Powering the Arduino Nano Matter using an external 3.3V source

Official Hardware Nano Family Nano Matter
1

Hi folks,

I've just obtained an Arduino Nano Matter board, have successfully ran the Hello World examples, and have gotten my first application to work — very exciting!

But now I've hit a problem. So far, I've been running on USB-C only, i.e., the Arduino Nano Matter board has been powered via USB-C and I've used the 3V3 pin to power my other electronic components. Now I want to use a stable 3.3V source that I have to power both the board and my electronic components. I read in the manual (https://docs.arduino.cc/tutorials/nano-matter/user-manual/#powering-the-board) that one can use the 3V3 PIN (not as power output but) as power input. So I tried to remove USB-C and power the chip via the 3V3 pin and the GND pin (I used the GND pin next to VIN and not the one next to D2). I have not changed any of the soldering jumpers (SJ2, SJ4, etc.) on the back side of the chip. Unfortunately, with this setup, nothing happens. I verified that 3V3-to-GND has the 3.3V coming from my source but that's it.

Can anybody advise on whether my setup is incorrect?

In the user manual, I have found the below figure butI am not 100% sure how to read it: do I have to cut SJ2?

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Ideally, I'd want a setup where I can easily switch between using USB-C and my 3.3V power source.

Thank you for any pointers, comments, or ideas!
Best,
Hbf

P.S. I'm not sure this is related or points to a problem with my chip so just mentioning in case it rings a bell to anyone: when connected to USB-C, the voltage from GND to the +5V pin (next to A7) is almost zero, not the 5V I'd expect.

2

Update: it seems no jumpers need to be cut with the Arduino Nano Matter.

The following setup worked for me after all (turns out I blew my multimeter's fuse and that was the reason why my initial experiment did not work):

  • No changes to the Nano Matter board’s jumpers.
  • For development, disconnect my 3.3V external source and power the Nano Matter via USB-C only. My other electronic components get powered from the Nano Matter’s 3V3 and GND pins.
  • For deployment, disconnect USB-C and connect my external 3.3V power source to the Nano Matter’s 3V3 and GND pins; my other electronic components use this power source as well. (This draws around 7-9mA without any power optimizations.)
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