Painting with Light to Measure Time
Recently I was faced with a dilemma while working from home. I needed to verify an implementation of first-order sigma-delta modulation used to adjust LED brightness. (I have described this in more detail in Modulation Alternatives for the Software Engineer.) I did not, however, have an oscilloscope.
And then I remembered something, about a technique called “light painting”: basically a long-exposure photograph where a...
The DSP Online Conference - Right Around the Corner!
It is Sunday night as I write this blog post with a few days to go before the virtual doors of the very first DSP Online Conference open..
It all started with a post in the DSPRelated forum about three months ago. We had just had a blast running the 2020 Embedded Online Conference and we thought it could be fun to organize a smaller event dedicated to the DSP community. So my goal with the post in the forum was to see if...
Review: Hands-On RTOS with Microcontrollers
Full disclosure: I was given a free copy of this book for evaluation.
Hands-On RTOS with Microcontrollers: Building real-time embedded systems using FreeRTOS, STM32 MCUs, and SEGGER debug tools by Brian Amos is an outstanding book. It lives up to its name, extremely hands-on and practical, taking you from knowing nothing about RTOS's (Real-Time Operating Systems) up to building real multithreaded embedded system applications running on real hardware.
It uses the ST Micro
Review: Project Management for the Unofficial Project Manager
Software development projects are notorious for having problems. Late, over budget, not working properly, making people's lives miserable all around. Embedded systems add the further complication of hardware to that.
How many of us have lived through problematic projects? Hopefully some of them have at least been ultimately successful to make all the suffering worth it in the end, but there are plenty that haven't.
I don't consider myself a project manager, or a manager...
Scorchers, Part 3: Bare-Metal Concurrency With Double-Buffering and the Revolving Fireplace
This is a short article about one technique for communicating between asynchronous processes on bare-metal embedded systems.
Q: Why did the multithreaded chicken cross the road?
A: to To other side. get the
There are many reasons why concurrency is
Absolute Beginner's Guide To Getting Started With Raspberry Pi
Contents:- Introduction
- Simplifications
- Decisions
- The Raspberry Pi
- Parts: What You Need
- Suppliers: Where To Order
- Shopping Lists: What To Order
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
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
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
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...
Boot sequence for an ARM based embedded system -2
In the last post, we discussed about the startup execution sequence on an ARM based embedded system in broader terms. In this post, we are going to cover the details of a startup code.These details are also available through various ARM resources , however for the sake of completion of our discussion , here is - the flow the startup code for an ARM based embedded system.
Step 1: The reset
On startup, the processor will jump to fixed location ,(most ARM cores support two vector...
MSP430 Launchpad Tutorial - Part 1 - Basics
TI's LaunchPad is a complete MSP430 development environment: all you have to do is download and install CCS IDE (login required), connect your G2231-ready LaunchPad to your computer with the included mini-usb cable, and you are ready to code!
Texas Instrument MSP430 LaunchPadSo, let's see how to start a new project in Code Composer Studio. This IDE is derived from Eclipse, so if you used it before you shouldn't have much problems.
We'll write a simple program that will...
Already 3000+ Attendees Registered for the Upcoming Embedded Online Conference
Chances are you already know, through the newsletter or banners on the Related sites, about the upcoming Embedded Online Conference.
Chances are you also already know that you have until the end of the month of February to register for free.
And chances are that you are one of the more than 3000 pro-active engineers who have already registered.
But If you are like me and have a tendency to do tomorrow what can be done today, maybe you haven't registered yet. You may...
R1C1R2C2: The Two-Pole Passive RC Filter
I keep running into this circuit every year or two, and need to do the same old calculations, which are kind of tiring. So I figured I’d just write up an article and then I can look it up the next time.
This is a two-pole passive RC filter. Doesn’t work as well as an LC filter or an active filter, but it is cheap. We’re going to find out a couple of things about its transfer function.
First let’s find out the transfer function of this circuit:
Not very...
Digital PLL's -- Part 1
1. Introduction
Figure 1.1 is a block diagram of a digital PLL (DPLL). The purpose of the DPLL is to lock the phase of a numerically controlled oscillator (NCO) to a reference signal. The loop includes a phase detector to compute phase error and a loop filter to set loop dynamic performance. The output of the loop filter controls the frequency and phase of the NCO, driving the phase error to zero.
