SiFive’s Freedom Everywhere 310 SoC based on open RISC-V architecture

BY MAJEED AHMAD

The first system-on-chip (SoC) based on RISC-V — the open and free instruction set architecture (ISA) spearheaded by the RISC-V Foundation — is finally here and it's accompanied with a $59 Arduino board that allows designers to play with and modify the microcontroller chip according to their specific project needs.

The Freedom Everywhere 310 SoC, or FE310, is the first commercial realization of SiFive's Freedom Everywhere family of customizable chips. It's a 32-bit RISC-V microcontroller that is aimed at enabling embedded, Internet of Things (IoT) and wearable applications. The chip has been built on TSMC's 180-nm process.

FE310 runs at 320-MHz speed and offers 1.61 DMIPS/MHz of raw performance as compared to 1.3 DMIPS/MHz for Intel Curie and 0.93 DMIPS/MHz for Atmel AVR chips. Likewise, regarding energy efficiency, the chip claims to accomplish 10 DMIPS/mW with 180ULL process and 75 DMIPS/mW using 65LP process.

The microcontroller chip comes with 16 Kbytes of data SRAM scratchpad and 16 Kbytes of L1 instruction cache. It also features flexible clock generation with on-chip oscillators and PLLs and comes with a wide array of peripherals such as UARTs, QSPI, PWMs, and timers.

SiFive has also made available the RTL code of the FE310 chip; it will allow system architects and embedded designers to see what's inside the chip. Consequently, they can customize their own chips on top of the basic FE310 design. However, for smaller firms without chip design capability, SiFive has the chip-as-a-service offerings that encompass design, software tools, production, and testing of a chip.

The FE310 chip comes along with an Arduino-compatible HiFive1 development board, so designers can figure out what they need in their version of the FE310 chip and develop software for it accordingly. The board boasts 19 digital IO pins, nine PWM pins, one SPI controller, and a 128-Mbyte external flash.

The $59 HiFive1 Arduino board will be available on Crowd Supply in February 2017. It's worth noting that the FE310 chip isn't offered separately; currently, it's only available on the HiFive1 board.

The HiFive1 supports Arduino IDE and is mainly targeted at makers and hackers seeking to acquire custom silicon solutions. SiFive claims that its development board is significantly faster than Intel's Curie-based Arduino 101 and ARM Cortex M0+ powered Arduino Zero.