Hello All,
I've built a datalogger using the Arduino nano 33 IOT arduino and I'm having some issues with the arduino internal counter. When I'm powering the board using an external AC/DC 5V converter the arduino counter has a delay when recording data from the external sensors. Over time this delay gets worse and worse when you compare the counter time/date to our external RTC time/date. However when you power the board off a USB/computer the delay is no longer there. I can even power up the unit with the AC/DC converter, see the delay slowly happening and if I plug in the USB quickly and unplug then it fixes the issue (the USB triggers something and the delay stops - even if you unplug it). I've narrowed down the issue to be a combination of D+, D-, and GND wires from the USB. The power line does not affect anything. My questions is what is the USB data lines changing in the micro controller that's causing this effect? Which registers are the data lines writing to that could help me narrow down why I do not get the delay when the USB is plugged in but I get the delay when I power the Arduino externally?
Any thoughts would help!
Thanks!