SparkFun Forums

[johndey]

I have a ESP8266-01S powered by FTDI. Voltage to the module verified as 3.3v. Yet LED power light on the module does not come on. All other module connections (except VCC a nd GND have been removed). Is my ESP module dead?

[johndey]

It appears that the bad red (power) LED did not affect the other functions of the module.

[Valen]

I don't know what the specs of your FTDI USB to serial thing are, but generally speaking they do not supply enough current to get the ESP working while it is transmitting. So it may stop working when the voltage collapses due to insufficient supply power. It doesn't have to be a bad led. Make sure the power supply is rated to give it 300 milli-amps.

That said, some early ESP-01 models (not this -01S) had the wrong current limiting resistor on it that would make the led burn out. You'd think they would have fixed that as well when putting a larger flashchip on it.

[johndey]

The "other functions" I was referring to are the compiling and loading functions. After I have debugged the code, I will replace the FTDI with an external power source.

The red LED has never come on, but the blue LED does flicker during loading, as it should.

So far it appears to be just a bad LED, and if that is all it is, I can live with that.

[Valen]

Debugging while susceptible to insufficient power supply only makes finding the actual cause more difficult. It's hard to differentiate a crash due to random powerglitches from a bug you haven't found out about yet. Just make sure you have a ways to know when it is about to start it's wifi transmitter or other power hungry functionality.

[johndey]

Upon closely examining my ESP8266-01S I do not think it comes equipped with both a RED (power) LED and a BLUE LED, but only with the blue LED. Anyways I got it to successfully compile and load my code.