Writing code for embedded applications can be difficult. There are all sorts of problems you can run into – race conditions, conflicting peripherals, unexpected program flow – any of these can cause havoc with your project. One thing that can really mess things up is if your microcontroller is getting stuck on a routine – without the right debugging hardware and software, this can be a tricky one to spot. [Terry] developed a microcontroller load meter just for this purpose.

It’s a simple setup – a routine named loadmeter-task on the microcontroller sends a train of pulses to a mechanical ammeter. The ammeter is then adjusted with a trimpot to read “0” when the chip is unloaded. As other tasks steal CPU time, there’s less time for loadmeter-task to send its pulses, so the meter falls to the left.

Overall it’s a quick and easy bit of code you could add to any project with a spare GPIO pin, that might help you debug. Plus it’s cool to know how hard your project is pushing the silicon.

If you’d like to know more about what your chip is doing, check out this post about the usefulness of in-circuit debugging, or read about Bil Herd’s experiments with ICE and OBD-II.