Share this project


Share this project

RetroCade Synth - One ChipTune board to rule them all!'s video poster

This revolutionary FPGA synth provides chiptune faves (C64 SID/YM2149) in one Arduino compatible, musician and hacker friendly board. Read more

Denver, CO Sound
Share this project
pledged of $6,000 goal
seconds to go


This project was successfully funded on July 4, 2012.

This revolutionary FPGA synth provides chiptune faves (C64 SID/YM2149) in one Arduino compatible, musician and hacker friendly board.

Denver, CO Sound
Share this project

About this project

Welcome to the R-R-R-R-RetroCade Synth from Gadget Factory.  This exciting new hardware synthesizer is built on Gadget Factory's own Papilio platform, and is designed with both hardware hackers and musicians in mind.  Musicians will love the ease of use and extreme retro glitchiness that the Retrocade has to offer. Hackers will love that it is open-source, and is designed to be HACKED.  Either way, you're in luck.  You will find no better, more flexible synthesizer at this price point anywhere else!

The RetroCade Synth boasts the capability to play the built-in Commodore 64 SID chip, the Yamaha YM-2149 chip, .mod files, and MIDI files - all at the same time! The RetroCade Synth can be played via any external MIDI control interface or via your favorite audio/ sequencing software. We have built a custom VST software dashboard which gives you visual control over all the various parameters the synth has to offer, and it is included at all hardware tiers here on Kickstarter.

So sit back, watch the videos, get amped up, and show your support for open-source projects! We thank you for taking the time to check us out!

Click here to watch the intro video in FULL HD!

What's Included

The RetroCade Synth is a combination of the Papilio FPGA board, the RetroCade MegaWing, and a control dashboard that runs on a computer*.

Papilio FPGA (Click to learn more)

  • Xilinx Spartan FPGA (Spartan 3E 500K or Spartan 6 LX9)
  • High Speed USB port for programming and communication
  • ZPUino Soft Processor
  • YM2149
  • MOS 6581 (I.E. C64 SID)

RetroCade MegaWing (Click for hi-res image)

  • 2 – ¼” Stereo Audio Jacks with 18 bit Delta Sigma DAC
  • MIDI – In, Out, Through
  • uSD Card for MOD, MIDI, YM, SID, and config files
  • MicroJoystick – 4 directions, Select
  • 2x16 LCD Display
  • 16 Analog inputs for sliders and knobs
  • 16 Digital inputs for switches and peripherals

Control Dashboard (Click for hi-res image)

  • Control all of the features of the audio chips from a computer.
  • Made with SynthMaker for easy customization
  • VST plugin or standalone executable

*NOTE: The RetroCade hardware does not require the Control Dashboard or a computer. All features of the RetroCade Synth are hardware based and only require the Papilio and RetroCade MegaWing combo.


Reaching our requested funding level of $6K will allow:

  • 50% - Manufacturing and delivery of everything in "What's Included".
  • 30% - Prototyping and testing of RetroCade MegaWing.
  • 15% - Creating documentation and a website.
  •   5% - Finding and squashing of bugs in the firmware and dashboard.

OVERFUNDING BONUS: Any overfunding of the project will be applied to a salary that will allow me to continue working full time as an Open Source developer. After delivery of the features in the "What's Included" section I will work on the following bonus features:

  • Adding as many chips as I can find Open Source VHDL implementations for. The ones I know of are; NES, Atari 2600, GameBoy, POKEY, sn76489.
  • Adding a library of digital effects that can be applied to any chip. For example the library will have the ADSR envelope from the SID that can be used with the POKEY or YM2149. Digital effects to implement; low pass filter, LFO, portamento, legato, and as many more as I can find or create.
  • Recreate the analog filters of the SID chip with digital techniques.
  • Add modern FPGA synths like the SK-Synth and the GateMan Poly Synth.

*NOTE: I would expect these bonus features to take around six months to complete, after the hardware is delivered.

Technical Details

If you are dying to learn more technical details then watch this video or check out the PDF.

Technical Details in PDF format.

ZPUino Soft Processor
ZPUino Soft Processor

At the heart of the RetroCade Synth is the ZPUino Soft Processor. The ZPUino allows the classic audio chips to be controlled by simple, easy to hack Arduino compatible sketches. RetroCade users can make quick changes to the ZPUino sketch in order to modify Control Changes, load YM or MOD files, or change how the RetroCade works! To learn more about the ZPUino visit the ZPUino home page.


The RetroCade Synth is an Open Source project that was built on top of the work of many other Open Source developers. This project would not be possible without their contributions and in some cases, direct support and help. The old saying about standing on the shoulders of giants is very applicable here. So it is important to take some time and give attribution and thanks to those giants:

  • First on the list is Alvaro Lopes, the man who made the ZPUino Soft Processor. The ZPUino is the heart of the RetroCade Synth and it was his act of adding support for the SID and YM chips that sparked the initial idea for the RetroCade. He has provided direct help and support every step of the way and without his influence there would be no RetroCade Synth. Alvaro has played a VERY big role in the development of the RetroCade Synth. All of the MOD functionality was implemented by Alvaro by turning the opensource PTplay project into a library that can run on the ZPUino.
  • Next is, who made the YM2149 VHDL file that makes it possible for the YM2149 to exist inside the Papilio FPGA. He has some really cool new hardware coming out soon so check out his website.
  • Finally is Jan Derogee, who made the C64 SID VHDL file. Jan was inspired by an interview with Robert Yannes, the original creator of the SID chip. In the interview Robert gave deep technical information about how the digital logic was implemented. Jan then recreated an Open Source version of the digital logic in VHDL. He even placed quotes from the interview in the source code for each section, which makes the source code a very educational read. Jan has asked that we only mention his name, and give the majority of the credit to Robert Yannes.


