iNES Mapper 103 describes a specific pirate port of the FDS version of Doki Doki Panic.
Writes to regions where RAM can be mapped will always write to RAM, even if RAM isn't enabled for reading.
Registers are not cleared on reset, and state is unknown on power-up. No bus conflicts.
Mask: $F000
7 bit 0 ---- ---- .... PPPP |||| ++++-- select 8 KiB PRG bank at $6000
Mask: $F000
7 bit 0 ---- ---- .... m... | +----- 0=V (PPU A10), 1=H (PPU A11)
Mask: $F000
7 bit 0 ---- ---- ...d .... | +------- 0=RAM available at $6000-$7FFF and $B800-$D7FF 1=ROM instead
This hardware involves three 7400, two 7410, a 7432, a 7474, a 74138, a 74157, and a 74161.
Categories: INES Mappers, Discrete logic mappers, FDS conversion mappers