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...
Byte and Switch (Part 1)
Imagine for a minute you have an electromagnet, and a microcontroller, and you want to use the microcontroller to turn the electromagnet on and off. Sounds pretty typical, right?We ask this question on our interviews of entry-level electrical...
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...
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).
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.
When a Mongoose met a MicroPython, part II
In the first part of this blog, we introduced this little framework to integrate MicroPython and Cesanta's Mongoose; where Mongoose runs when called by MicroPython and is able to run Python functions as callbacks for the events you decide in your event handler. Now we add MQTT to the equation, so we can subscribe to topics and publish messages right from MicroPython.
Getting Started With Zephyr: Saving Data To Files
In this blog post, I show how to implement a Zephyr application to mount a microSD card, create a new file on the microSD card, and write data to it. The lessons learned from such an application can be helpful for devices out in the field that need to write data to off-board memory periodically, especially in cases where Internet access may be sporadic.
Unuglify C++ FSM with DSL
Domain Specific Languages (DSL) are an effective way to avoid boilerplate or repetitive code. Using DSLs lets the programmer focus on the problem domain, rather than the mechanisms used to solve it. Here I show how to design and implement a DSL using the C++ preprocessor, using the FSM library, and the examples I presented in my previous articles.
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...
Getting Started With Zephyr: Devicetree Bndings
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.
Square root in fixed point VHDL
We will design and implement a fixed point square root function in VHDL. The algorithm is based on the recursive inverse square root algorithm based on Newton Raphson and offers parametrizable pipeline depth, word length and the algorithm is built on records and procedures.
Quaternions and the spatial rotations in motion enabled wearable devices. Exploiting the potential of smart IMUs attitude estimation.
Have you always wondered what a quaternion is? this is your post. Attitude or spatial orientation analysis is a powerful element in wearable devices (and many other systems). Commercially available sensors can provide this information out-of-the-box without requiring complex additional implementation of sensor fusion algorithms. Since these are already on-chip solutions devices can serve as a way to explore and analyze motion in several use cases. Mathematical analysis for processing quaternion is presented along with a brief introduction to them, Although they are not really easy to visualise, a couple fairly simple examples are provided which may allow you to gain some intuition on what's the logic behind them.
From Embedded Software Engineer to Musician
In his first blog post on EmbeddedRelated, Jean Labrosse, the author of the uC/OS series and founder of Micrium, discusses his transition from an embedded software engineer to a musician.
Jumping from MCUs to FPGAs - 5 things you need to know
Are you a microcontroller expert beckoned by the siren song of the FPGA? Not long ago, that was me. FPGA-expert friends of mine regularly extolled the virtues of these mysterious components and I wanted in. When I made the leap, I found a world seemingly very familiar, but in reality, vastly different. I found that my years of C programming and microcontroller use often gave pre preconceived interpretations of FPGA resource material which resulted in eye-roll class mistakes in my code. I’ve gleaned five things of vital importance to help you make that transition faster than I did.
Assembly language is best - except when it isn’t
A look at why writing in C often produces more efficient code than hand-written assembly language.
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
Getting Started With Zephyr: Devicetrees
This blog post provides an introduction to the "Devicetree", another unique concept in The Zephyr Project. We learn about the basic syntax of a device tree and how its structure and hierarchy mirror hardware, from the SoC to the final board. We also see how hardware described in a devicetree can be referenced and controlled in the source code of a Zephyr-based application.
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.
Debug, visualize and test embedded C/C++ through instrumentation
Instrumenting a firmware is a highly effective methodology for debugging and testing an embedded softwares. In this article, I will present a way of achieving this using Scrutiny, an open-source software suite developed as a personal initiative, designed to streamline debugging, telemetry, and hardware-in-the-loop (HIL) testing for embedded devices.
Working with Microchip PIC 8-bit Interrupts
This fifth and final post of the Getting Started with Microchip PIC 8 Bit Development series looks at interrupts on 8-bit PIC microcontrollers. After a review of basic interrupt functionality, actual implementation is explored through implementation of a four bit counter driven via Timer0 interrupts whose value is displayed through four LEDs on Microchip's Curiosity HPC Development Board.
Static or static
The keyword static in C and C++ has multiple uses, which are not always well understood.
Hidden Gems from the Embedded Online Conference Archives - Part 2
A look back at a deep dive into the Mars Perseverance flight software from one of the technical leads at JPL.
Optimizing Hardware Design: Reducing Iterations with DSM
Often, product teams curate feature roadmaps that fail to account for the interdependencies in product components. For this article, I wrote about how system architecture tools like Design(dependency) Structure matrix (DSM) can be used to evaluate feature roadmaps to avoid the purgatory of change propagation and accompanying endless Iteration loops. These iteration loops are sometimes affordable (manageable) in software development (Agile saves lives), but for hardware teams - especially small product teams and startups - the lost time, and money is the stuff of which product graves are made.
OS influence on power consumption
Power consumption of an embedded system may be influenced in software in general, but selection of an operating system can be key.
On hardware state machines: How to write a simple MAC controller using the RP2040 PIOs
Hardware state machines are nice, and the RP2040 has two blocks with up to four machines each. Their instruction set is limited, but powerful, and they can execute an instruction per cycle, pushing and popping from their FIFOs and shifting bytes in and out. The Raspberry Pi Pico does not have an Ethernet connection, but there are many PHY boards available… take a LAN8720 board and connect it to the Pico; you’re done. The firmware ? Introducing Mongoose…
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).
Shibboleths: The Perils of Voiceless Sibilant Fricatives, Idiot Lights, and Other Binary-Outcome Tests
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.
