[Embedded Bytes] Agentic Firmware, Zephyr 10, MISRA C++, and More

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Issue #207

Dear John,

Welcome back to Embedded Bytes!

In this edition, we're looking at how AI agents are moving beyond generating firmware to actually building, flashing, and debugging code on real hardware. I've got a new podcast episode, a free Zephyr AI Skills bundle for subscribers, and a working example using an NXP MCX board.

We'll also look at lessons from Artemis II, Zephyr's 10th anniversary and growing support from TI and Infineon, and an important update to MISRA C++.

I also have two announcements about upcoming opportunities to sharpen your embedded development skills:

1. AI for Embedded Developers: December 7–11, 2026

If you're interested in learning how to use AI to develop embedded software and firmware, I'll be running my AI for Embedded Developers course December 7–11, 2026.

We'll cover skills, agents, RAG, MCP, and agentic development techniques through two hours of hands-on labs and instruction each day. You'll learn practical techniques and workflows that 96% of developers aren't using today.

Register by November 1 to save $100 using code EMBEDDEDAIFOR2027.

2. Embedded Systems Summit: January 26–28, 2027

Registration for the Embedded Systems Summit is now open!

Stephane Boucher and I are bringing together about 100 embedded developers in Silicon Valley for three days of technical presentations, hands-on learning, and networking.

This year's Summit has a special focus on Zephyr RTOS and AI for embedded development, along with software architecture, real-time systems, and practical engineering techniques. It's an opportunity to learn directly from industry experts and connect with other embedded professionals.

Now, let's get into this edition!

Also in this edition:

• Episode #027: Agentic Firmware Development Is Here

• Free Download: Zephyr AI Skills

• The Embedded Toolbox: How Expensive Is Your ISR?

• Industry News and Insights

• Upcoming Industry Events

• Jobs

• Upgrade Your Skills, Processes, and Architecture

Happy Coding,

P.S. If this issue sparked a question, hit reply. The best questions become the next podcast episode, the next Toolbox, or the next blog post. I read every one.

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Episode #027: Agentic Firmware Development Is Here

In a recent poll of 50 embedded developers, every single one said they use AI. Only two were building skills, agents, or RAG databases. Only one was using MCPs.

Which means the gap between "I prompt ChatGPT sometimes" and "I run an agentic firmware workflow" is a lot wider than most teams think it is.

In Episode #027, I lay out what agentic firmware development actually looks like, why ad hoc prompting is not the same thing, and the four pieces you need to make it work: skills, agents, RAG databases, and MCP servers. We also walk through NXP's agentic toolkit, how to validate AI-generated code, and what the next six to twelve months of embedded development is going to look like.

Free Download: Zephyr AI Skills

Five AI skills that automate the core Zephyr board bring-up tasks: device tree edits, Kconfig tuning, peripheral setup, build failure diagnosis, and Renode simulation. They work with Claude Code or Cursor on your own Zephyr board, and they are free for Embedded Bytes subscribers.

The Embedded Toolbox

How Expensive Is Your ISR?

Vendor example code is written to prove the part can do something. It is not written for your production application.

I was recently working with an STM32 timer input capture to measure the frequency of an incoming signal. Starting from the IDE's generated example (which is how a lot of embedded projects start), I measured the ISR the simplest way I know: drive a GPIO low on entry, high on exit, scope on the pin.

24.3 microseconds.

That does not sound like much until you do the math. At a 20 kHz input, you get an interrupt every 50 microseconds. One ISR, nearly half the CPU.

Peeling it apart in two steps:

1. The generated handler called a generic timer IRQ dispatcher that checks every possible flag before reaching your callback. Replacing it with a handler specific to this timer and capture event dropped it to 21.7 microseconds. Better, but not the real problem.

2. The example was computing frequency and duty cycle inside the ISR on every capture. Fine for a demo. Terrible for production. Moving the math out of the ISR and leaving the handler to just capture values and flag new data dropped it to 7.5 microseconds. Less than a third of the original on the same hardware.

Could it go lower? Of course. The real answer when the hardware supports it is DMA, letting the timer capture values stream directly into a buffer so the CPU processes a block only when it needs to.

The point is this: don't treat vendor example code as gospel. Review it. Measure it. Understand what it is doing. Then adapt it.

When was the last time you measured how long your longest interrupt actually takes?

Industry News and Insights

From AI-Assisted to Agentic Zephyr Development: Build, Flash, Fix

(Beningo)

What happens when AI moves beyond generating code to building, flashing, and debugging real hardware? Using Claude Code and three Zephyr skills, I bring up an NXP FRDM-MCXA156 with an HDC3021 sensor. Along the way, the agent identifies a timing bug, investigates the root cause, and works toward a fix. A practical look at agentic Zephyr development in action.

Continue Reading . . .

What Artemis II Teaches Us About Building Mission-Critical Embedded Software

(DesignNews)

What can Artemis II teach embedded engineers about building mission-critical software? In my latest DesignNews column, I explore three lessons from NASA's successful lunar mission: why redundancy requires more than duplication, how layered architectures improve portability, and why simulation is essential for developing and validating reliable systems.

Continue Reading . . .

Zephyr Turns 10: TI and Infineon Upgrade to Platinum, Developer Summit Wraps in Prague

(Linux Foundation)

As Zephyr celebrates its 10th anniversary, Texas Instruments and Infineon have upgraded to Platinum membership, signaling growing industry commitment to the RTOS. The announcement coincided with the Zephyr Developer Summit in Prague, where developers explored functional safety, security, tooling, and applications across industries. Zephyr's momentum continues to build.

Continue Reading . . .

MISRA C++:2023 TC1:2026: What Changed, and Why Your Static Analysis Findings Will Shift

(MISRA via Parasoft)

MISRA C++:2023 has received its first technical update, clarifying nine guidelines and changing how several rules are applied. These changes affect rule scope, exceptions, and moved-from object handling. If you're developing safety-critical C++ software, expect changes in your static analysis results, even if your source code hasn't changed.

Continue Reading . . .