GPIO floating whilst power over ethernet and using internal pullup

OLIMEX / ESP32-POE

ESP32 IoT development board with 100Mb Ethernet and 802.3 Power Over Ethernet (POE)

Apache License 2.0

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GPIO floating whilst power over ethernet and using internal pullup #18

Closed trevm8 closed 3 years ago

trevm8 commented 3 years ago

I am using a pushbutton connected to GPIO3 and configured to use the internal pull-up resistor. I find that when I have non-powered wired ethernet connected and USB powered - the code executes as expected with consistent results recorded.

However; when I use the POE functionality, whilst using the exact same code - GPIO3 is now read as constantly changing low to high (floating).

I am using a TP-Link POE switch

DanKoloff commented 3 years ago

It should work but my general advice is to avoid using GPIO3 since it is connected to CH340T. gpio3-ch340t

However, if there is no way to avoid using it, try with external pull-up maybe the internal one is not good enough. I suspect when CH340T is not powered, maybe it gets powered from the GPIO3 line for some reason.