The Arduino software environment, including the IDE, libraries, and general approach, are geared toward education. It’s meant as a way to introduce embedded development to newbies. This is a great concept but it falls short when more serious development or more advanced education is required. I keep wrestling with how to address this. One way is by using Eclipse with the Arduino Plug-in. That provides a professional development environment, at least.
The code base for the Arduino is another frustration. Bluntly, the use of
main() being hidden really bugs me. The mixture of C and C++ in libraries and examples is another irritation. There is enough C++ being used that it makes sense it should be the standard. Plus a good portion of the library code could be a lot better. At this point fixing this would be a monumental task requiring many dedicated developers to do the rewrite. But there are a some things that can be done so let’s see a couple possibilities and how they would be used.
Continue reading “Code Craft-Embedding C++: Hacking the Arduino Software Environment”
The language C++ is big. There is no doubting that. One reason C++ is big is to allow flexibility in the technique used to solve a problem. If you have a really small system you can stick to procedural code encapsulated by classes. A project with a number of similar but slightly different entities might be best addressed through inheritance and polymorphism.
A third technique is using generics, which are implemented in C++ using templates. Templates have some similarities with #define macros but they are a great deal safer. The compiler does not see the code inserted by a macro until after it has been inserted into the source. If the code is bad the error messages can be very confusing since all the developer sees is the macro name. A template is checked for basic syntax errors by the compiler when it is first seen, and again later when the code is instantiated. That first step eliminates a lot of confusion since error messages appear at the location of the problem.
Continue reading “Code Craft – Embedding C++: Templates”
The popularity of KiCad keeps increasing, and not only are more people converting to it and using it for their projects, but there’s also a growing number of folks actively contributing to the project in the form of libraries, scripts and utilities to improve the work flow.
[Dave Vandenbout] a.k.a [xesscorp] has written a couple of utilities for KiCad. When working with large multi pin parts such as micro-controllers, creating a schematic symbol from scratch using the traditional KiCad schematic library editor can be quite tedious. KiPart is a python script that uses a CSV table as its input to generate the KiCad schematic symbol and is able to create multi-part symbols too. Usage is quite simple. The csv file needs a part name on its first row. The next row contains the headers. ‘Pin’ number and Pin ‘Name’ are the minimum required. Additionally, you can add in ‘Unit’, ‘Side’, ‘Type’, and ‘Style’. Unit is used when defining multi-unit parts. Side decides the location of the pin, Type its function, and Style is its graphic representation. Running the KiPart python script then results in a nice KiCad schematic symbol. Besides, KiPart can specifically generate schematic symbols for the Xilinx 7-Series FPGAs and the Cypress PSoC5LP. There are a whole host of options to customize the final output, for example ordering pin placement based on pin number, or pin name or pin function. Source files can be obtained from the [xesscorp] Github repository.
Another useful utility from [xesscorp] is KiCost. It is intended to be run as a script for generating part-cost spreadsheets for circuit boards developed with KiCad. The one piece of information you need to add to your schematic parts is a manufacturers part number. The KiCost Python script then processes the BOM XML file, reading the manufacturer part number, scraping the web sites of several popular distributors for price and inventory data, and creating a costing spreadsheet. You can grab the source files from the KiCost Github repository.
Check the two videos below where [Dave] walks through the two utilities.
Thanks to [RoGeorge] for sending in this tip by commenting on the Open Source FPGA Pi Hat built by [Dave] that we featured recently.
Continue reading “KiCad Utilities Generate Parts; Track Costs”
What is an embedded system? The general definition is a computer system dedicated to a specific purpose, i.e. not a general purpose system usable for different tasks. That is a very broad definition. I was just skimming the C++ coding guidelines for the Joint Strike Fighter. That’s a pretty big embedded system and the first DOD project that allowed C++! When you use an ATM to get money you’re using an embedded system. Those are basically hardened PCs. Then at the small end we have all the Internet of Things (IoT) gadgets.
The previous articles about embedding C++ discussing classes, virtual functions, and macros garnered many comments. I find both the positive and critical comments rewarding. More importantly, the critical comments point me toward issues or questions that need to be addressed, which is what got me onto the topic for this article. So thank you, all.
Let’s take a look at when embedded systems should or should not use C++, taking a hard look at the claim that there may be hidden activities ripe to upset your carefully planned code execution.
Continue reading “Code Craft-Embedding C++: Hidden Activities?”
Code.org annually sponsors an Hour of Code (December 7th to the 13th will be the third one). The goal is to try to teach kids the basics of computer science in just an hour. Microsoft has announced they will team with Code.org to bring Minecraft-based lessons to this year’s hour.
It makes sense when you remember that Microsoft bought Mojang (the company behind Minecraft) last year. Users can sign up for the free Hour of Code Minecraft module and learn how to make characters adventure through a Minecraft world using programming. There are other themed modules, too, including Star Wars, Frozen, and other kid-attracting motifs. There’s also a lot of videos (like the one below) that explain why you might want to learn about computer science.
If you think Minecraft isn’t a sufficient programming language, don’t be so sure. There are many Minecraft CPUs out there as well as a (very slow) word processor. If you want real hardware, you might check out our review of Minecraft-related projects from earlier this year.
Continue reading “Microsoft, Minecraft, and Kids”
Embedded C developers shy away from C++ out of concern for performance. The class construct is one of their main concerns. My previous article Code Craft – Embedding C++: Classes explored whether classes cause code bloat. There was little or no bloat and what is there assures that initialization occurs.
Using classes, and C++ overall, is advantageous because it produces cleaner looking code, in part, by organizing data and the operations on the data into one programming structure. This simple use of classes isn’t the raison d’etre for them but to provide inheritance, or more specifically polymorphism, (from Greek polys, “many, much” and morphē, “form, shape”).
Skeptics feel inheritance simply must introduce nasty increases in timing. Here I once more bravely assert that no such increases occur, and will offer side-by-side comparison as proof.
Continue reading “Code Craft – Embedding C++: Timing Virtual Functions”
For many embedded C developers the most predominate and questionable feature of C++ is the class. The concern is that classes are complex and therefore will introduce code bloat and increase runtimes in systems where timing is critical. Those concerns implicate C++ as not suitable for embedded systems. I’ll bravely assert up front that these concerns are unfounded.
When [Bjarne Stroustrup] created C++ he built it upon C to continue that language’s heritage of performance. Additionally, he added features in a way that if you don’t use them, you don’t pay for them.
Continue reading “Code Craft – Embedding C++: Classes”