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....
Favorite Tools: C++11 std::array
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...
The Other Kind of Bypass Capacitor
●1 commentThere’s a type of bypass capacitor I’d like to talk about today. It’s not the usual power supply bypass capacitor, aka decoupling capacitor, which is used to provide local charge storage to an integrated circuit, so that the...
It ain't heavy, it's my robot...
Unmanned Ground Vehicles - Design considerations for man-portable/packable vehiclesA UGV is “a ground based mechanical device that can sense and interact with its environment.” (Carlson, How) A Field Robot is expected to work outdoors,...
Unmanned Ground Vehicles - Design Considerations for Snow and Cold Environments
It's that time of year when the white stuff falls from the sky across the US, and with it comes lower temperatures. These conditions must be taken into consideration when designing a vehicle for outdoor use. A few definitions from...
Vala applications on Embedded Linux: maybe a cleaver chice [part 1]
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...
How to Succeed in Motor Control: Olaus Magnus, Donald Rumsfeld, and YouTube
Almost four years ago, I had this insight — we were doing it wrong! Most of the application notes on motor control were about the core algorithms: various six-step or field-oriented control methods, with Park and Clarke transforms,...
Round Round Get Around: Why Fixed-Point Right-Shifts Are Just Fine
Today’s topic is rounding in embedded systems, or more specifically, why you don’t need to worry about it in many cases.One of the issues faced in computer arithmetic is that exact arithmetic requires an ever-increasing bit length to...
Favorite Tools: C++11 User-defined literals
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...
Experiences with the Linux Real Time Scheduler
●1 commentI 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...
Round Round Get Around: Why Fixed-Point Right-Shifts Are Just Fine
Today’s topic is rounding in embedded systems, or more specifically, why you don’t need to worry about it in many cases.One of the issues faced in computer arithmetic is that exact arithmetic requires an ever-increasing bit length to...
VHDL tutorial - part 2 - Testbench
●4 comments[quicklinks]In an earlier article I walked through the VHDL coding of a simple design. In this article I will continue the process and create a test bench module to test the earlier design. The Xilinx ISE environment makes it pretty easy to start...
How to Build a Fixed-Point PI Controller That Just Works: Part I
●4 commentsThis two-part article explains five tips to make a fixed-point PI controller work well. I am not going to talk about loop tuning -- there are hundreds of articles and books about that; any control-systems course will go over loop tuning enough to...
How to Build a Fixed-Point PI Controller That Just Works: Part II
●4 commentsIn Part I we talked about some of the issues around discrete-time proportional-integral (PI) controllers: various forms and whether to use the canonical form for z-transforms (don't do it!) order of operation in the integral term: whether to...
VHDL tutorial - Creating a hierarchical design
[quicklinks]In earlier blog entries I introduced some of the basic VHDL concepts. First, developing a function ('VHDL tutorial') and later verifying and refining it ('VHDL tutorial - part 2 - Testbench' and 'VHDL tutorial - combining clocked and...
C++ on microcontrollers 1 - introduction, and an output pin class
●11 commentsThis 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...
Analog-to-Digital Confusion: Pitfalls of Driving an ADC
●2 commentsImagine the following scenario:You're a successful engineer (sounds nice, doesn't it!) working on a project with three or four circuit boards. More than even you can handle, so you give one of them over to your coworker Wayne to design....
Introduction to Microcontrollers - Driving WS2812 RGB LEDs
●4 comments[quicklinks] 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...
Introduction to Microcontrollers - Further Beginnings
●3 commentsEmbedded Programming Basics This tutorial entry will discuss some further embedded programming basics that you will need to understand before proceeding on to the LED blinky and other example programs. We will do this by looking at the...
Ten Little Algorithms, Part 1: Russian Peasant Multiplication
●1 commentThis blog needs some short posts to balance out the long ones, so I thought I’d cover some of the algorithms I’ve used over the years. Like the Euclidean algorithm and Extended Euclidean algorithm and Newton’s method —...
