The three laws of safe embedded systems
This short article is part of an ongoing series in which I aim to explore some techniques that may be useful for developers and organisations that are beginning their first safety-related embedded project.
Developing software for a safety-related embedded system for the first time
Developing a safety-related embedded product is not the same as writing ordinary firmware, and this article lays out eight practical steps to get you started. Using a washing-machine controller as a running example, it covers scoping, key requirements, hazard analysis, applicable standards, platform and MCU choices, runtime monitoring, and prototyping. The checklist helps teams prepare for verification, testing, and later certification work.
“Smarter” cars, unintended acceleration – and unintended consequences
In this article, I consider some recent press reports relating to embedded software in the automotive sector.
In The Times newspaper (London, 2015-10-16) the imminent arrival of Tesla cars that “use autopilot technology to park themselves and change lane without intervention from the driver” was noted.
By most definitions, the Tesla design incorporates what is sometimes called “Artificial Intelligence” (AI).Others might label it a “Smart” (or at least “Smarter”)...
Coding Step 3 - High-Level Requirements
Stephen Friederichs turns the series toward embedded code by showing how to write a single high-level requirement for an embedded Hello World. He explains when requirements pay off, how they support testing and scope control, and why you should not write them for every small script. He then lays out five practical rules and applies them to a concrete EHW-001 serial transmission requirement.
Lessons Learned from Embedded Code Reviews (Including Some Surprises)
Jason Sachs recounts a round of motor-controller code reviews and the practical lessons his team learned about quality and tooling. He explains how a simple "ready for review" checklist and automated style checks kept meetings focused on substantive issues, and why choosing the right review tool matters after discovering lost comments in Stash. Read for concrete tips on process, subgit mirroring, vera++, and Upsource.
Dark Corners of C - The Comma Operator
Ever seen a line like if (!dry_run && ((stdout_closed = true), close_stream(stdout) != 0)) and wondered what that comma means? Stephen Friederichs unpacks the rarely-discussed C comma operator, shows a circular-buffer example where it seemed to simplify looping, then demonstrates how precedence and readability problems (and even MISRA C bans) make it dangerous in practice. Read on for practical uses and cautionary lessons.
Ten Little Algorithms, Part 4: Topological Sort
Jason Sachs detours from signal processing to make topological sort feel practical and even a little funny, using a Martian Stew recipe to illustrate dependencies and cycles. He walks through two canonical algorithms, Kahn’s method and the depth-first-search variant, compares adjacency-list and matrix graph representations, and provides complete Python implementations so you can run and inspect cycle detection and ordering yourself.
Important Programming Concepts (Even on Embedded Systems) Part VI : Abstraction
Abstraction is essential, but it is not free. Jason Sachs walks through the many faces of abstraction—pattern recognition, generalization, simplification, and indirection—and shows how each helps and hurts real projects. Using examples from math, API design, UI toolkits, schematics, and embedded C, he gives practical context so firmware engineers can apply abstractions without causing maintenance or debugging headaches.
Coding Step 2 - Source Control
Articles in this series:
- Coding Step 0 - Development Environments
- Coding Step 1 - Hello World and Makefiles
- Coding Step 2 - Source Control
- Coding Step 3 - High-Level Requirements
- Coding Step 4 - Design
When I first started out in programming, version control was not an introductory topic. Not in the least because it required a 'server' (ie, a computer which a teenaged me couldn't afford) but because it seemed difficult and only useful to teams rather than...
Coding Step 1 - Hello World and Makefiles
Stephen Friederichs walks through compiling a C Hello World using GCC on Windows, then shows how a simple makefile can automate the process. You will see how output naming, project layout, and makefile targets work, and learn dependency rules based on timestamps plus how to force rebuilds with clean and FORCE targets. This is a practical first step to escape the IDE and use Unix-style build tools.
Favorite Tools: C++11 std::array
Firmware teams that avoid malloc or new need safer alternatives, and this post makes a strong case for C++11 std::array as that alternative. It highlights zero-overhead, type-safe, compile-time buffers and points to an ESP32 LED-strip demo where NUM_PIXELS_ fixes RAM usage at build time. Read it to see std::array used with std::rotate, passed to C libraries via data(), and as a low-risk path to std::vector later.
STM32 VS Code Extension Under The Hood
ST's STM32 VS Code extension hides useful CMake projects and VS Code tasks behind a friendly UI, but understanding what it generates lets you bend it to your needs. This video peels back the layers to show the generated CMake files, how to modify them, how to add a VS Code-invokable flash task, and how to enable C++ support alongside C. The STM32 F0 example and flash task are available on GitHub.
Linux Kernel Development - Part 1: Hello Kernel!
Skip userland and run code inside the kernel with a tiny "Hello Kernel" module that prints messages on load and unload. This introduction walks through required headers, the init and exit hooks, MODULE_* metadata, a kernel-friendly Makefile, and the basic workflow to build, insmod, rmmod and inspect messages with dmesg. It’s a hands-on first step into Linux kernel module development.
Tenderfoot: Embedded Software and Firmware Specialties
This post revisits an earlier Stack Overflow answer and breaks embedded firmware into practical specialties, from assembly optimization and device drivers to DSP, IoT networking, security, UI, and systems architecture. It outlines the core skills, tools, and math each specialty demands, and explains how product constraints and industries shape those roles. Newcomers get clear guidance on where to focus their learning and career development.
Review: Modern Software Engineering
Long-lived branches, manual releases, and slow feedback waste engineering time. This review of three Dave Farley books distills a practical playbook: continuous delivery pipelines, trunk-based development, and disciplined TDD to keep trunk always releasable. It shows how fast, automated feedback at every stage shrinks cycle time, reduces merge pain, and makes teams far more productive.
