ESP8266 Community Forum

- Sun May 17, 2015 11:27 pm #17715 I'm having the problem...

I have flash Blinky project, LED connected to between GPIO2 and GND. When my ESP01 is restarted, it will not boot normally. (LED always bright and Not Blinky ).

If I temporarily disconnect the LED circuit, the board will boot normally, and after reconnecting , my program works as desired (LED is Blinky normal ).

Is there anything I can do to get this unit booting normally without having to leave GPIO2 floating? Because in reality, LED port always connected to GPIO2 and GND.

- Mon May 18, 2015 8:51 am #17744 As you can see in https://github.com/esp8266/esp8266-wiki ... ot-Process, the GPIO2 needs to be pulled up to boot normally. If you attached a LED to GND, it will pull it down. So, simply reverse the LED with current limiting resistor to VCC instead.

- Mon May 18, 2015 11:17 am #17759 @martinayotte Can you help me Draw circuit ?

- Mon May 18, 2015 11:41 am #17761 Here are some images from the Web.

Sourcing a LED has the effect of pull-down, not good it the current case :


Sinking is acting like a pull-up, but the side effect is that logic is reversed, software setting GPIO to "1" turn off the LED while "0" make it glowing :