of unbanked CHR-RAM.
Mirroring is hard-wired.
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: $F030
D~[.... BBBB]
        ++++- PRG A18..14 when CPU A14=0
Note that writes to $5030 are ignored.
=See also=
[https://forums.nesdev.org/viewtopic.php?p=296603 PCB images and circuit diagram]

Latest revision as of 15:38, 22 October 2024

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: $F030
D~[.... BBBB]
        ++++- PRG A18..14 when CPU A14=0

Note that writes to $5030 are ignored.

See also

PCB images and circuit diagram