ESP8266 Community Forum

My ESP-01 has always had it's blue led ON; I have been uploading and running Arduino sketches on it for some time, so I always assumed that blue LED was the power on LED...

do you have a level converter on the TX line comming from Arduino if not you may have blown the Rx on the ESP
I did read yesterday [ don't remember where] that the ESP inputs had 6 volt protection....not sure if infor was reliable.

Are you sure Arduino is functioning ok , can you loop RX to TX to test?

I am with Barnabybear on this one...you have the factory test script and you need to get those ESPs into programming mode to put something useful on them

Barnabybear wrote:Hi,
Vcc -> 3.3V
CH_PD ->3.3V
RST -> 3.3V
GPIO 0 -> 3.3V via a resistor (anything between 1K & 10K)
GPIO 2 -> 3.3V via a resistor (anything between 1K & 10K)
GND -> GND
Tx -> Tx (with arduino as Tx is realy Rx)
Rx -> Rx (with arduino as Rx is realy Tx)

Set serial terminal to CR & NL, baud will be 9600 or 115,200 dependant on firmware.

This will get you into normal run mode. To flash, leave the GPIO 0 resistor in place but connect GPIO 0 to ground, power off then back on, flash then remove the GPIO 0 connection to ground.

Did you ever resove your constant Blue LED issue?