Enabling Linux software and firmware developers to build RISC-V PCs for the first time

Microsemi Corporation has announced the launch of the HiFive Unleashed Expansion Board, its latest collaboration with SiFive, the first fabless provider of customised, open-source-enabled semiconductors.

Leveraging the two companies’ strategic relationship as part of Microsemi‘s Mi-V(TM) RISC-V ecosystem, the new expansion board broadens the capabilities of SiFive’s HiFive Unleashed RISC-V development board, further enabling software and firmware engineers to write Linux-based applications targeting a 1GhZ+ RISC-V 64 bit central processing unit (CPU).



Microsemi‘s HiFive Unleashed Expansion Board allows developers to implement custom peripherals in the award-winning PolarFire field programmable gate array (FPGA).

Plugged into HiFive Unleashed developers can implement a full-fledged RISC-V personal computer (PC) by enabling standard PCI Express (PCIe) devices, USB and secure digital cards to connect to SiFive’s Freedom U540 RISC-V processor.

“Working together with SiFive to accelerate the growth of the RISC-V instruction set architecture (ISA) and our Mi-V ecosystem, the HiFive Unleashed Expansion Board and HiFive Unleashed development board give the broader Linux market an extremely robust platform for RISC-V development,” said Ted Speers, head of Product Planning for Microsemi’s Programmable business unit. “Our cost-optimized, lowest power, mid-range PolarFire FPGAs are an ideal solution for embedded development engineers to implement custom peripherals.”

The HiFive Unleashed Expansion Board and HiFive Unleashed allow designers to develop complete Linux applications on a modern RISC-V CPU running at 1 GHz+.

This makes the devices ideally suited for a variety of embedded applications within the communications, industrial, defence, medical and avionics markets, including control plane solutions, imaging/video processing, machine learning, control processing, time-sensitive networking, encryption and root of trust, secure wireless communications and aircraft networking.

“Microsemi has long been a strategic collaborator for SiFive, and its HiFive Unleashed Expansion Board will enable the RISC-V Community to continue to advance the cause of open source hardware,” said Yunsup Lee, co-founder and chief technology officer, SiFive. “With its HiFive Unleashed Expansion Board, Microsemi is enabling the next wave of RISC-V innovation. We look forward to our continued collaboration, and can’t wait to see what products come to market based on our technologies.”

The HiFive Unleashed Expansion Board offers numerous additional features, including a PCIe root complex, serial advanced technology attachment (SATA) port, M.2 SSD port, two USB ports, HDMI, double data rate fourth-generation (DDR4) memory expansion, an embedded multi-media controller (eMMC) managed NAND Flash and secure digital card slot.

“The RISC-V Foundation applauds the work Microsemi and SiFive have done in collaboration to deliver a comprehensive Linux software development platform for RISC-V,” said Rick O’Connor, executive director of the non-profit RISC-V Foundation. “Numerous commercial and open source developers are adopting RISC-V for Linux-based designs. Particularly in the embedded market, where a growing majority of today’s designs run Linux, this Microsemi/SiFive RISC-V solution offers a compelling development environment.”

RISC-V is a free and open ISA enabling a new era of processor innovation through open standard collaboration.

As the ISA is frozen, software which is written will always run on the RISC-V core, and since the RISC-V IP core is not encrypted, it can be used to ensure trust and certifications not possible with closed architectures.