Arduino Core on Zephyr 0.55: Getting ready for the final mile

We’re releasing version 0.55.0 of the Arduino^® Core on Zephyr today, and it’s a meaningful one. This update resolves one of the most common friction points users have reported, adds support for two widely-used libraries, and brings us noticeably closer to our June target for marking this core stable and ending the BETA program. Concurrently, we’ll begin deprecating the corresponding cores based on mbedOS.

If you’ve been following the beta, this one is worth updating to.

Unified monitor and serial

The single most requested fix in this cycle was simple and reasonable: Serial.println() should just work.

On previous releases, users running the Arduino^® UNO^™ Q board had to be intentional about how they routed output — adding #include <Arduino_RouterBridge.h> and being mindful of target differences between IDE 2 and Arduino^® App Lab. That friction is gone in 0.55.

We’ve reworked how outputs are routed and introduced a transparent alias, so printing to Serial or Monitor now delivers the expected result in both Arduino IDE 2 and Arduino App Lab. No bridge header required. If your existing sketch includes Arduino_RouterBridge.h, it’ll still compile cleanly; it’s just redundant now.

Print to your monitor without thinking about it.

New library support

Real-Time Clock (RTC): Projects running on Zephyr-supported boards can now use a reliable RTC to track time independently of uptime counters. Sync with a network time server, maintain a running clock with full calendar features, and build time-aware applications with confidence.

CAN Bus: The CAN library opens the door to automotive and industrial applications right from your UNO Q. Add a small CAN transceiver to your setup and you have everything you need to prototype automotive dashboards, robotics control systems, or any device network built on the CAN fieldbus standard.

Also in the Zephyr 0.55 release

• Dynamic Interrupts for UNO Q
• shiftIn / shiftOut functions for serial data reading and writing on pins
• Zephyr workqueue support for managing low-priority interrupts
  • Fixes compilation of libraries that hard-require wiring_private.h and pins_arduino.h
  • Plenty of bug fixes: PWM, WiFi, and more

Board support

Nicla Vision joins the supported lineup with this release. 

The full compatibility list as of 0.55.0:

• UNO Q
• Arduino^® Portenta^™ H7
• Portenta C33
• Arduino^® Opta^™ board
• Arduino^® Giga^™ Display Shield
• Arduino^® Nano^™ Matter board
• Nano 33 Bluetooth^® LE
• Arduino^® Nicla^™ Sense board
• Nicla Vision

How to get started

Search for “zephyr” in the Arduino IDE Board Manager, install the 0.55.0 release, and you’re ready to go. Check our full release notes available on GitHub and read our troubleshooting article for more information.

Contribute to the beta program!

This is your opportunity to shape the future of Arduino development! We welcome feedback, bug reports, and contributions to the core. Visit the GitHub Issues page to report bugs or suggest features. Your feedback will play a critical role in refining this integration and unlocking new possibilities for embedded systems.

Visit the Arduino Core-Zephyr GitHub repository today and start exploring this exciting new platform! Thank you for being a part of the Arduino community.

Thank you for being part of this!

Arduino, UNO, Portenta, Opta, Giga, Nano, and Nicla and the Arduino logo are trademarks or registered trademarks of Arduino S.r.l.