Difference between revisions of "INES Mapper 134"

From Nesdev wiki
Jump to: navigation, search
(Mode Register ($6000, write))
(CNROM register ($6002, write))
Line 46: Line 46:
 
  Mask: $E003
 
  Mask: $E003
  
Contains the 8 KiB CHR-ROM bank if $6000.3=1, masked to 128 or 256 KiB according to $6000.6.
+
Contains the 8 KiB CHR-ROM bank if $6000.3=1, masked to 128 or 256 KiB according to $6000.6. This register responds even if the "Lock" bit is set.
 +
 
 
==Unknown Register ($6003, write)==
 
==Unknown Register ($6003, write)==
 
  Mask: $E003
 
  Mask: $E003

Revision as of 11:33, 9 January 2021

iNES Mapper 134 denotes an MMC3-clone-based multicart PCB referred to alternatively as T4A54A, WX-KB4K, or BS-5652.

  • 2-in-1 Family Kid & Aladdin 4
  • Super Cool Boy 4-in-1 (CB-4034) (commonly-available ROM file has been hacked to run as INES Mapper 044)
  • Super Cool Boy 4-in-1 (CB-4035)
  • Super 4-in-1 1998 (JH-274)
  • 1998 HIGH 4-in-1 (YH-463)

Mode Register ($6000, write)

Mask: $E003

D~7654 3210
  ---------
  LD.. C...
  ||   +---- CHR-ROM banking mode
  ||          0: MMC3 (inner banks from $8000.0-$8000.5)
  ||          1: CNROM (8 KiB inner bank from $6002)
  |+-------- CPU $8000-$FFFF mode
  |           0: PRG-ROM
  |           1: Read solder pad setting
  +--------- $6xxx Register Lock (except $6002)
              0: unlocked
              1: locked, further writes ignored until reset

Outer Bank Register ($6001, write)

Mask: $E003

D~7654 3210
  ---------
  NcCC npPP
  |||| ||++- PRG A18..17
  |||| |+--- Outer PRG Bank Size
  |||| |      0: 256 KiB, PRG A17 from MMC3
  |||| |      1: 128 KiB, PRG A17 from $6001 bit 0
  |||| +---- PRG A14 mode in NROM mode ($6001 bit 7=1)
  ||||        0: PRG A14=CPU A14 (NROM-256)
  ||||        1: PRG A14=MMC3 PRG A14 (NROM-128)
  ||++------ CHR A18..17
  |+-------- Outer CHR Bank Size
  |           0: 256 KiB, CHR A17 from MMC3
  |           1: 128 KiB, CHR A17 from $6001 bit 4
  +--------- PRG-ROM banking mode
              0: MMC3
              1: NROM

In NROM mode, the MMC3 clone's CPU A13 and A14 inputs are held low, so that MMC3 register 6 applies to the entire CPU $8000-$FFFF range, with PRG A13 substituted by CPU A13 and PRG A14 subject to $6001.3.

CNROM register ($6002, write)

Mask: $E003

Contains the 8 KiB CHR-ROM bank if $6000.3=1, masked to 128 or 256 KiB according to $6000.6. This register responds even if the "Lock" bit is set.

Unknown Register ($6003, write)

Mask: $E003

MMC3-compatible registers ($8000-$FFFF)

Mask: $E001

See MMC3.