On June 21, Nuclei System Technology, a Shanghai-based RISC-V chip designer, closed a Series B of more than RMB 100 million (around $15.5 million). The financing round was the firm’s third  in the past year, according to local media reports. Backers of the company included state-owned China Electronics Technology Group and smartphone maker Xiaomi.

Founded in 2018, Nuclei System Technology is one of the largest Chinese companies designing chips using RISC-V, an open-source chip architecture that is gaining popularity among Chinese companies. While the basic RISC-V architecture is free to use, Nuclei’s designs are customized based on real-world needs and are ready to be manufactured. The company’s products are already being used by some of the country’s most popular payment systems, like Alipay and UnionPay.

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Nuclei is just the latest example of a rush into the RISC-V space in China. RISC-V is an  alternative to mainstream architectures like x86 and Arm, which are proprietary.  It was long considered a “hobbyist architecture.” Now, China’s semiconductor industry is taking RISC-V seriously. Alibaba and some of the country’s largest chipmakers are joining the bandwagon, rolling out RISC-V-based processors. 

That’s because RISC-V has given Chinese chip designers an alternative to the two dominant architectures:  US chipmaker Intel owns x86, and Japan’s SoftBank owns Arm Holdings, Ltd.. An open-source architecture could free chipmakers from relying on other architecture designers and spending high licensing fees.  

For now, RISC-V remains something  of a hipster architecture. But major companies are already experimenting with it for smartphones, and experts say it could be mature within a decade.

A lightweight architecture, RISC-V is expected to appear first in devices on the internet of things (IoT). It also has potential in data centers, especially those for the purpose of machine learning (ML) and artificial intelligence (AI), because of its ability to modify source code.  Chinese e-commerce giant Alibaba has made a phone prototype based on RISC-V that can execute simple tasks, though it is still an experiment. 

But most importantly, China’s chip industry is embracing RISC-V due to fear that its access to foreign-owned architecture might be blocked in geopolitical conflicts. The move coincides with the Chinese government’s push to replace foreign-made software, operating systems, and infrastructure for the public services and key industries(notably banking) , with homemade solutions—which are often based on open-source projects.

Nuclei said in a marketing blurb on its website that one of its advantages is that it’s “homegrown and self-reliant.”

“At present, the copyrights of mainstream architectures like x86 and Arm belong to US company Intel and Japanese company SoftBank, respectively,” said Wu Di, an analyst at Changsha-based brokerage Chasing Securities. “There is a growing risk of being restricted from using the architectures as the US strengthens its grip on Chinese tech companies.”

What is RISC-V?

RISC-V, created in 2010 by a group at University of California, Berkeley, is something like Linux for chips. But RISC-V is not a piece of software or hardware. It is an abstract model of a computer often referred to as an instruction set architecture (ISA). ISA, as David Patterson, vice chair of the board of the RISC-V Foundation, told Wired, is the language that hardware and software use to talk to each other.

Unlike many other ISA designs, including the popular Arm and x86, the RISC-V ISA is available under an open-source license, meaning that anyone can use the architecture to develop implementations of computers, like central processing units (CPUs), without any fees.

Compared to the two dominant architectures,  x86 and Arm, RISC-V has been designed to be lightweight and low-power. Thus, RISC-V is a better fit for small computing gadgets like the internet of things (IoT) devices, argued Fang Zhixi, chair of the RISC-V Foundation China Advisory Committee.

Sanction free

Another feature that distinguishes RISC-V from Arm and x86 is its business model. RISC-V’s open-source license is called Creative Commons Attribution 4.0 International. That means anyone can put it into commercial use, modify its code, and distribute copies without cost.

By comparison, both x86 and Arm are proprietary architectures. Currently, there are only three companies licensed to manufacture x86-architecture processors: US companies Intel and AMD and Taiwanese chipmaker VIA. UK-based Arm Ltd. has adopted a looser commercial license system, giving chipmakers worldwide the ability to design processors based on the architecture. As of September 2020, Arm had issued licenses to more than 150 Chinese chipmakers, including Chinese telecommunications equipment giant Huawei, according to local media reports (in Chinese). 

Being open-source also means that RISC-V is not subject to export controls. In May 2019, Arm told staff to stop working with Huawei after the Chinese firm was hit by a US sanction. In March, Arm said it will “potentially” be able to license its latest generation of the Arm architecture to Huawei. 

Huawei’s two-year-long drama with the US government leaves Chinese companies feeling that they can’t count on access to foreign-owned proprietary ISAs. 

Major players

RISC-V is still new to China’s chip industry and most companies in the sector are startups. Here are four Chinese semiconductor companies that are working with the architecture.

Nuclei System Technology is a semiconductor design company and provider of commercial RISC-V processor IP.

