October 17, 2013
Arduino Robotics

Arduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot.  This build is meant to be affordable, relatively easy and instructive.  The total cost of the build is around $50. 1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4. ## Arduino robotics #2 - chassis, locomotion and power October 16, 2013 Arduino Robotics Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around$50.

1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.

## Introduction to Microcontrollers - More Timers and Displays

By now you have seen four different ways to use timers in your programs.  Next we will look at some ways to produce the effect of multiple parallel streams of work in your program with the help of timers.  This effect is only an appearance, not a reality, since a single microcontroller (one core) can only run a single thread of code.  However, since microcontrollers are so fast in relation to a great many of the tasks to...

## Arduino robotics #1 - motor control

Arduino Robotics

Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot.  This build is meant to be affordable, relatively easy and instructive.  The total cost of the build is around \$50.

1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.

## Introduction to Microcontrollers - Adding Some Real-World Hardware

When 2 LEDs Just Don't Cut It Anymore

So far, we've done everything in this series using two LEDs and one button.  I'm guessing that the thrill of blinking an LED has worn off by now, hard as that is to imagine.  What's more, we've just about reached the limits of what we can learn with such limited I/O.  We have come to the point where we need to add some hardware to our setup to continue with additional concepts and microcontroller...

## Introduction to Microcontrollers - Timers

Timers - Because "When" Matters

Computer programs are odd things, for one reason because they have no concept of time.  They may have the concept of sequential execution, but the time between instructions can be essentially any number and the program won't notice or care (unless assumptions about time have been built into the program by the programmer).  But the real world is not like this.  In the real world, especially the real embedded world,...

## Introduction to Microcontrollers - More On Interrupts

September 25, 2013

A Little More Detail About The Interrupt Mechanism

It's time to look a little closer at what happens in an interrupt request and response.  Again this is in general terms, and different microcontroller designs may do things somewhat differently, but the basics remain the same.  Most but not all interrupt requests are latched, which means the interrupt event sets a flag that stays set even if the interrupt event then goes away.  It is this latched flag...

## Introduction to Microcontrollers - Interrupts

It's Too Soon To Talk About Interrupts!

That, at least, could be one reaction to this chapter.  But over the years I've become convinced that new microcontroller programmers should understand interrupts before being introduced to any complex peripherals such as timers, UARTs, ADCs, and all the other powerful function blocks found on a modern microcontroller.  Since these peripherals are commonly used with interrupts, any introduction to them that does not...

## Introduction to Microcontrollers - More On GPIO

Now that we have our LED Blinky program nailed down, it's time to look more closely at outputs, add button/switch inputs, and work with reading inputs and driving outputs based on those inputs.

It's ON - No, It's OFF - No, It's ON...

I have to confess, I cheated.  Well, let's say I glossed over something very important.  In our LED Blinky program, we never cared about whether an output '1' or an output '0' turned on the LED.  Since we were just...

## Introduction to Microcontrollers - Hello World

Embedded Hello World

A standard first program on an embedded platform is the blinking LED.  Getting an LED to blink demonstrates that you have your toolchain set up correctly, that you are able to download your program code into the μC, and that the μC and associated circuitry (e.g. the power supply) is all working.  It can even give you good evidence as to the clock rate that your microcontroller is running (something that trips up a great many people,...

## Trust, but Verify: Examining the Output of an Embedded Compiler

September 27, 2015

I work with motor control firmware on the Microchip dsPIC33 series of microcontrollers. The vast majority of that firmware is written in C, with only a few percent in assembly. And I got to thinking recently: I programmed in C and C++ on an Intel PC from roughly 1991 to 2009. But I don’t remember ever working with x86 assembly code. Not once. Not even reading it. Which seems odd. I do that all the time with embedded firmware. And I think you should too. Before I say why, here are...

## 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...

April 23, 2015
Introduction

With another colleague at work, we are currently developing an electronic board that will eventually be powered over Ethernet. To gain more experience with this technology, we prototyped a standalone power supply stage.

## 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...

## Choosing a Microcontroller for Your Vehicle

June 7, 20161 comment

There are many things to take into consideration when choosing a microcontroller or microprocessor for your autonomous vehicle.

Voltage

Some processors run on 5V and others use 3.3V.  Be sure to check the documentation before you buy.  Make sure your supply has a high enough amp rating that your microcontroller doesn't lose pwer.

Power

Can the system run using batteries?  Large, automotive sized vehicles can be run from large batteries or inverters in the vehicle.  Smaller...

## 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

## Embedded Systems - free EdX course by UT-Austin!

October 29, 20131 comment

I was very excited to see that there will be an Embedded Systems class available for free at https://www.edx.org/course/utaustin/ut-6-01x/embedded-systems-shape-world/1172

It's free to sign up and take the online class at the EdX website.

More exciting is that the class is based on a TI Launchpad Tiva microcontroller development board.  The Tiva Launchpad features an 80-MHz ARM Cortex M-4 MCU with 256 KB of flash storage, 32 KB of RAM and 43 general purpose I/O pins.

## Introduction to Deep Insight Analysis for RTOS Based Applications

September 20, 20171 comment

Over the past several years, embedded systems have become extremely complex. As systems become more complex, they become harder and more time consuming to debug. It isn’t uncommon for development teams to spend more than 40% development cycle time just debugging their systems. This is where deep insight analysis has the potential to dramatically decrease costs and time to market.

Defining Deep Insight Analysis

Deep insight analysis is a set of tools and techniques that can be...

## Cutting Through the Confusion with ARM Cortex-M Interrupt Priorities

February 26, 2016

The insanely popular ARM Cortex-M processor offers very versatile interrupt priority management, but unfortunately, the multiple priority numbering conventions used in managing the interrupt priorities are often counter-intuitive, inconsistent, and confusing, which can lead to bugs. In this post I attempt to explain the subject and cut through the confusion.

The Inverse Relationship Between Priority Numbers and Urgency of the Interrupts

The most important fact to know is that ARM...

## Ghidra disassembler / decompiler

September 8, 2019

Slightly off the normal embedded topic, embedded reverse engineering.

The NSA (National Security Agency) has released their Ghidra dis-assembler / decompiler as open source. The Malware people have taken to it alongside the established IDA Pro. There’s lots of videos from Malware reverse engineering people available on YouTube, however it supports embedded processors, namely...

6502, 68000, 6805m 80251, 80390, 8051, 8085, AARACH64, ARM, AVR8, AVR32, CR16C, Davilak, dsPIC30F,...