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Today Zephyr has become the leading open source RTOS for connected IoT devices. With developers worldwide, support for numerous architectures and a thriving ecosystem, in its short 10 year history Zephyr has evolved into a de facto industry standard. This success wasn’t always guaranteed.
Nordic Semiconductor started working with Zephyr back in 2016 and made the decision to join the Zephyr Project a year later. At the time it was a risky and difficult decision because of the potential disruption to Nordic’s business. Shifting resources from our mature and popular proprietary nRF5 SDK to an emerging technology ecosystem carried inherent risks, but it was a decision we knew we had to make.
Nordic’s product roadmap at the time was expanding not just with new generations of Bluetooth LE and multiprotocol SoCs, but also with the introduction of the cellular IoT modules and Wi-Fi companion ICs that are part of the Nordic product family today. To offer the best possible software solution to a growing and widening base of customers, we knew we needed a modern, scalable and complete software solution that could support the next billion IoT devices. We evaluated several options before making the decision to back Zephyr.
Why Zephyr?
In terms of our overall strategy we wanted something that would be a long term solution, so it was fundamental that whatever we went with had to be developed under an open governance and it had to be cross-architecture. Zephyr fit the bill because it is hosted under the Linux Foundation, and its design and build system make it portable across many different CPU architectures.
Nordic’s belief is that any good open source venture should be a communal endeavor without any single vendor controlling the project, and that is exactly how Zephyr works. There is no ‘pay to play’ regardless of your membership status, it is based entirely on technical merit.
From a cross-architecture perspective, at the time Nordic decided on Zephyr, we only had Arm Cortex M-based SoCs. But we knew that support for other architecture might be needed in the future, so we didn’t want an RTOS that would lock us into a single one. That has proven a wise decision as today Nordic’s next-generation nRF54L15 ultra-low power wireless SoC for example, includes an Arm Cortex M33 processor and a RISC-V coprocessor, both optimized for specific types of workloads.
- Read more: Why Nordic is getting involved in RISC-V
Other features that attracted us to Zephyr was that it was focused on small footprint, low power connected devices like many of Nordic’s own ICs. It also offers a permissive license in Apache 2.0, very good code quality with strict meritocratic code reviews, and a clean commit history.
As importantly it was a ‘batteries included’ solution, because Zephyr is much more than just an RTOS. Yes, Zephyr provides a lightweight kernel, but you also have the build and configuration system, the toolchain, a powerful device model, power management, protocol stacks, file systems, cryptography, device management, plenty of sensor drivers, logging tracing and debugging, emulation and simulation as well as a solid testing framework and tooling, just for starters. It is a powerful ecosystem and a full software solution for embedded products used in lots of different applications.
A commitment beyond code
Once Nordic committed to the Zephyr Project, we knew it was important to give it Nordic’s full support to ensure it was a success. We became a platinum member and took an active role on the governing board, including chairing it for a few years. We participate extensively in both technical and marketing committees, and devote significant engineering resources to upstream contributions. Of all the contributions made to the Zephyr Project down the years, Nordic is responsible for roughly a quarter of them.
Nordic’s dedicated engineers contributed thousands of hours to upstream Zephyr development, and built bridges between our nRF5 SDK and the Zephyr-based nRF Connect SDK. We collaborated with partners, customers and even competitors to strengthen the ecosystem, and invested heavily in educating the people who were going to use it, not least through the creation of DevAcademy.
- Read more: Skilled engineers drive Nordic success
DevAcademy launched in 2022, enables developers to learn about the Zephyr RTOS and the nRF Connect SDK. Now there are 20,000 developers enrolled in courses, and 8,400 certificates have been issued to people learning Zephyr and Zephyr-based firmware development.
In addition to educational resources we have nRF Connect for VS Code (IDE), a set of extensions that simplify your development experience and is built from the ground up for the nRF Connect SDK.
Inside the nRF Connect SDK
This hard work on Zephyr has resulted in the nRF Connect SDK that is available to clients today. The nRF Connect SDK uses Zephyr as its foundation – not just some parts of it, but all of it, including the kernel, build and configuration system, libraries, protocols and middleware. On top of Zephyr, the nRF Connect SDK includes some Nordic proprietary features and technology.
This powerful and comprehensive blend provides developers with a breadth and depth of functionality available out of the box: Samples, wireless stacks, networking protocols, drivers, security, and much more. This ensures developers can focus their time and energy where it matters most, in adding value and differentiation to their application. For designs that don’t require an RTOS or advanced features, there is an nRF Connect SDK Bare Metal option that lowers the entry barrier for developing simple Bluetooth applications, while also offering a clear upgrade path to Zephyr RTOS and the full capabilities of the nRF Connect SDK.
Ultimately Zephyr and Nordic’s nRF Connect SDK make complex things simple. If you have an embedded device and you want to develop firmware for it, Zephyr and the nRF Connect SDK brings all the pieces together to enable you to get to market faster.
