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.
Getting Started With CUDA C on an Nvidia Jetson: A Meaningful Algorithm
In this blog post, I demonstrate a use case and corresponding GPU implementation where meaningful performance gains are realized and observed. Specifically, I implement a "blurring" algorithm on a large 1000x1000 pixel image. I show that the GPU-based implementation is 1000x faster than the CPU-based implementation.
Introduction to PIC Timers
The fourth in a series of five posts looks at 8-bit PIC hardware timers. After a review of basic timer functionality, the Timer0 module operation and configuration is reviewed and a basic application implemented using Timer0 to blink external LEDs at a frequency of 0.5Hz.
You Don't Need an RTOS (Part 2)
In this second article, we'll tweak the simple superloop in three critical ways that will improve it's worst-case response time (WCRT) to be nearly as good as a preemptive RTOS ("real-time operating system"). We'll do this by adding task priorities, interrupts, and finite state machines. Additionally, we'll discuss how to incorporate a sleep mode when there's no work to be done and I'll also share with you a different variation on the superloop that can help schedule even the toughest of task sets.
Finite State Machines (FSM) in Embedded Systems (Part 3) - Unuglify C++ FSM with DSL
Domain Specific Languages (DSL) are an effective way to avoid boilerplate or repetitive code. Using DSLs lets the programmer focus on the problem domain, rather than the mechanisms used to solve it. Here I show how to design and implement a DSL using the C++ preprocessor, using the FSM library, and the examples I presented in my previous articles.
A design non-methodology
Although writing an RTOS or kernel may be an interesting project, it is unlikely to be a wise course of action.
Working with Microchip PIC 8-bit GPIO
The third in a series of five posts looks at GPIO with PIC 8-bit microcontrollers. After a detailed review of the registers for configuring and managing GPIO on the PIC18F47Q10 processor, a basic application is stood up programming those registers to blink external LEDs at 0.5Hz.
Blinkenlights 2.0
Nothing spells old movie computers like a panel of randomly blinking lights, but in fact, these so-called "blinkenlights" can be valuable indicators - especially in embedded systems where the user interface must be minimal, small and cheap. Control of these lights can be achieved using a very simple, real-time interpreted script, and this kind of solution may be extended to other and more complex embedded tasks.
You Don't Need an RTOS (Part 1)
In this first article, we'll compare our two contenders, the superloop and the RTOS. We'll define a few terms that help us describe exactly what functions a scheduler does and why an RTOS can help make certain systems work that wouldn't with a superloop. By the end of this article, you'll be able to: - Measure or calculate the deadlines, periods, and worst-case execution times for each task in your system, - Determine, using either a response-time analysis or a utilization test, if that set of tasks is schedulable using either a superloop or an RTOS, and - Assign RTOS task priorities optimally.
C++ Assertion? Well Yes, But Actually No.
Assertions are a double-edged sword - on one side you enforce program correctness catching bugs close to their origin, on the other your application is subject to run-time error, like any interpreted language. This article explores what C++ can offer to get the advantages of assertions, without risking the crashes by moving contract checking at compile time.
A Beginner's Guide to Embedded Systems
Embedded systems are everywhere, and this guide gives a practical, project-first roadmap for beginners. It explains what embedded systems are, the typical constraints you will face, and a clear learning sequence: circuit fundamentals, digital logic, C, and microcontrollers before moving on to RTOS or embedded Linux. The post also recommends hands-on dev boards and student clubs to accelerate real-world skills.
Intel 8088 - A blast from the past
The Intel 8088 is a reminder of how hands-on early microcomputer work really was. This short retrospective looks back at wire-wrapping, perfboard construction, and assembly language programming on a board built around the 8088 and its support chips. It is a fun contrast to today’s Raspberry Pi era, where far more performance comes in a sealed package you can’t build yourself.
Learning Rust For Embedded Systems
Rust eliminates whole classes of memory and concurrency bugs, making it a compelling choice for embedded projects, and the author recommends it for the VolksEEG project after a rapid evaluation. The post connects Rust fundamentals such as ownership and borrowing, RAII, traits, and unsafe blocks to familiar embedded patterns. It also provides a curated on-ramp of videos, books, and tools like Cargo, RTIC, and probe-rs to get hands-on quickly.
Using the C language to program the am335x PRU
Assembly-language PRU development is tedious and error prone, so Fabien Le Mentec shows how to use TI's PRU C toolchain to simplify the workflow. He walks through installing the CGT package, integrating the compiler with a modified prussdrv loader to honor the _c_int00 start symbol, and provides a BeagleBone Black example with build scripts and sources on GitHub. The post also covers inline assembly constraints and code-size tradeoffs.
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.
C to C++: 3 Proven Techniques for Embedded Systems Transformation
Jacob Beningo lays out a pragmatic, low-risk path for embedded teams to start using C++ without adding bloat or runtime cost. He recommends beginning by treating C++ as a cleaner C with namespaces, constexpr, and smart pointers, then adopting object-oriented design with composition, and finally introducing templates for static polymorphism where it makes sense. The post focuses on practical guardrails for resource-constrained firmware.
Modern C++ in embedded development: Static Classes
Static classes give embedded C++ developers a clear way to group module functions while preventing accidental instantiation. This post shows how to implement C#-style static classes in C++ by deleting the default constructor, then use templates and C++20 concepts to make firmware business logic platform independent and type safe. It also covers testability techniques, including mock wrappers for unavoidable static state.
Learning A New Microcontroller
Learning a new microcontroller becomes manageable with a repeatable, stepwise process that focuses on common peripherals, tools, and example programs. This post lays out hands-on exercises from blinky and UART echoes through I2C/SPI, PWM and ADC to DMA and RTOS variations, and shows how to evolve prototype code into reusable HAL and OSAL layers. Practical tips cover hardware setup, logic analyzers, and keeping an engineering notebook.
Are We Shooting Ourselves in the Foot with Stack Overflow?
Most traditional, beaten-path memory layouts allocate the stack space above the data sections in RAM, even though the stack grows “down” (towards the lower memory addresses) in most embedded processors. This arrangement puts your program data in the path of destruction of a stack overflow. In other words, you violate the first Gun Safety Rule (ALWAYS keep the gun pointed in a safe direction!) and you end up shooting yourself in the foot. This article shows how to locate the stack at the BEGINNING of RAM and thus point it in the "safe" direction.
Round Round Get Around: Why Fixed-Point Right-Shifts Are Just Fine
Jason Sachs explains why, in most embedded systems, simple bitwise right-shifts are an acceptable way to do fixed-point division rather than paying the runtime cost to round. He shows the cheap trick of adding 2^(N-1) to implement round-to-nearest, explains unbiased "round-to-even" issues, and compares arithmetic error to much larger ADC and sensor errors. The takeaway: save cycles unless your algorithm or inputs require extra precision.
Embedded Toolbox: Programmer's Calculator
A tiny but powerful cross-platform tool, QCalc evaluates full C-syntax expressions so you can paste results straight into firmware. It handles bitwise ops, mixed hex/decimal/binary constants, and scientific math, and it automatically shows integer results in formatted hex and binary. The post explains key features, variable handling, error messages, and how to run qcalc.tcl with the wish Tk interpreter.
Delayed printf for real-time logging
Yossi Kreinin demonstrates delayed printf, a technique that records printf format pointers and raw argument words into a compact buffer so logging does not disturb real-time timing. He walks through a small C++11 writer using variadic templates and an atomic buffer plus a gdb Python reader that reconstructs formatted messages from executables or core dumps. The result is readable post-processed logs with minimal runtime overhead.
Lazy Properties in Python Using Descriptors
Python descriptors let you outsource attribute lookup, and Jason Sachs walks through a practical use: lazy, cached properties. He presents a LazyProperty descriptor that defaults to a WeakKeyDictionary cache so computed results are stored on first access and automatically purged when objects are garbage collected. The post shows how to share caches by value using attrkey or swap cache classes for different use cases.
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.
Important Programming Concepts (Even on Embedded Systems) Part II: Immutability
Immutable data can make embedded code easier to reason about, reduce concurrency bugs, and eliminate defensive copies. Jason Sachs walks through practical techniques that work in resource-constrained systems, from using const and pseudo-immutability to separating old and new state, to the limits of fully persistent data structures when you lack dynamic memory. The article also compares register-level state flow and advocates message passing as a concurrency alternative.
C to C++: Using Abstract Interfaces to Create Hardware Abstraction Layers (HAL)
In C to C++, we've been exploring how to transition from a C developer to a C++ developer when working in embedded system. In this post, we will explore how to leverage classes to create hardware abstraction layers (HAL). You'll learn about the various inheritance mechanisms, what an virtual function is, and how to create an abstract class.
From bare-metal to RTOS: 5 Reasons to use an RTOS
Most developers default to bare-metal, but Jacob Beningo argues an RTOS often simplifies modern embedded design. He outlines five practical reasons to move to an RTOS: easier integration of connectivity stacks and GUIs, true preemptive scheduling with priorities, tunable footprints, API-driven portability, and a common toolset for tasks and synchronization. The piece helps decide when RTOS adoption speeds development.
Cortex-M Exception Handling (Part 2)
Exception entry and return on Cortex-M look simple, but the hardware does a lot to preserve context, enforce privilege, and pick the right stack. This post walks through the processor actions after an exception is accepted: which registers get pushed, how CONTROL, MSP and PSP affect stack selection, how EXC_RETURN encodes the return path, and why VTOR and vector table alignment matter for handler lookup.
Write Better Code with Block Diagrams and Flowcharts
Reading and writing code without architectural diagrams is like trying to follow complex instructions without any explanatory pictures: nigh impossible! By taking the time to draw out the block diagrams and flowcharts for your code, you can help identify problems before they arise and make your code easier to design, write, test, and debug. In this article, I'll briefly justify the importance of architectural drawings such as block diagrams and flowcharts and then teach you what they are and how to draw them. Using two simple examples, you'll see first-hand how these drawings can significantly amplify your understanding of a piece of code. Additionally, I'll give you a few tips for how to implement each drawing once you've completed it and I'll share with you a few neat tools to help you complete your next set of drawings.
C Programming Techniques: Function Call Inlining
Fabien Le Mentec shows how you can keep clean C interfaces while recovering the cycles lost to function call overhead. The post demonstrates static inline and header inclusion techniques, then compares generated ARM assembly for an inlined versus non inlined bit test. Read it to see concrete assembly differences, compiler hints, and the practical trade off between speed and code size on embedded targets.