  • Nuclei was founded in 2018 by Synopsys and Marvell veteran Hu Zhenbo. Hu told a forum (in Chinese) in 2018 that China had realized “self-sufficiency” in chip design, and the real problem that dogged China’s semiconductor industry was “the lack of ISAs.”
  • “RISC-V offers a new opportunity for China. RISC-V is likely to become a new mainstream architecture worldwide in the future and it is completely open. It will enable China to truly achieve the production of a mainstream and homegrown processor core,” he said at the time.
  • Nuclei has rolled out several generations of chip designs that can be used in IoT and manufacturing, according to its website. The company said its designs have been used to build trusted execution environments (TEE) for fintech giant Ant Group’s payment platform Alipay and financial services corporation UnionPay.

GigaDevice, one of China’s largest manufacturers of nonvolatile memory (NVM), in 2019 launched a general-purpose microcontroller based on RISC-V. A microcontroller is a device that is widely used in IoT.

  • The company is China’s largest maker of microcontrollers for IoT devices. It shipped (in Chinese) more than 200 million microcontrollers in 2020. Not all of the company’s microcontrollers are based on RISC-V.

Rivai, a Shenzhen-based startup, is a fabless chipmaker that designs RISC-V processors for IoT devices and artificial intelligence applications like robots and smart speakers.

  • The company said on its website (in Chinese) that it is backed by Chinese search engine Baidu and Kai-Fu Lee’s Sinovation Ventures, but it didn’t specify the amount or time of the investment.
  • Rivai was founded in 2018 by Tan Zhangxi. Tan is also the co-director of the RISC-V International Open Source Laboratory (RIOS Lab) at Tsinghua-Berkeley Shenzhen Institute.
  • Tan told Chinese media in an interview in January that RISC-V is “not a cheap alternative to Arm” because it can do a lot of things that can’t be done by Arm. “As the demand for customization increases, RISC-V is expected to generate a market for high-end IP customization that is different from the Arm era,” he said.

E-commerce giant Alibaba’s chip unit, T-Head, in July 2019 released its first RISC-V-based processor design, Xuantie 910. The company said it can be applied to the design of chips for fifth-generation (5G) wireless networks, artificial intelligence, as well as autonomous driving.

  • In May, the company announced (in Chinese) its second RISC-V-based processor, Xuantie 907. The company said at the launch that its Xuantie-series processors had cumulatively shipped more than 200 million units by the end of 2020. Most of T-Head’s Xuantie-series processors are based on architectures other than RISC-V.

State of play

Despite the promise, only a few Chinese companies have so far mass-produced processors based on RISC-V. Most of those processors are used in IoT devices, like surveillance cameras and smart refrigerators, rather than more sophisticated devices like smartphones and personal computers.

GigaDevice, a Chinese memory chipmaker, in 2019 launched its GD32V-series processors based on RISC-V. The company said the processors are mainly for devices like vehicular Global Positioning System (GPS) trackers, alarm systems, and point of sale (POS) devices, according to its website (in Chinese).

In January, T-Head, Alibaba’s chip unit, said it had  tested the Android mobile operating system on its RISC-V-based processor. However, the prototype system could only run simple apps like the clock and mail apps, but not complex operations like games.

RISC-V’s future in China

RISC-V is not coming to smartphones and laptops any time soon, but Chinese experts say RISC-V could emerge as a major ISA within the next decade.

One of the biggest problems for the 11-year-old architecture is the lack of an ecosystem, both in hardware and software. That includes systems on a chip (SoCs), developer boards, design tools, and the operating systems running on the chips.

Wu, the analyst at Chasing Securities, used the Android operating system as an analogy to argue that an ecosystem will not be a problem for RISC-V. 

“The RISC-V architecture is simple, efficient, free, and open, which also gives it a competitive advantage. In the face of the proprietary Symbian operating system, Android became one of the major OSs for mobile devices in the following decade by taking advantage of its open-source features,” he said, referring to a once-might mobile operating system on Nokia phones.

However, RISC-V is still a niche in China’s semiconductor market. Around 95% of Chinese-designed chips were based on the Arm architecture as of September 2020, according to a local media report.

Even if a RISC-V ecosystem readily arises for IoT devices, there are bigger obstacles to widespread RISC-V adoption.  “The hardest market to establish an ecosystem for is actually mobile, followed by desktop and server,” Allan He, vice chairman of China Software Industry Association’s Embedded Systems Association, told local media in 2019.

It will take a concerted effort (in Chinese) by chip designers to build up RISC-V’s ecosystem, said Hu Kangqiao, chief executive of Hexin Hulian, a Beijing-based company that designs home appliance chips based on RISC-V. “When the number of manufacturers designing RISC-V chips is in the same order of magnitude as ARM, it means that the RISC-V’s ecosystem is mature,” Hu said in 2020.

“That will take approximately five to 10 years,” he predicted. 

Wei Sheng

Writing about semiconductors and telecommunications.