Category: electronics

I've been doing some work recently with a little Silicon Labs EFM8UB3 microcontroller. This is a nice 8051 clone with a bunch of peripherals all in a QFN24 package. I've been using a minimal development board Silicon Labs calls the Thunderboard. It's mostly fine, but it has one failure mode that's pretty annoying. This article is about how to back out of that failure mode if you encounter it.

The Thunderboard has a built-in JLink debugger, and it's unfortunately possible to put the MCU into a state where the debugger can't talk to it. That means that you can't program the board any more, so you might think you're stuck. You're not!

One thing I need to do for my pump monitor is to determine when the pump is running. I'm going to do this by measuring the current flowing in the power cable to the pump. That seems like it ought to be an easy thing to do, but doing it safely (it's a 240V AC mains cable to the pump) and reliably is more complicated than I expected. There might be a simpler way to do things than what I'm trying to do, but this is a good opportunity to do a little bit of analogue electronics and to learn some things. (My analogue electronics skills are negligible, so I'm always on the lookout for small projects or parts of projects that have the right "challenge level" to help me get better!)

We live on the side of a hill where rainwater runs down into our garden, gathering at the lowest point to make a "sumpy" patch. The soil has a high clay content, so the runoff is efficient. We also have a cellar. (You can see where this is going already, right?) We have a shaft next to the house that contains a pump to clear out water draining into the sumpy area. A couple of months ago I took the lid off the shaft and found the pump under two metres of water, not running. Opening up the stairs down to the cellar revealed half a metre of water down there... Not good.

More datasheets and application notes: starting to learn about DACs in the Analog Mini-Tutorials series, another DC/DC converter (in a slightly less silly package), plus a couple of randoms.

An interesting application note about crystals (I know very little about them, and need to know more) and a paper about how best to solder QFN packages, plus some jellybeanish analogue ICs and a tiny tiny DC/DC converter.

Bit behind on this again, but I have some interesting ones for next week, so maybe that will make me stick with it better.

Got a bit distracted with reading microcontroller datasheets and reference manuals for some projects, mostly for the ST Micro STM32F767ZI and for the Silicon Labs "Universal Bee" series (I'm using the EFM8UB3 for a project at the moment). But here's some "normal" datasheet reading.

The whole "datasheet a day" thing got slightly derailed this month. I have been reading datasheets for projects, but my "datasheet a day" reading has been spent on Op Amps For Everyone, which is 464 pages of opampy goodness from Ron Mancini at TI. I certainly didn't understand it…

I just this week finished a project that has been hanging around for a while, mostly because it turned out to be much more work than I estimated. Earlier this year, I did some work using Nordic Semiconductor's nRF52840 ARM chip. Although the chip is nice, I didn't enjoy the…

Slightly fewer datasheets this week, because I'm reading "Op Amps For Everyone", which is a 464-page thing about op amps from TI. That's a bit too long to manage one of them in a day!

I tried one new thing this week with the datasheets. I took a number of datasheets for "standard" diodes, and just looked through them to get a sense of the kinds of parameters that are usually quoted for these things. It was a useful exercise, and I'll do the same for some transistors next week. Otherwise, I continued with ploughing through the Analog Devices "mini-tutorials" series. They're of varying difficulty and relevance, but they all feel like things it would be good to know about.

I've had some time to work on my Teensy Load project recently. I got the boards a couple of weeks ago, assembled one, found that it didn't really work, and tracked that problem down to a wrong-way-round diode (due to a weird symbol definition I'd used from the wrong KiCad library).

And yesterday I did some end-to-end testing using the tl-meter software that I wrote. And it (partially) worked!

More datasheets!

My regular Sunday datasheets round-up...

More datasheets/app notes/unclassifiable electronics things. I should get around to writing some blog articles about something else as well, eh?

The daily datasheet thing continues. It's been surprisingly easy to get in at least one a day, mostly because a lot of them are quite short. This week, one day was taken up with reading a big pile of datasheets for motor driver ICs, which was repetitive but educational.

Here's this week's datasheet-a-day reading...

I started a new thing this last week. I've been impressed by Adrian Colyer's the morning paper for a long time. It's a project where Colyer read and commented on a computer science paper every week day during term time, and wrote a summary of the paper. Some of the summaries are quite long. It was really useful, for those of us who were working in a similar field, because it meant that we could get a quick overview of papers without going to the trouble of reading them.

I have no intention of displaying the level of diligence that Colyer did, but it did make me think about a less ambitious "read a thing every day" project. I've been thinking of it as "datasheet a day", but I've been reading a mixture of datasheets and application notes.

I completed a fun little electronics project yesterday: a small solder fume extractor based on a PC fan. I've been calling it the Solder Snorter, in homage to Jon Thomasson's Solder Sniffer 9000 — this thing is more or less a redo of that idea.

I've been making some progress with Contextual Electronics, and have been learning a lot, although some of the learning has been a little painful and frustrating.

I've started learning electronics recently, following Chris Gammell's Contextual Electronics course, which is really good. One of the first exercises there is called "Getting to Blinky", and it's mostly about getting used to using the KiCad EDA suite, and getting over the initial barrier to getting PCBs made.

I worked through the tutorial, but didn't really feel like sending boards out just for a blinky. I wanted to do something more entertaining. It seemed like it might be fun to make blinkies that blinked messages. In Morse code? Yeah, why not?