When it comes to chiptunes, the original Nintendo Entertainment System and the Game Boy get all the accolades. The OPL synths have all the fun. But there’s another chip out there in dusty old machines that is at least as interesting with a repertoire at least as influential as the Mega Man 2 OST. It’s the YM2612, the chip in the Sega Mega Drive/Genesis.
[natalie] created a portable device capable of playing back the files targeting the sound chips in this venerable machine. It’s the MegaGRRL, and it’s the iPod for the original Genesis sound tracks.
Inside the MegaGRRL is an ESP32 in the form of an ESP-WROOM-32 module. There is, of course a YM2612 chip in there, along with a headphone amplifier and a battery charger. The display is a fairly standard and cheap affair that’s 240 x 320 pixels in full color, and there are seven buttons on this device, because of course you need an A, B, and C button.
Combined with a 3D printed enclosure, the GameGRRL does exactly what it says it will: it plays all the music from old Sega games. Now, when you’re in the inevitable argument with someone over the fact that Michael Jackson wrote the Sonic 3 soundtrack, the proof is right in your pocket. Of if you want to jam out on the Toe Jam And Earl soundtrack, that’s right there too. You can check out the video demos below.
The interesting aspect of these chips is how they use registers to change the audio output. Essentially, there is a complicated register map (one section of his write-up is simply called “Register Hell”) that can be called in order to access the various types of effects one would normally see on a synthesizer. It’s not straightforward at all, though, and got even more complicated once [Aidan] started adding MIDI functionality to it as well. Once he finished sifting through the Sega Genesis technical manuals and a bunch of registers, though, he had a unique synthesizer working that doesn’t sound like anything you’ve ever heard, unless you’ve ever played a Genesis.
If you’d like to check out his first project, the MegaBlaster, which plays the sound files of the old Genesis games directly, we featured that a while ago. Keep in mind though that his latest project isn’t just an updated MegaBlaster, though. He built this entire thing from the ground up.
Chiptune is a musical genre built upon the creation of music through the use of chip-based sound synthesizers, found in early game consoles. The Commodore 64’s venerable SID chip and the Game Boy Sound System are the by far the most popular on the scene. However, the Sega Genesis took a different path at the end of the videogame chipmusic era, packing a YM2612 FM synthesis chip to deliver fat basslines and searing solos. [Thea] has always been a fan of these electric 90s sounds, and thus decided to build the Genesynth.
The synth initially allowed only for playback of existing video game scores, but its capability has been expanded as [Thea] took the project from breadboard to protoboard to custom PCBs – with anime artwork, to boot. The synth uses a Teensy 3.5 as the brains, speaking USB to enable the synth to receive MIDI commands from music software. All parameters are exposed over the interface, and [Thea] has several videos showing the Genesynth under control from an Ableton Push.
The sound capabilities of the YM2612 are of an entirely different character to most chiptunes, by virtue of the FM synthesis engine. FM synthesis is a little less intuitive then classical additive synthesis, but we still see it crop up now and then.
[Aidan Lawrence] likes classic synthesized video game music in the same way that other people “like” breathing and eating. He spent a good deal of 2017 working on a line of devices based on the Yamaha YM2612 used in the Sega Genesis to get his feet wet in the world of gaming synths, and is now ready to take the wraps off his latest and most refined creation.
The YM2151 Arcade Classic is an open source hardware player for Video Game Music (VGM) files. It uses no emulation, the files are played on the device’s YM2151 chip in the same way they would have been on a real arcade cabinet at the time of their release. Interestingly, as some arcade machines were exceedingly rare or even scrapped before release, [Aidan] believes that his player may be the first time some of these songs have ever been played (at least in public) on real hardware.
The YM2151 synthesizer is powered by a STM32 “Blue Pill” board, which was selected as much for its capabilities as it was its low cost. The STM32 loads the VGM files from an SD card, and puts track information for the currently playing song on the 128×32 OLED display. A few tactile switches under the screen allow for shuffling through the songs stored on the card, and a slide switch for mute rounds out the simplistic but functional user interface.
In the GitHub repository, [Aidan] has provided the source code, schematics, Bill of Materials, and KiCad-generated Gerber files; everything you need to create your own version of his player. After listening to it rock out for a few minutes in the video after the break, we’re tempted to take him up on that offer.