ESP 8266 reverse digitalWrite behaviour on which pins? I am using a device with an ESP 8266 microcontroller. I have discovered that setting LED_BUILTIN to HIGH turns the built-in LED off and  setting LED_BUILTIN to LOW turns the built-in LED on. This seems to be because the microcontroller can sink more current than it can source.

Before I start using this microcontroller, I would like to know which other pins have this reverse behaviour. I've looked up datasheets for the ESP 8266 but I don't see how to discern this information. I would simply write a sketch to test, but I'm not sure what I might damage, and I'm not sure how to determine when an output pin is in the high-impedance state anyway.

On the ESP 8266, how to know which pins are HIGH -&gt; 0v and which pins are HIGH -&gt; 5v? Are the HIGH -&gt; 0v pins necessarily LOW -&gt; 5v? Where is this documented?
The esp8266 must have a pull-up on io 2 for boot configuration. The Wemos D1 boards put the LED in series with the pull-up resistor on io 2. This creates the 'reversed' LED behavior.



The large D1s are retired and it is hard to find a good and readable schematics. The cut out is from D1 mini schematics.