NES 2.0 Mapper 336

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Revision as of 15:34, 6 June 2024 by NewRisingSun (talk | contribs) (Add submappers and mirroring bit.)
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NES 2.0 mapper 336 is used for multicarts containing several UNROM games. Its UNIF board name is BMC-K-3046.

Submapper 0:

  • 11-in-1 (K-3046)
  • 2-in-1 (YH-217)
  • 2-in-1 (YH-218)

Submapper 1:

  • Top Gun III 2-in-1

Submapper 2:

  • 4-in-1 (YH-4109)

Banks

  • CPU $8000-$BFFF: Switchable 16 KiB inner PRG-ROM bank and switchable 128 KiB outer PRG-ROM bank
  • CPU $C000-$FFFF: Fixed 16 KiB inner PRG-ROM bank #7 and switchable 128 KiB outer PRG-ROM bank
  • PPU $0000-$1FFF: Unbanked 8 KiB CHR-RAM

Data Latch ($C000-$FFFF)

Mask: $8000

D~7654 3210
  ---------
  ..OO OIII
    || |+++- Select 16 KiB inner PRG-ROM bank at CPU $8000-$BFFF
    ++-+---- Select 128 KiB outer PRG-ROM bank at CPU $8000-$FFFF
    |  +---- Mirroring (Submapper 2), 1=H, 0=V
    +------- Mirroring (Submappers 0/1), 1=H, 0=V

Note

Submappers 0 and 2 have no bus conflicts. Submapper 1 does: D0-D2 are affected by normal AND-type bus conflicts, while D3 has a resistor in the signal path to ensure that the ROM bit always "wins", similar to INES Mapper 144. This behavior is necessary for proper function.