## Scorchers, Part 3: Bare-Metal Concurrency With Double-Buffering and the Revolving Fireplace

July 25, 2020

This is a short article about one technique for communicating between asynchronous processes on bare-metal embedded systems.

A: to To other side. get the

— Jason Whittington

There are many reasons why concurrency is

July 12, 2020
Contents:

## Make Hardware Great Again

By now you're aware of the collective angst in the US about 5G. Why is the US not a leader in 5G ? Could that also happen -- indeed, is it happening -- in AI ? If we lead in other areas, why not 5G ? What makes it so hard ?

This hand-wringing has reached the highest levels in US government. Recently the Wall Street Journal reported on a DoJ promoted plan 1 to help Cisco buy Ericsson or Nokia, to give the US a leg up in 5G. This is not a new plan,...

## Tolerance Analysis

May 31, 2020

Today we’re going to talk about tolerance analysis. This is a topic that I have danced around in several previous articles, but never really touched upon in its own right. The closest I’ve come is Margin Call, where I discussed several different techniques of determining design margin, and ran through some calculations to justify that it was safe to allow a certain amount of current through an IRFP260N MOSFET.

Tolerance analysis...

## The Self-Directed Virtual Internship

May 3, 2020

A number of my LinkedIn connections are college and university students at the bachelor's, master's, and doctoral levels, from all over the world. The embedded systems community constantly amazes me.

One fallout they're experiencing from COVID19 is cancellation of summer internships. This is very unfortunate, because an internship represents maintaining educational momentum and preparing for launch of a career with a taste of the real working world, along with some financial...

## Simple Automated Log Processing

April 25, 2020

Text log data offers a wealth of information from an embedded system. At least during prototyping and development phases, most systems have some kind of serial log output, or use semihosting methods to log to a serial output channel in a debugger. Then you can capture the logs to a file.

The problem is that they tend to accumulate large volumes of data. Logs can be many thousands of lines long, especially when you run long duration tests. Finding information and evaluating trends in the...

## Scorchers, Part 2: Unknown Bugs and Popcorn

This is a short article about diminishing returns in the context of software releases.

Those of you who have been working professionally on software or firmware have probably faced this dilemma before. The scrum masters of the world will probably harp on terms like the Definition of Done and the Minimum Viable Product. Blah blah blah. In simple terms, how do you know when your product is ready to release? This is both an easy and a difficult question to answer.

What makes...

## Some Advice For Working From Home

March 28, 20201 comment

The other day I posted a short video of my WFH setup (and here's a May 1st upgrade). Today I have some general advice for WFH for people who are new to it.

I've been doing it randomly for the past 5 years, usually just one or two days a week here and there. Now it's a full-time thing for the duration of the coronavirus. So some of this wanders afield a bit, settling in for the long haul.

Some of it is based on things I've built up over years. It's unreasonable to expect that...

## UML Statechart tip: Handling errors when entering a state

This is my second post with advice and tips on designing software with UML statecharts. My first entry is here.

It has been nearly 20 years since I first studied UML statecharts. Since that initial exposure (thank you Samek!), I have applied event driven active object statechart designs to numerous projects [3]. Nothing has abated my preference for this pattern in my firmware and embedded software projects. Through the years I have taken note of a handful of common challenges when...

## Examining The Stack For Fun And Profit

February 19, 20201 comment

Well, maybe not so much for profit, but certainly for fun. This is a wandering journey of exploration and discovery, learning a variety of interesting and useful things.

One of the concerns with an embedded system is how much memory it needs, known as the memory footprint. This consists of the persistent storage needed for the program (i.e. the flash memory or filesystem space that stores the executable image), and the volatile storage needed to hold the data while executing over long...

## 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 engineers: what do you put between the microcontroller and the electromagnet?We used to think this kind of question was too easy, but there are a surprising number of subtleties here (and maybe a surprising number of job candidates that were missing...

## 10 Circuit Components You Should Know

Chefs have their miscellaneous ingredients, like condensed milk, cream of tartar, and xanthan gum. As engineers, we too have quite our pick of circuits, and a good circuit designer should know what's out there. Not just the bread and butter ingredients like resistors, capacitors, op-amps, and comparators, but the miscellaneous "gadget" components as well.

