NES 2.0 Mapper 261: Difference between revisions

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(Created page with "201NES 2.0 Mapper 261 is used for the TXC 6-in-1 multicart (MGC-023). Its UNIF board name is '''BMC-11160'''. ==Data latch== Mask: $8000 B...")
 
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[[Category:Multicart mappers|201]]NES 2.0 Mapper 261 is used for the TXC 6-in-1 multicart (MGC-023). Its UNIF board name is '''BMC-11160'''.  
[[Category:Multicart mappers]]
NES 2.0 Mapper 261 was assigned by FCEUX for the ''200-in-1 - Elfland'' multicart. Its UNIF board name is '''BMC-810544-C-A1'''.


==Data latch==
=Address latch=
  Mask: $8000
  A~1... ..PP PmpM CCCC
          || |||| ++++- Select 8 KiB CHR-ROM bank at PPU $0000-$1FFF
Bit 76543210
          || |||+------ Select nametable mirroring type
    M.PP..CC
          || |||        0: Vertical
    | || ++- Select 8 KiB (inner) CHR-ROM bank at PPU $0000-$1FFF
          || |||        1: Horizontal
    | ++----- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF, and 32 KiB (outer) CHR-ROM bank
          || ||+------- Lowest bit of 16 KiB PRG-ROM bank number
    +-------- Select nametable mirroring, 0=horizontal, 1=vertical
          || ||        at CPU $8000-$BFFF/$C000-$FFF in NROM-128 mode
          || |+-------- PRG-ROM banking mode
          || |          0: NROM-128 (16 KiB PRG-ROM at $8000-$BFFF, mirrored)
          || |          1: NROM-256 (32 KiB PRG-ROM at $8000-$FFFF)
          ++-+--------- Select 32 KiB CHR-ROM bank in NROM-256 mode/
                        bits 1-3 of 16 KiB PRG-ROM bank in NROM-128 mode
 
The first game on that multicart, ''Elfland'', is actually a CNROM game that writes to the multicart address latch to switch CHR-ROM banks.

Revision as of 15:17, 2 March 2018

NES 2.0 Mapper 261 was assigned by FCEUX for the 200-in-1 - Elfland multicart. Its UNIF board name is BMC-810544-C-A1.

Address latch

A~1... ..PP PmpM CCCC
         || |||| ++++- Select 8 KiB CHR-ROM bank at PPU $0000-$1FFF
         || |||+------ Select nametable mirroring type
         || |||         0: Vertical
         || |||         1: Horizontal
         || ||+------- Lowest bit of 16 KiB PRG-ROM bank number
         || ||         at CPU $8000-$BFFF/$C000-$FFF in NROM-128 mode
         || |+-------- PRG-ROM banking mode
         || |           0: NROM-128 (16 KiB PRG-ROM at $8000-$BFFF, mirrored)
         || |           1: NROM-256 (32 KiB PRG-ROM at $8000-$FFFF)
         ++-+--------- Select 32 KiB CHR-ROM bank in NROM-256 mode/
                       bits 1-3 of 16 KiB PRG-ROM bank in NROM-128 mode

The first game on that multicart, Elfland, is actually a CNROM game that writes to the multicart address latch to switch CHR-ROM banks.

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