Sebastian Holzapfel's Tiliqua Puts a Little Lattice FPGA in Your Eurorack Synth Setup
With eight audio channels as standard, expandable to 24, MIDI, and USB connectivity, the Tiliqua targets flexibility.
UPDATE (5/6/2025): The Tiliqua, designed to put a field-programmable gate array (FPGA) into any Eurorack synthesizer setup, has now launched on Crowd Supply with hardware priced at $299 with free US shipping.
Rewards for the crowdfunding campaign include the Tiliqua itself at $299, an optional 4" 720×720 circular display at $199, an audio expansion board at $89, and additional SoldierCrab FPGA systems-on-modules (SOMs) for use in self-built Tiliqua boards or other projects at $89.
The campaign is live on Crowd Supply; all hardware is expected to ship in late November this year.
Original article continues below.
Sebastian Holzapfel, of German open source audio hardware specialist apfelaudio, wants to put a little FPGA in your Eurorack synthesizer setup — literally, with the Tiliqua module.
"Tiliqua aims to make FPGA-based audio and video synthesis accessible to everyone," Holzapfel explains of his creation. "The Tiliqua hardware architecture, alongside a comprehensive collection of example projects built in Python (Amaranth HDL [Hardware Description Language]), allows you to experiment with synthesis techniques that are out of reach of embedded microcontroller-based platforms. Think extreme oversampling for alias-free audio-rate modulation, low-latency effects, video synthesis, and high-speed USB audio."
The Tiliqua itself, designed to slot straight in to a Eurorack setup, is based on an open-hardware FPGA module dubbed the soldiercrab and built around the Lattice ECP5 field-programmable gate array chip, with 25k logic elements, 16MB of HyperRAM/octal-SPI RAM, 16MB of SPI flash, and a high-speed USB PHY. This connects to a motherboard that offers a switched rotary encoder with bar-graph display, the FPGA's USB port and a debug port handled by a Raspberry Pi RP2040 microcontroller, two expansion ports, a 720p60 display output, and a MIDI input jack.
A third board, the audio interface, completes the Tiliqua's design, delivering four input and four output DC-coupled audio channels supporting up to 24-bit audio at 192kHz sampling rates. For compositions that don't need that many channels, any input or output can double as a touch or proximity sensor input, while each channel has user-programmable red/green LEDs with pulse-width modulation (PWM) support.
"Tiliqua can store up to 8 projects (bitstreams) simultaneously — you can switch between them at runtime without needing a PC," Holzapfel notes of the FPGA's flexibility. "Out of the box, Tiliqua can be: a video synthesizer (vectorscope display with audio-rate beam modulation); a multichannel wavetable oscillator (1MHz oversampling for audio-rate FM [Frequency Modulation]); a high-speed 4 in/4 out USB 2.0 audio interface; a polyphonic MIDI/touch synthesizer; a multichannel diffusion delay; a multichannel pitch shifter; a MIDI/CV converter; [and] a matrix mixer."
Design files for the project have been published on GitHub under the Strongly Reciprocal variant of the CERN Open Hardware License Version 2; Holzapfel is preparing to launch a crowdfunding campaign for the Tiliqua on Crowd Supply soon.
