NES 2.0 Mapper 285: Difference between revisions

From NESdev Wiki
Jump to navigationJump to search
(Created page with "285NES 2.0 Mapper 285 is used for the ''A65AS'' multicarts. Its UNIF board name is '''BMC-A65AS'''. =Banks= * CPU $8000-$BFFF: In 16 KiB mode:...")
 
(Disambiguate two incompatible mappers that had unfortunately been assigned to the same UNIF MAPR.)
Line 1: Line 1:
[[Category:Multicart mappers|285]]NES 2.0 Mapper 285 is used for the ''A65AS'' multicarts. Its UNIF board name is '''BMC-A65AS'''.
{{DEFAULTSORT:534}}[[Category:Multicart mappers]][[Category:Mappers with CHR RAM]]'''NES 2.0 Mapper 285''' is used for the ''A65AS'' and ''JY-066'' multicarts. The UNIF board name for both incompatible variants is '''BMC-A65AS'''.


=Banks=
=Banks=
Line 7: Line 7:
* PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM
* PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM


=Data Latch=
=Data Latch (CPU $8000-$FFFF)=
* CPU $8000-$FFFF:
==A65AS (Submapper 0)==
  Bit 7654 3210
  Bit 7654 3210
     ---------
     ---------
     SM1O HBBB
     SPMO OBBB
    |||| |+++- Select 16 KiB inner PRG-ROM bank at CPU $8000-$BFFF in 16 KiB mode (bit 6=0)
    |||| |++-- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF in 32 KiB mode (bit 6=1)
    |||+-+---- Select 128 KiB outer PRG-ROM bank at CPU $8000-$FFFF in 16 KiB mode (bit 6=0)
    ||+------- Select nametable mirroring
    ||        0: Vertical (bit 7=0)/Single-screen, page 0 (bit 7=1)
    ||        1: Horizontal (bit 7=0)/Single-screen, page 1 (bit 7=1)
    |+-------- Select PRG banking mode
    |          0: 16 KiB
    |          1: 32 KiB
    +--------- Select nametable mirroring type
                0: Horizontal/vertical (selected via bit 3)
                1: Single-screen (selected via bit 5)
==JY-066 (Submapper 1)==
Bit 7654 3210
    ---------
    SPMO HBBB
     |||| |+++- Select 16 KiB inner PRG-ROM bank at CPU $8000-$BFFF in 16 KiB mode (bit 6=0)
     |||| |+++- Select 16 KiB inner PRG-ROM bank at CPU $8000-$BFFF in 16 KiB mode (bit 6=0)
     |||| |++-- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF in 32 KiB mode (bit 6=1)
     |||| |++-- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF in 32 KiB mode (bit 6=1)

Revision as of 12:31, 8 February 2024

NES 2.0 Mapper 285 is used for the A65AS and JY-066 multicarts. The UNIF board name for both incompatible variants is BMC-A65AS.

Banks

  • CPU $8000-$BFFF: In 16 KiB mode: 16 KiB switchable inner bank, 128 KiB switchable outer bank
  • CPU $C000-$FFFF: In 16 KiB mode: 16 KiB fixed inner bank 7, 128 KiB switchable outer bank
  • CPU $8000-$FFFF: In 32 KiB mode: 32 KiB switchable bank
  • PPU $0000-$1FFF: 8 KiB unbanked CHR-RAM

Data Latch (CPU $8000-$FFFF)

A65AS (Submapper 0)

Bit 7654 3210
    ---------
    SPMO OBBB
    |||| |+++- Select 16 KiB inner PRG-ROM bank at CPU $8000-$BFFF in 16 KiB mode (bit 6=0)
    |||| |++-- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF in 32 KiB mode (bit 6=1)
    |||+-+---- Select 128 KiB outer PRG-ROM bank at CPU $8000-$FFFF in 16 KiB mode (bit 6=0)
    ||+------- Select nametable mirroring
    ||         0: Vertical (bit 7=0)/Single-screen, page 0 (bit 7=1)
    ||         1: Horizontal (bit 7=0)/Single-screen, page 1 (bit 7=1)
    |+-------- Select PRG banking mode
    |          0: 16 KiB
    |          1: 32 KiB
    +--------- Select nametable mirroring type
               0: Horizontal/vertical (selected via bit 3)
               1: Single-screen (selected via bit 5)

JY-066 (Submapper 1)

Bit 7654 3210
    ---------
    SPMO HBBB
    |||| |+++- Select 16 KiB inner PRG-ROM bank at CPU $8000-$BFFF in 16 KiB mode (bit 6=0)
    |||| |++-- Select 32 KiB PRG-ROM bank at CPU $8000-$FFFF in 32 KiB mode (bit 6=1)
    |||| +---- Select nametable mirroring if bit 7=0
    ||||       0: Vertical
    ||||       1: Horizontal
    ||++------ Select 128 KiB outer PRG-ROM bank at CPU $8000-$FFFF in 16 KiB mode (bit 6=0)
    ||+------- Select nametable mirroring if bit 7=1
    ||         0: Single-screen, page 0
    ||         1: Single-screen, page 1
    |+-------- Select PRG banking mode
    |          0: 16 KiB
    |          1: 32 KiB
    +--------- Select nametable mirroring type
               0: Horizontal/vertical (selected via bit 3)
               1: Single-screen (selected via bit 5)