::|CONTENTS
- System Specifications
- Sound Hardware
- Modifications
- Programming
- See also
The GameBoy is a hand-held game console developed and manufactured by Nintendo and was first released in 1989. It is the second most successful hand-held console in history, only beaten by the Nintendo DS, and originally came bundled with the famous Tetris puzzle game. Throughout the console's lifespan, many new models were released; examples include the Game Boy Pocket, the Game Boy Light, and the
Game Boy Color. It was then followed up by the
Game Boy Advance in 2001.
For the corresponding battle format, including a list of tools for music creation, refer to the
gameboy (format) article.
System Specifications
CPU: Sharp LR35902 at 4.19MHz; the Game Boy Color runs at 8.38MHz—this CPU is similar to the Intel 8080 and the Zilog
Z80.
RAM: 8kb; Game Boy Color has 32kb.
Video RAM (VRAM): 8kb; Game Boy Color has 16kb.
Display: 160 x 144 pixels.
Framerate: 59.73 frames per second.
Color Palette: 4 (off and LCD intensity levels 1-3); Game Boy Color has a 32,768 (15-bit) palette.
Sound: See the "Sound Hardware" section below.
The Game Boy can also communicate via built-in serial ports. These ports are used to connect two or more systems together for multiplayer games or other uses.
Game cartridges varied in size from 256Kbit to 8Mbit.
Sound Hardware
Much like the
2a03 CPU found in the NES, the Game Boy does not feature a dedicated sound chip; the sound-processing hardware is integrated directly into the CPU itself. The system has four channels of sound—two pulse waves, a variable waveform channel, and a noise channel. The pulse and noise channels function similarly to those of the NES, however one of the pulse channels has a tone sweep function and the noise channel generally can produce a greater range of tones. It also features stereo sound, but it is quite coarse: you can only pan channels fully to the right or fully to the left.
The first two channels are for pulse waves, both with a selectable duty cycle of 12.5%, 25%, 50%, or 75%, just like the
NES. Both channels have an 11-bit period, sixteen levels of volume, and an optional note cutoff length. The first pulse channel also has a hardware frequency sweep.
The wave channel has a 16-byte (32-sample), four-bit user-definable waveform. Like the pulse channels, it also has an 11-bit period and a note cutoff length, but only four volume settings: 100%, 50%, 25%, and off—the volume settings are simply shifts of the sample data, and often do not sound very good. Depending on the composition software used, sample playback may also be possible, but not at the same time as a defined wave.
The fourth channel is a noise channel which generates random noise using a linear feedback shift register (LFSR). It has sixteen volume levels and two different modes, 7-bit and 15-bit. The 15-bit mode is similar to standard white noise, and is commonly used for percussion; the 7-bit mode sounds more tonal and metallic. It functions and sounds similar to the noise channel of the NES, but can produce a larger range of tones.
Though rarely discussed, there is also a fifth channel. There is a pin on the cartridge for sound chip expansions (similar to how the NES used chip expansions such as the VRC6), but it was never utilized.
See the pandocs (linked in the "Programming" section) for more detailed and technical information on the system's sound capabilities.
Modifications
Modding is extremely popular in the Game Boy scene, and for good reason—there are plentiful amounts of aftermarket parts available and no shortage of different modifications that one can do to a given Game Boy console. Almost every mod requires some amount of soldering, but if you don't know how, fear not—modded systems can easily be purchased from sites like eBay or Etsy. This section lists and summarizes some of the ways you can modify your Game Boy.
ProSound (aka line-out mod)
Most models have a headphone output, but it is not very "clean"—the sound is often muddied with hissing, buzzing, or white noise. To fix this, one can perform the "ProSound" mod (which is nothing more than adding a line-out jack). The specific steps depend on which Game Boy you intend to perform this mod on, but it typically involves tapping the sound output directly from the CPU or volume wheel and wiring it to the headphone jack, additional RCA jacks, or a new headphone jack. The latter two require shell modification, and may be difficult on more compact models such as the Game Boy Pocket or Game Boy Color. To find a tutorial for performing this mod on your Game Boy, simply search for "[Game Boy model] ProSound mod" on your search engine of choice. If you intend to make your songs on real hardware or at least make hardware recordings, this modification is a must.
