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...


Important Programming Concepts (Even on Embedded Systems) Part V: State Machines

Jason Sachs January 5, 20158 comments

Other articles in this series:

Oh, hell, this article just had to be about state machines, didn’t it? State machines! Those damned little circles and arrows and q’s.

Yeah, I know you don’t like them. They bring back bad memories from University, those Mealy and Moore machines with their state transition tables, the ones you had to write up...


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...


Important Programming Concepts (Even on Embedded Systems) Part IV: Singletons

Jason Sachs November 11, 20142 comments

Other articles in this series:

Today’s topic is the singleton. This article is unique (pun intended) in that unlike the others in this series, I tried to figure out a word to use that would be a positive concept to encourage, as an alternative to singletons, but


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,...


Important Programming Concepts (Even on Embedded Systems) Part III: Volatility

Jason Sachs October 10, 2014

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:


You Will Make Mistakes

Jason Sachs 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...


Introduction to Microcontrollers - Ada - 7 Segments and Catching Errors

Mike Silva September 22, 20145 comments

7 Segments the Ada Way

Here is the Ada version (I should say AN Ada version) of the 7 segment multiplexing code presented in the last installment.  The hardware now is the STM32F407 Discover board, which is a Cortex M4F board.  There are lots of differences in GPIO and timer setup, but if you understoold the previous code in C you should not have much trouble understanding this code in Ada.

As interesting as the Ada approach to the task is the Ada ability to detect...


Important Programming Concepts (Even on Embedded Systems) Part II: Immutability

Jason Sachs September 14, 2014

Other articles in this series:

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...


Important Programming Concepts (Even on Embedded Systems) Part I: Idempotence

Jason Sachs August 26, 20145 comments

There are literally hundreds, if not thousands, of subtle concepts that contribute to high quality software design. Many of them are well-known, and can be found in books or the Internet. I’m going to highlight a few of the ones I think are important and often overlooked.

But first let’s start with a short diversion. I’m going to make a bold statement: unless you’re a novice, there’s at least one thing in computer programming about which you’ve picked up...


Continuous Integration for Embedded Systems

Dr. Tayyar GUZEL September 5, 20172 comments

It is no secret that anyone who wants to streamline project management, reduce risk and improve the quality needs some form of "automation" in SW development processes. What is commonly used in most companies as a tool for such automation is called Continuous Integration (CI). It is a good practice for embedded systems as well even though it is much harder to use CI for embedded systems compared to pure software development because embedded systems mostly depend on...


Important Programming Concepts (Even on Embedded Systems) Part VI : Abstraction

Jason Sachs June 16, 20153 comments

Earlier articles:

We have come to the last part of the Important Programming Concepts series, on abstraction. I thought I might also talk about why there isn’t a Part VII, but decided it would distract from this article — so if you want to know the reason, along with what’s next,


Tenderfoot: Embedded Software and Firmware Specialties

Matthew Eshleman August 20, 201710 comments

Once upon a time (seven years ago) I answered a question on Stack Overflow. Then Stephane suggested I turn that answer into a blog post. Great idea! This post dives deeper into the original question: “Is it possible to fragment this field (embedded software and firmware) into sub-fields?”

This post represents a detailed and updated response to my original Stack Overflow answer. I hope this post provides guidance and useful information to the “tenderfoots” in the...


Watchdog Timer Anti-patterns

Alexandru Lazar 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...


Coding Step 3 - High-Level Requirements

Stephen Friederichs August 17, 20152 comments

Articles in this series:

If this series of articles has been light on one thing it's 'coding'. If it's been light on two things the second is 'embedded'. In three articles I haven't gotten past Hello World on a desktop PC. That changes (slowly) with this article. In this article I'll...


Designing Embedded System with FPGA - 1

Pragnesh Patel October 28, 200711 comments

With the introduction of soft processors and related tools (like EDK from Xilinx), implementation of basic embedded system in FPGA is made easy. This requires very little or almost no knowledge of VHDL programming. Actually that’s how I started. If user is interested in taking full advantage of FPGA and its parallel processing power, then yes, detail understanding of soft processor, its peripheral bus and VHDL programming is required.

 

I will start with...


Favorite Tools - Look Up Tables

Matthew Eshleman October 22, 20163 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...


Project Directory Organization

Stephen Friederichs August 20, 20142 comments

A recent question on Reddit’s C Programming sub asked what sort of directory structure people use for their projects. Perhaps not unsurprisingly this didn’t elicit a flood of answers - maybe there are no organizational schemes that people are happy with or perhaps few people consider it a glamorous topic (not that the C Programming subreddit is filled with glamorous people -no offense I love you all). Personally I find it to be a very interesting topic. Organization and process are...


Get your microcontroller and PC to talk

Jayaraman Kiruthi Vasan August 15, 20115 comments

(and get it done free ‘n’ easy!)

 

The Need

Specifications can dynamically change during the product development cycle. Bosses/clients suddenly approach us with additional requirements, which, however simple, can put us in a fix.  One such requirement could be to have a PC based design interface for a standalone microcontroller project.

On many occasions, the required PC software has to just behave like a slave...


Dark Corners of C - The Comma Operator

Stephen Friederichs July 23, 20158 comments

I've been programming in C for 16 years or so and the language has existed for much much longer than that. You might think that there'd be nothing left to surprise me after so long - but you'd be wrong. Imagine my surprise the first time I saw a line of code that looked something like this:

if (!dry_run && ((stdout_closed = true), close_stream (stdout) != 0))

My mind couldn't parse it - what's a comma doing in there (after...