Scorchers, Part 3: Bare-Metal Concurrency With Double-Buffering and the Revolving Fireplace
This is a short article about one technique for communicating between asynchronous processes on bare-metal embedded systems.
Q: Why did the multithreaded chicken cross the road?
A: to To other side. get the
There are many reasons why concurrency is
Round-robin or RTOS for my embedded system
First of all, I would like to introduce myself. I am Manuel Herrera. I am starting to write blogs about the situations that I have faced over the years of my career and discussed with colleagues.
To begin, I would like to open a conversation with a dilemma that is present when starting a project ... must I use or not any operating system?
I hope it helps you to form your own criteria and above all that you enjoy it.
Does my embedded system need an...
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...
AI at the Edge - Can I run a neural network in a resource-constrained device?
Hello Related Communities,
This is my first time blogging since joining Stephane in November. He and I were at Embedded World together and he asked me to write about some of the important trends as they relate to all of you. I expect to post others in the near future, but the biggest trend in the embedded space was all of the activity around artificial intelligence (AI) at the edge.
This trend caught me a bit by surprise. I have been doing a lot of reading about AI over the last...
Introduction to Deep Insight Analysis for RTOS Based Applications
Over the past several years, embedded systems have become extremely complex. As systems become more complex, they become harder and more time consuming to debug. It isn’t uncommon for development teams to spend more than 40% development cycle time just debugging their systems. This is where deep insight analysis has the potential to dramatically decrease costs and time to market.
Defining Deep Insight Analysis
Deep insight analysis is a set of tools and techniques that can be...
From bare-metal to RTOS: 5 Reasons to use an RTOS
Developers can come up with amazing and convoluted reasons to not use an RTOS. I have heard excuses ranging from they are too expensive (despite open source solutions) all the way to they aren’t efficient and use too much memory. In some circumstances some excuses are justified but there are many reasons why a developer should look to an RTOS to help with their real-time scheduling needs.
From bare-metal to RTOS Quick LinksFrom Baremetal to RTOS: A review of scheduling techniques
Transitioning from bare-metal embedded software development to a real-time operating system (RTOS) can be a difficult endeavor. Many developers struggle with the question of whether they should use an RTOS or simply use a bare-metal scheduler. One of the goals of this series is to walk developers through the transition and decision making process of abandoning bare-metal thinking and getting up to speed quickly with RTOSes. Before diving into the details of RTOSes, the appropriate first step...
Choosing a Microcontroller for Your Vehicle
There are many things to take into consideration when choosing a microcontroller or microprocessor for your autonomous vehicle.
Voltage
Some processors run on 5V and others use 3.3V. Be sure to check the documentation before you buy. Make sure your supply has a high enough amp rating that your microcontroller doesn't lose pwer.
Power
Can the system run using batteries? Large, automotive sized vehicles can be run from large batteries or inverters in the vehicle. Smaller...
Cutting Through the Confusion with ARM Cortex-M Interrupt Priorities
The insanely popular ARM Cortex-M processor offers very versatile interrupt priority management, but unfortunately, the multiple priority numbering conventions used in managing the interrupt priorities are often counter-intuitive, inconsistent, and confusing, which can lead to bugs. In this post I attempt to explain the subject and cut through the confusion.
The Inverse Relationship Between Priority Numbers and Urgency of the Interrupts
The most important fact to know is that ARM...
Cortex-M Exception Handling (Part 2)
The first part of this article described the conditions for an exception request to be accepted by a Cortex-M processor, mainly concerning the relationship of its priority with respect to the current execution priority. This part will describe instead what happens after an exception request is accepted and becomes active.
PROCESSOR OPERATION AND PRIVILEGE MODEBefore discussing in detail the sequence of actions that occurs within the processor after an exception request...
Cortex-M Exception Handling (Part 2)
The first part of this article described the conditions for an exception request to be accepted by a Cortex-M processor, mainly concerning the relationship of its priority with respect to the current execution priority. This part will describe instead what happens after an exception request is accepted and becomes active.
PROCESSOR OPERATION AND PRIVILEGE MODEBefore discussing in detail the sequence of actions that occurs within the processor after an exception request...
Getting Started with (Apache) NuttX RTOS Part 2 - Looking Inside and Creating Your Customized Image
In the previous article (https://www.embeddedrelated.com/showarticle/1524.p...) we saw how to run NuttX RTOS using the SIMulator. Today we will see how NuttX's directory tree is organized and how to use the menuconfig to enable some applications, including some tricks to search and solve dependencies.
NuttX Directories organization:
If you have previously compiled the Linux kernel or the U-Boot bootloader you will see that the NuttX source tree organization is...
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...
Introduction to Microcontrollers - Button Matrix & Auto Repeating
Too Many Buttons, Not Enough Inputs
Assigning one GPIO input to each button can use up a lot of GPIO pins. Numeric input requires at least 10 buttons, plus however many additional control or function buttons. This can quickly get expensive, GPIO pin-wise, and also connector-wise if the keypad is off the uC PCB as it often would be. A very common response to this expense is to wire buttons (keys, etc) in a matrix. By connecting our buttons in an...