Frontlighting and Backlighting
Every early Game Boy model (sans the rare and Japan-exclusive Game Boy Light) features an unlit screen. Due to this, it can be difficult to see the screen in low-light conditions. These mods alleviate that, making the display more visible even when there is no ambient light. It is a trade-off, however—the light panel consumes additional power, so your batteries will not last as long. To many, this mod is still well worth the extra power consumption, and is practically a must if you intend to travel with your system. Much like the ProSound mod, specific instructions vary by model. The Game Boy and Game Boy Pocket use a backlight, while the Game Boy Color uses a frontlight. Use your favorite search engine to find a video or tutorial on how to perform the mod on your console.
Overclocking and Underclocking
If you've heard of overclocking in general, then you probably know that it allows a piece of electronics hardware to run at a faster speed than was originally intended. In contrast, underclocking is the opposite; it decreases the speed at which an electronic runs. The Game Boy ordinarily runs at a clock speed of 4.19MHz (Game Boy Color 8.38MHz), but overclocking/underclocking can push it above or below that speed. This makes the system in its entirety run faster or slower, and as such it isn't exactly practical for making music since it changes the pitch. It can, however, be used to create bizarre sounds or to reach lower or higher frequencies than the Game Boy can normally generate. Every Game Boy has a crystal which regulates the frequency to its normal speed, so this mod involves replacing it. You have two choices: you can replace the default crystal with a different one, or install a variable clock. The latter is adjustable and ideal if you don't want to always be overclocked/underclocked, but it requires shell modification and can be difficult on more compact Game Boy models.
MIDI Control
This is not a mod, per se, but is still useful for music so it is included in this list. It involves using an external device to send/receive MIDI input to/from the Game Boy for use in music software. This is typically achieved by using what is called an
ArduinoBoy. This device allows serial MIDI communication to and from the Game Boy through its link port for controlling software such as LSDj or mGB. Depending on your setup, this may not be a necessity, but if you want to create music for the system through external software with MIDI commands or sync it to another piece of music hardware it is a must.
New Parts
As mentioned above, there is a thriving market of aftermarket parts. If you have a beat up system, no worries; you can easily purchase a variety of new parts for your system such as a new shell, new buttons, or new screen bezel. The aftermarket is unfortunately limited to cosmetic parts (i.e. plastic stuff), so if you need to get your hands on something like a replacement screen you will have to salvage them from other systems. Nonetheless, if you want your system to feel like new again, this is a great way to do so!
Rechargeable Battery Pack
Most models of the Game Boy only accept AA or AAA batteries. With this mod, you can replace them with a rechargeable battery pack instead. The benefits are obvious, but this is one of the more difficult mods; shell modification is always required and there are little to no kits available for it. Even so, this may be a mod worthy of your time if you find yourself always burning through your supply of batteries.
Programming
(This section is a stub. If you know anything about programming the Game Boy, please help by adding more information!)
For developing your own Game Boy software, check out
GBDK-2020 on GitHub. Some people may prefer to program the Game Boy in assembly, in which case you can use
WLA-DX or
RGBDS as an assembler. For creating games, another option is
GB Studio, a quick and easy, drag and drop development tool for creating Gameboy (and Gameboy Color) games which are playable on a real system.
Resources
Game Boy Development Kit Tutorial
Pan Docs (details hardware and software interfaces and general development information)
BGB (accurate emulator and debugger, Windows-only but runs in Wine)
See also
Game Boy Camera
Game Boy Color
gameboy (format)
gbstudio (format)
deflemask (format)
