NES 2.0 Mapper 412: Difference between revisions

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NES 2.0 Mapper 412 is used for the Intellivision 10-in-1 Plug 'n Play 2nd Edition.
{{DEFAULTSORT:412}}[[Category:Multicart mappers]][[Category:Mappers with scanline IRQs]][[Category:MMC3-like mappers]]
'''NES 2.0 Mapper 412''' denotes an "MMC3 plus NROM" multicart mapper, used for the ''Intellivision 10-in-1 Plug 'n Play 2nd Edition'' as well as assorted multicarts from Henggedianzi. It uses an [[MMC3]] clone with additional outer bank registers at $6000-$7FFF that are accessible via the MMC3's WRAM interface, meaning that WRAM must be enabled via $A001 for them to be written to.
 
==8 KiB CHR Bank Register ($6000, write)==
D~[BBBB BB..]  Mask: $E003, reset value: 0
    ++++-++---- CHR A18..A13
Only applicable in NROM banking mode ($6002.1=1).
==Mode Register ($6001, write)==
D~[CARQ DBPL]  Mask: $E003, reset value: 0
    |||| |||+-- Lock register $6001
    |||| ||+--- 0: PRG A17 from MMC3, 1: from A Bit
    |||| |+---- PRG A18 if Q=2
    |||| +----- CHR A18
    |||+------- 0: PRG A18 from MMC3, 1: from B Bit
    ||+-------- 0: CHR A17 from MMC3, 1: from C Bit
    |+--------- PRG A17 if P=1
    +---------- CHR A17 if R=1
==PRG Bank Register ($6002, write)==
D~[BBBB bQP.]  Mask: $E003, reset value: 0
    |||| ||+--- 0: MMC3 banking, 1: NROM PRG/CHR banking
    |||| |+---- 0: NROM-128, 1: NROM-256 banking, only if P=1
    |||| +----- PRG A14 if P=1 and Q=0
    ++++------- PRG A18..A15 if P=1

Revision as of 14:28, 21 June 2023

NES 2.0 Mapper 412 denotes an "MMC3 plus NROM" multicart mapper, used for the Intellivision 10-in-1 Plug 'n Play 2nd Edition as well as assorted multicarts from Henggedianzi. It uses an MMC3 clone with additional outer bank registers at $6000-$7FFF that are accessible via the MMC3's WRAM interface, meaning that WRAM must be enabled via $A001 for them to be written to.

8 KiB CHR Bank Register ($6000, write)

D~[BBBB BB..]  Mask: $E003, reset value: 0
   ++++-++---- CHR A18..A13

Only applicable in NROM banking mode ($6002.1=1).

Mode Register ($6001, write)

D~[CARQ DBPL]  Mask: $E003, reset value: 0
   |||| |||+-- Lock register $6001
   |||| ||+--- 0: PRG A17 from MMC3, 1: from A Bit
   |||| |+---- PRG A18 if Q=2
   |||| +----- CHR A18
   |||+------- 0: PRG A18 from MMC3, 1: from B Bit
   ||+-------- 0: CHR A17 from MMC3, 1: from C Bit
   |+--------- PRG A17 if P=1
   +---------- CHR A17 if R=1

PRG Bank Register ($6002, write)

D~[BBBB bQP.]  Mask: $E003, reset value: 0
   |||| ||+--- 0: MMC3 banking, 1: NROM PRG/CHR banking
   |||| |+---- 0: NROM-128, 1: NROM-256 banking, only if P=1
   |||| +----- PRG A14 if P=1 and Q=0
   ++++------- PRG A18..A15 if P=1