Attie Grande

computer booper / electronics wizard.
things are never as simple as they first appear.
ally 🌈🦕🦄

Last Notes

2026-04-09 16:37:17 GMT

It seems the JST website (they make connectors) might be somewhat vulnerable to SQL injection...
How did I find this out? ... I typed in a full MPN into the search box, with brackets in it.
BM08B-SURS-TF(LF)(SN)

2026-03-31 16:06:58 GMT

A customer wants to use a particular SOM, and in particular the QSPI interface.
I said that the QSPI interface is busy with onboard NAND, and can't be used via the main connectors.
They replied with a ChatGPT screenshot saying "yes, we can use it, we just need to do ${pinmux}".
They replied ~1 hr later saying that they don't want to use the specific module anymore.
I took a brief look at the ChatGPT screenshot and the SOM docs, and unsurprisingly the pins ChatGPT nominated are mostly LVDS, but also a hard GND pin.
Yay, winning.

2026-03-09 20:07:02 GMT

Out of all the incredibly loud things I've experienced in my life, I'd rank the top two as:
1. Looking up the bum of a Vulcan bomber giving it full send for a short takeoff at Farnborough Airshow. Holy shit. It tickled the insides of my ears.
2. A 4 week old baby. Any earlier and they've not fully got the pipes working yet - a distinctly softer timbre. This also appears to be about when they start becoming inconsolably angry about unknowable things - the limbs start flailing and joining in with the crying too... and you have to hold them close which only compounds the loudness issue.
... in related news, Thing 2 made an appearance in our household around 4 weeks ago.

2026-02-02 12:29:06 GMT

What is your favourite way to protect an ADC input? Things like STM32 have no real protection on pins in analog mode, which makes a basic potential divider approach paired with over-voltage a concerning situation.
Consider measuring battery voltage, where the battery is much higher than the ADC's max (e.g: +12v vs +3.3v).
Zeners start to have non-trivial leakage current near their working voltage - when you protect the ADC properly, the signal distorts at higher voltages.