An Open Hardware Eurorack Compatible Audio FPGA Front End

An Open Hardware Eurorack Compatible Audio FPGA Front End

[Sebastian Holzapfel] has developed an audio frontend (eurorack-pmod) for FPGA-centered audio purposes, which is created to suit into a standard Eurorack enclosure. The venture, launched underneath CERN Open-Hardware License V2, is designed in KiCAD utilizing the AK4619VN four-channel audio codec by Asahi Kasei microdevices. (and guess what people, there is a good deal of those in stock!)

A basic architecture to get your FPGA conversing to the audio planet

The AK4619 is an audio frontend device, meant for computerized head device apps, and incorporates four audio ADCs and four DACs. These enable the eurorack-pmod to take care of four incoming and four outgoing channels at the very same time. With an I2S or PCM interface, which is hooked up to a PMOD connector on the rear, an exterior FPGA board of your preference can be related, of which there is quite some option. [Sebastian] supplies some instance code focused at the iCEBreaker FPGA board which can all be handled by the Yosys toolchain. This deals with the particulars of the AK4619 codec, as properly as a board-stage calibration, to enable the consumer to focus on the software code. That could possibly be a pure synthesizer, some kind of DSP audio effect, or some thing in amongst. The Verilog code itself is very easy, so should be effortlessly transportable to any other FPGA board the person has entry to.

Some code for illustration cores is provided, with a VCO, programmable filter, hold off/decimator, and a number of other goodies, so a lot of illustrations to begin with for your to start with FPGA synth project! For finding out and simulation functions [Sebastian] has furnished the needed setups to drive the VCV Rack audio simulator, as perfectly as a handy guidebook for jogging Verilog simulation inside VCV.

FPGA audio synthesis is almost nothing new all over right here, but new projects in this room are often thrilling. As for earlier will work, here’s a person based on an outdated Xilinx Spartan 6 board, and yet another for the more recent Zynq.