Should You Build For Windows, Mac, IOS, Android, Or Linux? Yes!

October 1, 2020 by Al Williams 36 Comments

The holy grail of computer languages is to write code once and have it deploy effortlessly everywhere. Java likes to take credit for the idea, but UCSD P-Code was way before that and you could argue that mainframes had I/O abstraction like Fortran unit numbers even earlier. More modern efforts include Qt, GTK, and other things. Naturally, all of these fall short in some way. Now Google enters the fray with Flutter.

Flutter isn’t new, but in the past, it only handled Android and iOS. Now it can target desktop platforms and can even produce JavaScript. We haven’t played with the system enough to say how successful it is, but you can try it in your browser if you want some first-hand experience.

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Even More Firmware In Your Firmware

October 1, 2020 by Kerry Scharfglass 13 Comments

There are many ways to update an embedded system in the field. Images can fly through the air one a time, travel by sneaker or hitch a ride on other passing data. OK, maybe that’s a stretch, but there are certainly a plethora of ways to get those sweet update bytes into a target system. How are those bytes assembled, and what are the tools that do the assembly? This is the problem I needed to solve.

Recall, my system wasn’t a particularly novel one (see the block diagram below). Just a few computers asking each other for an update over some serial busses. I had chosen to bundle the payload firmware images into the binary for the intermediate microcontroller which was to carry out the update process. The additional constraint was that the blending of the three firmware images (one carrier and two payload) needed to happen long after compile time, on a different system with a separate toolchain. There were ultimately two options that fit the bill.

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Hyper Links And Hyperfunctional Text CAD

September 30, 2020 by Brian McEvoy 61 Comments

Strong opinions exist on both sides about OpenSCAD. The lightweight program takes megabytes of space, not gigabytes, so many people have a copy, even if they’ve never written a shape. Some people adore the text-only modeling language, and some people abhor the minimal function list. [Johnathon ‘Zalo’ Selstad] appreciates the idea but wants to see something more robust, and he wants to see it in your browser. His project CascadeStudio has a GitHub repo and a live link so you can start tinkering in a new window straight away.

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Boot Sector Pong As A Crash Course In Assembly

September 28, 2020 by Tom Nardi 13 Comments

Have you ever wanted to develop a playable game small enough to fit into a disk’s 512 byte boot sector? How about watching somebody develop a program in assembly for nearly two hours? If you answered yes to either of those questions, or ideally both of them, you’re going to love this project from [Queso Fuego].

Whether you just want to check out the public domain source code or watch along as he literally starts from a blank file and codes every line for your viewing pleasure, chances are good that you’ll pick up a trick or two from this project. For example, he explains how all of the “graphics” in the game are done in 80 x 25 text mode simply by setting the background color of character cells without printing any text to them.

We really like the presentation in the video after the break, which was recorded over the course of multiple days, judging by the changing light levels in the background. As he types out each line of code, he explains what its function is and gives any background information necessary to explain how it will fit into the larger program. If you’ve ever wondered if you had what it takes to program in ASM, watching this video is a great way to decide.

[Queso Fuego] mentions that this project, and his research into this sort of low-level programming, came about due to the social distancing boredom that many of us are feeling. While we’re certainly not advocating for him to kept locked in his home permanently, with projects like this, you’ve got to admit it seems like a win for the rest of us.

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Parsing Math In Python

September 18, 2020 by Al Williams 10 Comments

Programming computers used to be harder. Don’t get us wrong — today, people tend to solve harder problems with computers, but the fundamental act of programming is easier. We have high-level languages, toolkits, and even help from our operating systems. Most people never have to figure out how to directly read from a disk drive, deblock the data into records, and perform multiplication using nothing but shifts and adds. While that’s a good thing, sometimes it is good to study the basics. That was [gnebehay’s] thought when his university studies were too high level, so he decided to write an arithmetic expression parser in Python. It came out in about 100 lines of code.

Interpreting math expressions is one of those things that seems simple until you get into it. The first problem is correctly lexing the input — a term that means splitting into tokens. For a human, it seems simple that 5-3 is three tokens, {5, -, and 3} and that’s easy to figure out. But what about 5+-3? That’s also three tokens: {5,+,-3}. Tricky.

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Putting The Firmware In Your Firmware

September 15, 2020 by Kerry Scharfglass 12 Comments

Performing over-the-air updates of devices in the field can be a tricky business. Reliability and recovery is of course key, but even getting the right bits to the right storage sectors can be a challenge. Recently I’ve been working on a project which called for the design of a new pathway to update some small microcontrollers which were decidedly inconvenient.

There are many pieces to a project like this; a bootloader to perform the actual updating, a robust communication protocol, recovery pathways, a file transfer mechanism, and more. What made these micros particularly inconvenient was that they weren’t network-connected themselves, but required a hop through another intermediate controller, which itself was also not connected to the network. Predictably, the otherwise simple “file transfer” step quickly ballooned out into a complex onion of tasks to complete before the rest of the project could continue. As they say, it’s micros all the way down.