Sleep mode

Sleep mode is a standby feature that allows a platform to reserve power while still keeping the system on and the game's progress intact. Sleep mode has been present in several Nintendo handhelds starting with the Game Boy Advance up to the Nintendo 3DS. With the Nintendo DS line in addition to the Game Boy Advance SP, sleep mode can be activated simply by slowing the handheld shut, while with the GBA putting the system into sleep mode is a bit more complicated.

Game Boy Advance
The Game Boy Advance's sleep mode causes the screen and sound to shut off while still retaining the game's progress. The purpose of this is to augment the system's battery power. Users can put their system into sleep mode by going into a game's menu and doing it manually. Getting the system out of sleep mode is a bit more complicated. To do so, the player has to press the L and R buttons at the same time and hold down select. After releasing these buttons, the system will turn back on.