Fomu

by Sutajio Kosagi

An FPGA board that fits inside your USB port

View all updates Dec 18, 2018

The Fomu Campaign is Now Live

With our previous project, Tomu, we wanted to bring tiny ARM computers to the masses. Tomu was designed to be simple for end-users to get started with, and powerful enough for some really interesting projects. With our new project, Fomu, we want to replicate the same ease-of-use, but with a more advanced FPGA board. Until recently, the technology just wasn’t there. Thanks to three key areas, we believe the world is ready to fill their USB ports with FPGAs.

The Right FPGA

First of all, until recently, there wasn’t a compelling FPGA to use. Sometimes, a single component makes an entire project possible. With Tomu, the EFM32HG part enabled the project to be self-contained and keep component count low. Similarly, Fomu simply wouldn’t be what it is without the iCE40UP5K. This part, which only became widely available in 2017, combines a reasonable number of logic cells and a generous amount of RAM, all in a small package size. Without this unique trifecta, Fomu could not exist.

Advanced PCB Fabrication Techniques

Next, there is the simple act of putting everything together. Most PCBs have two layers. With Tomu, one of those layers is entirely taken up by USB pads, which means Tomu is essentially a one-layer board. Fomu has the same USB pads on one side and has to cram even more components onto the same amount of space as Tomu, which means we need to get fancy when fabricating the PCB. The cost and availability of these advanced techniques is only getting better. The end result will be a board that is tiny but mighty.

A Complete Toolchain

Finally, the tooling wasn’t there until recently. Yosys is a fantastic FPGA synthesis tool that will turn Verilog code into a series of LUTs, and Project IceStorm is a great documentation and tool resource for working with iCE40 parts, but there wasn’t a very good tool to go between them. Previous place-and-route projects ignored things like timing, which is critical for stability. With the release of nextpnr, the open source community now has a viable, compelling place-and-route tool that I’m confident will produce stable outputs.

Fomu is an exciting project. It will bring FPGAs to the masses, letting users choose just how far they want to go down the rabbit hole of system design. From using Fomu as a simple MicroPython shell, to developing operating systems, to writing in hardware descriptor languages directly, I’m excited to see what you do with Fomu.


$30,708 raised

of $10,000 goal

307% Funded! Order Below

Product Choices

$5

Buy us a Beer!

Thanks for helping make Fomu a reality! You will be rewarded with good karma and regular backer updates.


$45

Fomu for One

An FPGA for your USB port! Includes one pre-flashed Fomu and a plastic case. The price will increase once the campaign is over, so back us today!


$69

For Me, For You, Fomu

Projects are better with a friend. Or maybe you want to have a spare. Either way, you will receive two pre-flashed Fomu boards with plastic cases. This low price will increase after the campaign finishes!


$249

Fomu Ten-pack

Ten of our pre-flashed Fomu boards with plastic cases, each designed to fit into a single USB Type-A port. Bring FPGA development with you wherever you go, and share your RISC-V projects with up to nine other people.


$1,999

Fomu 100-pack

This is a lot of USB FPGAs. Perfect for a hackfest, conference, large classroom, or for someone with many, many friends. You will receive 100 pre-flashed Fomu boards with plastic cases.


$99

Fomu EVT Board ( + Fomu for One)

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. 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 campaign ends! Backers who select "Fomu EVT Board" will also receive one Fomu production board when they ship by 2019-06-30.

Credits

Sutajio Kosagi

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


Sean Cross

Tim Ansell

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