## Round-robin or RTOS for my embedded system

June 9, 20194 comments

First of all, I would like to introduce myself. I am Manuel Herrera. I am starting to write blogs about the situations that I have faced over the years of my career and discussed with colleagues.

To begin, I would like to open a conversation with a dilemma that is present when starting a project ... must I use or not any operating system?

I hope it helps you to form your own criteria and above all that you enjoy it.

Does my embedded system need an...

## Watchdog Timer Anti-patterns

June 8, 2019

The humble watchdog timer has been an essential part of our reliability tool chest for decades now. The way it works is straightforward and easy to understand, and most practical designs are easy to interface with.

There is a wealth of reference material that covers both the theory behind watchdog timers and practical design tips. But what we'll talk about today is of a slightly different nature.

Despite its straightforward operation and long history, the watchdog timer does occasionally get...

## Mutex vs. Semaphores – Part 2: The Mutex & Mutual Exclusion Problems

May 15, 20194 comments

Part 1 of this series we looked at the history of the binary and counting semaphore, and then went on to discuss some of the associated problem areas. In this posting I aim to show how a different RTOS construct, the mutex, may overcome some, if not all, of these weaknesses.

To address the problems associated with semaphore, a new concept was developed during the late 1980’s. I have struggled to find it’s first clear definition, but the major use of the term mutex (another...

## Designing Communication Protocols, Practical Aspects

May 14, 2019

For most embedded developers always comes the time when they have to make their embedded MCU talk to another system. That other system will be a PC or a different embedded system or a smartphone etc. For the purpose of this article I am assuming that we are in the control of the protocol between the two ends and we don’t have to follow something that is already in place on one side.

So let’s say that we have our embedded MCU, we have implemented and configured the USB stack (or just...

## A brief overview of flight control software

May 3, 20191 comment

It has been a long time since the first drones appeared. If you are interested in such a topic, you may be confused about how and where to jump in. Since I went through the same phase, I'd like to write my findings here and help others.

For this blog post, I've created chart and table with all open source flight control programs I've been able to find.

The chart shows the course of development of the existing software. It is separated in years and you can see when which project...

## Debugging DSP code.

May 1, 2019

I am fascinated with neural network processing and have been playing with them since the 80's.

I am a frequent contributor to the Numenta forum. Numenta is the current project of Jeff Hawins, the guy that gave us the Palm Pilot. They are working with the HTM model. This is a system based on studies of the functions of the cortical column and has some very interesting properties: It processes sequential data streams and has very effective one shot learning. The data is arranged in Sparse...

## Mutex vs. Semaphore - Part 1

April 12, 20195 comments

It never ceases to amaze me how often I see postings in forums asking the difference between a semaphore and a mutex. Probably what baffles me more is that over 90% of the time the responses given are either incorrect or missing the key differences. The most often quoted response is that of the “The Toilet Example (c) Copyright 2005, Niclas Winquist” . This summarises the differences as:

• A mutex is really a semaphore with value 1

No, no, and no again....

## Patents and the little guy working at home

April 11, 20191 comment
There are pluses and minuses to having patents. As it stands now the patent system is horribly broken and not doing what the founders intended when they set it up.I have some patents through work and it does look nice to see my name on the patent database. It's kinda like wetting yourself in a dark suit - it gives you a warm feeling but nobody notices.Don Lancaster makes a compelling argument that for the little guy it’s best to avoid the whole mess to the degree possible.

## A Balancing Act

April 10, 20191 comment

For the second live streaming session, I give myself a 5/10.

I felt much more comfortable and was way better prepared than when I did my first session - and that's why I went from 3/10 to 5/10 in my system of self-awarded rating - but my attempt at 'live' humor fell rather flat I think and I had some technical difficulties with the live streaming itself.   So I believe 5/10 is fair and leaves lots of room for improvement.

As far as my attempt at humor is concerned, you...

## Public speaking

April 3, 20192 comments

Public Speaking: This common task goes with embedded system engineering. Pitching a project. Presenting at a conference. Delivering a status report. Teaching. All part of the job.

Stephane Boucher did a v-blog post here last week and is naturally apprehensive about how he did.

