Before you get your hopes up, the image below is a concept design made by Cem Tezcan of a Handheld Retro PC - Commodore HX-64. Just a concept, but cool nonetheless. You can check out more images here.
Chiptune is synthesized electronic music made using programmable sound generator sound chips found in vintage arcade machines, computers and video game consoles.
Think of a sound chip as a little synth within your Game Boy or Commodore 64. A sound chip is an integrated circuit designed to produce sound. Since the 90s, the standard way to do this is through Pulse Code Modulation or PCM - a method used to digitally represent analog signals.
The Commodore 64 in particular used a sound chip called “SID”, or Sound Interface Design, or to put it even more intricately, MOS Technology 6581. The SID was devised by engineer Robert "Bob" Yannes, who later co-founded Ensoniq.
The Game Boy and Commodore 64 use a waveform generator to produce different sound waves. The Game Boy uses two pulse channels (a channel for 4-bit pulse-code modulation (PCM) playback, and a pseudo-random-noise generator). The Commodore 64 uses the aforementioned SID chip and uses three channels (switchable between pulse, saw-tooth, triangle, and noise).
Since you couldn’t really make polyphonic music (more than one note at a time), a lot of early video game music featured arpeggios (notes that compose a chord played in a rising or descending order). My favorite example of a video game soundtrack that features an arpeggio is “Track 1” from Top Gear on Super Nintendo - although being from the 90s, the SNES used a more advanced sound chip, “S-SMP”.
The first video game to implement a continuous background soundtrack with Chiptune was Tomohiro Nishikado's 1978 release Space Invaders, which had four simple chromatic descending bass notes repeating in a loop.
Pioneers Yellow Magic Orchestra started using computers to produce synthesized music in the late 1970s. Within their 1978 self-titled debut album are samples from arcade games like Space Invaders. Sega's 1982 arcade game Super Locomotive even featured a chiptune cover version of YMO's "Rydeen".
Off to play some video games!