NULL pointer protection with ARM Cortex-M MPU
This post explains how you can set up the ARM Cortex-M MPU (Memory Protection Unit) to protect thy code from dragons, demons, core dumps, and numberless other foul creatures awaiting thee after thou dereference the NULL pointer.
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).
OOKLONE: a cheap RF 433.92MHz OOK frame cloner
Introduction
A few weeks ago, I bought a set of cheap wireless outlets and reimplemented the protocol for further inclusion in a domotics platform. I wrote a post about it here:
//www.embeddedrelated.com/showarticle/620.php
Following that, I had access to another outlet from a different vendor:
http://www.castorama.fr/store/Prise-telecommandee-BLYSS---Interieur-prod4470027.html
The device documentation mentions that it operates on the same frequency as the previous...
Round-robin or RTOS for my embedded system
First of all, I would like to introduce myself. I am Manuel Herrera. I am starting to write blogs about the situations that I have faced over the years of my career and discussed with colleagues.
To begin, I would like to open a conversation with a dilemma that is present when starting a project ... must I use or not any operating system?
I hope it helps you to form your own criteria and above all that you enjoy it.
Does my embedded system need an...
Energia - program a TI MSP430 using Arduino sketches
TI MSP430 Launchpad
I started tinkering with microcontroller a couple of years ago with an Arduino Uno. I had a little experience with C, so programming in the Arduino environment has been relatively easy and straightforward for me. My code is not necessarily elegant or efficient, but I can usually figure out how to make an Arduino do what I want it to do eventually. A lot of credit to the Arduino userbase, as it is very easy to figure most things out with a quick Google...
Introduction to Microcontrollers - 7-segment displays & Multiplexing
Doing the 7 Segment ShuffleThe 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 digits. What makes the 7-seg interesting is that it presents an opportunity to make a trade off between GPIO (output pins) for time. Every 7-seg display requires 8 outputs (the 7 segments and usually either a decimal point or a...
Scorchers, Part 3: Bare-Metal Concurrency With Double-Buffering and the Revolving Fireplace
This is a short article about one technique for communicating between asynchronous processes on bare-metal embedded systems.
Q: Why did the multithreaded chicken cross the road?
A: to To other side. get the
There are many reasons why concurrency is
Arduino robotics #2 - chassis, locomotion and power
Arduino RoboticsBeginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around $50.
1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.Round-robin or RTOS for my embedded system
First of all, I would like to introduce myself. I am Manuel Herrera. I am starting to write blogs about the situations that I have faced over the years of my career and discussed with colleagues.
To begin, I would like to open a conversation with a dilemma that is present when starting a project ... must I use or not any operating system?
I hope it helps you to form your own criteria and above all that you enjoy it.
Does my embedded system need an...
C to C++: 5 Tips for Refactoring C Code into C++
The article titled "Simple Tips to Refactor C Code into C++: Improve Embedded Development" provides essential guidance for embedded developers transitioning from C to C++. The series covers fundamental details necessary for a seamless transition and emphasizes utilizing C++ as a better C rather than diving into complex language features. The article introduces five practical tips for refactoring C code into C++. Replace #define with constexpr and const: Discouraging the use of #define macros, the article advocates for safer alternatives like constexpr and const to improve type safety, debugging, namespaces, and compile-time computation. Use Namespaces: Demonstrating the benefits of organizing code into separate logical groupings through namespaces, the article explains how namespaces help avoid naming conflicts and improve code readability. Replace C-style Pointers with Smart Pointers and References: Emphasizing the significance of avoiding raw pointers, the article suggests replacing them with C++ smart pointers (unique_ptr, shared_ptr, weak_ptr) and using references
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...
Trust, but Verify: Examining the Output of an Embedded Compiler
I work with motor control firmware on the Microchip dsPIC33 series of microcontrollers. The vast majority of that firmware is written in C, with only a few percent in assembly. And I got to thinking recently: I programmed in C and C++ on an Intel PC from roughly 1991 to 2009. But I don’t remember ever working with x86 assembly code. Not once. Not even reading it. Which seems odd. I do that all the time with embedded firmware. And I think you should too. Before I say why, here are...
Learning A New Microcontroller
Contents:
- Introduction
- The Peripherals
- System Complexity
- Support Software
- Do It Like Phil
- The Programs
- WET And DRY Code
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.
Getting Started With Zephyr: Devicetree Overlays
In this blog post, I show how the Devicetree overlay is a valuable construct in The Zephyr Project RTOS. Overlays allow embedded software engineers to override the default pin configuration specified in Zephyr for a particular board. In this blog post, I use I2C as an example. Specifically, I showed the default I2C pins used for the nRF52840 development kit in the nominal Zephyr Devicetree. Then, I demonstrated how an overlay can be used to override this pin configuration and the final result.
Getting Started with (Apache) NuttX RTOS - Part 1
NuttX RTOS is used in many products from companies like Sony, Xiaomi, Samsung, Google/Fitbit, WildernessLabs and many other companis. So, probably you are already using NuttX even without knowing it, like the you was using Linux on your TV, WiFi router more than 10 years ago and didn't know too! Today you will have the chance to discover a little bit of this fantastic Linux-like RTOS! Are you ready? So, let's get started!
