Ancient History

Mike January 18, 201612 comments

The other day I was downloading an IDE for a new (to me) OS.  When I went to compile some sample code, it failed.  I went onto a forum, where I was told "if you read the release notes you'd know that the peripheral libraries are in a legacy download".  Well damn!  Looking back at my previous versions I realized I must have done that and forgotten about it.  Everything changes, and keeping up with it takes time and effort.

When I first started with microprocessors we...

Steering an autonomous vehicle - two basic ways

Ed Nutter January 15, 2016

While there are many types of steering mechanisms, for now, I will be concentrating on two of them.

The first is known as Ackerman-type steering. On a rear-wheel-drive four-wheeled car, the rear wheels push the vehicle while the two front wheels pivot left and right, either by using a servo or a geared motor, to steer the vehicle.  Understeer is when the vehicle tries to push through the turn too wide, possibly causing the vehicle to drive off the outside of the course.   ...

Dealing With Fixed Point Fractions

Mike January 5, 20163 comments

Fixed point fractional representation always gives me a headache because I screw it up the first time I try to implement an algorithm. The difference between integer operations and fractional operations is in the overflow.  If the representation fits in the fixed point result, you can not tell the difference between fixed point integer and fixed point fractions.  When integers overflow, they lose data off the most significant bits.  When fractions overflow, they lose data off...

A quick look at the Line Follower Vehicle

Ed Nutter January 3, 20162 comments

In its most basic form, a Line Following Vehicle (LFV) consists of a line sensor, a vehicle, some way to process the signal, and batteries.

A basic line can consist of black 3/4" electrical tape on a white background. Other lines consist of a white line on a black background. While usually solid, a line can consist of dashes and even change between colors. Turns are generally sweeping and gradual, but can include angles. Each of these changes adds a layer of difficulty to the...

Analyzing the Linker Map file with a little help from the ELF and the DWARF

Govind Mukundan December 27, 201520 comments

When you're writing firmware, there always comes a time when you need to check the resources consumed by your efforts - perhaps because you're running out of RAM or Flash or you want to optimize something. The map file generated by your linker is a useful tool to aid in the resource analysis. I wanted to filter and sort the data generated in an interactive way so I wrote a C# WinForms application that reads the data from the map and presents it in a list view (using the awesome

Mathematics and Cryptography

Mike December 14, 20153 comments

The mathematics of number theory and elliptic curves can take a life time to learn because they are very deep subjects.  As engineers we don't have time to earn PhD's in math along with all the things we have to learn just to make communications systems work.  However, a little learning can go a long way to helping make our communications systems secure - we don't need to know everything. The following articles are broken down into two realms, number theory and elliptic...

Global Variables vs. Safe Software

Stephen Friederichs December 9, 2015

It seems that Reddit's programming and technology subreddits have only recently caught up to 2013. If you take a look, you'll find plenty of discussion and controversy surrounding a 2013 blog post from Safety Research & Strategies Inc. regarding the software failings behind Toyota's unintended acceleration problems. 

The article is a good overview, but for full credit you should read the writeups, presentations and testimony from 

Elliptic Curve Digital Signatures

Mike December 9, 2015

A digital signature is used to prove a message is connected to a specific sender.  The sender can not deny they sent that message once signed, and no one can modify the message and maintain the signature. The message itself is not necessarily secret. Certificates of authenticity, digital cash, and software distribution use digital signatures so recipients can verify they are getting what they paid for.

Since messages can be of any length and mathematical algorithms always use fixed...

Margin Call: Fermi Problems, Highway Horrors, Black Swans, and Why You Should Worry About When You Should Worry

Jason Sachs December 6, 20152 comments

“Reports that say that something hasn’t happened are always interesting to me, because as we know, there are known knowns; there are things we know that we know. There are known unknowns; that is to say, there are things that we now know we don’t know. But there are also unknown unknowns — there are things we do not know we don’t know.” — Donald Rumsfeld, February 2002

Today’s topic is engineering margin.

XKCD had a what-if column involving Fermi...

Elliptic Curve Key Exchange

Mike December 3, 2015

Elliptic Curve Cryptography is used to create a Public Key system that allows two people (or computers) to exchange public data so that both sides know a secret that no one else can find in a reasonable time.  The simplest method uses a fixed public key for each person.  Once cracked, every message ever sent with that key is open.  More advanced key exchange systems have "perfect forward secrecy" which means that even if one message key is cracked, no other message will...

Have You Ever Seen an Ideal Op-Amp?