  • Greg Hopper aka Hoppasaurus - Special thanks for writing original music for the demo, spending countless hours helping to debug the hardware, providing pro audio support, and playing a live performance for the video. I couldn't have done it without all your support and endless supply of cup of noodles.
  • PulkoMandy - Special thanks for letting us use a portion of your song, Renegade Remix, as a backing track in the demo.


  • No.

    The RetroCade Synth is a hardware project that does not need a computer or touchscreen. The touchscreen was used to demonstrate what can be done with the Dashboard. The touchscreen is just using remote control software to control the Dashboard running on a computer.

    Last updated:
  • Control from the computer is done as Control Change's over the MIDI interface. For the demo I used a USB to MIDI dongle to accomplish that. But for the final release I will be working on a method that will send MIDI data over the Papilio's USB port so no MIDI dongle will be required.

    Additionally, since all the MIDI functionality is defined in the Arduino sketch running on the ZPUino it is very easy for people to hack in any behavior they desire. It's easy to link functionality to an analog slider, a serial message, a light sensor, or anything you can dream up!

    Last updated:
  • All levels are for assembled circuit boards, I just started thinking about making an enclosure. If I can work something out in the next couple weeks I'll add new levels that people can upgrade to.

    Last updated:
  • No, all of the digital logic was recreated, by Jan Derogee, from an interview with Robert Yannes. To recreate the analog filters we will need to use DSP techniques inside the FPGA. With enough funding this is on the list of things we will be working on, and of course, its Open Source so anyone is welcome to jump in and work on it too.

    Last updated:
  • The prototype level does not specify it very well. :) Sorry about that!

    Ok, so the prototype level will get everything from the Sponsor level:
    - Name on the sponsor list on the website and in the source code package.
    - RetroCade MegaWing
    - Papilio Plus LX9
    - Arcade MegaWing

    Plus, any prototypes I make I will be sending out an assembled version to the prototype backers as early as possible. So as soon as the RetroCade MegaWing arrives from the PCB manufacturer I will do my best to assemble prototype boards within a week and have them shipped out. I'm probably going to be making a new revision of the Arcade MegaWing as well and I would send out protoypes of that board too.

    I expect that the RetroCade MegaWing will be ready before the Papilio Plus boards are ready so I plan on shipping out a Papilio One along with the RetroCade MegaWing. Finally, backers at the prototype level will also receive a final production copy of everything as well.


    Last updated:
  • The VST plugin is made with an application called "SynthMaker" which is unfortunately Windows PC only. But I am building everything so that it is only sending MIDI commands, the hardware does everything in response to MIDI CC's. So we are not stuck with SynthMaker, it will just be the reference app.

    I do intent to release a MIDI implementation chart so people can setup their own MIDI controllers. In the demo we have the MIDI keyboard setup so all the knobs and sliders directly control the RetroCade parameters.

    I very much want to see other control dashboards setup with apps like MIDI Touch , DSMI, and TouchDAW. If I don't personally make them then hopefully someone in the community will. :)

    Additionally, I'm adding an expansion port to the design. So it will be possible to add a low cost WIFI module that I'm designing to the RetroCade so tablets and DS control apps can bypass the need for a PC and directly control the RetroCade. That should be pretty darn cool. :)

    Last updated:


  • You selected
    Pledge $5 or more

    6 backers

    Become a backer and get access to all project updates and messages!

    Estimated delivery:
  • You selected
    Pledge $40 or more

    10 backers

    RetroCade MegaWing - For those who already have a Papilio FPGA board.
    (Add $5 for International Shipping)

    Estimated delivery:
  • You selected
    Pledge $100 or more

    15 backers

    RetroCade MegaWing + Papilio One 500K
    This combo can do everything currently planned for the RetroCade project.
    (Add $5 for International Shipping)

    Estimated delivery:
  • You selected
    Pledge $130 or more

    3 backers

    RetroCade MegaWing + Papilio One 500K + Arcade MegaWing. When you are done playing sweet music with the RetroCade MegaWing swap in the Arcade MegaWing and play sweet video games! Check out for more info.
    (Add $5 for International Shipping)

    Estimated delivery:
  • You selected
    Pledge $150 or more

    24 backers

    RetroCade MegaWing + Papilio Plus LX9
    The Papilio Plus is an advanced Papilio board with 4Mb of SRAM and a Spartan 6 LX9. This option will make you future proof for any kind of new feature we dream up.
    (Add $5 for International Shipping)

    Estimated delivery:
  • You selected
    Pledge $180 or more

    23 backers

    RetroCade MegaWing + Papilio Plus LX9 + Arcade MegaWing. When you are done playing sweet music with the RetroCade MegaWing swap in the Arcade MegaWing and play sweet video games! Check out for more info.
    (Add $5 for International Shipping)

    Estimated delivery:
  • You selected
    Pledge $250 or more

    1 backer

    Sponsor - Like the Retrocade so much that you want to pay a little more to support the project and see all those extra features implemented? Sponsors get RetroCade MegaWing + Papilio Plus LX9 + Arcade MegaWing + their name on the final RetroCade website under a sponsors section!

    Estimated delivery:
  • You selected
    Pledge $350 or more

    6 backers Limited (4 left of 10)

    Prototyper - Get prototypes sent to you as soon as I get them! Get access to all the latest development files, access to any private Retrocade chat rooms, and most importantly - prototype hardware before anyone else!

    Estimated delivery:

Funding period

- (30 days)