Tag Archives: SiFive

HiFive Unleashed – The First RISC-V-based Linux development board

RISC-V is an open specification of an Instruction Set Architecture (ISA). That is, it describes the way in which software talks to an underlying processor – just like the x86 ISA for Intel/AMD processors and the ARM ISA for ARM processors. Unlike those, however, the RISC-V ISA is open so that anyone can build a processor that supports it. Just as Linux revolutionize the software world, RISC-V could create a substantial impact on the hardware world. This open-source chip project is might just go out to break the dominance of proprietary chips offered by Intel, AMD, and ARM.

hifive-unleashed-board
Hi-Five Unleashed-board

Silicon Valley-based company SiFive has released the world first RISC-V based Linux development board called Hi-Five Unleashed. SiFive which has previously released the HiFive1, a RISC-V-based, Open-Source, Arduino-Compatible Development Kit. The HiFive Unleashed is powerful enough to run Linux distributions.

HiFive Unleased Block Diagram

Hi-Five Unleashed was designed around the RISC-V based, quad-core, 1.5GHz U540 SoC (Freedom U540). The Freedom U540 is the first multi-core SoC featuring the open source RISC-V ISA with 4x 1.5GHz “U54” cores and a management core, fabricated with TSMC’s 28nm HPC process, and also the first to offer cache coherence. The U54-MC Core’s high-performance and flexible memory system make it ideal for applications such as AI, machine learning, networking, gateways, and smart IoT devices. It has no GPUs or other coprocessors, but the open source hardware design is intended to encourage third parties to collaborate to develop one.

The Hi-Five Unleashed is a minimalist board that uses one Freedom U540 paired with 8GB DDR4 ECC RAM, as well as 32MB Quad SPI Flash, a microSD card slot for external storage, a Gigabit Ethernet port, and an FMC connector for future expansion cards. The development board is still barebone for now and mostly intended for developers and not the general public; it lacks hobbyist helpful resources like a video output and USB support, none of those are available on the board.

The following are some of the HiFive Unleashed specifications:

  • SoC – SiFive Freedom U540 with 4x U54 RV64GC application cores @ up to 1.5GHz with Sv39 virtual memory support
    • 1x E51 RV64IMAC Management Core
    • 2 MB L2 cache
    • 28 nm TSMC process
  • System Memory – 8GB DDR4 with ECC
  • Storage –  32MB Quad SPI Flash from ISSI
    • MicroSD card for removable storage
  • Connectivity – Gigabit Ethernet port
  • Debugging – Micro USB port connector to FTDI chip
  • Expansion – FMC Connector for future add-in cards
  • Misc – On-off switch, various configuration jumpers
  • Power Supply – 12V DC input

The board is currently available for order at Crowd Supply for $999 and is expected to ship on June 30th. An earlier access board goes for $1250, which will ship on March 31st. RISC-V has grown from an academic project which first started in 2006 at UC Berkely, and now to a welcome, acceptable alternative to existing ISA and a potential game-changer in the long run.

In the future, we are not only going to build powerful open source based system but also understand their internal working and avoid something like the Spectre and Meltdown bugs that affected the likes of Intel processor.

Cinque, Combining RISC-V With Arduino

After announcing “HiFive1” at the end of 2016, SiFive is introducing its second RISC-V based development board “The Arduino Cinque“. It is the first Arduino board that is featuring RISC-V instruction set architecture.

Arduino Cinque is running SiFive’s Freedom E310, one of the fastest and powerful microcontrollers in the hardware market. It also includes built-in Wi-Fi and Bluetooth capabilities by using the efficient, low-power Espressif ESP32 chip. During the Maker Faire Bay Area on May 20th, only some prototypes of Arduino Cinque were available for demonstration.

The FE310 SoC features the E31 CPU Coreplex (32-bit RV32IMAC Core) with 16KB L1 instruction cache and 16KB data SRAM scratchpad. It runs at 320 MHz operating speed and it also has a debugging module, one-time programmable non-volatile memory (OTP), and on-chip oscillators and PLLS. FE310 also supports UART, QSPI, PWM, and timer peripherals and low-power standby mode.

