Back from Embedded World 2023
It was great to be back in Nuremberg for Embedded World after three long years. The trade show is probably the most significant event in the embedded systems industry, and it was a relief to see that it has survived the pandemic with more than 900 vendors exhibiting.
I recorded this video on the very first day when the doors opened. What you see in the video is probably 10% or less of the full show floor. I am always impressed by the size of...
Cracking the (embedded) Coding Interview
You never forget the day you land your first job.
The thrill of receiving that call from your recruiter to tell you that you bagged your dream role! The relief when you finally see the offer letter you’ve been working towards for years. The pride in your parents' voices when you call home and say “Hey look Ma, I’ve made it!”
But before that, there’s the grueling screening process to get through. Tech interviews often last up to three months and companies can have five...
Visual Studio Code Extensions for Embedded Software Development
Visual Studio Code has become one of the most popular IDEs in the world. To date, software developers have downloaded it more than 40 million times! I suspect you’ve at least heard of it, if not already attempting to use it. Visual Studio Code allows developers to easily customize their development environment which can help them accelerate development, minimize bugs, and make developing software overall much better.
One challenge with Visual Studio Code is that embedded software...
What to See at Embedded World 2023
Embedded World 2023 is just around the corner, and I am thrilled to be attending this year's edition in Nuremberg, Germany. The last time I was there was three years ago, and the world was on the cusp of a major pandemic. It was a surreal experience as many booths and exhibits were empty and cordoned off by security tape due to last-minute cancellations. It was clear that something big was happening.
But with more than 900 vendors exhibiting this year, I'm glad to see that Embedded...
Review: Embedded Software Design: A Practical Approach to Architecture, Processes, and Coding Techniques
Introduction
Full disclosure: I was given a copy of this book to review.
Embedded Software Design: A Practical Approach to Architecture, Processes, and Coding Techniques, by Jacob Beningo, is an excellent introduction to strategies for embedded systems design and bringing those designs to fruition. Renowned embedded systems expert Jack Ganssle was the technical reviewer.
This is a practical how-to book on the modern professional practice of embedded systems...
C to C++: 3 Proven Techniques for Embedded Systems Transformation
For 50 years, the C programming language has dominated the embedded software industry. Even today, more than 80% of embedded projects are using C; however, over the last few years, many teams have begun transitioning from C to C++. C++ offers embedded developers a robust, modern set of tools that can be used to write flexible, scalable, and reusable applications. As embedded applications become more complex and connected, teams need a more modern language to help them deal with the software...
Libgpiod - Toggling GPIOs The Right Way In Embedded Linux
Overview
We all know that GPIO is one of the core elements of any embedded system. We use GPIOs to control LEDs and use them to monitor switches and button presses. In modern embedded systems, GPIOs can also be used as pins for other peripheral busses, such as SPI and I2C. Similar to the previous article on interacting with peripherals on an SPI bus in userspace via SPIdev (https://www.embeddedrelated.com/showarticle/1485.php), we can also control GPIOs from userspace on an embedded...
Basler pylon on Raspberry Pi with Yocto
Camera vendors are increasing offering Yocto layers to simplify the integration of drivers and the creation of cross-compilation environments. This article demonstrates how Yocto can be used to integrate Basler pylon into a Raspberry Pi Linux image.
Basler's pylon Camera Software Suite includes an SDK, a viewer and drivers for development and operation of vision software using Basler cameras. When deployed in Windows environments, pylon is usually installed on a booted Windows image using...
Supply Chain Games: What Have We Learned From the Great Semiconductor Shortage of 2021? (Part 4)
Today we’re going to look at what’s been going on this past year in the chip shortage, particularly in the automotive markets. I’m going to share some recent events and statements that may shed some light on what’s been happening.
In Part Three we went through a deep dive on some aspects of Moore’s Law, the semiconductor foundries, and semiconductor economics, and we looked at the game Supply Chain Idle. We touched on a couple of important points about the...
Supply Chain Games: What Have We Learned From the Great Semiconductor Shortage of 2021? (Part 3)
Hello again! Today we’re going to take a closer look at Moore’s Law, semiconductor foundries, and semiconductor economics — and a game that explores the effect of changing economics on the supply chain.
We’ll try to answer some of these questions:
- What does Moore’s Law really mean, and how does it impact the economics of semiconductor manufacturing?
- How does the foundry business model work, and how is it affected by the different mix of technology...
VolksEEG: Rust Development On Adafruit nRF52840 Feather Express
Contents:Discrete-Time PLLs, Part 1: Basics
In this series of tutorials on discrete-time PLLs we will be focusing on Phase-Locked Loops that can be implemented in discrete-time signal proessors such as FPGAs, DSPs and of course, MATLAB.
C to C++: Templates and Generics – Supercharging Type Flexibility
"C to C++: Templates and Generics – Supercharging Type Flexibility" illuminates the rigidity of C when managing multiple types and the confusion of code replication or macro complexity. In contrast, C++ offers templates, acting as type-agnostic blueprints for classes and functions, which allows for the creation of versatile and reusable code without redundancy. By using templates, developers can define operations like add once and apply them to any data type, simplifying codebases significantly. Generics further this concept, enabling a single code structure to handle diverse data types efficiently—a boon for embedded systems where operations must be performed on varying data, yet code efficiency is critical due to resource limitations. The blog walks through practical applications, showcasing how templates streamline processes and ensure type safety with static_assert, all while weighing the pros and cons of their use in embedded software, advocating for careful practice to harness their full potential.
