Now for something that does not have to do with Nixie Tubes I’ve been interested in Arduinos and the Maker Movement for sometime; This is why my Nixie Tube driver designs are based in part on the Arduino’s Atmega 328 processor; There are a dog’s breakfast of microcontrollers to choose from. But the ’328 stood out because of the wide acceptance of the Arduino; That would mean that the tools would be ubiquitous and there would far more resources available on the net.
I ran into just one big problem; I ran out of memory; You can only cram so much functionality into 32kB of flash memory; In fact, I’ve been forced to create different releases of the software for the different types of clocks by “ifdef”ing out functionality of one model to make room for the functionality of another. To put it plainly, this sucked.
I have some experience with Embedded Linux. And there’s no shortage of boards which are capable of running full-fledged Linux. I’ve had in the back of my mind the notion to design a board that could run Linux.
Then there were shields. Over 200 and counting. Granted many are one-offs that aren’t for sale, but plenty of them are. It would make sense to leverage my Linux board by making it compatible with The Shield Standard; Such that it is; It is not much more than a mechanical definition and some minimal number of digital and analog I/O. Maybe some PWM and SPI or async serial. That’s about it. That’s OK. At least this is a starting point.
Ok. Which Linux-capable processor should i use ? There’s also a dog’s breakfast of these. Most important: It must be cheap. And it should run full Linux. The Linux Board Support Package must exist. Schematics for reference designs must exist. The part that met all these requirements the best turned out to the same one that is used in the Chumby — The Freescale I.MX233. The Chumby people make all the code and documentation available. Plus, the part costs just $5 bucks in the USA quantity 100. Great !
Wind the clock forward a few months. Omit a ton of details. The first article is booting and running Linux. I am about to send the next spin of the board design out for fabrication: