BusyBox; The Swiss Army Knife of Embedded Linux
In this article we cover the BusyBox, how it's designed to be optimized for embedded targets, and how to configure and build it in different ways, we also covered the license and limitation, which led to the development of ToyBox, I hope you enjoyed the article, please leave a comment for any correction or suggestions.
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.
Using (Apache) NuttX USERLED Subsystem
In the previous article (https://embeddedrelated.com/showarticle/1623.php) we saw how to use GPIOs on NuttX testing on RaspberryPi Pico as example. In that article we used the GPIO output to control an LED, but there is a better way to do that. Of course, NuttX has an LED subsystem similar to Linux LED subsystem: it is called USERLED. Today we will see how to control LEDs using NuttX's USERLED subsystem.
The main advantage of using the USERLED...
3D printing for embedded development
Used mostly for creating little plastic objects, the desktop 3D printer is not an obvious addition to the embedded developer's toolbox. However, if you're looking for more reasons to get one, or already have one that's mostly gathering dust, here are a couple of embedded-related ways to get more value out of it.
Unraveling the Enigma: Object Detection in the World of Pixels
Exploring the realm of embedded systems co-design for object recognition, this blog navigates the convergence of hardware and software in revolutionizing industries. Delving into real-time image analysis and environmental sensing, the discussion highlights advanced object detection and image segmentation techniques. With insights into Convolutional Neural Networks (CNNs) decoding pixel data and autonomously extracting features, the blog emphasizes their pivotal role in modern computer vision. Practical examples, including digit classification using TensorFlow and Keras on the MNIST dataset, underscore the power of CNNs. Through industry insights and visualization aids, the blog unveils a tapestry of innovation, charting a course towards seamless interaction between intelligent embedded systems and the world.
Finite State Machines (FSM) in Embedded Systems (Part 1) - 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.
How Embedded Linux is used in Spacecrafts !
This article dives into the application of Linux in spacecraft, examining the challenges it poses and proposing potential solutions. Real-life examples will be discussed, while also addressing the drawbacks of employing Linux in safety-critical missions.
Getting Started With Zephyr: Bluetooth Low Energy
In this blog post, I show how to enable BLE support in a Zephyr application. First, I show the necessary configuration options in Kconfig. Then, I show how to use the Zephyr functions and macros to create a custom service and characteristic for a contrived application.
++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.
Help, My Serial Data Has Been Framed: How To Handle Packets When All You Have Are Streams
Today we're going to talk about data framing and something called COBS, which will make your life easier the next time you use serial communications on an embedded system -- but first, here's a quiz:
Quick Diversion, Part I: Which of the following is the toughest area of electrical engineering? analog circuit design digital circuit design power electronics communications radiofrequency (RF) circuit design electromagnetic...Lost Secrets of the H-Bridge, Part IV: DC Link Decoupling and Why Electrolytic Capacitors Are Not Enough
Those of you who read my earlier articles about H-bridges, and followed them closely, have noticed there's some unfinished business. Well, here it is. Just so you know, I've been nervous about writing the fourth (and hopefully final) part of this series for a while. Fourth installments after a hiatus can bring bad vibes. I mean, look what it did to George Lucas: now we have Star Wars Episode I: The Phantom Menace and
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...
Absolute Beginner's Guide To Getting Started With Raspberry Pi
Contents:
- Introduction
- Simplifications
- Decisions
- The Raspberry Pi
- Parts: What You Need
- Suppliers: Where To Order
- Shopping Lists: What To Order
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.
How Embedded Linux is used in Spacecrafts !
This article dives into the application of Linux in spacecraft, examining the challenges it poses and proposing potential solutions. Real-life examples will be discussed, while also addressing the drawbacks of employing Linux in safety-critical missions.
Zebras Hate You For No Reason: Why Amdahl's Law is Misleading in a World of Cats (And Maybe in Ours Too)
I’ve been wasting far too much of my free time lately on this stupid addicting game called the Kittens Game. It starts so innocently. You are a kitten in a catnip forest. Gather catnip.
And you click on Gather catnip and off you go. Soon you’re hunting unicorns and building Huts and studying Mathematics and Theology and so on. AND IT’S JUST A TEXT GAME! HTML and Javascript, that’s it, no pictures. It’s an example of an
VHDL tutorial - A practical example - part 1 - Hardware
In previous posts I described some simple VHDL examples. This time let's try something a little more complex. This is part one of a multiple part article. This is intended to be a detailed description of one of several initial designs that I developed for a client. This design never made it into a product, but a similar design was used and is currently being produced. As a considerable amount of work was put into this effort, I decided to share this design...