Coroutines in one page of C
A coroutine is a function that you can jump back into after returning from it - and it remembers where it was in the code, and all the variables. This is very useful at times.
One use is generating a sequence of values. Here's how you can generate all the x,y pairs in a 2D range in Python:
def iterate(max_x, max_y): for x in range(max_x): for y in range(max_y): yield x,y for x,y in iterate(2,2): print x,yThis prints:
0 0 0 1 1 0 1 1The yield keyword is like...
Cortex-M Exception Handling (Part 1)
This article describes how Cortex-M processors handle interrupts and, more generally, exceptions, a concept that plays a central role in the design and implementation of most embedded systems.
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.
Designing Communication Protocols, Practical Aspects
For most embedded developers always comes the time when they have to make their embedded MCU talk to another system. That other system will be a PC or a different embedded system or a smartphone etc. For the purpose of this article I am assuming that we are in the control of the protocol between the two ends and we don’t have to follow something that is already in place on one side.
So let’s say that we have our embedded MCU, we have implemented and configured the USB stack (or just...
Getting Started With Zephyr: Devicetree Bindings
This blog post shines some light on how devicetrees are used in The Zephyr Project. Specifically, we understand the mechanisms that enable us to use nodes in the devicetree in the C source files. We use a sample provided in the Zephyr repository itself and work our way through portions of the Zephyr codebase to get insight into the mechanisms that make this possible.
Practical CRCs for Embedded Systems
CRCs are a very practical tool for embedded systems: you're likely to need to use one as part of a communications protocol or to verify the integrity of a program image before writing it to flash. But CRCs can be difficult to understand and tricky to implement. The first time I attempted to write CRC code from scratch I failed once. Then twice. Then three times. Eventually I gave up and used an existing library. I consider myself intelligent: I got A's...
Using GPIO in (Apache) NuttX RTOS
In the previous article (https://embeddedrelated.com/showarticle/1610.php) we saw how to compile and run NuttX on three low cost boards (RaspberryPi Pico, ESP32-Devkit and STM32F4Discovery). Today we will see how to use GPIO pins and read and write logic level signals from/to the MCU pins.
Everybody knows that blinking a LED is the "Hello World" program of embedded system engineer. Controlling a GPIO we can do exactly that! Although it is important to know that NuttX...
Favorite Tools: C++11 std::array
Many embedded software and firmware projects must be developed to high standards of reliability. To meet these reliability requirements, firmware project teams will consider many design tradeoffs. For example, an engineering team may avoid or outright ban the use of dynamic memory allocation, a feature typically accessed via the C library call "malloc" or the C++ allocator "new". When authoring software under such...
The Other Kind of Bypass Capacitor
There’s a type of bypass capacitor I’d like to talk about today.
It’s not the usual power supply bypass capacitor, aka decoupling capacitor, which is used to provide local charge storage to an integrated circuit, so that the high-frequency supply currents to the IC can bypass (hence the name) all the series resistance and inductance from the power supply. This reduces the noise on a DC voltage supply. I’ve...
Linear Feedback Shift Registers for the Uninitiated, Part VII: LFSR Implementations, Idiomatic C, and Compiler Explorer
The last four articles were on algorithms used to compute with finite fields and shift registers:
- multiplicative inverse
- discrete logarithm
- determining characteristic polynomial from the LFSR output
Today we’re going to come back down to earth and show how to implement LFSR updates on a microcontroller. We’ll also talk a little bit about something called “idiomatic C” and a neat online tool for experimenting with the C compiler.
C to C++: Bridging the Gap from C Structures to Classes
In our last post, C to C++: Proven Techniques for Embedded Systems Transformation, we started to discuss the different ways that C++ can be used to write embedded software. You saw that there is no reason to be overwhelmed by trying to adopt complex topics like metaprogramming out of the gate. An important concept to understand is that you can make the transition gradually into C++ while still receiving the many benefits that C++ has to offer.
One of the first...
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...
PC and SP for a small CPU
Ok, let's make a small stack-based CPU.
I will start where the rubber meets the road - the PC/stack subsystem that I like referring to as the 'legs'. As usual, I will present a design with a twist.
Not having a large design team, deadlines and million-dollar fab runs when designing CPUs creates a truly different environment. I can actually sit at the kitchen table and doodle around with CPU designs to my heart's content. I can try really ridiculous approaches, and work without a...
Interfacing LINUX with microcontrollers
Introduction
I am increasingly asked to work on small spare time projects where a user needs to control some device over the INTERNET. Recently, a friend needed to control heater relays and measure the temperature of its geographically distant secondary house. Another case relates to the control of a pan tilt home monitoring camera. A last one is the control of an old XY plotter DACs.
In both applications, the user wants to access the system over a web browser using HTTP. From the user...
Levitating Globe Teardown, Part 2
Part 1 of this article was really more of an extended (and cynical) product review. In this part of the article, I actually take things apart (sometimes a bit more suddenly than I meant to) and show you some innards.First the globe. I knew there was a magnet in there someplace, because it's obviously plastic and it also attracts metal. I had intended to gently part the globe at the glue bond along the equator. I started by trying to gently flex the thing on my work...
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.
Lost Secrets of the H-Bridge, Part II: Ripple Current in the DC Link Capacitor
In my last post, I talked about ripple current in inductive loads.
One of the assumptions we made was that the DC link was, in fact, a DC voltage source. In reality that's an approximation; no DC voltage source is perfect, and current flow will alter the DC link voltage. To analyze this, we need to go back and look at how much current actually is being drawn from the DC link. Below is an example. This is the same kind of graph as last time, except we added two...
