NES 2.0 Mapper 282

NES 2.0 Mapper 282 is used by at least three J.Y. multicarts:

• 1997 Super HIK 18-in-1 (JY-101)
• 1997 Super HIK 21-in-1 (JY-105)
• 1998 Super HIK 5-in-1 (JY-114)
• Super 25-in-1 Final Fight (SC-128)

Each of them have 1 MiB each of PRG-ROM and CHR-ROM. They use the J.Y. Company ASIC. Register $D003 controls 256 KiB outer banks.

Outer Bank Register ($D003)

Mask: $F003

7654 3210
---- ----
..LM CPPc
  || |||+- Select 256 KiB outer CHR-ROM bank (CHR A18), ignored if L=1
  || |++-- Select 256/512 KiB outer PRG-ROM bank
  || +---- If bit 4==1: Select 512 KiB outer CHR-ROM bank
  |+------ 0: Ignore bit 3
  |        1: Obey bit 3
  +------- Select outer CHR-ROM bank size
            0: Mask $900x/$A00x to 256 KiB, use c
            1: Mask $900x/$A00x to 512 KiB, ignore c

PRG ($8000-$8FFF) and CHR ($9000-$AFFF) bank select register bits that select 256 KiB banks (L=0)/512 KiB banks (L=1) are masked off.

For a description of all other registers, see J.Y. Company ASIC.

Trivia

Some of the multicarts show different version of menu according to what $5000 is returned from the mapper (the value that is read is masked with $C0, so only bits 7 & 6 matters.):

1997 Super HIK 18-in-1 (JY-101)
 $00   -> 18 in 1
 $40   -> 900 in 1
 $80   -> 1600 in 1
 $C0   -> 6000000 in 1

1997 Super HIK 21-in-1 (JY-105)
 $00   -> 21 in 1
 $40   -> 350 in 1
 $80   -> 1200 in 1
 $C0   -> 7000000 in 1