HiFive Unleashed Expansion boards?

As luck would have it my favourite laptop died yesterday (Bamboo case). Motherboard is bricked after many years of faithful service. I’ve said previously that the HiFive unleashed would make a pretty good laptop with it’s quad core 64bit Arch and clock frequency. So it would be brilliant to have a HiFive Unleashed based laptop, (it’d certainly fit in the case) but there’s no interface to some of the essential peripherals, screen, USB, Keyboard, touchpad.

I guess given how open the project is I could start creating my own expansion boards but is there any coming from official channels? Or are community members working on any such peripheral interfaces?

Perhaps that’s a stupid idea but if nothing else, (given my starting place) I’d learn a lot even getting the board talking to a USB EHCI. Actually as I think the first run has sold it’s a fairly stupid idea. :wink:

If you look in the https://github.com/sifive/freedom repository, you will see a target called u500vc707iofpga. If you synthesis that onto a VC707 FPGA board you can use PCIe with the Aloe board. There is also a pre-configured expansion boards coming from Microsemi in the near future. However, if you want to roll your own board, you can start today working from that public FPGA image.

Thanks a million for that feedback. I’m never going to have the funds for a VC707, I wish :wink: But that is excellent that expansion boards are coming. I’d love to roll my own and hope that at some point in time another production run of the unleashed boards is done, and I’ll be able to get one.

This board is now available (just 15 of them):

The docs say it requires Windows to run PolarFire, which is used to flash the FPGA.


From their PDF doc:


“A Gold license is required to reprogram the Microsemi HiFive Unleashed
expansion kit. The same procedure used for licensing the PolarFire evaluation
kit can be used for this kit. A software ID letter enclosed with the kit contains
the software ID and instructions on how to generate a Libero Gold license.”

You can use FPExpress to program the board from linux.

Cool, thanks. FlashPro Express:


Unfortunately it isn’t free software either, but it lists RHEL and CentOS as supported.



We’ve been using it also from Ubuntu. I think you’ll have a hard time finding an open-source FPGA synthesis tool that works on most modern FPGAs. Until there’s an FPGA vendor that considers an open-source toolchain a benefit, the best we’ll get are tools built from reverse engineering commercial FPGAs.

Project IceStorm is probably furthest along, but can’t program anything that is powerful enough to run Linux.


Every time I meet/talk with Xilinx I push for them to open up more…



That tool supports an FPGA with 8k LUTs and 206 IOs. I’ll wager you could fit a linux-capable risc-v core + simple DDR controller with some work.

There’s this, from the same person who does the icestorm work.