If you have not seen it you can catch it here:

First - Stephane - You did fine!

I spent some time (5 quarters, 3 classes a day, computer technology in a tech school) in a classroom and am comfortable in front of a...

## Introduction to Microcontrollers - Beginnings

August 20, 201312 comments

Welcome to this Introduction to Microcontroller Programming tutorial series. If you are looking to learn the basics of embedded programming for microcontrollers (and a bit of embedded hardware design as well), I hope these tutorials will help you along that journey. These are my first postings here, and I am writing this tutorial series because over the years I have seen countless newbies asking the same questions and tripping over the same stumbling blocks, and I thought I might be able to...

## MSP430 Launchpad Tutorial - Part 2 - Interrupts and timers

June 17, 201339 comments

What is an "interrupt"? It is a signal that informs our MCU that a certain event has happened, causing the interruption of the normal flow of the main program and the execution of an "interrupt routine", that handles the event and takes a specified action.

Interrupts are essential to avoid wasting the processor's valuable time in polling loops, waiting for external events (in fact they are used in Real-Time Operating Systems,

## How FPGAs work, and why you'll buy one

June 20, 201314 comments

Today, pretty much everyone has a CPU, a DSP and a GPU, buried somewhere in their PC, phone, car, etc. Most don't know or care that they bought any of these, but they did.

Will everyone, at some future point, also buy an FPGA? The market size of FPGAs today is about 1% of the annual global semiconductor sales (~$3B vs ~$300B). Will FPGA eventually...

## MSP430 LaunchPad Tutorial - Part 4 - UART Transmission

July 3, 201320 comments

Today we are going to learn how to communicate using UART with the Launchpad. For this purpose I will replace the default microcontroller that comes with the board with the MSP430G2553. It is the most powerful device in the MSP430 Value Line and it comes with an integrated hardware UART module, along with 16 Kb of Flash memory, 512 bytes of SRAM and an 8-channel, 10 bit ADC.

UART communication can be useful when dealing with sensors: as a basic example, we could...

## VHDL tutorial - A practical example - part 3 - VHDL testbench

June 25, 20117 comments

In part 1 of this series we focused on the hardware design, including some of the VHDL definitions of the I/O characteristics of the CPLD part.  In part 2, we described the VHDL logic of the CPLD for this design.  In part 3, we will show the entire VHDL design and the associated tests used to prove that we have, in fact, designed what we started out to design.

First, let's pull all of the pieces of the prior design together into a...

## My Love-Hate Relationship with Stack Overflow: Arthur S., Arthur T., and the Soup Nazi

February 15, 201551 comments

Warning: In the interest of maintaining a coherent stream of consciousness, I’m lowering the setting on my profanity filter for this post. Just wanted to let you know ahead of time.

I’ve been a user of Stack Overflow since December of 2008. And I say “user” both in the software sense, and in the drug-addict sense. I’m Jason S, user #44330, and I’m a programming addict. (Hi, Jason S.) The Gravatar, in case you were wondering, is a screen...

## Adventures in Signal Processing with Python

June 23, 201311 comments

Author’s note: This article was originally called Adventures in Signal Processing with Python (MATLAB? We don’t need no stinkin' MATLAB!) — the allusion to The Treasure of the Sierra Madre has been removed, in deference to being a good neighbor to The MathWorks. While I don’t make it a secret of my dislike of many aspects of MATLAB — which I mention later in this article — I do hope they can improve their software and reduce the price. Please note this...

## MSP430 Launchpad Tutorial - Part 1 - Basics

June 14, 201319 comments

TI's LaunchPad is a complete MSP430 development environment: all you have to do is download and install CCS IDE (login required), connect your G2231-ready LaunchPad to your computer with the included mini-usb cable, and you are ready to code!

Texas Instrument MSP430 LaunchPad

So, let's see how to start a new project in Code Composer Studio. This IDE is derived from Eclipse, so if you used it before you shouldn't have much problems.

We'll write a simple program that will...

