NES 2.0 mapper 327 is used for a 6-in-1 multicart. Its UNIF board name is BMC-10-24-C-A1.
Mask: $E000
A~FEDC BA98 7654 3210
-------------------
0110 .... ..CT POOO
|| |+++- Select 128 KiB PRG-ROM and CHR-ROM outer bank
|| +---- Select MMC3 inner PRG-ROM bank address mask
|| 0: 128 KiB
|| 1: 256 KiB
|+------ Select CHR memory type
| 0: CHR-ROM
| 1: CHR-RAM
+------- Select MMC3 inner CHR-ROM bank address mask
0: 128 KiB
1: 256 KiB
As it uses the MMC3 clones's WRAM interface, writing to the Outer Bank register requires enabling and not write-protecting WRAM in the MMC's $A001 register. Note that there are also 8 KiB of WRAM in the same address range. The outer bank register becomes locked against further writes once an outer bank other than 0 is selected, and is only unlocked on power-up.
Mask: $E001 See MMC3.
Categories: Mappers with scanline IRQs, MMC3 with CHR ROM and CHR RAM, MMC3-like mappers, Multicart mappers