ESP8266 Community Forum

- Sun May 24, 2015 1:22 pm #18328 I would love to read that too! I can only tell you that in my case it worked when I just removed the pull down resistors. Well it flashes on startup (which I tried to stop with these), but once the esp's program kicks in everything works fine. Well and it does boot up, which helps
I read here http://www.esp8266.com/viewtopic.php?f=13&t=1730&start=10 that some bigger values for the resistors should work too... once I fiend the time i'll test that.

- Sun May 24, 2015 3:29 pm #18339 The way I do this is I just stick a 10K pull up resistor tied to Vcc. It is not enough to light the LED and since, during boot up, the GPIO2 is configured as an input, it is basically floating, hence there isn't enough current for the LED to go on so the voltage reads high to the GPIO2. Seems to work for me and keeps it as positive logic.

- Wed Jul 08, 2015 10:46 pm #22812

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 :

This is great. It works for me with this setup.
The problem I have now is that when it boots up, the led is ON, even though I set the pin to HIGH at void setup.
I am using Blynk and I cannot find a basic guidance how to invert the pin logic.
Is there another way to make the LED off after it boots up?
Thanks !

- Thu Jul 16, 2015 9:01 am #23427 Make your own firmware