## Discrete-Time PLLs, Part 1: Basics

Design Files: Part1.slx

Hi everyone,

In this series of tutorials on discrete-time PLLs we will be focusing on Phase-Locked Loops that can be implemented in discrete-time signal proessors such as FPGAs, DSPs and of course, MATLAB.

In the first part of the series, we will be reviewing the basics of continuous-time baseband PLLs and we will see some useful mathematics that will give us insight into the inners working of PLLs. In the second part, we will focus on...

## Mounting plate for Arduino

November 30, 2015

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.

I am using thin plexiglass type glazing material from the hardware store.  You can use the thicker material, but may have to purchase longer screws for stand-offs depending on what you use.

I like using the small Plano tackle boxes, because they can hold the plate, a few parts, batteries and a...

## 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. The main reason of discussing this topic in detail is that, in the past few years, the degree of sophistication (and complexity) of microcontrollers in handling interrupts steadily increased, bringing them on a par with general-purpose processors.

## Coding Step 4 - Design

November 24, 2015

Articles in this series:

The last article in this series discussed how to write functional high-level requirements: specifications for what your software is supposed to do. Software design is the other side of the coin....

## Polynomial Inverse

One of the important steps of computing point addition over elliptic curves is a division of two polynomials.  When working in $GF(2^n)$ we don't have large enough powers to actually do a division, so we compute the inverse of the denominator and then multiply.  This is usually done using Euclid's method, but if squaring and multiplying are fast we can take advantage of these operations and compute the multiplicative inverse in just a few steps.

The first time I ran across this...

## Motion Sensor with Raspberry Pi and MPU6050 - Part 1

November 21, 2015

This blog will help you build your own, low cost 3-axis motion sensor using Raspberry Pi and Invensense MPU6050. For the benefit of the beginners, I will be beginning with the basics - setting up Raspberry Pi in part 1 of this blog series and then proceed to interfacing the MEMS based tri-axial motion sensing unit - MPU6050 to Raspberry Pi board in part 2. The final part no. 3 will be about acquiring data on the client computer. I have  tried multiple...

## One Clock Cycle Polynomial Math

Error correction codes and cryptographic computations are most easily performed working with $GF(2^n)$  polynomials.  By using very special values of $n$ we can build circuits which multiply and square in one clock cycle on an FPGA. These circuits come about by flipping back and forth between a standard polynomial basis and a normal basis representation of elements in $GF(2^n)$.

A normal basis is yet another form of polynomial but instead of adding powers of $\beta$ we add...

## Basic hand tools for electronics assembly

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...

## Elliptic Curve Cryptography

Secure online communications require encryption.  One standard is AES (Advanced Encryption Standard) from NIST.  But for this to work, both sides need the same key for encryption and decryption.  This is called Private Key encryption.  Public Key encryption is used to create a private key between two sides that have not previously communicated.  Compared to the history of encryption, Public Key methods are very recent having been started in the 1970's.  Elliptic...

## The three laws of safe embedded systems

November 12, 20151 comment

This short article is part of an ongoing series in which I aim to explore some techniques that may be useful for developers and organisations that are beginning their first safety-related embedded project.

In the last two weeks, I’ve had the opportunity to discuss the contents of my previous article on this site with a group of very smart and enthusiastic engineers in Cairo (Egypt). As part of this discussion, it has become clear that I should add a few more details to explain the work...

## Basic hand tools for electronics assembly

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...

## Free Goodies from Embedded World - Full Inventory and Upcoming Draw Live-Streaming Date

March 22, 20191 comment

Chances are that you already know that I went to Embedded World a few weeks ago and came back with a bag full of "goodies".  Initially, my vision was to do a single draw for one person to win it all, but I didn't expect to come back with so much stuff and so many development kits.   Based on your feedback, it seems like you guys agree that It wouldn't make sense for one person to win everything as no-one could make good use of all the boards and there would be lots of...

## Dealing With Fixed Point Fractions

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...

## Two jobs

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...

## Code Metrics - SLOC Count

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...

## The Other Kind of Bypass Capacitor

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...

## You Will Make Mistakes

September 28, 20141 comment
</scorpion>: FAIL

Anyone out there see the TV pilot of Scorpion? Genius hacker squad meets Homeland Security in a fast-paced thriller to save hundreds of airplanes from crashing after LAX air traffic control software upgrade fails and they didn’t save a backup of the old version (ZOMG!!!) so thousands of people are going to die because the planes… well, they just can’t land! They just can’t. Even if the weather is sunny and calm and there could quite possibly...

## How to install Ubuntu 12.04 Precise, Xubuntu-desktop and Open JDK-7 on Beagleboard Rev. C2

My aim was to install Ubuntu 12.04, Xubuntu-desktop graphical user interface and Java virtual machine (Open JDK-7) on my beagleboard so that I could run my java application on the monitor connected to the BB. I encountered several problems and solved them one by one. Following is how I've done it..

I had all the accesorries for the beagleboard (usb hub, dvi-to-hdmi cable, usb-ethernet converter, usb keyboard, usb mouse and a hdmi enabled monitor).

My host PC also has a Ubuntu 12.04...