This blog was originally published on the Infineon website. It is written by Dave Egan, Director of Product Marketing at Infineon.
Introduction
Infineon has a long and successful track record in the world of Bluetooth software that continues to reach new milestones. This summer (2024), Infineon officially released Zephyr support for the AIROC™ CYW20829, its latest Bluetooth Low Energy (LE) MCU in the market. With that, developers choosing the CYW20829 will now have two software development environment options to select from: One based on the open-source Zephyr OS, which includes its own Bluetooth LE stack, and one based on Infineon’s own ModusToolboxTM and AIROCTM Bluetooth stack. This article reviews some of the advantages and tradeoffs that come with each dev environment option.
Zephyr® supports Infineon’s latest Bluetooth® wireless MCU, AIROC CYW20829
The Zephyr OS 3.7.0 release in July 2024 (link here) added support for Infineon’s CYW20829 Bluetooth wireless MCU. This means that Infineon customers may now develop Bluetooth applications on CYW20829 using Zephyr OS with the Zephyr Bluetooth LE stack.
Why is Infineon enabling Zephyr® OS on its latest Bluetooth® part?
Infineon is listening to its customers and the market and wants to provide the flexibility that the market needs in order to grow and thrive.
Zephyr OS provides product developers with a software platform that enables re-use of software while keeping the toolchain the same. Once Zephyr OS supports a particular wireless MCU and Bluetooth controller, everything else is abstracted, so software written for Zephyr is hardware agnostic. The application uses Zephyr HAL APIs to access peripherals and the Zephyr Bluetooth LE stack. As well as enabling the re-use of software, this also supports the migration from one Bluetooth chipset to another with minimal effort during the lifetime of the project, so developers can take advantage of the latest available technology.
Customers also want to protect their products against potential supply chain issues like those they experienced as a result of the Covid pandemic and subsequent capacity constraints. They want to be able to switch Bluetooth chip supplier or retain multiple suppliers without having to put significant investment of time and effort into reworking their software application or maintaining multiple software skews. By providing a software platform, Zephyr removes an element of software stickiness, thus focusing competition in the market on chip features, performance and cost, which greatly benefits the customer.
Another reason for adopting Zephyr may be a more philosophical one, related to adoption of open-source software. Some software development teams have a strong preference for open-source software because of the following characteristics:
- Pace of development: often, an open-source community, collaborating across borders, time zones and languages, with a common goal, can keep up with technology and standards innovation better than any one team or company. This is not yet the case for Bluetooth LE features in Zephyr, but longer term this proves true for most technologies.
- Security: while it may seem counter-intuitive, many security experts agree that the more people involved in writing the code, the safer it is. It means more scrutiny from a diverse group of engineers, more chances to catch bugs, keep on top of security advisories and vulnerabilities.
- Development tools: many newly built applications contain open-source code and many organizations are using open-source tools and have open source in their code base. In addition, open source often provides more flexibility in terms of which development tools and environments can be used.
- Productivity: with open source, developers can often find code to do what they need, code that is already designed, written and tested, and often this code is available for free. This means that companies can focus on the value that they bring to their product and spend less time on the more routine functionality of their applications.
When should Infineon CYW20829 customers develop their application with ModusToolboxTM and AIROCTM Bluetooth® stack?
Bluetooth LE is used in a wide variety of applications as diverse as game controllers, PC peripherals, wearables, electronic shelf labels, asset tracking, and automotive applications such as car access, tire pressure monitoring, and battery management systems. Such diversity often requires Infineon engineers to tweak and optimize application software, as well as the AIROC Bluetooth stack, and even the Bluetooth controller firmware, to fine tune performance to meet customer and market requirements. While this could perhaps be done in a Zephyr environment, it could be argued that in some cases the application is so niche as to be un-interesting to the Zephyr community, and it may take some time to develop and have modifications adopted by the community.
AIROC Bluetooth stack contains all of the latest Bluetooth LE features, and even some advanced features not yet released by the Bluetooth SIG, while the Zephyr Bluetooth LE stack usually only contains features that have already been released for some time. So, if a project needs to use advanced or very recently available Bluetooth LE features on CYW20829, it might need to use AIROC Bluetooth stack.
There are also some features and libraries available to Infineon customers and developers through ModusToolbox that are not accessible through Zephyr OS.
The ModusToolbox Library Manager pulls in Middleware directly from Infineon and partner GitHub repositories and integrates them as part of the application build. ModusToolbox includes configurators and tuners for Infineon technologies such as CAPSENSETM. ModusToolbox includes a Project Creator, Device Configurator, Device level configurators for QSPI, SmartIO, SeqLCD and Secure Policy Configurator that is not available when a project is developed in Zephyr OS.
Bluetooth® development options summarized:
| ModusToolboxTM / AIROCTM | Zephyr® OS | |
| Project type | Better for complex applications | Better for basic Bluetooth LE applications |
| Coding | Good for implementation flexibility | Good for porting to multiple chipsets |
| Bluetooth version | Latest, plus advanced features | Lags behind the latest release |
| Software features | Access to Infineon Middleware | Supported by Zephyr community |
What is Infineon’s approach to Bluetooth® software going forward?
Infineon is embracing the Zephyr OS development environment and community, and all future Bluetooth wireless MCUs will be integrated into Zephyr OS. Infineon will also continue to develop and support AIROC Bluetooth stack through ModusToolbox for the majority of customers who continue to wish to develop their applications in this environment. We will always listen to customers and the market to decide how we innovate and develop our products and we will offer the flexibility of development of Bluetooth applications through ModusToolbox or Zephyr OS. Learn more on the boards support page.
Conclusion
With the release of Zephyr OS 3.7.0, which now includes support for Infineon’s CYW20829 Bluetooth wireless MCU, Infineon customers have the option of developing their Bluetooth® applications with Zephyr OS using Zephyr Bluetooth LE stack or with ModusToolbox using AIROC Bluetooth stack.
There are good reasons to use Zephyr OS for development of Bluetooth applications, including the benefits of an open-source community developing, testing and fixing software, as well as having a platform to enabled software re-use and removing software as a differentiator for suppliers.
There are also good reasons to continue using ModusToolbox and AIROC Bluetooth stack, especially for applications that require advanced features, Infineon-specific functionality, and customizations to fine tune performance.
Infineon provides flexibility and options for its customers to select which way they want to develop their Bluetooth applications on AIROC™ CYW20829 and future bluetooth connected devices, and will support development with Zephyr OS or with ModusToolbox and AIROC Bluetooth stack moving forward.
If you’d like to learn more about Infineon and Zephyr, join us at Open Source Summit Europe, happening on September 16-18 in Vienna, Austria. Zephyr is hosting a workshop on Thursday, September 19 at 9 am – 12:30 pm.
The Zephyr Workshop is designed to introduce you to the leading Open Source RTOS built with safety and security in mind. Attendees will learn why Zephyr is gaining the attention of developers and product makers. This session will provide a general overview of the Zephyr OS along with an overview of how to begin building Bluetooth® Low Energy applications using Zephyr RTOS. The hands-on portion of the session will feature the building of two connected applications using Infineon’s AIROC™ CYW20829 Bluetooth® LE MCU Evaluation Kit.
How to Register: Pre-registration is required. To register for Zephyr Workshop, add it to your Open Source Summit Europe registration.