NES 2.0 Mapper 493

NES 2.0 Mapper denotes the prototype board used for the Maxivision 30 Super Games prototype multicart.

Overview

• CPU $8000-$FFFF: 32 KiB switchable window into 1 MiB PRG-ROM
• PPU $0000-$1FFF: 8 KiB switchable window into 1 MiB CHR-ROM
• Nametable arrangement: Hard-wired to Horizontal ("Vertical mirroring")

Registers

There are two writable registers in the CPU $6000-$FFFF address range.

Outer PRG/CHR Bank Register

D~[.... BBBB] A~[011. .... .... ....] (Address &0xE000)==0x6000
        ++++- PRG/CHR A19..A16 (64 KiB outer PRG/CHR bank)

Inner PRG/CHR Bank Register

D~[.CCC ...P] A~[1... .... .... ....] (Address &0x8000)==0x8000, bus conflicts
    |||    +- PRG A15 (32 KiB inner PRG bank)
    +++------ CHR A15..A13 (8 KiB inner CHR bank)

Comparison to other mappers

• It is INES Mapper 011 restricted to 64 KiB PRG/CHR sizes per game, with an additional outer bank register.
• It is similar to INES Mapper 046, with the difference that the same bits control both the outer PRG and outer CHR banks.