NES 2.0 Mapper 529
NES 2.0 Mapper 529 denotes the YY0807, J-2148 and T-230 PCBs, used for particular bootlegs version of Datach Dragon Ball Z (T-230 PCB, with CHR-RAM) and Dragon Ball Z Gaiden (YY0807/J-2148 PCBs, with CHR-ROM). It's a VRC4 clone (A2/A3, VRC4e) connected such that the $800x register has no effect, and the $A00x register selects a 16 KiB PRG-ROM bank, similar to the games' original Bandai mappers. Its UNIF board name is UNL-T-230.
Similarly to the Bandai mappers, it also supports saving data to serial EEPROM. The presence of EEPROM is denoted via the NES 2.0 header's PRG-NVRAM field indicating 256 byte of non-volatile save data. Unlike the original Bandai FCG boards that used an I²C interface, the bootleg variants use a 93C56 EEPROM via a Microwire interface, operated using the following registers:
Read Microwire Interface ($5000, read)
Mask: $F000 D~[.... ...D] +- Serial Data Output from the 93C56 EEPROM
Write Microwrite Interface ($8800, write)
Mask: $8800 D~[.... .ECD] ||+- Serial Data Input to 93C56 EEPROM |+-- Serial Clock to 93C56 EEPROM +--- Chip Select to 93C56 EEPROM
This register's address range overrides the VRC4's. The game writes to the $FFFx address range to operate this register.
The 93C56's EEPROM's org pin is tied to Vcc, indicating a 16-bit word length.
See also: Board pictures and circuit diagrams