Strange dependency (U8g2 + WiFiNINA + Serial)

Hi there,

I'm building a project based on Nano 33 IoT and a display based on UC1701 using U8g2 lib. What I face are the following scenarios:

  • board connected to USB power: Everything fine

  • board NOT connected to USB (powered by external VIN supply):

  • U8g2/Display enabled + WiFiNINA disabled: fine

  • U8g2/Display disabled + WiFiNINA enabled: fine

  • U8g2/Display enabled + WiFiNINA enabled: reset loop

Any idea?


Please READ THIS POST to help you get the best out of the forum.

These steps may also save you some unnecessary time and effort in the forum.

  • If applicable provide your SKETCH inside CODE TAGS ( </> ).
  • If applicable provide a schematic even if hand drawn.
  • Ensure you turn off any additional security / antivirus just to test.
  • Where possible use USB 2.0 ports or a USB 2.0 POWERED HUB.
  • Try other computers where possible.
  • Try other USB leads where possible.
  • Avoid cloud / network based installations where possible OR Ensure your Network / Cloud based software is RUNNING.
  • You do not have the correct driver installed.
  • There may be a problem with the PC.
  • You may be selecting the wrong COM port.
  • There is a problem with the board.
  • You have something connected to pins 0 and 1.

Thank you so much - your reply was not of any help at all. Maybe you face beginners every once in a while being too lazy (stupid?) to search a forum, but this hopefully does not apply to the majority of guys asking for help.

Uploading a sketch with >3000 LoC in 20 files or posting a schematic of a device with 58 components incl. display and a handful of ICs raises the complexity of understanding the original problem.

Anyway, studying the thread regarding VIN supply in this forum gave hints enough to solve the problem.


My answer was based on a lack of detail from you.
Hence the link at the top.