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.
VHDL tutorial - part 2 - Testbench
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 the testing process. To start the process, select "New Source" from the menu items under "Project". This launches the "New Source Wizard". From within the Wizard select "VHDL Test Bench" and enter the name of the new module (click 'Next' to...
Introduction to Microcontrollers - More On Interrupts
A Little More Detail About The Interrupt Mechanism
It's time to look a little closer at what happens in an interrupt request and response. Again this is in general terms, and different microcontroller designs may do things somewhat differently, but the basics remain the same. Most but not all interrupt requests are latched, which means the interrupt event sets a flag that stays set even if the interrupt event then goes away. It is this latched flag...
Delayed printf for real-time logging
You often debug by adding a few printfs and looking at the logs. In some real-time/low-level contexts though, you don't have time for text formatting.
You don't want prints to affect timing too much, because then timing-related bugs you're chasing might disappear. And you certainly don't want the system to stop functioning altogether because prints cause it to miss real-time deadlines.
A common alternative to prints is more "raw" logging - an event buffer, where event is a union keeping...
Use DPLL to Lock Digital Oscillator to 1PPS Signal
Introduction
There are occasions where it is desirable to lock a digital oscillator to an external time reference such as the 1PPS (One Pulse Per Second) signal output from a GPS receiver. One approach would be to synchronize a fixed frequency oscillator on the leading edge of the 1PPS signal. In many cases, this will result in adequate performance. However, in situations where simple synchronization does not provide adequate performance, digital phase-lock techniques can be applied to a...
Free Goodies from Embedded World - Full Inventory and Upcoming Draw Live-Streaming Date
Chances are that you already know that I went to Embedded World a few weeks ago and came back with a bag full of "goodies". Initially, my vision was to do a single draw for one person to win it all, but I didn't expect to come back with so much stuff and so many development kits. Based on your feedback, it seems like you guys agree that It wouldn't make sense for one person to win everything as no-one could make good use of all the boards and there would be lots of...
Lazy Properties in Python Using Descriptors
This is a bit of a side tangent from my normal at-least-vaguely-embedded-related articles, but I wanted to share a moment of enlightenment I had recently about descriptors in Python. The easiest way to explain a descriptor is a way to outsource attribute lookup and modification.
Python has a bunch of “magic” methods that are hooks into various object-oriented mechanisms that let you do all sorts of ridiculously clever things. Whether or not they’re a good idea is another...
Byte and Switch (Part 2)
In part 1 we talked about the use of a MOSFET for a power switch. Here's a different circuit that also uses a MOSFET, this time as a switch for signals:
We have a thermistor Rth that is located somewhere in an assembly, that connects to a circuit board. This acts as a variable resistor that changes with temperature. If we use it in a voltage divider, the midpoint of the voltage divider has a voltage that depends on temperature. Resistors R3 and R4 form our reference resistance; when...
Two Capacitors Are Better Than One
I was looking for a good reference for some ADC-driving circuits, and ran across this diagram in Walt Jung’s Op-Amp Applications Handbook:
And I smiled to myself, because I immediately remembered a circuit I hadn’t used for years. Years! But it’s something you should file away in your bag of tricks.
Take a look at the RC-RC circuit formed by R1, R2, C1, and C2. It’s basically a stacked RC low-pass filter. The question is, why are there two capacitors?
I...
Android for Embedded Devices - 5 Reasons why Android is used in Embedded Devices
The embedded purists are going to hate me for this. How can you even think of using Android on an embedded system ? It’s after all a mobile phone operating system/software.
Sigh !! Yes I did not like Android to begin with, as well - for use on an Embedded System. But sometimes I think the market and needs decide what has to be used and what should not be. This is one such thing. Over the past few years, I have learned to love Android as an embedded operating system....
The Least Interesting Circuit in the World
It does nothing, most of the time.
It cannot compute pi. It won’t oscillate. It doesn’t light up.
Often it makes other circuits stop working.
It is… the least interesting circuit in the world.
What is it?
About 25 years ago, I took a digital computer architecture course, and we were each given use of an ugly briefcase containing a bunch of solderless breadboards and a power supply and switches and LEDs — and a bunch of
The habitat of hardware bugs
The Moscow apartment which little me called home was also home to many other creatures, from smallish cockroaches to biggish rats. But of course we rarely met them face to face. Evolution has weeded out those animals imprudent enough to crash your dinner. However, when we moved a cupboard one time, we had the pleasure to meet a few hundreds of fabulously evolved cockroaches.
In this sense, logical bugs aren't different from actual insects. You won't find...
