The Game Boy Advance is backward compatible with most games previously released for the Game Boy or the Game Boy Color, as well as new software developed to take advantage of the new technical capabilities of the system. It is powered by two AA batteries, which give about 5–10 hours of play time, as well as an optional power supply that plugs directly into the GBA's battery bracket.

Processors

The GBA has a custom 32-bit 16.8-MHz ARM processor (ARM7TDMI) based on a RISC architecture, which is much more suited to the C programming language than the 8-bit Z80-like processor used in older Game Boy models. The ARM processor can run both 32-bit ARM and 16-bit "Thumb" instruction set encodings. The system also contains an 8.4-MHz Z80-like processor to provide support for legacy GB software; however, both processors cannot be active at the same time.

Dimensions

Length: 144.5 mm

Width: 24.5 mm

Height: 82 mm

Weight: 140 grams

Display

The 2.9" LCD is capable of a maximum of 240×160 pixels in 15-bit color (32,768 colors). This display includes more pixels than Game Boy's 160×144; when playing legacy games, the user can press the "L" or "R" button to switch the display between 160×144 with a black border and scaling to 240×144 pixels. Early games had very dark color palettes because the display in the development kits was much brighter than the one in the production units; the production display has a gamma value of 4. Newer titles use gamma correction in their palettes.

If the color LCD has a fault, it is that the Game Boy Advance is lit by ambient light. Users quickly learned to tilt the device to take advantage of window or overhead illumination. An aftermarket internal lighting kit known as the Afterburner was briefly popular before the introduction of the Game Boy Advance SP, and influenced the development of the new model.

Graphics

The GBA has hardware support for simple 2D operations using graphical elements called sprites. It can scale, rotate, sum-blend, and alpha-blend sprites against a background (with one alpha value for the whole screen, not the alpha-blending of image edges seen in the PNG format), and it can change the scaling and rotation of sprites and the background on each scanline to give a pseudo-3D effect.

The GBA's picture generator has six display modes (three tiled and three bitmap) and 96 KiB of dedicated RAM. In tiled display modes, the system can manage four pixel-to-pixel layers, two pixel-to-pixel layers and one affine layer, or two affine layers, and it uses 64 KiB of RAM for tile and map data and 32 KiB for sprite cel data. In bitmap modes, it can display one large 16-bit bitmap, two 8-bit bitmaps (with page flipping), or one small 16-bit bitmap (with page flipping), and it uses 80 KiB of RAM for bitmap data and 16 KiB for sprite cel data. In all modes, it can show up to 128 sprites (individually controllable small moving objects) of 8×8 up to 64×64 pixels in either 4-bit or 8-bit indexed color. Each sprite can be drawn using either direct pixel mapping or affine mapping; it's possible to fit more direct sprites on a scanline.

Later games pushed the GBA to its limits with simple 3D graphics. These games include Wolfenstein 3D, Duke Nukem Advance, and Doom and Doom 2. Utilizing 2D sprites for objects and 3D graphics for architecture, these games usually achieve a passable framerate, although sometimes in large environments or with many objects onscreen the framerate will drop to a very noticeable level. Some feel that such 3D games are a logical and welcome step for the GBA, while others feel that they are overly ambitious and beyond the capabilities of the system. With the release of the DS, future 3D games for the GBA will most likely be limited.

Media

The interface from the GBA unit to the ROM cartridge includes only a 24-bit address bus multiplexed with a 16-bit data bus. (Mattel's Intellivision console had previously used a multiplexed bus.) This setup limits the directly addressable memory to 16 binary megawords (that is, 256 binary mebibits or 32 binary mebibytes), but bankswitching hardware on the cartridge can extend this by controlling the ROM's upper address lines from software, effectively switching other parts of the ROM into the GBA's address space. Still, as of 2005, no published GBA titles have even executed such bankswitching hardware because 32 MiB of ROM is still too expensive for the price point at which most GBA games are sold. (It would possibly have to retail for $39.99 to $49.99)

By early 2002, hardware became readily available for moving user code onto the GBA. For example, in December 2001, a flash memory cartridge and its writing hardware was selling for less than $200 U.S., along with a $50 device to emulate the netbooting master. By April 2003, the prices had come down to under $100 for the flash cartridge and writer and $30 for the boot cable. Because of the drop in prices for programming equipment, a homebrew software development community has sprung up. Nintendo, however, has a history of viewing such devices as nothing more than piracy tools, since they can be used to copy cartridges containing copyrighted software. In February 2002, Nintendo began sending threatening letters to some United States resellers of such devices. Previous lawsuits had banned the importation of similar devices for the 8-bit Game Boy.

Connectivity
4-Player connection with 2 GBAs, 1 GBA SP, and 1 GameCube with a Game Boy Player attached
Enlarge
4-Player connection with 2 GBAs, 1 GBA SP, and 1 GameCube with a Game Boy Player attached

The GBA also has a serial port for connecting to other GBA units in a setup similar to a token ring network over a bus physical topology. A GBA can also receive up to 256 KiB of bootstrap code through the port, even when no cartridge is present (sometimes known as multiboot or netboot). This is used for multiplayer GBA connections, where multiple GBAs can play with only one cartridge; one GBA with a cartridge sends boot code to the other cartridge-less GBAs.

The serial port can (with a suitable cable) also connect to a standard RS-232 serial port for debugging purposes and (hypothetically) Internet play, although a TCP/IP stack has yet to be implemented in a GBA game. The release of the Nintendo DS in 2004 made this further unlikely, given the built-in Wi-Fi of that system's release.

To link GBA games, a GBA link cable is required. To link regular GB or GB Color games, the older GB link cable is required, even if two GBAs are being used.

Nintendo also introduced connectivity between the Game Boy Advance to the GameCube console through the GameCube-Game Boy Advance cable. This function could unlock data, act as a second screen, among other things. It did not catch on very well and not too many games added such connectivity.

The Game Boy Advance Wireless Adapter was released on September 7, 2004 in the United States. It allows GBAs to be linked without cords, and with more than four players at a time. It came bundled with Pokémon FireRed and LeafGreen. However, a game has to be designed with the wireless adapter in mind, and there are only a few such games.

The Game Boy micro featured another port design; in order to make the system so small, the link port was shrunken. Nintendo has released a GBM-GBM and a GBM-GBA adapter to restore full multiplayer compatibility. Nintendo has also released a special Game Boy Micro Wireless Adapter for wireless play. These items currently only sold on Nintendo.com.