Using the Beaglebone PRU to achieve realtime at low cost
Introduction I work as an engineer in a synchrotron facility. A few weeks ago, I helped the people in charge of the power supply developments to integrate a realtime control algorithm on a prototype platform: a BeagleBone Black (BBB) running...
You Don't Need an RTOS (Part 3)
In this third article I'll share with you a few cooperative schedulers (with a mix of both free and commercial licenses) that implement a few of the OS primitives that the "Superduperloop" is currently missing, possibly giving you a ready-to-go solution for your system. On the other hand, I don't think it's all that hard to add thread flags, binary and counting semaphores, event flags, mailboxes/queues, a simple Observer pattern, and something I call a "marquee" to the "Superduperloop"; I'll show you how to do that in the second half of this article and the next. Although it will take a little more work than just using one of the projects above, it will give you the maximum amount of control over your system and it will let you write tasks in ways you could only dream of using an RTOS or other off-the-shelf system.
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).
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.
Getting Started With Zephyr: Kconfig
In this blog post, we briefly look at Kconfig, one of the core pieces of the Zephyr infrastructure. Kconfig allows embedded software developers to turn specific subsystems on or off within Zephyr efficiently and control their behavior. We also learn how we can practically use Kconfig to control the features of our application using the two most common mechanisms.
Favorite Tools - Look Up Tables
As we grow in our engineering careers, we must continually add new tools to our collective tool kits. One favorite tool in my toolkit will be obvious to many experienced embedded software engineers. I still remember learning this approach early...
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.
Using the C language to program the am335x PRU
Introduction Some weeks ago, I published an article on how we used the PRU to implement a power supply control loop having hard realtime constraints: http://www.embeddedrelated.com/showarticle/586.php Writing this kind of logic in assembly...
Round Round Get Around: Why Fixed-Point Right-Shifts Are Just Fine
Today’s topic is rounding in embedded systems, or more specifically, why you don’t need to worry about it in many cases.One of the issues faced in computer arithmetic is that exact arithmetic requires an ever-increasing bit length to...
Product quality: belief or proof?
Embedded software development is a challenging activity, so it is essential to have tools and IP that is of the best quality. However, assessing that quality can be, in itself, a challenge.
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).
Simulating Your Embedded Project on Your Computer (Part 1)
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 this two-part blog series, I'll share with you the arguments in favor of simulation (so, hopefully, you too believe in its value) and I'll show you what works (and what doesn't work) to help you to simply, easily, and quickly simulate your embedded project on your computer.
Understanding Yocto Project Layers: A Modular Approach to Embedded Systems Development
My friend, the compiler
Modern compilers were given great powers, but we don't always know where and when they'll use them. This may cause us to either worry needlessly or trust unjustifiably, as demonstrated by a little example in this post.
What I Learned From Crashing and Burning in Grad School
Have you ever felt so consumed by something that it started to crowd other parts of your life? So obsessed with success in a particular area that you could hardly think about anything else? I found myself in exactly that spot in 2018 when I first started graduate school; I wanted to succeed so badly that I worked myself to the bone and I let even my marriage and my health suffer in service to it. This state of being is, believe it or not, NOT conducive to success, in neither the long-term nor the short-term. But it took two authors and one pivotal book for me to understand that, to see the pit I had dug for myself, and to begin the path back out. In this blog, I want to share with you my journey in the hopes that you can avoid the mistakes I made.
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
Stand-by or boot-up
Many factors affect the usability of devices - a key one is how long it takes to start up.
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 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...
Soft Skills For Embedded Systems Software Developers
Contents: Introduction The Skills Interpersonal Tips For Interpersonal Skills Communications Tips For Speaking Tips For Writing Tips For Diagramming Time Management Tips For Time Management Deep Focus Tips For Deep...
Ten Little Algorithms, Part 3: Welford's Method (and Friends)
Other articles in this series: Part 1: Russian Peasant Multiplication Part 2: The Single-Pole Low-Pass Filter Last time we talked about a low-pass filter, and we saw that a one-line algorithm could filter out high-frequency noise, and...
Lost Secrets of the H-Bridge, Part III: Practical Issues of Inductor and Capacitor Ripple Current
We've been analyzing the ripple current in an H-bridge, both in an inductive load and the DC link capacitor. Here's a really quick recap; if you want to get into more details, go back and read part I and part II until you've got equations coming...
Analog-to-Digital Confusion: Pitfalls of Driving an ADC
Imagine the following scenario:You're a successful engineer (sounds nice, doesn't it!) working on a project with three or four circuit boards. More than even you can handle, so you give one of them over to your coworker Wayne to design....
Beyond the RTOS: A Better Way to Design Real-Time Embedded Software
An RTOS (Real-Time Operating System) is the most universally accepted way of designing and implementing embedded software. It is the most sought after component of any system that outgrows the venerable "superloop". But it is also the design...
Introduction to Microcontrollers - Driving WS2812 RGB LEDs
[quicklinks] This tutorial chapter is a bit of a detour, but I think an interesting and useful one. It introduces a bit of assembly language programming, and demonstrates bit-banging a tight serial data protocol. And it deals...
How to Deploy Local LLMs for Embedded Software Development: Terminology and Motivation
In this blog post series, I walk you through creating a fully local, offline AI pipeline. In this first post, I outline the motivation and relevant terminology that are important before we dive into hardware selection and implementation of the pipeline.
The Data Problem Slowing Down Semiconductor Adoption
Silicon is shipping faster than ever. Devices are not. The 18 to 36 month gap between a chip becoming available and a product reaching the market is now almost entirely software integration, written by hand, rewritten for every operating system and every safety target. The fix isn't more engineers or better tools. It's better data, and a shared way to describe how chips actually behave.
