The Genesis Engine is a hardware sound board built around real Yamaha YM2612 FM/DAC and SN76489 PSG chips, plus a full software ecosystem that lets you:

• play VGM/VGZ files from flash, SD, or a PC
• drive the board from a Genesis / Mega Drive emulator (BlastEm) in real time
• use it as a MIDI-controlled FM/PSG synth with a dedicated desktop editor
• script and experiment at the register level if you want to go deep

The YM2612 + SN76489 combo covers Sega Genesis / Mega Drive, and the SN76489 alone covers Master System, Game Gear, ColecoVision, IBM PCjr, Tandy 1000, etc. That makes this board useful well beyond a single console’s music.

What the main library does (GenesisEngine)

Repo: https://github.com/aarontodd82/GenesisEngine

The Arduino/Teensy/ESP32 library provides these example workflows:

• BasicPlayback
  VGM playback from flash (PROGMEM). Minimal setup example.

• SDCardPlayer
  SD card player with a serial menu for browsing, playing & playlists; ideal for large VGM/VGZ libraries.

• SerialStreaming
  Stream VGM data from a PC to the board in real time over USB serial.

• EmulatorBridge
  Real-time audio from Genesis emulators (BlastEm), sending register writes to the hardware.

• SimpleSynth
  Direct chip-control demo using the synthesis utilities (FM/PSG frequency helpers, default patches, etc.).

• MIDISynth
  Full MIDI synth with voice allocation and patch management, showing the board as a proper hardware FM/PSG synth.

Emulator bridge (BlastEm fork)

(See video below)

Repo: https://github.com/aarontodd82/blastem-genesis-engine

This is a modified build of BlastEm that streams real-time YM2612 and SN76489 register writes to the Genesis Engine over serial using VGM-style timing.

• BlastEm keeps its cycle-accurate emulation, but instead of mixing audio internally, it sends writes out.
• The microcontroller + Genesis Engine board receive those writes (e.g., at 1 Mbaud) and apply them to the real chips.

Result: you play a game in BlastEm, and you hear it through actual YM2612 + SN76489 hardware on your bench.

Desktop Synth App & Patch Editor

Repo: https://github.com/aarontodd82/GenesisEngineSynthApp

The Genesis Engine Synth App is the companion desktop app for the MIDISynth firmware:

• Creates a “Genesis Engine” virtual MIDI port for DAWs (macOS/Linux native; loopMIDI on Windows).
• MIDI-to-Serial bridge for Arduino/Teensy boards that don’t show up as native USB MIDI.
• FM patch editor for the YM2612 with visual envelopes, algorithm view, and interactive widgets.
• PSG envelope editor for SN76489 volume shapes.
• Patch management: 16 FM slots, 8 PSG slots, save/load banks.
• Supports TFI/DMP/OPN patch formats.
• Live Edit mode: edits are sent to hardware in real time while you play.

This setup basically turns the board + MCU into a usable FM/PSG hardware synth you can design sounds for from a DAW.

Raspberry Pi support

In addition to MCU targets, there’s a Raspberry Pi driver and examples (separate repo) that let you:

• run the board as a Pi-based VGM player
• script it from Python
• use it as a network/bridge target in more complex setups

Repo: https://github.com/aarontodd82/genesis-engine-pi

Hardware details

On the hardware side, the board is designed to be easy to drive but still accurate:

• Bus interface
• Uses an SPI-driven shift-register approach (CD74HCT164E) so you only need 7 pins.

• Works with 3.3 V and 5 V logic, which covers Teensy, ESP32, and AVR boards without extra level shifting.

• Clocks

• Crystal/oscillator values chosen so the YM2612 and SN76489 play accurately and at correct pitch relationships, matching original hardware expectations.

• Analog output

• Stereo output with a better op-amp stage (TLV2462CP) for low noise and proper L/R separation.

• KiCad

• Full KiCad schematics and PCB are in the hardware/ directory of the main repo if you want to study or modify the design.

Open source

Everything is open:

• Board design (KiCad)
• Firmware and Arduino/Teensy/ESP32 library
• Emulator bridge fork of BlastEm
• Desktop Synth App

Main library: https://github.com/aarontodd82/GenesisEngine
BlastEm hardware bridge: https://github.com/aarontodd82/blastem-genesis-engine
Synth app: https://github.com/aarontodd82/GenesisEngineSynthApp Raspberry Pi library: https://github.com/aarontodd82/genesis-engine-pi