NES 2.0 Mapper 521: Difference between revisions
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=Banks= | =Banks= | ||
*CPU $8000-$BFFF: 16 KiB switchable PRG-ROM bank | *CPU $8000-$BFFF: 16 KiB switchable PRG-ROM bank | ||
*CPU $C000-$FFFF: 16 KiB fixed 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. | *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: $5030 | |||
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] | |||
Revision as of 21:09, 21 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: $5030
D~[.... BBBB]
++++- PRG A18..14 when CPU A14=0
Note that writes to $5030 are ignored.