The availability of the Arduino Cinque provides the many dreamers, tinkerers, professional makers and aspiring entrepreneurs access to state-of-the-art silicon on one of the world’s most popular development architectures. Using an open-source chip built on top of RISC-V is the natural evolution of open-source hardware, and the Arduino Cinque has the ability to put powerful SiFive silicon into the hands of makers around the world.
~ Dale Dougherty, founder and executive chairman of Maker Media

Details and other specifications of the Cinque are still poor, but we can expect its strength from the chips and SoCs it uses. It uses STM32F103, that has Cortex-M3 core with a maximum CPU speed of 72 MHz, to provide the board with USB to UART translation. ESP32 is also used as for Wi-Fi and Bluetooth connectivity.

Espressif ESP32 Specifications

  • 240 MHz dual core Tensilica LX6 micrcontroller
  • 520KB SRAM
  • 802.11 BGN HT40 Wi-Fi transceiver, baseband, stack, and LWIP
  • Classic and BLE integrated dual mode Bluetooth
  • 16 MB flash memory
  • On-board PCB antenna
  • IPEX connector for use with external antenna
  • Ultra-low noise analog amplifier
  • Hall sensor
  • 32 KHz crystal oscillator
  • GPIOs for UART, SPI, I2S, I2C, DAC, and PWM
A first look at the RISC-V-based Arduino Cinque, a SiFive R&D project.
A first look at the RISC-V-based Arduino Cinque, a SiFive R&D project.

The RISC-V Foundation is working to spread the idea and the benefits of the open-source ISA. Its efforts include hosting workshops, participating in conferences, and collaborating with academia and industry. The foundation had also worked with researchers from Princeton University to identify flaws with the ISA design. They presented their findings at the 22nd ACM International Conference on Architectural Support for Programming Languages and Operating Systems.

Open Source Meets Hardware: Open Processor Core

SiFive, the first fabless provider of customized, open-source-enabled semiconductors, had recently announced the availability of its Freedom Everywhere 310 (FE310) system on a chip (SoC), the industry’s first commercially available SoC based on the free and open RISC-V instruction set architecture.

The Freedom E310 (FE310) is the first member of the Freedom Everywhere family of customizable SoCs. Designed for microcontroller, embedded, IoT, and wearable applications, the FE310 features SiFive’s E31 CPU Coreplex, a high-performance, 32-bit RV32IMAC core. Running at 320+ MHz, the FE310 is among the fastest microcontrollers in the market. Additional features include a 16KB L1 Instruction Cache, a 16KB Data SRAM scratchpad, hardware multiply/divide, a debug module, flexible clock generation with on-chip oscillators and PLLs, and a wide variety of peripherals including UARTs, QSPI, PWMs, and timers. Multiple power domains and a low-power standby mode ensure a wide variety of applications can benefit from the FE310.

Furthermore, SiFive launched an open source low-cost HiFive1 software development board based on FE310. As part of this availability, SiFive also has contributed the register-transfer level (RTL) code for FE310 to the open-source community.

The Arduino compatible HiFive1 was live on a crowdfunding campaign on Crowdsupply  and the board reached around $57,000 funding. Check this video to know more about HiFive1:

SiFive is now fulfilling a dream of a lot of developers: a custom silicon designed just for you! With the RTL code open, chip designers are now able to customize  their own SoC on top of the base FE310 by accessing the open source files provided on Github. But don’t worry, even if you don’t have the expertise needed to develop your own core, SiFive is offering a new service called “ chips-as-a-service” that can customize the FE310 to meet your unique needs. All you need is to register here dev.sifive.com, try out your ideas and finally contact the company to finalize the design of your new chip.

This service has completely a new business model for silicon chips businesses, and SiFive is willing to establish a “chip design factory” that can handle 1000 new chip designs a year. It is said that SiFive can start manufacturing the cusomized MCUs in less than 6 months after making sure that each use case is compatible with the Freedom E310 core.

