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Cabin crew, prepare for native_sim! — Zephyr Podcast #029

By April 3, 2026No Comments

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The summary below was automatically generated using the assistance of AI tools.

Episode Summary

  • Raspberry Pi Price Increases: Raspberry Pi has raised prices across the board and introduced an unusual 3GB RAM variant of the Pi 4 (two 1.5GB modules). The announcement landed on April 1st — but was not a joke. The top-spec Compute Module 5 (16GB RAM, 64GB eMMC, wireless) now runs about $428. The hosts also note that Mouser raised their free shipping threshold from €50 to €75, alongside significant price hikes on components — a spool of wire doubled in price. Benjamin was shopping for demo hardware for the upcoming Zephyr 4.4 release and felt the sting firsthand.
  • Zephyr 4.4 Demo Teaser — Biometrics & Security: Benjamin is working on a Zephyr 4.4 demo centered around security. He’s experimenting with a DFRobot biometric sensor module that does face and palm-vein recognition over UART, and exposes its camera as a USB Video Class (UVC) webcam. This showcases two new Zephyr 4.4 features: the biometrics API (for enrollment and verification of fingerprints, faces, etc.) and USB host support for webcams. The broader demo theme will also touch on WireGuard VPN integration.
  • Fabio’s Kitchen Timer — Native Sim on an Airplane: Fabio built a kitchen timer using an STM32C0 and hand-soldered 0201 LEDs driving a seven-segment display. He developed the firmware on an airplane using native_sim, replacing the LCD output with print statements — wisely avoiding pulling out a countdown-timer-looking device with wires mid-flight. A Zephyr seven-segment display driver already exists, so integration was straightforward via devicetree. The display code “just worked.”
  • The USB-C Connector Dev Board: A fun hardware project spotted on social media: a dev board built into the form factor of a USB-C connector, using an ATtiny16. Fabio challenges the community to remake it with an STM32C071 (small enough, no external crystal needed) and run Zephyr on it.
  • LogScope VS Code Extension: Benjamin recommends LogScope, a VS Code extension tailored for embedded log viewing. It color-codes Zephyr log levels, lets you filter by log module, supports pattern-based grep, decodes BLE HCI traffic, and can log directly via J-Link RTT. Crucially, it auto-reconnects when a serial link drops — no crashes when you unplug your board. The hosts also discuss the cost landscape of J-Link debuggers: the EDU version for non-commercial use, and the on-board J-Link (JLink OB) that ships on many Nordic dev kits as a cost-effective alternative.
  • Freeze PR Policy Being Formalized: A new PR formalizes the release freeze policy — what qualifies as a bug fix post-RC1/RC2, whether separate issues are needed for late PRs, and setting clear expectations for contributors. Previously this was enforced by release managers’ best judgment, which occasionally led to confusion. Fabio notes the project sometimes over-formalizes processes, but agrees this particular one addresses a real point of contention around late-cycle bug fix merges.
  • Luca’s Zephyr Presentation at Arduino Days 2026: At Arduino Days 2026, Luca from Arduino presented on their Zephyr integration story. Arduino previously used Mbed OS as their core, which has been discontinued. The key challenge: Zephyr is optimized for build-time configuration via devicetree and Kconfig, while Arduino’s programming model is inherently dynamic (runtime pin mapping, device enable/disable). The Arduino team built the necessary infrastructure to bridge this gap, and that work will benefit the broader Zephyr community for any use case requiring runtime dynamicity.
  • Tasmota & Bluepad32 — Ecosystem Lock-in Discussion: The hosts discuss Tasmota, a popular open-source ESP32 firmware for home automation that provides a web UI for runtime GPIO/peripheral configuration without writing code. They also mention Bluepad32, an ESP32 project for interfacing with game controllers (PlayStation, etc.) for robot control. Both are locked to the ESP32 ecosystem — the hosts wish for a Zephyr-based equivalent that could run on any supported hardware. Fabio admits he “hates them conceptually” for the inefficiency but acknowledges the value for non-programmers who just want to build devices.
  • ST Standard Serial Page EEPROM: ST is working on bringing support for a new class of external non-volatile memory to Zephyr — a Quad-SPI EEPROM with byte-level write granularity (unlike typical Quad-SPI flash with 4KB minimum erase pages). This makes it much more efficient for applications that need fine-grained persistent storage. Expected to land in Zephyr 4.5. ST has been proactive with upstream contributions — similar to how they submitted the STM32C5 PR just days after the chip announcement.
  • DEVICE_API_EXTENDS: A new PR from Pieter proposes DEVICE_API_EXTENDS, a mechanism for devices that implement multiple APIs (e.g., an I3C controller that also exposes I2C). Zephyr’s driver model has a one-to-one device-to-API mapping, which doesn’t fit well for such cases. The solution nests the child API pointer inside the parent API struct and uses iterable sections for efficient lookup and compile-time validation. It was discussed at an architecture meeting; competing proposals may emerge, but Fabio likes this approach. The hosts encourage the community to review the PR and provide feedback.
  • QUIC Protocol Support: A pull request adding QUIC protocol support is in the works for a future Zephyr release. QUIC is the UDP-based transport underlying HTTP/3, offering reliable data transfer with lower overhead than TCP (multiplexed streams, built-in TLS, reduced handshake latency). The implementation is substantial — over 20,000 lines of code. The hosts note QUIC is already widely deployed (it powers much of Google’s infrastructure) and discuss how it improves on HTTP/2’s multiplexing model.
  • JavaScript on Microcontrollers — Moddable SDK Tech Talk: An upcoming Zephyr Tech Talk will cover running JavaScript on microcontrollers using the Moddable SDK, which now supports Zephyr alongside ESP32 and Raspberry Pi Pico. The hosts see this as a growing trend: as MCUs get more capable and application processors get more expensive, scripting languages become increasingly practical for IoT applications where developers just want a timer that sends an MQTT packet every 10 seconds.
  • Zephyr 4.4 Release Countdown: The release is expected the week of April 13th (~10 days from recording). The project is entering final freeze — contributors are encouraged to focus on documentation, release notes polish, and code sample improvements.