INES Mapper 101

This mapper was allocated for a naïve misdumping of the JF-10 board that contains Urusei Yatsura - Lum no Wedding Bell, which assumed the bank bits were reversed. Otherwise, it is entirely identical to J87.

Registers

Bank Select ($6000-$7FFF)

This will select an 8 KB CHR ROM bank for PPU $0000-$1FFF.

7  bit  0
---- ----
CCCC CCHL
|||| ||||
|||| |||+- (Normal) Low CHR bit
|||| ||+-- (Normal) High CHR bit
++++-++++- (Oversize only) Extra CHR bits

This is the same as J87 but with the bits in order, and so has a better defined oversize extension; or the same as CNROM without bus conflicts.