INES Mapper 133
iNES Mapper 133 is used for the Sachen unlicensed game Jovial Race and the original Joy Van release of Master Chu and the Drunkhard Hu (盜帥). It's almost identical to NINA-06. Its UNIF MAPR is UNL-SA-72008.
Mask: $E100 $4100: [.... .PCC] - Select 32 KiB PRG bank and 8 KiB CHR bank
Another physical release instead wired a Namco 108 clone in an inscrutably complex way:
Mask: $E001
$8000: [..B. .B.B] - Select register for writing
$8001: [...X XPCC] - Write value to register
| ||||
| ||++--- select 8 KiB CHR bank
| |+----- select 32 KiB PRG bank
+-+------ analog feedback path
Four of the registers produce an analog feedback path through the 108's CHR registers:
| XX bits | if this register was selected by the XX bits, switch to using contents of register |
|---|---|
| $00 | $04 |
| $08 | $24 |
| $10 | $01 |
| $18 | $21 |
If this feedback path doesn't settle on one specific register, then the selected banks will rapidly switch between all the registers specified by the feedback path, and the 108 clone will get hot.
Since both games' physical releases retain the write to $4120 with content as described above, there is currently no need for emulators to emulate the Namco 108 clone variant of the board.
See also:
