C++ on microcontrollers 1 - introduction, and an output pin class
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...
Introduction to Microcontrollers - Buttons and Bouncing
[quicklinks] What Is A Button? To your hardware, that is. As discussed in Introduction to Microcontrollers - More On GPIO, a button (or key, or switch, or any form of mechanical contact) is generally hooked up to a microcontroller...
Important Programming Concepts (Even on Embedded Systems) Part V: State Machines
Other articles in this series: Part I: Idempotence Part II: Immutability Part III: Volatility Part IV: Singletons Part VI: Abstraction Oh, hell, this article just had to be about state machines, didn’t it? State machines! Those...
Endianness and Serial Communication
Endianness is a consideration that is easily overlooked in the design of embedded systems. I myself am amply guilty of this oversight. It’s something you don’t ever have to worry about if you’re only working with a single...
There's a State in This Machine!
An introduction to state machines and their implementation. Working from an intuitive definition of the state machine concept, we will start with a straightforward implementation then we evolve it into a more robust and engineered solution.
Linear Feedback Shift Registers for the Uninitiated, Part XI: Pseudorandom Number Generation
Last time we looked at the use of LFSRs in counters and position encoders. This time we’re going to look at pseudorandom number generation, and why you may — or may not — want to use LFSRs for this purpose. But first —...
Introduction to Microcontrollers - Timers
[quicklinks] Timers - Because "When" Matters Computer programs are odd things, for one reason because they have no concept of time. They may have the concept of sequential execution, but the time between instructions can be...
Linear Feedback Shift Registers for the Uninitiated, Part IX: Decimation, Trace Parity, and Cyclotomic Cosets
Embedded Programming Video Course Shows How OOP Works Under the Hood
If you'd like to understand how Object-Oriented Programming (OOP) really works under the hood, here is a free video course for you: OOP part-1: Encapsulation: This first lesson on Object-Oriented Programming (OOP) introduces the concept of...
Introduction to Microcontrollers - 7-segment displays & Multiplexing
[quicklinks] Doing the 7 Segment Shuffle The 7 segment display is ubiquitous in the modern world. Just about every digital clock, calculator and movie bomb has one. The treadmills at my gym have 6 or 7, each one displaying 3 or 4...
OS influence on power consumption
Power consumption of an embedded system may be influenced in software in general, but selection of an operating system can be key.
On optimizing manual soldering
When faced with manual soldering of thousands of components, speed and efficiency become pivotal. Here are some takeaways from my own experience attempting to optimize such a process.
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…
Graphical medicine
Although an appealing user interface is a good option for any device, in medical applications it can be a life saver.
Pay it Forward
A popular car bumper sticker reads, "If you can read this, thank a teacher!" I might say, "If you can read THIS (article on Embedded Related), then you've been blessed with great experiences and/or great educators or volunteers that got you excited about tech and helped you believe that you had a future in this field!" Why not pay it forward by helping other children have those same great experiences? As we enter another season of giving, I hope you consider doing what you can to support the hundreds or thousands of non-profit organizations, educators, and volunteers around the world who are getting kids excited about tech the same way YOU got excited about tech. In this article, I'll share with you a handful of organizations that I know of or donate to that have this mission. How do you like to give back?
Zephyr: West Manifest For Application Development
In this blog post, I show a simpler way to create custom West manifest files. This technique eliminates the need to duplicate the complex West manifest from upstream Zephyr. I also show how we can use the West manifest to include out-of-tree board and SoC definitions, and include our own out-of-tree drivers.
Simulating Your Embedded Project on Your Computer (Part 2)
Having a simulation of your embedded project is like having a superpower that improves the quality and pace of your development ten times over! To be useful, though, it can't take longer to develop the simulation than it takes to develop the application code and for many simulation techniques "the juice isn't worth the squeeze"! In the last article, I showed you how to use the terminal (i.e. printf/getchar) to easily make a completely functional simulation. In this article, we'll take simulation to the next level, either in terms of realism (by using virtual hardware) or in terms of user experience (by using a GUI to simulate our hardware, instead of using the terminal).
How to Achieve Deterministic Behavior in Real-Time Embedded Systems
Ensuring deterministic behavior in real-time embedded systems is paramount for their reliability and performance. The ability to predict precisely how a system will respond to various inputs at any given time is crucial in critical applications such as medical devices, aerospace systems, and automotive safety mechanisms. Achieving deterministic behavior involves meticulous design, stringent testing, and adherence to strict timing constraints.
You Don't Need an RTOS (Part 4)
In this fourth (and final!) article I'll share with you the last of the inter-process communication (IPC) methods I mentioned in Part 3: mailboxes/queues, counting semaphores, the Observer pattern, and something I'm calling a "marquee". When we're done, we'll have created the scaffolding for tasks to interact in all sorts of different the ways. Additionally, I'll share with you another alternative design for a non-preemptive scheduler called a dispatch queue that is simple to conceptualize and, like the time-triggered scheduler, can help you schedule some of your most difficult task sets.
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.
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.
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.
Embedded Programming Video Course Shows How OOP Works Under the Hood
If you'd like to understand how Object-Oriented Programming (OOP) really works under the hood, here is a free video course for you: OOP part-1: Encapsulation: This first lesson on Object-Oriented Programming (OOP) introduces the concept of...
VHDL tutorial - part 2 - Testbench
[quicklinks]In an earlier article I walked through the VHDL coding of a simple design. In this article I will continue the process and create a test bench module to test the earlier design. The Xilinx ISE environment makes it pretty easy to start...
Endianness and Serial Communication
Endianness is a consideration that is easily overlooked in the design of embedded systems. I myself am amply guilty of this oversight. It’s something you don’t ever have to worry about if you’re only working with a single...
Boot Sequence for an ARM based embedded system
Hello all, Allow me to introduce myself. I am Deeksha and I come from plains of North India. My tryst with embedded technologies has been 5 years long and every single day I am amazed with the vastness and learning involved. The thing with...
Thermistor signal conditioning: Dos and Don'ts, Tips and Tricks
In an earlier blog entry, I mentioned this circuit for thermistor signal conditioning: It is worth a little more explanation on thermistor signal conditioning; it's something that's often done poorly, whereas it's among the easiest...