“We started with this revolutionary concept — that instruction sets should be free and open – and were amazed by the incredible rippling effect this has had on the semiconductor industry because it provided a viable alternative to what was previously closed and proprietary,” said Krste Asanovic, co-founder and chief architect, SiFive. “In the few short months since we’ve announced the Freedom Platforms, we’ve seen a tremendous response to our vision of customizable SoCs. The FE310 is a major step forward in the movement toward open-source and mass customization, and SiFive is excited to bring the opportunity for innovation back into the hands of system architects.”

Opening the source of processors’ core has its pros and cons for SiFive. A new business model is assigned to SiFive due to the “chips-as-a-service” feature but in the same time it will open up some new ventures for smaller companies and hardware manufacturers to compete with the market dominating companies. Open source MCUs will bring a lot of updates to the hardware development scene and will pave the way for a whole new business of customized chip design provided by talented hardware system developers and architects.

To know more about the custom design feature visit the developers section of SiFive dev.sifive.com. Documentation of the SiFive new chip is available here and also source codes and files of the RTL code are provided at Github.

HiFive1, An Open-Source RISC-V Development Kit

By bringing the power of open-source and agile hardware design to the semiconductor industry, SiFive aims to increase the performance and efficiency of customized silicon chips with lower cost.

The Freedom E310 (FE310) is the first member of the Freedom Everywhere SoCs family, a series of customizable microcontroller SoC platforms, designed based on SiFive’s E31 CPU Coreplex CPU for microcontroller, embedded, IoT, and wearable applications. The SiFive’s E31 CPU Coreplex is a high-performance, 32-bit RV32IMAC core. Running at 320+ MHz.

FE310 Block Diagram
FE310 Block Diagram

SiFive recently announced the ‘HiFive1’, an open-source Arduino-compatible RISC-V development board that features the FE310 SoC. It is a 68 x 51 mm board consists of 19 Digital I/O pins, 9 PWM pins, and 128 Mbit Off-Chip flash memory. HiFive1 operates at 3.3V and 1.8V and is fed with 5V via USB or with 7-12V DC jack. The board can be programed using Arduino IDE or Freedom E SDK.

HiFive1’s Specifications:
  • Microcontroller: SiFive Freedom E310 (FE310)
    • CPU: SiFive E31 CPU
    • Architecture: 32-bit RV32IMAC
    • Speed: 320+ MHz
    • Performance: 1.61 DMIPs/MHz, 2.73 Coremark/MHz
    • Memory: 16 KB Instruction Cache, 16 KB Data Scratchpad
    • Other Features: Hardware Multiply/Divide, Debug Module, Flexible Clock Generation with on-chip oscillators and PLLs
  • Operating Voltage: 3.3 V and 1.8 V
  • Input Voltage: 5 V USB or 7-12 VDC Jack
  • IO Voltages: Both 3.3 V or 5 V supported
  • Digital I/O Pins: 19
  • PWM Pins: 9
  • SPI Controllers/HW CS Pins: 1/3
  • External Interrupt Pins: 19
  • External Wakeup Pins: 1
  • Flash Memory: 128 Mbit Off-Chip (ISSI SPI Flash)
  • Host Interface (microUSB): Program, Debug, and Serial Communication
  • Dimensions: 68 mm x 51 mm
  • Weight: 22 g
HiFive1 Top View
HiFive1 Top View

riscv-blog-logoRISC-V is an open source instruction set architecture (ISA) that became a standard open architecture for industry implementations under the governance of the RISC-V Foundation. The RISC-V ISA was originally designed and developed in the Computer Science Division at the University of California to support computer architecture researches and education.

In a comparison with Arduino boards, the HiFive has 10x faster CPU clock, larger Flash memory, and lower power consumption. The table below shows the difference between Arduino UNO, Arduino Zero, and Arduino 101:

Comparison

HiFive may be a helpful tool for system architects, hardware hackers and makers, to develop RISC-V applications, customize their own microcontroller, support open-source chips and open hardware. It is also good as a getting started kit to learn more about RISC-V.

You can order a HiFive board for $59 at its crowdfunding campaign, and the full documentation is available here.