GreenWaves’ RISC-V Core to Supersede Cortex Cores in the IoT

November 26, 2016 by Robin Mitchell

Fab-less semiconductor company, GreenWaves Technologies, has developed a new processor designed for IoT applications that they claim that will outmatch ARM Cortex processors.

Fab-less semiconductor company, GreenWaves Technologies, has developed a new processor designed for IoT applications that they claim that will outmatch ARM Cortex processors. What makes this core different and how will it benefit innovation in the growing IoT infrastructure?

The Rise of the IoT

Technology has radically changed in the past three decades. The 90s saw the rise of powerful computing with GUI operating systems becoming commonplace. At the same time, Hypertext Transfer Protocol (HTTP) along with Hypertext Markup Language (HTML) were laying out the foundation to the internet which would change the world forever. The 2000s decade saw the rise of mobile computing, multi-core computers, the dependence on the internet (and, of course, Britney Spears).

The current decade, however, has begun to see a shift from powerful computing and functional internet use to internet integration via the Internet of Things (IoT). Along with this has come commercialization of the internet (video streaming, gaming, etc.). With devices becoming more dependent on the internet, it is important that manufacturers and engineers alike appreciate this shift in demand and adjust their designs to suit this need.


IoT-Specific Hardware

One common example of hardware that needs updating is the PIC microcontroller range produced by Microchip. The range is very well suited for generic embedded systems but is increasingly becoming outdated in applications involving the IoT. This is because they rely on an external controller for Wi-Fi connections as well as TCP protocol handling. While some PIC devices do contain hardware TCP stacks, they are far and few between.

To help with the lack of IoT ability in such microcontrollers, companies such as Espressif have designed the ESP8266 range of Wi-Fi controllers. One module, in particular, the ESP-01, has been hugely popular in the hobby market as it is very simple to communicate with. The module uses the standard UART protocol while using a simple command structure involving AT commands followed by the specific command (for example, AT returns OK from the device and AT+CWMODE? returns the current Wi-Fi mode setup).

The module, itself, utilizes eight pins with only three of those pins being needed for development purposes. (Technically, only four wires are needed for normal operation; power, ground, TX, and RX).


The IoT could be the next best thing since sliced bread. Image via Pixabay


ARM processors have been particularly ideal for IoT applications as they were originally designed for mobile and low power applications which is ideal for devices that are both mobile and wireless. ARM-based devices also have a large variety of toolchains and programming environments making them ideal for higher level programming languages such as C and C++. However, while ARM may have enjoyed being the processor of choice for IoT applications, a startup company has designed a new RISC core that claims to outmatch the ARM processor.


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An IoT-Focused Processor?

Fabless chip company GreenWaves Technologies has designed a processor which they claim is the industry's first IoT processor. This chip, the GAP8 multi-core processor, is based on the RISC-V core developed by the University of Bologna and ETZ Zurich. GreenWaves Technologies hopes that the processor, which is twice as energy efficient as ARM cores (Cortex M0 to M7), will become the go-to processor for all designers in the IoT Field.


The GAP8 processor lay. Image courtesy of GreenWaves. Click to enlarge.


The 8-core processor contains many functional units designed to make IoT applications easier and faster than ever before. Applications involving image processing and analytical tasks (for example, biometric systems and danger awareness systems in automobiles) will be given a speed boost thanks to the TPU (TensorFlow Processing Unit). The TPU is designed to help solve neural network-based algorithms with emphasis on low-precision arithmetic and utilizing the multiple cores on the chip.

The processor also contains many onboard peripherals including smart IOs, voltage regulators, an RTC, UART, I2C, I2S, JTAG, and LVDS, which is particularly helpful when trying to reduce the number of components in a design. Built into the processor are also a Shared L1 Memory, Share Instruction Cache, and Logarithmic Interconnect. Also supported by the GAP8 processor is 802.15.4g, LTE Cat-M and Cat-N1, and 802.11ah (Wi-Fi HaLow).

What makes this processor potentially an IoT leader is that simulations predict up to 12 billion operations per second where low-power applications (such as battery-powered Wi-Fi sensors) can expect 400 million operations per second at 1mW of power consumption.

The chip is targeting TSMC’s 55nm process and is planned for tape out in December this year. Programming the GAP8 processor can be done in languages such as C and C++ using a standard GCC compiler (with extensions), which makes transition for preexisting designs not only easier but also mitigates against the requirement of having to learn a language variant specific to a microcontroller (for example, C18, XC8, Thumb, Thumb-2, etc.).

GreenWaves vs. ARM

GreenWaves Technologies is a very similar company to ARM Holdings as both companies do not produce any devices at all. Instead, they design the core and processor architecture, then license the design out to other device producers and generate revenue on royalties and license fees.

The GAP8 processor, if it lives up to the hype, could be a very strong candidate for future IoT devices involving data analytics, neural networking, and low power requirements. If successful, ARM Holdings may need to develop their own IoT processor to keep a foot in the constantly growing market.

As ARM is already established, their advantage could be the use of already available cores, combining them with more hardware-based stacks and IoT useful modules. For example, a Wi-Fi module could be built into the ARM processor along with a hardware TCP stack, which could make internet connections trivial while keeping power consumption low (as in the GAP8 processor). The inbuilt Wi-Fi module could then use a simple command structure as IoT-based devices only need to relay small amounts of information such as temperature readings and control signals.


ARM will need to respond to the IoT processor. Image courtesy of Socram8888 (own work) [CC BY 2.0]


Just like the rise of computing during the 80s and the rise of the internet in the 90s, this decade could very well be marked as the beginning of the IoT race. It's a good bet that companies will continue competing to produce processors and hardware that consume little power while providing connectivity and functionality.

Just like the rise of the internet, no one knows what the IoT race will create and how the IoT will be used in daily life. Will there be more biometrics in houses? Will there be voice recognition modules that relay data back to a home automation controller? These are questions that both today’s and tomorrow’s engineers will have to answer.  


Featured image courtesy of GreenWaves Technologies.