Module parameters:
- Output type: N-channel Open-Drain (equivalent to an open collector)
- Max output voltage: 24 V DC
- Max Output current: 50 mA
- Pulse length: >= 50 ms
- Output resistance: 110 Ω
- Output capacity: 1 nF
According to the Beginner's guide to the ESP8266 GPIO 0-15 all have a built-in pull-up resistor.
My questions are:
- Is the internal pull-up resistor connected to the GPIO after boot by default?
- If not, how to configure input to activate internal pull-up on the start?
- Or it is necessary to use external pull-up?