One application of the DPLL is to recover the timing in a digital...
Endianness and Serial Communication
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...
Coroutines in one page of C
A coroutine is a function that you can jump back into after returning from it - and it remembers where it was in the code, and all the variables. This is very useful at times.
One use is generating a sequence of values. Here's how you can generate all the x,y pairs in a 2D range in Python:
def iterate(max_x, max_y): for x in range(max_x): for y in range(max_y): yield x,y for x,y in iterate(2,2): print x,yThis prints:
0 0 0 1 1 0 1 1The yield keyword is like...
Ten Little Algorithms, Part 3: Welford's Method (and Friends)
Other articles in this series:
- Part 1: Russian Peasant Multiplication
- Part 2: The Single-Pole Low-Pass Filter
- Part 4: Topological Sort
- Part 5: Quadratic Extremum Interpolation and Chandrupatla's Method
- Part 6: Green’s Theorem and Swept-Area Detection
Last time we talked about a low-pass filter, and we saw that a one-line...
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,...
How FPGAs work, and why you'll buy one
Today, pretty much everyone has a CPU, a DSP and a GPU, buried somewhere in their PC, phone, car, etc. Most don't know or care that they bought any of these, but they did.
Will everyone, at some future point, also buy an FPGA? The market size of FPGAs today is about 1% of the annual global semiconductor sales (~$3B vs ~$300B). Will FPGA eventually...
Introduction to Microcontrollers - Driving WS2812 RGB LEDs
This tutorial chapter is a bit of a detour, but I think an interesting and useful one. It introduces a bit of assembly language programming, and demonstrates bit-banging a tight serial data protocol. And it deals with RGB LEDs, which are just very fun in their own right, especially these new parts. So I thought I'd post this to give readers time for some holiday lighting experimenting.
Back To The FutureRemember how we started this...
Boot Sequence for an ARM based embedded system
Hello all,
Allow me to introduce myself. I am Deeksha and I come from plains of North India. My tryst with embedded technologies has been 5 years long and every single day I am amazed with the vastness and learning involved. The thing with embedded technologies is either you are into it, or you aren't. You cannot just hang around half-heartedly (I guess that holds true for every field, for that matter).You have to keep the learning and sharing process going on. And that is the reason I am...
Important Programming Concepts (Even on Embedded Systems) Part I: Idempotence
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...
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...
C++ on microcontrollers 1 - introduction, and an output pin class
This blog series is about the use of C++ for modern microcontrollers. My plan is to show the gradual development of a basic I/O library. I will introduce the object-oriented C++ features that are used step by step, to provide a gentle yet practical introduction into C++ for C programmers. Reader input is very much appreciated, you might even steer me in the direction you find most interesting.
I am lazy. I am also a programmer. Luckily, being a lazy...
10 Software Tools You Should Know
Unless you're designing small analog electronic circuits, it's pretty hard these days to get things done in embedded systems design without the help of computers. I thought I'd share a list of software tools that help me get my job done. Most of these are free or inexpensive. Most of them are also for working with software. If you never have to design, read, or edit any software, then you're one of a few people that won't benefit from reading this.
Disclaimer: the "best" software...
Using the C language to program the am335x PRU
Introduction
Some weeks ago, I published an article on how we used the PRU to implement a power supply control loop having hard realtime constraints:
//www.embeddedrelated.com/showarticle/586.php
Writing this kind of logic in assembly language is not easy. First the assembly language itself may be difficult to learn depending on your background. Then, fixed and floating point arithmetics require lot of code. While macros help to handle the complexity, they still are error prone as you...
Introduction to Microcontrollers - Hello World
Embedded Hello WorldA 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,...
Zebras Hate You For No Reason: Why Amdahl's Law is Misleading in a World of Cats (And Maybe in Ours Too)
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
VHDL tutorial
When I was first introduced to "Programmable Logic" several years ago, it was an answer to many of the challenges that I was struggling with. Though the parts were primitive by today's standards (simple PALs verses FPGA), they were an extremely cost effective tool addressing the need for specialized logic blocks.
