ESP8266 Community Forum

- Fri Feb 13, 2015 5:05 pm #9686 PullDown can not ever be working on GPIOs 0-15. They have only PullUps.
GPIO16 has a PullDown, but does not have PullUp

- Fri Feb 13, 2015 5:07 pm #9687 GPIOs 0-15 have only pullups available
GPIO16 has only pulldown available

- Fri Feb 13, 2015 8:47 pm #9703

BTW, my intention of using pull-down is to be able to connect a switch to GPIO0 or GPIO2 of an ESP-01 board.

I don't get your need for a pulldown here. Just connect a resistor from VCC to the GPIO and a button from the GPIO to GND.

Adding unneeded external resistors is so arduino.

- Sat Feb 14, 2015 3:00 am #9723

I don't get your need for a pulldown here. Just connect a resistor from VCC to the GPIO and a button from the GPIO to GND.

In your scenario, the external resistor isn't even needed: The same could be achieved with the internal pull-up. The problem with this configuration is, that if the switch is closed and a power cycle happens, the ESP is starting up in flash-mode, and not executing the user code anymore. Not very reliable.

What's the issue with having it read 1 in open state?

As said, the problem is pulling the GPIO to 0 in closed state during power up.