NES 2.0 Mapper 396

NES 2.0 Mapper 396 denotes the 晶太 YY850437C and Realtec GN-51 multicart PCBs, basically an UNROM mapper with an outer bank register. Its UNIF MAPR is BMC-830752C.

• 1995 Super 8-in-1 (JY-050 rev0)
• Super 8-in-1 Gold Card Series (JY-085)
• Super 8-in-1 Gold Card Series (JY-086)
• 2-in-1 (GN-51)

Outer Bank Register ($A000-$BFFF)

Mask: $E000

D~7654 3210
  ---------
  .Mm. .ppp
   ||   +++- PRG A19..A17
   |+------- Mirroring (GN-51), 1=Horizontal
   +-------- Mirroring (YY850437C), 1=Horizontal

No bus conflicts. Since no multicart menu sets the respective "other" mirroring bit, submapper-less emulation is possible by selecting horizontal mirroring if either bit is 1, and vertical mirroring if both are 0.

Inner Bank Register ($8000-$9FFF, $C000-$FFFF)

Mask: $E000

D~7654 3210
  ---------
  .... .PPP
        +++- PRG A16..A14 if CPU A14=0

No bus conflicts.