ESP8266 Community Forum

- Mon Apr 11, 2016 6:20 am #45272 Hello everybody,
I just bought an ESP 12-Q and I wonder which outputs I can use without problems.
Is there a problem using GPIO0, GPIO2 and GPIO15 ?
Can I use GPIO9 and GPIO10 ?
Thanks in advance for your answers.


(sorry if I make some mistakes but english is not my native language...)

- Mon Apr 11, 2016 9:40 am #45288 The GPIO15/GPIO2/GPIO0 are used to determine boot mode at reset or power-up.
They can still be used as GPIOs after the boot is done. But you need to be careful about the boot state.
Here are sveral thread explaining how to connect LED or Relay for example :
viewtopic.php?f=6&t=9454#p45277

For GPIO9/GPIO10, they are used by the Flash in QIO mode, but they can become available with some hardware modifications and using the Flash in DIO mode only (a bit slower though than QIO), here is the explanation :

http://smarpl.com/content/esp8266-esp-2 ... and-gpio10

- Mon Apr 11, 2016 10:44 am #45297 Thanks for your answer.
So if I understand well, if I connect LEDs in sink mode on GPIO0 and GPIO2 and if I connect a pull-down resistor on GPIO15, it will work fine ?

- Tue Apr 12, 2016 7:48 am #45355 Yes !