A normal cartridge has a battery backup for save data, but using a small coin cell to run an STM32 would kill the battery quickly. To get around that, the cartridge writes the states to ...

The concept involves hydrogen cartridges that are compact and light enough to be carried by hand, with one model wearing what looks like an oversized AA battery on his back in a specially design ...

The biggest change this time around is the addition of 32 KB of battery-backed SRAM that gives games (or any other software that might be on the cartridge) some persistent storage to work with.