ESP8266 Community Forum

I'm reading https://espressif.com/sites/default/fil ... nce_en.pdf to figure out how ESP8266 registers work and in section 2.2.3. GPIO Input Register i see the note I don't really understand:

"The GPIO input detection function is enabled by default" what does it mean?

I think it means that the GPIO pins are configured as inputs by default, i.e. after a reset. This is the same for most microcontrollers, in my experience. You don't want GPIO pins starting up as ouputs, as that could cause problems with turning external devices on or off, or, more usually, cause a conflict if that GPIO pin was connected to another, external output.

Anyway don't interpret it as "a GPIO PIN interrupt is always connected", because that isn't the case, you need to set up one explicitly.