Complete
MegaGRRL Desktop boards are now available for purchase from
Denjhang's Retro Hardware on Tindie.
These are not produced by me, but Denjhang has my permission to sell these.
Please note several MegaMods are also available for sale, but only OPNA and OPL3 mods were designed by kunoichi labs and have official support.
No cartridges needed, just an SD card.
MegaGRRL Desktop plays
VGM files — sample-accurate logs of music from games. A dedicated community of chiptune enthusiasts has ripped the music from nearly every Genesis game ever made, and the VGM files they've created can simply be copied to the SD card. An 8GB card can store the entire
Project 2612 library, with room to spare.
No file size limits or timing glitches.
MegaGRRL Desktop runs a VGM playback engine focused on accuracy and compatibility on its powerful dual-core 240MHz ESP32 microcontroller. Some other projects load music data into fixed memory buffers or external RAM/flash which can limit maximum file size. In contrast, the MegaGRRL playback engine continuously streams data from the SD card, allowing even the largest VGMs to be played accurately and without slowdown. The most commonly-used parts of the VGM file format's DAC Stream specification are also supported, allowing homebrew music exported from trackers such as Deflemask to be played.
MegaGRRL Desktop also supports easy swapping between YM2612 and YM3438 sound chips. While these chips are functionally identical, differences in their output stages impart a unique character to the sound. Some people enjoy the classic grittiness of the YM2612 in the Model 1 Sega Genesis, while others prefer the cleaner sound of the YM3438 in the Model 2. Simply replace the chip and flip a few DIP switches — no soldering or hardware mods required.
Eleven LEDs show the status of all sound chip channels, providing fun eye candy during playback. If you're an FM synth nerd, you can independently mute channels to deconstruct the track and hear how it's made. An audio mixing control allows the balance between FM and DCSG to be fine-tuned.
The original portable MegaGRRL design is almost 100% surface-mount, which can be difficult for beginners to solder.
MegaGRRL Desktop uses through-hole parts wherever possible to make assembly much easier. The design uses common components which can be found at most electronic parts distributors.
We're passionate about this stuff and believe in giving back to the community. That's why
MegaGRRL Desktop is an open source project. Source code can be obtained from the original
MegaGRRL repo, and the schematic and PCB files for the desktop version can be found in the
MegaGRRL Desktop repo.
Nutrition Facts
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MCU
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Espressif ESP32, dual-core 240MHz
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Sound Chips
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Yamaha YM2612 or YM3438, TI SN76489AN
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Audio Output
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3.5mm headphone/line output, with volume control
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Storage
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SD card (or MicroSD with adapter), up to 64GB SDXC tested
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Supported Formats
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VGM or VGZ files using YM2612 or SN76489 chips, any clock rate
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Display
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2.8" 240x320 color LCD
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Controls
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4-way D-pad, 3 softkeys, power switch, volume control
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Indicators
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11 sound chip channel status LEDs, 3 user-assignable LEDs
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Power
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9~12VDC 500mA (center positive 2.1mm barrel jack)
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Allergen Information:Manufactured in a facility that processes integrated circuits.
Contains no emulators.
MegaGRRL Desktop is not a MIDI instrument — its specialty is VGM playback only. We're looking into adding MIDI synth capability to future projects, but at this time, MegaGRRL Desktop is a VGM playback-only machine.