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.
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.
Mask: $E000 D~7654 3210 --------- .... .PPP +++- PRG A16..A14 if CPU A14=0
No bus conflicts.
Categories: Mappers with CHR RAM, Multicart mappers