The Return of the RISC-V HiFive1

Alasdair Allan
3 min readMar 16, 2019


Since the Bay Area startup SiFive announced the release of their Freedom Everywhere 310 (FE310) system-on-chip (SoC) — the industry’s first commercially-available SoC based on the open source architecture—back in 2016, the RISC-V architecture has undergone what can only be called a renaissance. After nearly a decade of neglect, the last two years has seen a big uptick in the adoption of the the RISC-V standard.

The release of the first Arduino-compatible development board, called the HiFive1, was seen as a real milestone by the open hardware community and now SiFive is back with the HiFive1 Rev B, now raising on Crowd Supply.

The HiFive1 Rev B. (📷: SiFive)

The board is based on SiFive’s new FE310-G002, an upgraded version of the original FE310 SoC. Like the original FE310, the newer chip is built around SiFive’s E31 32-bit RV32IMAC core running at 320MHz, but adds support for the latest RISC-V Debug Spec, hardware I2C, and an additional UART over the original chip.

However, the biggest obvious difference between the original HiFive1 board and the new Rev B is that unlike the older board, which operated at 1.8V, the new board supports 3.3V I/O on the GPIO pins only so that the pins can be driven directly from the F310.

The ESP32 serves as “a wireless modem” for the FE310-G002 processor. (📷: SiFive)

Wi-Fi and Bluetooth on the board is provided by an Espressif ESP32 module, which while now a fairly common move by manufacturers, is more than somewhat over-specified for the job. This leaves me surprised that a cheaper, albeit less powerful, ESP8266-based module wasn’t used instead if they’re the board really only uses it as “…a wireless modem.” Although the description of the module as a “co-processor” does keep the possibility open that it ESP32 might be accessible from code for more than wireless support?

The HiFive1 Rev B is now raising on Crowd Supply. (📹: SiFive)

The new HiFive1 Rev B is currently on Crowd Supply. A single HiFive1 Rev B board costs $49, with free U.S. shipping, or an additional $12 for worldwide shipping. Although if you’re more interested in getting your hands on the new FE310–G002 SoC, a five pack of chips can be picked up for just $25 with free U.S. shipping, or another $10 for worldwide shipping. Orders placed now will be out for delivery towards the middle of April.