Zebras Hate You For No Reason: Why Amdahl's Law is Misleading in a World of Cats (And Maybe in Ours Too)

Jason Sachs February 27, 20171 comment

I’ve been wasting far too much of my free time lately on this stupid addicting game called the Kittens Game. It starts so innocently. You are a kitten in a catnip forest. Gather catnip.

And you click on Gather catnip and off you go. Soon you’re hunting unicorns and building Huts and studying Mathematics and Theology and so on. AND IT’S JUST A TEXT GAME! HTML and Javascript, that’s it, no pictures. It’s an example of an


Favorite Tools: C++11 std::array

Matthew Eshleman February 26, 20172 comments

Many embedded software and firmware projects must be developed to high standards of reliability. To meet these reliability requirements, firmware project teams will consider many design tradeoffs. For example, an engineering team may avoid or outright ban the use of dynamic memory allocation, a feature typically accessed via the C library call "malloc" or the C++ allocator "new". When authoring software under such...


Vala applications on Embedded Linux: maybe a clever choice [part 1]

Felipe Lavratti December 19, 2016

Vala is a sexy, open source, high level programming language that appeared in 2006, it counts with a modern typing system, is object oriented, compiled and statically typed, it has a almost identical syntax to C# and is maintained by GNOME. The language was created as a power abstraction of the GLib and GTK libraries, two considerably lightweight and powerful libraries written in C, and it is used in projects such as GNOME Clocks, Shotwell, GXml and Elementary OS.

namespace...

Favorite Tools: C++11 User-defined literals

Matthew Eshleman November 14, 20161 comment

In many software domains units of measurement are frequently critical to the software's data processing requirements. Those same units, or rather the use of the wrong units, are often the source of bugs and disastrous mistakes. Although useful for other purposes, user-defined literals are an excellent addition to the C++11 standard and handy when working with units of measurement.

Suppose a device measures velocity. To help prevent errors, the software specification requires...


Surprising Linux Real Time Scheduler Behavior

Matthew Eshleman November 5, 2016

I have recently been helping with embedded software design and development for a data acquisition and visualization device. The software executes within an embedded Linux context and consists of various animated user interfaces rendering the acquired data.

The data is received via a UART and a SPI connection. During project development we noticed poor UART data latency issues during heavy user interface animations. For this product to properly meet its acquisition requirements, the UART...


Favorite Tools - Look Up Tables

Matthew Eshleman October 22, 20162 comments

As we grow in our engineering careers, we must continually add new tools to our collective tool kits. One favorite tool in my toolkit will be obvious to many experienced embedded software engineers. I still remember learning this approach early in my career via code written by colleague David Starling. The tool in question: 

Look up tables 

Look up tables simplify code and improve firmware maintenance. What is a look up table? A look up table is often nothing more complex than a...


From bare-metal to RTOS: 5 Reasons to use an RTOS

Jacob Beningo October 18, 20167 comments

Developers can come up with amazing and convoluted reasons to not use an RTOS. I have heard excuses ranging from they are too expensive (despite open source solutions) all the way to they aren’t efficient and use too much memory. In some circumstances some excuses are justified but there are many reasons why a developer should look to an RTOS to help with their real-time scheduling needs.

From bare-metal to RTOS Quick Links
  • Part 1: 

Best Firmware Architecture Attributes

Dr. Tayyar GUZEL June 4, 20166 comments

Architecture of a firmware (FW) in a way defines the life-cycle of your product. Often companies start with a simple-version of a product as a response to the time-to-market caveat of the business, make some cash out of the product with a simple feature set. It takes only less than 2-3 years to reach a point where the company needs to develop multiple products derived from the same code base and multiple teams need to develop...


Modern Embedded Systems Programming: Beyond the RTOS

Miro Samek April 27, 20167 comments

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...


Embedded Firmware Refactoring, Optimisation and Migration

Ian Smith March 29, 2016

Legacy products are often based on older hardware platforms which often become under-powered or run out of memory which constrains further product development. Customers are always looking for new features and improved performance but often either don’t want to invest in new hardware or need to retain the current field population of devices.

These are ongoing challenges for any product manufacturer, but are particularly highlighted in embedded systems where product...


C Programming Techniques: Function Call Inlining

Fabien Le Mentec April 29, 20137 comments
Introduction

Abstraction is a key to manage software systems as they increase in size and complexity. As shown in a previous post, abstraction requires a developper to clearly define a software interface for both data and functions, and eventually hide the underlying implementation.When using the C language, the interface is often exposed in a header '.h' file, while the implementation is put in one or more  corresponding '.c' files.

First, separating an interface from its...


Coding - Step 0: Setting Up a Development Environment

Stephen Friederichs November 25, 20145 comments

Articles in this series:

You can easily find a million articles out there discussing compiler nuances, weighing the pros and cons of various data structures or discussing the  optimization of databases. Those sorts of articles are fascinating reads for advanced programmers but...


Coding Step 1 - Hello World and Makefiles

Stephen Friederichs February 10, 20156 comments

Articles in this series:

Step 0 discussed how to install GCC and the make utility with the expectation of writing and compiling your first C program. In this article, I discuss how to use those tools we installed last time. Specifically, how to use GCC to compile a C program and...


From bare-metal to RTOS: 5 Reasons to use an RTOS

Jacob Beningo October 18, 20167 comments

Developers can come up with amazing and convoluted reasons to not use an RTOS. I have heard excuses ranging from they are too expensive (despite open source solutions) all the way to they aren’t efficient and use too much memory. In some circumstances some excuses are justified but there are many reasons why a developer should look to an RTOS to help with their real-time scheduling needs.

From bare-metal to RTOS Quick Links
  • Part 1: 

OOKLONE: a cheap RF 433.92MHz OOK frame cloner

Fabien Le Mentec August 12, 201417 comments
Introduction

A few weeks ago, I bought a set of cheap wireless outlets and reimplemented the protocol for further inclusion in a domotics platform. I wrote a post about it here:

//www.embeddedrelated.com/showarticle/620.php

Following that, I had access to another outlet from a different vendor:

http://www.castorama.fr/store/Prise-telecommandee-BLYSS---Interieur-prod4470027.html

The device documentation mentions that it operates on the same frequency as the previous...


The CRC Wild Goose Chase: PPP Does What?!?!?!

Jason Sachs October 23, 20142 comments

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,...


Coding Step 2 - Source Control

Articles in this series:

When I first started out in programming, version control was not an introductory topic. Not in the least because it required a 'server' (ie, a computer which a teenaged me couldn't afford) but because it seemed difficult and only useful to teams rather than...


Android for Embedded Devices - 5 Reasons why Android is used in Embedded Devices

Maharajan Veerabahu November 6, 20173 comments

The embedded purists are going to hate me for this. How can you even think of using Android on an embedded system ? It’s after all a mobile phone operating system/software. 

Sigh !! Yes I did not like Android to begin with, as well - for use on an Embedded System. But sometimes I think the market and needs decide what has to be used and what should not be. This is one such thing. Over the past few years, I have learned to love Android as an embedded operating system....


Lazy Properties in Python Using Descriptors

Jason Sachs November 7, 2017

This is a bit of a side tangent from my normal at-least-vaguely-embedded-related articles, but I wanted to share a moment of enlightenment I had recently about descriptors in Python. The easiest way to explain a descriptor is a way to outsource attribute lookup and modification.

Python has a bunch of “magic” methods that are hooks into various object-oriented mechanisms that let you do all sorts of ridiculously clever things. Whether or not they’re a good idea is another...


Cortex-M Exception Handling (Part 1)

Ivan Cibrario Bertolotti November 28, 20152 comments

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.