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Memfault State of IoT Report

Flood Fill, or: The Joy of Resource Constraints

Ido Gendel November 13, 2023

When transferred from the PC world to a microcontroller, a famous, tried-and-true graphics algorithm is no longer viable. The challenge of creating an alternative under severe resource constraints is an intriguing puzzle, the kind that keeps embedded development fun and interesting.


Embedded Systems Roadmaps

Nathan Jones November 9, 2023

What skills should every embedded systems engineer have? What should you study next to improve yourself as an embedded systems engineer? In this article I'll share with you a few lists from well-respected sources that seek to answer these questions, with the hope of helping provide you a path to mastery. Whether you've only just finished your first Arduino project or you've been building embedded systems for decades, I believe there's something in here for everyone to help improve themselves as embedded systems engineers.


Embedded Systems Co-design for Object Recognition: A Synergistic Approach

Charu Pande November 4, 2023

Embedded systems co-design for object recognition is essential for real-time image analysis and environmental sensing across various sectors. This methodology harmonizes hardware and software to optimize efficiency and performance. It relies on hardware accelerators, customized neural network architectures, memory hierarchy optimization, and power management to achieve benefits like enhanced performance, lower latency, energy efficiency, real-time responsiveness, and resource optimization. While challenges exist, co-designed systems find applications in consumer electronics, smart cameras, industrial automation, healthcare, and autonomous vehicles, revolutionizing these industries. As technology advances, co-design will continue to shape the future of intelligent embedded systems, making the world safer and more efficient.


What is Pulse Width Modulation and How Does It Work?

Lance Harvie November 2, 2023

Pulse Width Modulation (PWM) is a technique used to control the average voltage supplied to a device or component by adjusting the width of a series of pulses. It works by rapidly turning a signal on and off at a specific frequency. The crucial element of PWM is the duty cycle, which represents the percentage of time the signal is “on” (high voltage) compared to the total time of one cycle.


Getting Started With Zephyr: Saving Data To Files

Mohammed Billoo October 31, 2023

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.


Elliptic Curve Cryptography - Extension Fields

Mike October 29, 2023

An introduction to the pairing of points on elliptic curves. Point pairing normally requires curves over an extension field because the structure of an elliptic curve has two independent sets of points if it is large enough. The rules of pairings are described in a general way to show they can be useful for verification purposes.


Software is free and can right any wrong

Colin Walls October 26, 2023

Software changes are so much easier than hardware modifications, so the temptation is always to take this approach to fixing bugs. This may not always be a good idea.


Modern C++ in embedded development: Static Classes

Amar Mahmutbegovic October 25, 20231 comment

There is a concept of static class in C#. It is a class that contains only static members and methods, and it can’t be instantiated. In C#, a static class is declared using the static keyword. 

Static classes are used to group functions that belong to the same logical unit or software module and that may have a shared state (member variables). 

Static class in C++

The concept of a static class can be implemented in C++ as a class with all static methods and members and by deleting...


Creating a Hardware Abstraction Layer (HAL) in C

Jacob Beningo October 23, 20233 comments

In my last post, C to C++: Using Abstract Interfaces to Create Hardware Abstraction Layers (HAL), I discussed how vital hardware abstraction layers are and how to use a C++ abstract interface to create them. You may be thinking, that’s great for C++, but I work in C! How do I create a HAL that can easily swap in and out different drivers? In today’s post, I will walk through exactly how to do that while using the I2C bus as an example.


Elliptic Curve Cryptography - Key Exchange and Signatures

Mike October 21, 2023

Elliptic curve mathematics over finite fields helps solve the problem of exchanging secret keys for encrypted messages as well as proving a specific person signed a particular document. This article goes over simple algorithms for key exchange and digital signature using elliptic curve mathematics. These methods are the essence of elliptic curve cryptography (ECC) used in applications such as SSH, TLS and HTTPS.


How to Build a Fixed-Point PI Controller That Just Works: Part II

Jason Sachs March 24, 20122 comments

In Part I we talked about some of the issues around discrete-time proportional-integral (PI) controllers:

  • various forms and whether to use the canonical form for z-transforms (don't do it!)
  • order of operation in the integral term: whether to scale and then integrate (my recommendation), or integrate and then scale.
  • saturation and anti-windup

In this part we'll talk about the issues surrounding fixed-point implementations of PI controllers. First let's recap the conceptual structure...


PID Without a PhD

Tim Wescott April 26, 201612 comments

I both consult and teach in the area of digital control. Through both of these efforts, I have found that while there certainly are control problems that require all the expertise I can bring to bear, there are a great number of control problems that can be solved with the most basic knowledge of simple controllers, without resort to any formal control theory at all.

This article will tell you how to implement a simple controller in software and how to tune it without getting into heavy...


From Baremetal to RTOS: A review of scheduling techniques

Jacob Beningo June 8, 201617 comments

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...


Introduction to Microcontrollers - Button Matrix & Auto Repeating

Mike Silva November 12, 2013

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...


Round Round Get Around: Why Fixed-Point Right-Shifts Are Just Fine

Jason Sachs November 22, 20163 comments

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 avoid overflow. Adding or subtracting two 16-bit integers produces a 17-bit result; multiplying two 16-bit integers produces a 32-bit result. In fixed-point arithmetic we typically multiply and shift right; for example, if we wanted to multiply some...


Development of the MOS Technology 6502: A Historical Perspective

Jason Sachs June 18, 20222 comments

One ubiquitous microprocessor of the late 1970s and 1980s was the MOS Technology MCS 6502. I included a section on the development of the 6502 in Part 2 of Supply Chain Games, and have posted it as an excerpt here, as I believe it is deserving in its own right.

(Note: MOS Technology is pronounced with the individual letters M-O-S “em oh ess”,[1] not “moss”, and should not be confused with another semiconductor company,


Which MOSFET topology?

Jason Sachs September 1, 20119 comments

A recent electronics.StackExchange question brings up a good topic for discussion. Let's say you have a power supply and a 2-wire load you want to be able to switch on and off from the power supply using a MOSFET. How do you choose which circuit topology to choose? You basically have four options, shown below:

From left to right, these are:

High-side switch, N-channel MOSFET High-side switch, P-channel MOSFET Low-side switch, N-channel...

BGA and QFP at Home 1 - A Practical Guide.

Victor Yurkovsky October 13, 20134 comments

It is almost universally accepted by the hobbyists that you can't work with high-density packages at home.  That is entirely incorrect.  I've been assembling and reflowing BGA circuit boards at home for a few years now.  BGAs and 0.5mm-pitch QFPs are well within the realm of a determined amateur. 

This series of articles presents practical information on designing and assembling boards with high-density packages at home.  While the focus is on FPGA packages, most of...


Embedded Toolbox: Programmer's Calculator

Miro Samek June 27, 20178 comments

Like any craftsman, I have accumulated quite a few tools during my embedded software development career. Some of them proved to me more useful than others. And these generally useful tools ended up in my Embedded Toolbox. In this blog, I'd like to share some of my tools with you. Today, I'd like to start with my cross-platform Programmer's Calculator called QCalc.

I'm sure that you already have your favorite calculator online or on your smartphone. But can your calculator accept...


Memfault State of IoT Report