Here are ten circuit components you may not have heard of, but which are occasionally quite useful.

1. Multifunction gate (

## Endianness and Serial Communication

May 20, 20131 comment

Endianness is a consideration that is easily overlooked in the design of embedded systems. I myself am amply guilty of this oversight. It’s something you don’t ever have to worry about if you’re only working with a single processor or two processors that have the same endianness.  You can even avoid it if you have two processors that have different endianness but never transmit data between themselves that consists of more than one byte.  It’s easy to lull...

## Data Hiding in C

Strictly speaking, C is not an object-oriented language. Although it provides some features that fit into the object-oriented paradigm it has never had the full object-oriented focus that its successor C++ offers. C++ introduced some very useful concepts and abilities that I miss when I’m developing in ANSI C. One such concept is protected member variables and functions.

When you declare a class in C++ you can also declare member variables and functions as part of that class. Often, these...

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

This two-part article explains five tips to make a fixed-point PI controller work well. I am not going to talk about loop tuning -- there are hundreds of articles and books about that; any control-systems course will go over loop tuning enough to help you understand the fundamentals. There will always be some differences for each system you have to control, but the goals are the same: drive the average error to zero, keep the system stable, and maximize performance (keep overshoot and delay...

## Ten Little Algorithms, Part 1: Russian Peasant Multiplication

This blog needs some short posts to balance out the long ones, so I thought I’d cover some of the algorithms I’ve used over the years. Like the Euclidean algorithm and Extended Euclidean algorithm and Newton’s method — except those you should know already, and if not, you should be locked in a room until you do. Someday one of them may save your life. Well, you never know.

Other articles in this series:

• Part 1:

Arduino Robotics

If...

## 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...

## October winner announced

November 15, 20121 comment

If you are a regular visitor of EmbeddedRelated, you are most likely aware that I have been running monthly draws lately for users of the site who are helping me to clean up the archives by rating threads in the forums section.

For the month of August, the member "Cryptoman" won a iPad, and for the month of September, 10 members won \$50 each.

For October, the winner of the new iPod Touch is the member with the username "hssathya".

The winner of the next draw will win...

## Behold, the New Comments System!

I have just finished implementing a new system for commenting the blogs.  It uses Ajax extensively, so the page won't reload if you post a comment.  And it is a 'threaded' system, which means that if you post a reply to a comment, it will be attached to it.

What do you think?  I personally love it.  Please go ahead and test it with a quick comment.

Although it is better to be logged in to post a comment, non-registered users can also comment, but they will have...

## Best Embedded Systems pdf Documents Out There

There are thousands of pdf documents related to Embedded Systems available online.  In fact, when I do a search in Google for:

embedded systems filetype:pdf

I get 4,340,000 results! A huge mix of articles, promotional documents, theses, etc.

Out of these 4 millions+ documents, I suspect that there must be at least a few hundreds jewels that deserve to be given more visibility.

Today, I am asking for your help (again!) to build a directory of some of the most useful pdf files out...

## New Discussion Group for Users of TI ARM based MCUs

June 14, 2010

If you are a user of an ARM based TI Microcontroller, please feel free to join the new "TI ARM processors MCUs" discussion group by sending a blank email to: tiarm-subscribe@yahoogroups.com This discussion group will be moderated, so you don't have to worry about receiving more spam than you probably already get. It usually takes a few weeks for a group to gain momentum, so don't worry if the activity level is low for a little while, but make sure to join so you don't miss the good...

## New TI MCU Resource Center

April 1, 2010

I am happy to announce the publication of the new "TI MCU Resource Center" on EmbeddedRelated.com, where TI will regularly add videos and articles to keep you informed on their latest and greatest MCU related products.

To access the new section, you'll find a link in the main menu of the site at the top of the page.

## Blogs Section Now Online!

September 18, 2007

I am happy to announce that the blog section is now online.

Last week, I sent an email to all the members of EmbeddedRelated.com to ask for embedded systems experts who would be interested in blogging on the site. The response was very positive and I have selected 10 highly qualified individuals who will soon be writing here about all sorts of embedded systems related subjects. I am currently in the process of receiving their info (bio, photo, username, etc) and creating their bloggers'...