NES 2.0 Mapper 387

NES 2.0 Mapper 387 denotes J.Y. Company's YY850735C and YY850817C circuit boards, used for the multicarts:

• 1996 Super HiK 4-in-1 (JY-087)
• 1996 Super HIK 4-in-1 (JY-089)
• 1996 Super HIK 4-in-1 (JY-093)
• 1996 Super HIK 4-in-1 (JY-094)

It uses the J.Y. Company ASIC, has 512 MiB of PRG-ROM and 1 MiB of CHR-ROM. NES 2.0 Mapper 386 is almost the same but changes the outer PRG bank size from 128 to 256 KiB.

Outer Bank Register ($D003)

Mask: $F003

7654 3210
---- ----
..L? PCpc
  || |||+- CHR A18, ignored if L=1
  || ||+-- PRG A17
  || |+--- CHR A19
  || +---- PRG A18
  |+------ Always 1
  +------- Select outer CHR-ROM bank size
            0: Mask $900x/$A00x to 256 KiB, use c
            1: Mask $900x/$A00x to 512 KiB, ignore c   

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