ESP8266 Community Forum

- Thu Jul 06, 2017 11:46 am #67985

I read that they have internal pull-up resistors.

Don't trust some Internet reading blindly !
Maybe the place you read that were using a NodeMCU or Wemos board that have those external pullups added.

I don't remember where I read it, but it was specifically about internal to the ESP8266 IC itself.
Most of the tutorials on the internet do not show any pull-up for GPIO0 and GPIO2 and RESET pins.
There doesn't seem to be a definitive source for proper connection of the ESP8266.

- Thu Jul 06, 2017 12:28 pm #67987 There are internal pull ups on the IO pins (Pull down on GPIO16) but they are not on by default. They are turned on by program control. But the mode state has to established before any code can run, that is why the lines need to be controlled by external resistors. (external to the CPU)

Anyone can write a tutorial. Anyone can be an "Expurt" (sic)

- Thu Jul 06, 2017 1:04 pm #67990

Most of the tutorials on the internet do not show any pull-up for GPIO0 and GPIO2 and RESET pins.

Yes, the web is full of nonsense.

- Thu Jul 06, 2017 1:29 pm #67992

There doesn't seem to be a definitive source for proper connection of the ESP8266.

Sure there is ! This Wiki page is there for almost 3 years :
wiki/doku.php?id=esp8266_gpio_pin_allocations