Jason Sachs April 30, 2012

Somewhere, along with unicorns and the Loch Ness Monster, lies a small colony of ideal op-amps. Op-amp is short for operational amplifier, and we start our education on them by learning about these mythical beasts, which have the following properties:

  • Infinite gain
  • Infinite input impedance
  • Zero output impedance

And on top of it all, they will do whatever it takes to change their output in order to make their two inputs equal.

But they don't exist. Real op-amps have...

Went 280km/h (174mph) in a Porsche Panamera in Germany!

Stephane Boucher July 10, 201712 comments

Those of you who've been following my blog lately already know that I am going through some sort of mid-life crisis that involves going out there to meet people and make videos.  It all started with Embedded World early this year, then continued at ESC Boston a couple of months ago and the latest chapter just concluded as I returned from Germany after spending a week at SEGGER's headquarters to produce a video to highlight their 25th anniversary.  

Oscilloscope review: Hameg HMO2024

Jason Sachs March 28, 20133 comments

Last year I wrote about some of the key characteristics of oscilloscopes that are important to me for working with embedded microcontrollers. In that blog entry I rated the Agilent MSOX3024A 4-channel 16-digital-input oscilloscope highly.

Since then I have moved to a different career, and I am again on the lookout for an oscilloscope. I still consider the Agilent MSOX3024A the best choice for a...

Code Metrics - SLOC Count

Stephen Friederichs August 19, 2013

Many programmers will start having flashbacks at the title of this article because it contains the words 'metrics' and 'SLOC'.  Newer programmers are probably wondering what all of the fuss is about - most probably have no negative connotations with the term 'code metrics' and some may not even know what SLOC is.  While there is much baggage associated with metrics and SLOC you shouldn't be afraid to gather fundamentally useful data such as SLOC count from your programming projects...

Metal detection: beat frequency oscillator

Fabien Le Mentec January 30, 20161 comment
Plan Introduction Theory Electronics Software Tests ReferencesNext part: building the detector 1. Introduction

This article discusses the implementation of a beat frequency oscillator (BFO) stage for metal detector. While they are mentioned here and there, the article does not detail other important electronic stages such as the power supply, and user interface, the coil or the detector frame. I may write other articles on these topics, and other detection methods.Before...

Basic hand tools for electronics assembly

Ed Nutter November 20, 20153 comments

Though the software tools vary with different microcontrollers, many hardware tools are the same.

If you are working on larger robotic or automotive systems, you will need a 3/8" and 1/2" drive socket set. There are occasions when even larger drive socket sets are needed. For small robots and taking things apart, the 1/4" drive socket set is useful. The sizes usually range from 5/32" to 9/16" and 4mm to 15mm.  You will need both shallow and deep sockets, both standard and...

Continuous Integration for Embedded Systems

Dr. Tayyar GUZEL September 5, 20172 comments

It is no secret that anyone who wants to streamline project management, reduce risk and improve the quality needs some form of "automation" in SW development processes. What is commonly used in most companies as a tool for such automation is called Continuous Integration (CI). It is a good practice for embedded systems as well even though it is much harder to use CI for embedded systems compared to pure software development because embedded systems mostly depend on...

Two jobs

Stephane Boucher December 5, 201223 comments

For those of you following closely embeddedrelated and the other related sites, you might have noticed that I have been less active for the last couple of months, and I will use this blog post to explain why. The main reason is that I got myself involved into a project that ended up using a better part of my cpu than I originally thought it would.

edit - video of the event:

I currently have two jobs: one as an electrical/dsp engineer recycled as a web publisher and the other...

The Other Kind of Bypass Capacitor

Jason Sachs January 3, 20173 comments

There’s a type of bypass capacitor I’d like to talk about today.

It’s not the usual power supply bypass capacitor, aka decoupling capacitor, which is used to provide local charge storage to an integrated circuit, so that the high-frequency supply currents to the IC can bypass (hence the name) all the series resistance and inductance from the power supply. This reduces the noise on a DC voltage supply. I’ve...

Ada 2012 for ARM M3/M4 Released for Download

Mike Silva August 4, 201412 comments
Previous Ada Tutorials

Ada 2012 Comes to ARM Cortex M3/M4

It's Here!

Great news - AdaCore now has their initial ARM Ada port available on their download site.  You can get it by going to and working your way to the page titled "Download GNAT GPL and SPARK GPL Editions".  There, under "Select Configurations" you will see ARM ELF for Linux and for Windows.  Those are the ones you want.

Porting the Ada...