Mounting plate for Arduino
While having a breadboard with your microcontroller is necessary, it is very cumbersome if the two aren't fastened together somehow. You can buy mounting plates, but I choose to make one.
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.
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...
Improving the Reload2 active load
Introduction
With another colleague at work, we are currently developing an electronic board that will eventually be powered over Ethernet. To gain more experience with this technology, we prototyped a standalone power supply stage.
We want to test this stage with different load profiles. While we already have professional grade active loads at work, I had previously read about the Reload2 product from Arachnidlabs, a low cost active load sold on Hackaday:
Slew Rate Limiters: Nonlinear and Proud of It!
I first learned about slew rate limits when I was in college. Usually the subject comes up when talking about the nonideal behavior of op-amps. In order for the op-amp output to swing up and down quickly, it has to charge up an internal capacitor with a transistor circuit that’s limited in its current capability. So the slew rate limit \( \frac{dV}{dt} = \frac{I_{\rm max}}{C} \). And as long as the amplitude and frequency aren’t too high, you won’t notice it. But try to...
Introduction to Microcontrollers - 7-segment displays & Multiplexing
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 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...
OOKLONE: a cheap RF 433.92MHz OOK frame cloner
IntroductionA 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...
Reverse engineering wireless wall outlets
IntroductionI am improving the domotics framework that I described in a previous article://www.embeddedrelated.com/showarticle/605.php
I want to support wireless wall outlets, allowing me to switch devices power from a remote location over HTTP.
To do so, I could design my own wireless wall outlets and use a hardware similar to the previous one, based on the NRF905 chipset. The problem is that such a product would not be certified, and that would be an issue regarding the home insurance,...
A wireless door monitor based on the BANO framework
IntroductionI have been thinking for a while about a system to monitor the states of my flat and my garage doors from a remote place. Functionnaly, I wanted to monitor the state of my doors from a remote place. A typical situation is when I leave for holidays, but it can also be useful from the work office. To do so, I would centralize the information on a server connected on the Internet that I could query using a web browser. The server itself would be located in the appartement, where...
Using a RTLSDR dongle to validate NRF905 configuration
I am currently working on a system to monitor the garage door status from my flat. Both places are 7 floors apart, and I need to send the data wirelessly. I chose to operate on the 433MHz carrier, and I ordered 2 PTR8000 modules: http://www.electrodragon.com/w/NRF905_Transceiver_433MHz-Wireless_ModuleThe PTR8000 is based on the dual band sub 1GHz NRF905 chipset from NORDICSEMI: http://www.nordicsemi.com/eng/Products/Sub-1-GHz-RF/nRF905I...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...
Introduction to Microcontrollers - More Timers and Displays
Building Your World Around TimersBy now you have seen four different ways to use timers in your programs. Next we will look at some ways to produce the effect of multiple parallel streams of work in your program with the help of timers. This effect is only an appearance, not a reality, since a single microcontroller (one core) can only run a single thread of code. However, since microcontrollers are so fast in relation to a great many of the tasks to...
Arduino robotics #1 - motor control
Arduino Robotics
Beginner 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.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.
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.
Getting Started with the Microchip PIC® Microcontroller
This first post of a five part series looks at the available hardware options for getting started with Microchip 8-bit PIC® Microcontroller, explores the MPLAB® X Integrated Development Environment and walks through setting up a project to expose the configured clock to an external pin and implement a single output GPIO to light an LED.
STM32 VS Code Extension Under The Hood
VS Code is becoming the "go to" environment for many developers. Increasingly, toolchain providers are publishing VS Code extensions and ST has recently followed suit. Additionally, CMake is significantly growing in popularity, with many projects adopting it for its ease of use and flexibility. This video shows how the STM32 VS Code extension works under the hood and how to get more out of it.
Specifically, we'll review the CMake files generated by the VS Code extension and how to modify...
Reverse engineering wireless wall outlets
IntroductionI am improving the domotics framework that I described in a previous article://www.embeddedrelated.com/showarticle/605.php
I want to support wireless wall outlets, allowing me to switch devices power from a remote location over HTTP.
To do so, I could design my own wireless wall outlets and use a hardware similar to the previous one, based on the NRF905 chipset. The problem is that such a product would not be certified, and that would be an issue regarding the home insurance,...
OOKLONE: a cheap RF 433.92MHz OOK frame cloner
IntroductionA 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...
Essential Elements to choose a right Processor
Recently I was working for an automotive client where I was supposed to choose a suitable microcontroller for my project. I started listing down the various microcontrollers available in the market, finally I made a big list and it became tough to finalize the best one. Most of the selected controllers were meeting my requirements, and it was really a tough task to choose the right one.
Then I started listing down the aspects...
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...
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.
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.
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.
Improving the Reload2 active load
IntroductionWith another colleague at work, we are currently developing an electronic board that will eventually be powered over Ethernet. To gain more experience with this technology, we prototyped a standalone power supply stage.
We want to test this stage with different load profiles. While we already have professional grade active loads at work, I had previously read about the Reload2 product from Arachnidlabs, a low cost active load sold on Hackaday:
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 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.
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...
Getting Started With Zephyr: Writing Data to EEPROM
In this blog post, I show how to implement a Zephyr application to interact with EEPROM. I show how the Zephyr device driver model allows application writers to be free of the underlying implementation details. Unfortunately, the application didn't work as expected, and I'm still troubleshooting the cause.
7 Essential Steps for Reducing Power Consumption in Embedded Devices
Reducing the amount of power your embedded device is consuming is not trivial. With so many devices moving to battery operations today, maximizing battery life can be the difference between a happy, raving customer and an unhappy one that ruins your company's reputation. This post explores seven steps for optimizing your embedded systems' power consumption. You'll gain insights into the steps and techniques necessary along with receiving a few resources to help you on your journey.
