by Sutajio Kosagi

An FPGA board that fits inside your USB port

View all updates Aug 07, 2019

First Batch Shipping from Factory

The first batch of Fomus have begun to make their way to Crowd Supply in Portland. Once they get there, Crowd Supply can begin sending out Fomu boards to each of the backers. We’re still waiting on the next batch, which we expect to be complete in late August, but we’re happy that the first few hundred units have started their journey to you. Please check your shipping address in your Crowd Supply account and update if necessary.

We were all set to ship two weeks ago, but we discovered a problem that is the bane of any FPGA or silicon project: clock domain crossing issues. Silicon manufacture isn’t as uniform a process as you’d think, and the timing guarantees you get are only valid within a single clock domain. We tracked down the source of the instability, added a two-stage flip-flop, and generated 200 different bitstreams to test on multiple machines. I put together a short blog post going into a little more detail on the issues. With the fixed bitstream, we had a 100% pass rate, and so we re-tested all the Fomu units in the factory and have shipped them to Crowd Supply.

We’re still working on building the next batch of units, and while we’re working on that, we’re improving the Fomu firmware. We’ll send an update once we have more information!


Fomu will be at CCCamp 2019! We’re tentatively scheduled to have a workshop on 21 August at 17:00 +0200 CEST in the "Curie" tent. Come say hello and get introduced to Fomu.

As always, thanks you for your support!

$67,541 raised

of $10,000 goal

675% Funded! Order Below

Product Choices



An FPGA for your USB port! Includes one pre-flashed Fomu and a plastic case.


Fomu EVT Board

An EVT board revision is used to validate the schematic is correct, and to help develop the software. This EVT board is what we'll use to develop the USB stack and to make sure we've got the power and other hardware parts wired up right. Designed to mount onto a Raspberry Pi to upload a bitstream and debug the CPU.This is a limited-time production board, and won't be produced after the few remaining sell.


Sutajio Kosagi

Sutajio Ko-usagi supports and produces open hardware products designed by bunnie and xobs.

Sean Cross

Tim Ansell

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