Connectiong GPIO2 to GND on Startup results in junk in COM

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Re: Connectiong GPIO2 to GND on Startup results in junk in

By andyjwang
- Thu Jun 04, 2015 5:38 pm #19485 Can uber4 provide the diagram of how you connected gpio 2 to led please? :?:

pzwolinski wrote:
I'm having the same problem...

I have an LED connected to between GPIO2 and GND. When my ESP01 is restarted, it will not boot normally, which is a bummer. If I temporarily disconnect the LED circuit, the board will boot normally, and after reconnecting, my program works as desired (able to toggle the LED over wifi).

Is there anything I can do to get this unit booting normally without having to leave GPIO2 floating?


I had the same problem and I fixed with a 2,2k pull up resistor (4,7k or higher was not working).
Doing this GPIO2 will be high by default while it resets (1-2 seconds), but you allways can write to low.
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Re: Connectiong GPIO2 to GND on Startup results in junk in

By Baoshi
- Thu Jun 04, 2015 8:03 pm #19495 GPIO2 is UART1 TX after reset. ESP8266 will send data OUT from this pin. AT firmware also use this pin as output. Never Never short this pin to GND or connect it via a LED to GND. Doing this will fry your chip. I have some corpses lying around because I mistaken GPIO2 with GPIO0.
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