Zephyr RTOS Emerging Technologies

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 that showcase Zephyr RTOS with emerging technologies including, “Porting an AI Powered Wearable Health Monitor to Zephyr on Open Hardware,” “ ZVM: Zephyr-based Virtual Machine,” “Greybus for Robotics with Zephyr RTOS,” “Open Source Ultra-Wideband RTLS with Zephyr,” and Enabling Sound Open Firmware on Arm® Cortex®-a Based Devices Using Zephyr RTOS.”

Porting an AI Powered Wearable Health Monitor to Zephyr on Open Hardware – Szymon Duchniewicz, Open Technology Engineer at Avanade & Jakub Duchniewicz,Team Leader and Senior Embedded/Software Engineer at Tietoevry

To RTOS or not to RTOS? Szymon and Jakub will introduce obstacles they faced and decisions behind moving a closed-source single-threaded wearable health monitor to an RTOS, open-hardware based system with an AI model deployed on a Field-Programmable Gate Array (FPGA). They will share tips on how to get started with Zephyr development, when and why to build a system using an RTOS. They will also share best practices and experiences on deploying a Machine Learning model to an embedded FPGA and interacting with it from Zephyr OS. The project dissected in this talk uses QuickLogic’s and Antmicro’s QuickFeather board, powered by Open Hardware EOS S3 System on Chip. The Machine Learning Model is deployed using TensorFlow Lite and then integrated using an open source FPGA toolchain. Device collects data from an SPO2 sensor that is parsed by Zephyr at runtime and finally passed to the model deployed on the FPGA for inference. The results are then returned to the Zephyr RTOS and displayed on a small OLED screen. The model is trained using open source data pertaining to blood pressure estimation based on SPO2 levels and is tailored specifically for deployment in embedded scenarios.

[embedyt] https://www.youtube.com/watch?v=fBMeNOOghD4[/embedyt]

ZVM: Zephyr-based Virtual Machine – Guoqi Xie, Professor at Hunan University

In connected devices with mixed-criticality deployment, virtual machine technology (i.e., hypervisor) enables secure isolation and management. Most of the existing mainstream commercial hypervisor solutions are closed-source, while the open-source Linux KVM solution is a non-real-time virtual machine. Based on ARM64 and Zephyr RTOS, we developed an embedded real-time virtual machine named ZVM (Zephyr-based Virtual Machine). We can start and run Linux OS and Zephyr RTOS in ZVM. The main functional modules for implementing ZVM include CPU virtualization, memory virtualization, interrupt virtualization, I/O virtualization, and timer virtualization. We completed the implementation, integration and optimization of each virtualization module. ZVM is an open source embedded real-time virtual machine with a good license.

[embedyt] https://www.youtube.com/watch?v=PY64voxdhAU[/embedyt]

Greybus for Robotics with Zephyr RTOS – Vaishnav Achath, Software Engineer at Texas Instruments Inc.

Greybus is an application layer protocol developed originally for Google’s modular smartphone project Ara and is a part of the Linux kernel, Greybus can be thought of as an Remote Procedure Call(RPC) framework which has tight integrations within linux kernel subsystems. In the past there has been multiple attempts for using Greybus for IoT applications where a remote node running generic greybus firmware will appear on the host running Linux as virtual devices and users can hook device drivers to these virtual devices. Thus reusing existing device drivers in Linux for remote microcontroller nodes running Zephyr greybus firmware(See https://git.beagleboard.org/beagleconnect/freedom for more info). This presentation discusses the method of using the greybus for robotics applications an real-time control applications where the traditional greybus frameworks transaction delays are not practical, thus a method of record and playback is added to the RPC framework on the Zephyr remote side which helps offload real-time control applications through greybus. The presentation also will include a demonstration of running a control loop on a remote microcontroller node running Zephyr and Linux host controlling through userspace drivers without modifying remote node firmware.

[embedyt] https://www.youtube.com/watch?v=fHEWMk2oe6Y[/embedyt]

Open Source Ultra-Wideband RTLS with Zephyr – Aleksander Wójtowicz, Software Engineer, AVSystem

Ultra-wideband radio technology, due to its unique physical characteristics, has enabled numerous use cases for systems which require precise distance measurement between some devices. One of these cases is a Real Time Positioning System (RTLS), whose task is to precisely track 3D positions of some objects with a tracker attached. In this presentation, Aleksander presents a open source RTLS solution based on Zephyr RTOS and Decawave’s (now Qorvo) MDEK1001 Ultra-wideband devkit. The presentation begins with the generic introduction into RTLS, followed by the description of the designed system. In the second part, Aleksander shares his experience on using Zephyr as a beginner and its unique features that have enabled him to rapidly implement the software for embedded devices. Finally, he’ll speak about work that needs to be done to transform the solution into a generic Zephyr module, and how Zephyr facilitates the process of making code portable to numerous hardware platforms.

[embedyt] https://www.youtube.com/watch?v=wH8xA537b-g[/embedyt]

Enabling Sound Open Firmware on Arm® Cortex®-a Based Devices Using Zephyr RTOS – Daniel Baluta, Software Engineer at NXP

Sound Open Firmware is an open source audio DSP firmware that provides firmware source code, tools, and debug capabilities to enable developers to add more value and customization to their projects. While initially developed on the Cadence® Tensilica® HiFi 4 DSP, the firmware has a modular and generic codebase that can be ported to different architectures. This presentation will focus on how to move this code to newer Cortex-A devices that don’t incorporate a separate DSP. The task starts with using Jailhouse hypervisor to reserve the Arm Cortex-A core to run the Sound Open Firmware as an application inside Zephyr RTOS. This presentation will detail the general solution involving running Linux OS and Zephyr RTOS on separate ARM® Cortex- A cores with the help of Jailhouse hypervisor. The presentation will focus on the process of enabling Zephyr on a Cortex-A55 core, and then integrating Sound Open Firmware applications.

[embedyt] https://www.youtube.com/watch?v=pgGuxAhUHTE[/embedyt]

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.