Remember Y2K?
There was fear that the turn of the century at the end of 1999 would cause problems with many embedded systems. There is evidence that the same issue may occur in 2038.
Coding - Step 0: Setting Up a Development Environment
Stephen Friederichs walks through setting up a minimal C development environment without an IDE, focusing on Windows. He explains why learning command-line toolchains matters, recommends GCC and Make as a durable base, and gives step-by-step MinGW installation and PATH configuration plus editor suggestions. The guide gets you compiling with mingw32-make and gcc so you can move on to makefiles and project structure.
Coding Step 2 - Source Control
Articles in this series:
- Coding Step 0 - Development Environments
- Coding Step 1 - Hello World and Makefiles
- Coding Step 2 - Source Control
- Coding Step 3 - High-Level Requirements
- Coding Step 4 - Design
When I first started out in programming, version control was not an introductory topic. Not in the least because it required a 'server' (ie, a computer which a teenaged me couldn't afford) but because it seemed difficult and only useful to teams rather than...
Tenderfoot: Recommended Reading
Twenty years on, these are the books that turned an electrical engineer into an embedded software pro. Matthew Eshleman walks through influential reads from Code Complete to Practical Statecharts and Test Driven Development, explaining how each shaped his design, estimation, and testing practices. This short list is a practical starting point for 'tenderfoots' launching an embedded firmware career.
AI at the Edge - Can I run a neural network in a resource-constrained device?
AI at the edge is no longer science fiction, it can run on tiny, resource-constrained devices like Arm Cortex-M4 and M7 microcontrollers. This post introduces inference-only neural networks on MCUs, explains why edge AI matters for power, latency, and privacy, and points to practical toolchains such as STM32Cube.AI, Arm NN, and AWS Greengrass to get started quickly.
Tenderfoot: Recommended Reading
Twenty years on, these are the books that turned an electrical engineer into an embedded software pro. Matthew Eshleman walks through influential reads from Code Complete to Practical Statecharts and Test Driven Development, explaining how each shaped his design, estimation, and testing practices. This short list is a practical starting point for 'tenderfoots' launching an embedded firmware career.
Review: Modern Software Engineering
Long-lived branches, manual releases, and slow feedback waste engineering time. This review of three Dave Farley books distills a practical playbook: continuous delivery pipelines, trunk-based development, and disciplined TDD to keep trunk always releasable. It shows how fast, automated feedback at every stage shrinks cycle time, reduces merge pain, and makes teams far more productive.
The Hardest Bug I Never Solved
A single overlooked sentence in the STM32 datasheet turned intermittent startup resets into a major time-leach. Senior engineers chased DMA buffers and overflows for hours until Unni discovered the ISR vector table had been relocated to RAM with only 256 byte alignment while the MCU required 512 bytes. The misalignment caused interrupts to jump to the reset handler, and fixing the alignment stopped the reboot loop for good.
Introduction to Deep Insight Analysis for RTOS Based Applications
Debugging can consume over 40% of a development cycle, and Jacob Beningo argues RTOS projects need more than breakpoints and assertions. He presents deep insight analysis as a trio of techniques—RTOS-aware debugging, run-time analysis, and profiling with coverage—that expose what the system is actually doing. These methods help engineers cut guesswork and speed verification of complex embedded applications.
Embedded Firmware Refactoring, Optimisation and Migration
Legacy embedded products often hit CPU, memory, or power limits long before customers stop wanting new features. This article lays out three practical paths: squeeze more from the current build with optimisation, make the codebase maintainable through refactoring, or port firmware to new hardware when constraints demand it. Read on for a pragmatic view of when each approach makes sense and how to reduce risk.
Working with Microchip PIC 8-bit Interrupts
This fifth and final post of the Getting Started with Microchip PIC 8 Bit Development series looks at interrupts on 8-bit PIC microcontrollers. After a review of basic interrupt functionality, an actual implementation is explored with the development of a four bit counter driven via Timer0 interrupts whose value is displayed through four LEDs on Microchip's Curiosity HPC Development Board.
C++ on microcontrollers 3 – a first shot at an hc595 class with 8 output pins
This blog series is about the use of C++ for modern microcontrollers. My plan is to show the gradual development of a basic I/O library. I will introduce the object-oriented C++ features that are used step by step, to provide a gentle yet practical introduction into C++ for C programmers. Reader input is very much appreciated, you might even steer me in the direction you find most interesting.
In the first part of...
Vala applications on Embedded Linux: maybe a clever choice [part 1]
If you need a high-level language for constrained embedded Linux devices, Vala is worth a look. It compiles to C and relies mainly on GLib, giving you native performance and minimal runtime dependencies. With reference counting instead of a garbage collector, modern language features, and a small storage footprint, Vala can outperform Python, Java, or Qt on low-RAM, low-storage boards. This first part focuses on dependencies, ABI compatibility, runtime characteristics, and a real-world example.
3 Overlooked Embedded Software Elements
Jacob Beningo points out three often-overlooked elements that can make embedded projects less painful and faster to ship. He highlights model-generated code for off-target iteration, configuration-generated code to manage SKUs and avoid fragile conditional compilation, and automated test harnesses to catch regressions early. The post gives practical reasons to consider each approach and how they fit into modern embedded DevOps.
Getting Started with the Microchip PIC® Microcontroller
This first post of a five part series looks at the available hardware options for getting started with Microchip 8-bit PIC® Microcontroller, explores the MPLAB® X Integrated Development Environment and walks through setting up a project to expose the configured clock to an external pin and implement a single output GPIO to light an LED.
