Rx pin of ESP8266 works at 5V and not 3,3V?

Wireless & IoT
1

Hi, I think that ESP8266 is damaged!!

I bought this component https://www.sparkfun.com/products/13678.

First test, i connected the ESP8266 with Arduino UNO and if i use 5V works fine,

ARDUINO UNO ESP8266

GND------------------GND

5V---------------------Vcc

No connected------ Reset

5V---------------------EN

2---------------------Tx

3---------------------Rx

Second test,if i use 3,3V the Rx pin works fine because the voltaje the Rx pin received of Arduino UNO is 4.78V.

ARDUINO UNO-------- ESP8266 ----------Volt

GND--------------------GND

3.3V---------------------Vcc

No connected--------- Reset

3.3V---------------------EN

2-------------------------Tx -------------------3.3

3-------------------------Rx ------------------4.78

Third test, i connected the ESP8266 with Arduino Pro mini at 3,3V but the Rx pin doesnt work? Somebody knows what happening? I reset the module, i restored as well.

ARDUINO Pro mini------- ESP8266 ------ volts

GND------------------------GND

3.3V-------------------------Vcc

No connected------ ------Reset

3.3V-------------------------EN

2----------------------------Tx --------------3.3

3----------------------------Rx --------------3.3

Somebody knows what happening? I need to update the firmware and how i can do?

I will appreciate your attention,

Many thanks.

2

The documentation of Espressif, the maker of the ESP8266 says the maximum supply voltage is 3.6 volt. So applying 5 volt to it is asking for trouble. Yes it may work in the beginning. But eventually something may break.

In the third test you are supplying it with the 3.3 volt generated on the Arduino Pro Mini board. Depending on which chip the regulator is it seems it is limited to 150 ma. (see : https://www.sparkfun.com/products/11114) The ESP8266 can draw more than that if it starts transmitting Wifi at power up. It may just be a case of power brownout which makes the device go in reset. That should be visible in the serial monitor output.

[EDIT: Oops, was link to the 5 volt version]

3

I will be less cautious than Valen. You probably did damage the ESP8266 by connecting it to 5V.

I’m surprised if it still works, and would just throw it out anyway, because it can’t be trusted now.

But take heart, we have all made that mistake. Chalk it up to experience.

4

My Esp8266 got damaged.i accidentally fed 5v instead of 3.3v . Be careful.

5

5 volt probably did kill it. But in the interest of learning this is a common mistake that should be ruled out also.