## VHDL tutorial - part 2 - Testbench

October 30, 20073 comments

In an earlier article I walked through the VHDL coding of a simple design. In this article I will continue the process and create a test bench module to test the earlier design. The Xilinx ISE environment makes it pretty easy to start the testing process. To start the process, select "New Source" from the menu items under "Project". This launches the "New Source Wizard". From within the Wizard select "VHDL Test Bench" and enter the name of the new module (click 'Next' to...

## Using the Beaglebone PRU to achieve realtime at low cost

April 25, 20148 comments
Introduction

I work as an engineer in a synchrotron facility. A few weeks ago, I helped the people in charge of the power supply developments to integrate a realtime control algorithm on a prototype platform: a BeagleBone Black (BBB) running Linux. I had already worked with this board in the past, and I found it very interesting given its excellent resources versus price ratio (around 40 euros). This time, I was impressed by its realtime capabilities. I thought it would be a good idea to...

## A Balancing Act

April 10, 20191 comment

For the second live streaming session, I give myself a 5/10.

I felt much more comfortable and was way better prepared than when I did my first session - and that's why I went from 3/10 to 5/10 in my system of self-awarded rating - but my attempt at 'live' humor fell rather flat I think and I had some technical difficulties with the live streaming itself.   So I believe 5/10 is fair and leaves lots of room for improvement.

As far as my attempt at humor is concerned, you...

## The Ice is Broken

April 1, 20196 comments

When I suggested that you lower you expectations before watching my first live session, I wasn't kidding.

Still, I was hoping I would do much better than what I had prepared you for but obviously it wasn't meant to be.

Don't get me wrong, a few things went very well, like the technical aspects for instance.  I thought the improvised studio looked pretty good, the audio sounded fine and the HD stream was nice and steady.

And my mom thinks that I looked handsome...

## Lower your Expectations

March 26, 20196 comments

This Friday, I will for the first time be the person in front of the camera, the star of my own show on EmbeddedRelated.tv.  I will be experimenting with talking live to the *Related sites community, using the 'Free Goodies' prize draw as a pretext.

This could become a very effective way to communicate with you and part of me is genuinely excited and really looking forward to go live.

But there is another part of me that is slightly...

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

March 22, 2019

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...

## Free Goodies from Embedded World - What to Do Next?

March 6, 20193 comments

I told you I would go on a hunt for free stuff at Embedded World in order to build a bundle for someone to win.

## Back from Embedded World 2019 - Funny Stories and Live-Streaming Woes

March 1, 20191 comment

When the idea of live-streaming parts of Embedded World came to me,  I got so excited that I knew I had to make it happen.  I perceived the opportunity as a win-win-win-win.

• win #1 - Engineers who could not make it to Embedded World would be able to sample the huge event,
• win #2 - The organisation behind EW would benefit from the extra exposure
• win #3 - Lecturers and vendors who would be live-streamed would reach a (much) larger audience
• win #4 - I would get...

## Spread the Word and Run a Chance to Win a Bundle of Goodies from Embedded World

February 21, 2019

Do you have a Twitter and/or Linkedin account?

If you do, please consider paying close attention for the next few days to the EmbeddedRelated Twitter account and to my personal Linkedin account (feel free to connect).  This is where I will be posting lots of updates about how the EmbeddedRelated.tv live streaming experience is going at Embedded World.

The most successful this live broadcasting experience will be, the better the chances that I will be able to do it...

## Launch of EmbeddedRelated.tv

February 21, 2019

With the upcoming Embedded Word just around the corner, I am very excited to launch the EmbeddedRelated.tv platform.

This is where you will find the schedule for all the live broadcasts that I will be doing from Embedded World next week.  Please note that the schedule will be evolving constantly, even during the show, so I suggest your refresh the page often.  For instance, I am still unsure if I will be able to do the 'opening of the doors' broadcast as...

## Live Streaming from Embedded World!

February 12, 2019

For those of you who won't be attending Embedded World this year, I will try to be your eyes and ears by video streaming live from the show floor.

I am not talking improvised streaming from a phone, but real, high quality HD streaming with a high-end camera and a device that will bond three internet connections (one wifi and two cellular) to ensure a steady, and hopefully reliable, stream. All this to hopefully give those of you who cannot be there in person a virtual...

February 5, 2019