NES 2.0 Mapper 373 is used for a Super 4-in-1 multicart (PCB ID SFC-13). It is INES Mapper 045 but with one bit of outer bank register #2 working as a GNROM switch.
Mask: $F001 D~7654 3210 --------- PPRC cccc |||| ++++- Select number of CHR bits from MMC3 |||| ($F: 256 KiB, $E: 128 KiB ... $7-$0: 1 KiB) |||+------ Select CHR A18 ||+------- Select MMC3 (0)/GNROM-like (1) PRG mode ++-------- Select CHR A20-A21 and PRG A21-22
In GNROM-like mode, the MMC3 clone's CPU A14 input is held low, so that MMC3 registers #6 and #7 apply both to $8000/$C000 and $A000/$E000, with the bank number ANDed with NOT $02 in the lower range and ORed with $02 in the upper range.
Categories: Mappers with scanline IRQs, MMC3-like mappers, Multicart mappers