I have continued to incorporate these powerful blocks into many of my latest designs. My current favorite part line is the Xilinx CoolRunner series (XC2Cxxx). In this...
Went 280km/h (174mph) in a Porsche Panamera in Germany!
Those of you who've been following my blog lately already know that I am going through some sort of mid-life crisis that involves going out there to meet people and make videos. It all started with Embedded World early this year, then continued at ESC Boston a couple of months ago and the latest chapter just concluded as I returned from Germany after spending a week at SEGGER's headquarters to produce a video to highlight their 25th anniversary.
VERY Fast Japanese Sumo Robots
For some reasons, I could not stop watching. I would love to have the maker of one of these robots to blog about the project here on EmbeddedRelated.com, the sensors, microcontroller, algorithms and the challenges... This would make for a very interesting read! Do you know someone?
Going back to Germany!
A couple of blog posts ago, I wrote that the decision to go to ESC Boston ended up being a great one for many different reasons. I came back from the conference energized and really happy that I went.
These feelings were amplified a few days after my return when I received an email from Rolf Segger, the founder of SEGGER Microcontroller (check out their very new website), asking if I would be interested in visiting their headquarters...
ESC Boston's Videos are Now Up
In my last blog, I told you about my experience at ESC Boston and the few videos that I was planning to produce and publish. Here they are, please have a look and any feedback (positive or negative) is appreciated.
Short HighlightThis is a very short (one minute) montage of some of the footage that I shot at the show & conference. In future shows, I absolutely need to insert clips here and there of engineers saying a few words about the conference (why they...
Back from ESC Boston
NOT going to ESC Boston would have allowed me to stay home, in my comfort zone.
NOT going to ESC Boston would have saved me from driving in the absolutely horrible & stressful Boston traffic1.
NOT going to ESC Boston would have saved me from having to go through a full search & questioning session at the Canada Customs on my return2.
2017/06/06 update: Videos are now up!So two days...
Launch of Youtube Channel: My First Videos - Embedded World 2017
I went to Embedded World 2017 in Nuremberg with an ambitious plan; I would make video highlights of several exhibits (booths) to be presented to the *Related sites audience. I would try to make the vendors focus their pitch on the essential in order to produce a one to three minutes video per booth.
So far my experience with making videos was limited to family videos, so I knew I had lots of reading to do and lots of Youtube videos and tutorials to watch. Trade shows are...
Who else is going to Embedded World 2017 in Nuremberg?
These days I am particularly excited. In a little bit less than a month and a half, I will be travelling to Nuremberg in Germany to attend Embedded World, by far the biggest Embedded Systems trade show with over 1000 vendors displaying their products and services.
I have downloaded the Duolingo app and I'm trying to do a minimum of 30 minutes per day to learn some German. So far, I know that 'Frau' is a woman, 'Mann' is a man, 'Danke' is thank you and 'tschüss' is bye - still a...
New Comments System (please help me test it)
I thought it would take me a day or two to implement, it took almost two weeks...
But here it is, the new comments systems for blogs, heavily inspired by the forum system I developed earlier this year.
Which means that:
- You can easily add images, either by drag and drop or through the 'Insert Image' button
- You can add MathML, TeX and ASCIImath equations and they will be rendered with Mathjax
- You can add code snippets and they will be highlighted with highlights.js
- You can edit...
3 Good News
Good News #1Last week, I announced a new and ambitious reward program that will be funded by the new Vendors Directory.
This week, I am happy to announce that we have our firsts two sponsors! Quantum Leaps & Abelon Systems have agreed to pay the sponsorship fee to be listed in the new Vendors Directory. Because of their support, there is now some money in the reward pool ($1,000) and enough to pay for the firsts 500 'beers' awarded. Please...
The New Forum is LIVE!
After months of hard word, I am very excited to introduce to you the new forum interface.
Here are the key features:
1- Easily add images to a post by drag & dropping the images in the editor
2- Easily attach files to a post by drag & dropping the files in the editor
3- Add latex equations to a post and they will be rendered with Mathjax (tutorial)
4- Add a code snippet and surround the code with
