Getting Started With Zephyr: DTS vs DTSI vs Overlays
Devicetrees can be daunting for traditional embedded software engineers that are new to Zephyr. In this blog post, I address these fears and show how navigating Devicetrees can be much easier if you understand that they represent the layered structure of the underlying hardware.
Getting Started With Zephyr: Using GDB To Fix a Driver Bug
In this blog post, I show how to use GDB to debug an issue encountered with a TSL2591 light sensor driver in Zephyr. The fix was submitted and successfully incorporated into The Zephyr Project.
Static or static
The keyword static in C and C++ has multiple uses, which are not always well understood.
On hardware state machines: How to write a simple MAC controller using the RP2040 PIOs
Hardware state machines are nice, and the RP2040 has two blocks with up to four machines each. Their instruction set is limited, but powerful, and they can execute an instruction per cycle, pushing and popping from their FIFOs and shifting bytes in and out. The Raspberry Pi Pico does not have an Ethernet connection, but there are many PHY boards available… take a LAN8720 board and connect it to the Pico; you’re done. The firmware ? Introducing Mongoose…
Picowoose: The Raspberry Pi Pico-W meets Mongoose
This example application describes the way to adapt the George Robotics CYW43 driver, present in the Pico-SDK, to work with Cesanta's Mongoose. We are then able to use Mongoose internal TCP/IP stack (with TLS 1.3), instead of lwIP (and MbedTLS).
Small or fast?
Developers of software for desktop computers take code optimization for granted. Embedded developers typically need to pay much more attention to the details
Memory Mapped I/O in C
Interacting with memory mapped device registers is at the base of all embedded development. Let's explore what tools the C language - standard of the industry - provide the developer with to face this task.
Some Embedded System Software Design Resources
Embedded systems span many architectures and run-times, so there is no single definitive resource. This curated list brings together practical embedded-focused books by Elecia White and Jacob Beningo, general design guidance from Robert Martin, and a TDD primer by James W. Grenning, plus concrete advice on BDD-style TDD and off-target testing. Skim the list in a day, then try the techniques hands-on.
When a Mongoose met a MicroPython, part II
In the first part of this blog, we introduced this little framework to integrate MicroPython and Cesanta's Mongoose; where Mongoose runs when called by MicroPython and is able to run Python functions as callbacks for the events you decide in your event handler. Now we add MQTT to the equation, so we can subscribe to topics and publish messages right from MicroPython.
ANCS and HID: Controlling Your iPhone From Zephyr
In this blog post, we see how certain BLE services can be used to control an iPhone from a Nordic nRF52840 using The Zephyr Project. Specifically, we see how to control certain multimedia functionality using the HID service. Finally, we learn how to use the ANCS client library provided by Nordic in The Zephyr Project to accept or decline an incoming call.
++i and i++ : what’s the difference?
Although the ++ and -- operators are well known, there are facets of their operation and implementation that are less familiar to many developers.
Creating a Hardware Abstraction Layer (HAL) in C
In my last post, C to C++: Using Abstract Interfaces to Create Hardware Abstraction Layers (HAL), I discussed how vital hardware abstraction layers are and how to use a C++ abstract interface to create them. You may be thinking, that’s great for C++, but I work in C! How do I create a HAL that can easily swap in and out different drivers? In today’s post, I will walk through exactly how to do that while using the I2C bus as an example.
Cracking the (embedded) Coding Interview
Landing your first embedded job is thrilling, but surviving months of interviews is brutal. This post condenses one engineer’s recent experience into a pragmatic playbook, covering behavioral prep, targeted coding practice, and the embedded theory you actually get asked about. Read it for a focused roadmap: what to study, which platforms to use, and how to present yourself so interviewers root for you.
Memory Mapped I/O in C
Interacting with memory mapped device registers is at the base of all embedded development. Let's explore what tools the C language - standard of the industry - provide the developer with to face this task.
Modern C++ in Embedded Development: (Don't Fear) The ++
While C is still the language of choice for embedded development, the adoption of C++ has grown steadily. Yet, reservations about dynamic memory allocation and fears of unnecessary code bloat have kept many in the C camp. This discourse aims to explore the intricacies of employing C++ in embedded systems, negotiating the issues of dynamic memory allocation, and exploiting the benefits of C++ offerings like std::array and constexpr. Moreover, it ventures into the details of the zero-overhead principle and the nuanced distinctions between C and C++. The takeaway? Armed with the right knowledge and a careful approach, C++ can indeed serve as a powerful, safer, and more efficient tool for embedded development.
Finite State Machines (FSM) in Embedded Systems (Part 2) - Simple C++ State Machine Engine
When implementing state machines in your project it is an advantage to rely on a tried and tested state machine engine. This component is reused for every kind of application and helps the developer focus on the domain part of the software. In this article, the design process that turns a custom C++ code into a finite-state machine engine is fully described with motivations and tradeoffs for each iteration.
Visual Studio Code Extensions for Embedded Software Development
Visual Studio Code can be a solid embedded development environment, if you equip it with the right extensions. Jacob Beningo walks through tools for Cortex-M debugging, register and RTOS inspection, build system support, formatting, linting, and vendor-specific workflows. It is a practical tour of the extensions that help VS Code feel much less like a general-purpose editor and more like an embedded IDE.
