Six Software Design Tools
Contents: IntroductionHere are six tools to help you with software design. The first two are very simple, almost deceptively trivial, while the last four are more involved. They apply universally, to all types of software, all types of systems, and all languages. This is part of good engineering discipline.
At face value, this is just a bunch of acronyms,...
Review: Prototype to Product
Prototype to Product: A Practical Guide for Getting to Market, by Alan Cohen, is a must-read for anyone involved in product development, whether in a technical, management, or executive role.
I was reminded of it by Cohen's recent episode on Embedded.fm, 388: Brains Generate EMF, which is worth listening to a couple times through, especially if you're interested in medical device development. And in fact his first episode there,
Definite Article: Notes on Traceability
Electronic component distibutor Digi-Key recently announced part tracing for surface-mount components purchased in cut-tape form. This is a big deal, and it’s a feature that is a good example of traceability. Some thing or process that has traceability basically just means that it’s possible to determine an object’s history or provenance: where it came from and what has happened to it since its creation. There are a...
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...
Racing to Sleep
Today we’re going to talk about low-power design.
Suppose I’m an electrical engineer working with wildlife biologists who are gathering field data on the Saskatchewan ringed-neck mountain goat. My team has designed a device called the BigBrotherBear 2000 (BBB2000) with a trip cable and a motor and a camera and a temperature sensor and a hot-wire anemometer and a real-time clock and an SD card and a battery and a LoRa transceiver. The idea is something like...
Shibboleths: The Perils of Voiceless Sibilant Fricatives, Idiot Lights, and Other Binary-Outcome Tests
AS-SALT, JORDAN — Dr. Reza Al-Faisal once had a job offer from Google to work on cutting-edge voice recognition projects. He turned it down. The 37-year-old Stanford-trained professor of engineering at Al-Balqa’ Applied University now leads a small cadre of graduate students in a government-sponsored program to keep Jordanian society secure from what has now become an overwhelming influx of refugees from the Palestinian-controlled West Bank. “Sometimes they visit relatives...
Embedded Programming Video Course Shows How OOP Works Under the Hood
If you'd like to understand how Object-Oriented Programming (OOP) really works under the hood, here is a free video course for you:
OOP part-1: Encapsulation: This first lesson on Object-Oriented Programming (OOP) introduces the concept of Encapsulation, which is the ability to package data and functions together into classes. You'll see how you can emulate Encapsulation in C, what kind of code is generated, and how to debug such code. Next, you will translate the C design into C++ using...
Round-robin or RTOS for my embedded system
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...
Designing Communication Protocols, Practical Aspects
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...
Mutex vs. Semaphore - Part 1
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....
Round-robin or RTOS for my embedded system
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...
The CRC Wild Goose Chase: PPP Does What?!?!?!
I got a bad feeling yesterday when I had to include reference information about a 16-bit CRC in a serial protocol document I was writing. And I knew it wasn’t going to end well.
The last time I looked into CRC algorithms was about five years ago. And the time before that… sometime back in 2004 or 2005? It seems like it comes up periodically, like the seventeen-year locust or sunspots or El Niño,...
Stand-by or boot-up
Many factors affect the usability of devices - a key one is how long it takes to start up.
Open-Source Licenses Made Easy with Buildroot and Yocto for Embedded Linux
In this article I will try to explain what are the copyrights/copyleft, what are the popular opensource software licenses, and how to make sure that your Embedded Linux system complies with them using popular build systems ; Buildroot or YOCTO projec
Important Programming Concepts (Even on Embedded Systems) Part III: Volatility
1vol·a·tile adjective \ˈvä-lə-təl, especially British -ˌtī(-ə)l\ : likely to change in a very sudden or extreme way : having or showing extreme or sudden changes of emotion : likely to become dangerous or out of control
— Merriam-Webster Online Dictionary
Other articles in this series:
Important Programming Concepts (Even on Embedded Systems) Part II: Immutability
Other articles in this series:
- Part I: Idempotence
- Part III: Volatility
- Part IV: Singletons
- Part V: State Machines
- Part VI: Abstraction
This article will discuss immutability, and some of its variations in the topic of functional programming.
There are a whole series of benefits to using program variables that… well, that aren’t actually variable, but instead are immutable. The impact of...
Developing software for a safety-related embedded system for the first time
I spend most of my working life with organisations that develop software for high-reliability, real-time embedded systems. Some of these systems are created in compliance with IEC 61508, ISO 26262, DO-178C or similar international standards.
