Bank Switching - Video Game Consoles

Video Game Consoles

Bank switching was also utilized in some video game consoles. The Atari 2600, for instance, could only address 4 KB of ROM, so later 2600 game cartridges contained their own bank switching hardware in order to permit the use of more ROM and thus allow for more sophisticated games (via more program code and, equally important, larger amounts of game data such as graphics and different game stages). The Nintendo Entertainment System contained a modified 6502 but its cartridges sometimes contained a megabit or more of ROM, addressed via bank switching called a Multi-Memory Controller. Game Boy cartridges used a chip called MBC (Memory Bank Controller), which not only offered ROM bank switching, but also cartridge SRAM bank switching, and even access to such peripherals as infrared links or rumble motors. Bank switching was still being used on later game systems. Several Sega Mega Drive cartridges were over 4MB in size and required the use of this technique (4MB being the maximum address size). The GP2X handheld from Gamepark Holdings uses bank switching in order to control the start address (or memory offset) for the second processor.