Zephyr Technologies: Zbus, CAN, Devicetree, Bluetooth & more

The Zephyr Developer Summit, hosted under the first-ever Embedded Open Source Summit in Prague, Czech Republic, on June 27-30 included presentations, BoFs, and training designed for real time problem solving and deep discussions. More than 1,300 people registered for the EOSS conference – representing 375 organizations across 56 countries around the globe. Zephyr had 75+ technical sessions (in-person and on-demand) for 3 tracks focused on users of Zephyr, developers contributing upstream, and maintainer-specific topics.

All of the videos from the Zephyr Developer Summit can be found on the Zephyr Youtube Channel. Each week, we’ll highlight a few videos in a blog for easy access. Today, we’re featuring a few sessions focused on Zephyr Technologies including, “Zbus – the Lightweight and Flexible Zephyr Message Bus,” “Overview of CAN Subsystem in Zephyr,” “System Devicetree Support in Zephyr” and “Differentiating Bluetooth Low Energy Products by Exploiting and Exploring Zephyr Bluetooth Controller Implementations.”

Zbus – the Lightweight and Flexible Zephyr Message Bus – Rodrigo Peixoto, Embedded software engineer at Edge-UFAL/Citrinio

This presentation is about the Zbus – a lightweight and flexible message bus that enables threads to talk to one another. In this talk, Rodrigo will explain in detail the new way message bus, which allows many-to-many communication and the event-driven approach. Then, he will highlight the challenges and benefits of using that, showing examples and applications. In the end, he will present the roadmap features for the bus.

“Overview of CAN Subsystem in Zephyr” – Navin Sankar, Embedded Software Engineer at Next Big Thing AG

The Controller Area Network is a widely used communication protocol in the automotive industry and beyond. This protocol provides a reliable, efficient and flexible way to transmit data between electronic devices, particularly in environments where electromagnetic interference and harsh conditions are common. The session will provide an overview of the CAN protocol, its history, features, CAN bit timing calculation and configuration of classic CAN and CANFD message frame format. This discussion also focuses on driver implementation, error detection and configuring & testing the zephyr application with tool like can-utils.

System Devicetree Support in Zephyr – Marti Bolivar, Principal Software Engineer at Ampere

Zephyr’s support for AMP SoCs… works, but has several well-known usability problems due to workarounds for deficiencies in our hardware support features at the following layers: – devicetree – hardware model – build system This talk will introduce the system devicetree specification and its role in solving some of these problems. System Devicetree is an extension of the standard Devicetree Specification. Its main extensions to the base specification allow simultaneous representation of multiple CPU clusters within a heterogenous SoC, along with their individual memory maps, memory partitions for different executable images, and peripheral assignments. The main goals of this talk are to define the problems being solved, the reasons why our current build system infrastructure doesn’t suffice, and discuss where system devicetree can help. We will also cover the current status of ongoing work to support system devicetree in the Zephyr build system.

Differentiating Bluetooth Low Energy Products by Exploiting and Exploring Zephyr Bluetooth Controller Implementations – Vinayak Kariappa Chettimada, Principal R&D Engineer at Nordic Semiconductor ASA

Since its original contribution to Zephyr Project in early 2016 and till date there has been constant enhancements by community members to feature set in the Zephyr Bluetooth Controller. With Bluetooth Core Specification v5.x versions, there is support for Longer Range, Higher Throughput, Direction Finding, and LE Isochronous Channels supporting LE Audio solutions. Besides Zephyr Bluetooth Controller’s architecture permitting support for multiple vendor radio support, it is highly configurable, well structured and modular at primitives/utilities to allow easy replacement with enhanced implementations.

This video will briefly touch base on supported mature features set, implementation architectures, ideology, configurations to differentiate products, development plan/strategy, conformance and quality. Presentation details CPU utilization, execution context safety, race-to-idle concepts, memory and power consumption optimizations.

Watch the rest of the Zephyr Developer Summit videos here. The schedule and links to the PPT presentations can be found here. Photos from the EOSS can be found here.

For more information about the 2024 event, stay tuned by subscribing to the Zephyr quarterly newsletter or connect with us on @ZephyrIoT, Zephyr Project LinkedIn or the Zephyr Discord Channel to talk with community and TSC members.