Finite State Machines (FSM) in Embedded Systems (Part 4) - Let 'em talk
No state machine is an island. State machines do not exist in a vacuum, they need to "talk" to their environment and each other to share information and provide synchronization to perform the system functions. In this conclusive article, you will find what kind of problems and which critical areas you need to pay attention to when designing a concurrent system. Although the focus is on state machines, the consideration applies to every system that involves more than one execution thread.
Working with Strings in Embedded C++
This article discusses the use of strings in embedded systems. It explains how the need for and use of strings in embedded systems has changed with the advent of cheaper, full graphic displays and the growth of the ‘Internet of Things’ (IoT). The article also covers character literals, C-Strings and string literals, and the difference in memory models between them. It also highlights the safety and security issues that arise from using strings in embedded systems. Finally, it explains how C++11 introduced a Raw string literal type that is useful for storing file paths or regular expressions.
Getting Started With Zephyr: DTS vs DTSI vs Overlays
Devicetrees can be daunting for traditional embedded software engineers that are new to Zephyr. In this blog post, I address these fears and show how navigating Devicetrees can be much easier if you understand that they represent the layered structure of the underlying hardware.
Cracking the (embedded) Coding Interview
Landing your first embedded job is thrilling, but surviving months of interviews is brutal. This post condenses one engineer’s recent experience into a pragmatic playbook, covering behavioral prep, targeted coding practice, and the embedded theory you actually get asked about. Read it for a focused roadmap: what to study, which platforms to use, and how to present yourself so interviewers root for you.
Creating a Hardware Abstraction Layer (HAL) in C
In my last post, C to C++: Using Abstract Interfaces to Create Hardware Abstraction Layers (HAL), I discussed how vital hardware abstraction layers are and how to use a C++ abstract interface to create them. You may be thinking, that’s great for C++, but I work in C! How do I create a HAL that can easily swap in and out different drivers? In today’s post, I will walk through exactly how to do that while using the I2C bus as an example.
Visual Studio Code Extensions for Embedded Software Development
Visual Studio Code can be a solid embedded development environment, if you equip it with the right extensions. Jacob Beningo walks through tools for Cortex-M debugging, register and RTOS inspection, build system support, formatting, linting, and vendor-specific workflows. It is a practical tour of the extensions that help VS Code feel much less like a general-purpose editor and more like an embedded IDE.
++i and i++ : what’s the difference?
Although the ++ and -- operators are well known, there are facets of their operation and implementation that are less familiar to many developers.
Modern C++ in Embedded Development: (Don't Fear) The ++
While C is still the language of choice for embedded development, the adoption of C++ has grown steadily. Yet, reservations about dynamic memory allocation and fears of unnecessary code bloat have kept many in the C camp. This discourse aims to explore the intricacies of employing C++ in embedded systems, negotiating the issues of dynamic memory allocation, and exploiting the benefits of C++ offerings like std::array and constexpr. Moreover, it ventures into the details of the zero-overhead principle and the nuanced distinctions between C and C++. The takeaway? Armed with the right knowledge and a careful approach, C++ can indeed serve as a powerful, safer, and more efficient tool for embedded development.
C to C++: 3 Reasons to Migrate
Embedded C still powers most devices, but rising system complexity is revealing its limits. In this post Jacob Beningo kicks off a series on moving from C to C++, offering three practical reasons to start the migration now. He argues for an incremental approach that keeps low-level, hardware-dependent code in C while adopting C++ for higher-level, object-oriented application logic so teams can keep shipping during the transition.
Finite State Machines (FSM) in Embedded Systems (Part 2) - Simple C++ State Machine Engine
When implementing state machines in your project it is an advantage to rely on a tried and tested state machine engine. This component is reused for every kind of application and helps the developer focus on the domain part of the software. In this article, the design process that turns a custom C++ code into a finite-state machine engine is fully described with motivations and tradeoffs for each iteration.
Memory Mapped I/O in C
Interacting with memory mapped device registers is at the base of all embedded development. Let's explore what tools the C language - standard of the industry - provide the developer with to face this task.
C to C++: Bridging the Gap from C Structures to Classes
Jacob Beningo walks through a practical, beginner-friendly path from C structures to C++ classes for embedded systems, using an LED example to make the ideas concrete. You will see how function pointers in C approximate methods, how C++ structs and classes let you place methods with data, and how access specifiers and constructors improve encapsulation and initialization. This gives a low-risk way to start adopting C++ features.
Creating a GPIO HAL and Driver in C
Creating a GPIO Hardware Abstraction Layer (HAL) in C allows for flexible microcontroller interfacing, overcoming the challenge of variability across silicon vendors. This method involves reviewing datasheets, identifying features, designing interfaces, and iterative development, as detailed in the "Reusable Firmware" process. A simplified approach prioritizes essential functions like initialization and read/write operations, showcased through a minimal interface example. The post also highlights the use of AI to expedite HAL generation. A detailed GPIO HAL version is provided, featuring extended capabilities and facilitating driver connection through direct assignments or wrappers. The significance of a configuration table for adaptable peripheral setup is emphasized. Ultimately, the blog illustrates the ease and scalability of developing a GPIO HAL and driver in C, promoting hardware-independent and extensible code for various interfaces, such as SPI, I2C, PWM, and timers, underscoring the abstraction benefits.