When working with organisations that are developing software for their first safety-related design, I’m often asked to identify the key issues that distinguish this process from the techniques used to develop “ordinary” embedded software.
...Implementation Complexity, Part I: The Tower of Babel, Gremlins, and The Mythical Man-Month
I thought I'd post a follow-up, in a sense, to an older post about complexity in consumer electronics I wrote a year and a half ago. That was kind of a rant against overly complex user interfaces. I am a huge opponent of unnecessary complexity in almost any kind of interface, whether a user interface or a programming interface or an electrical interface. Interfaces should be clean and simple.
Now, instead of interface complexity, I'll be talking about implementation complexity, with a...
Modern Embedded Systems Programming: Beyond the RTOS
An RTOS (Real-Time Operating System) is the most universally accepted way of designing and implementing embedded software. It is the most sought after component of any system that outgrows the venerable "superloop". But it is also the design strategy that implies a certain programming paradigm, which leads to particularly brittle designs that often work only by chance. I'm talking about sequential programming based on blocking.
Blocking occurs any time you wait explicitly in-line for...
The three laws of safe embedded systems
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.
Margin Call: Fermi Problems, Highway Horrors, Black Swans, and Why You Should Worry About When You Should Worry
“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...
Embedded Programming Video Course Shows How OOP Works Under the Hood
If you'd like to understand how Object-Oriented Programming (OOP) really works under the hood, here is a free video course for you:
OOP part-1: Encapsulation: This first lesson on Object-Oriented Programming (OOP) introduces the concept of Encapsulation, which is the ability to package data and functions together into classes. You'll see how you can emulate Encapsulation in C, what kind of code is generated, and how to debug such code. Next, you will translate the C design into C++ using...
How Embedded Linux is used in Spacecrafts !
This article dives into the application of Linux in spacecraft, examining the challenges it poses and proposing potential solutions. Real-life examples will be discussed, while also addressing the drawbacks of employing Linux in safety-critical missions.
Implementation Complexity, Part I: The Tower of Babel, Gremlins, and The Mythical Man-Month
I thought I'd post a follow-up, in a sense, to an older post about complexity in consumer electronics I wrote a year and a half ago. That was kind of a rant against overly complex user interfaces. I am a huge opponent of unnecessary complexity in almost any kind of interface, whether a user interface or a programming interface or an electrical interface. Interfaces should be clean and simple.
Now, instead of interface complexity, I'll be talking about implementation complexity, with a...
Developing software for a safety-related embedded system for the first time
I spend most of my working life with organisations that develop software for high-reliability, real-time embedded systems. Some of these systems are created in compliance with IEC 61508, ISO 26262, DO-178C or similar international standards.
When working with organisations that are developing software for their first safety-related design, I’m often asked to identify the key issues that distinguish this process from the techniques used to develop “ordinary” embedded software.
...Modern Embedded Systems Programming: Beyond the RTOS
An RTOS (Real-Time Operating System) is the most universally accepted way of designing and implementing embedded software. It is the most sought after component of any system that outgrows the venerable "superloop". But it is also the design strategy that implies a certain programming paradigm, which leads to particularly brittle designs that often work only by chance. I'm talking about sequential programming based on blocking.
Blocking occurs any time you wait explicitly in-line for...
Implementation Complexity, Part II: Catastrophe, Dear Liza, and the M Word
In my last post, I talked about the Tower of Babel as a warning against implementation complexity, and I mentioned a number of issues that can occur at the time of design or construction of a project.
The Tower of Babel, Pieter Bruegel the Elder, c. 1563 (from Wikipedia)
Success and throwing it over the wallOK, so let's say that the right people get together into a well-functioning team, and build our Tower of Babel, whether it's the Empire State Building, or the electrical grid, or...
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...
Racing to Sleep
Today we’re going to talk about low-power design.
Suppose I’m an electrical engineer working with wildlife biologists who are gathering field data on the Saskatchewan ringed-neck mountain goat. My team has designed a device called the BigBrotherBear 2000 (BBB2000) with a trip cable and a motor and a camera and a temperature sensor and a hot-wire anemometer and a real-time clock and an SD card and a battery and a LoRa transceiver. The idea is something like...
Efficiency Through the Looking-Glass
If you've ever designed or purchased a power supply, chances are you have had to work with efficiency calculations. I can remember in my beginning electronic circuits course in college, in the last lecture when the professor was talking about switching power converters, and saying how all of a sudden you could take a linear regulator that was 40% efficient and turn it into a switching regulator that was 80% efficient. I think that was the nail in the coffin for any plans I had to pursue a...