Mapper 3: CNROM

Max PRG banks2
Max CHR banks?
BankswitchingCHR

Notes:

This is mostly like Mapper 0 except that the CHR can bankswitch. When the NES turns on, the first 8k of the CHR is used.

A bank switch occurs when memory is written to anywhere in $8000-$FFFF. When a bank switch occurs, it loads the 8k of the specified CHR bank and places it into the PPU.

All the bits tell what CHR bank to load from the ROM. CCCCCCCC