ESP8266 Community Forum

- Thu Apr 23, 2020 2:24 pm #86728 I'm currently using a ESP-01 module with an arduino uno. I keep getting the following error: esptool.FatalError: Failed to connect to ESP8266: Invalid head of packet (0x00). I'm running the blink example code for esp8266; I've tried using the reset button when uploading my code and occasionally this causes it to time out instead, but I usually get the same error no matter what. I've got 3.3V and EN to 3.3V, GND and IO0 to GND, TX to TX, RX to RX, and RST to a button. Any idea how to fix this?

- Fri Apr 24, 2020 3:54 am #86736 GPIO0 is sampled during start up after reset or power up to determine the start up mode of the ESP8266 (0 = serial upload new firmware, 1 = normal run).

If you have it permanently grounded then it will always be in upload mode and never run the real code on the ESP8266.

You probably want to put a push button switch between GPIO0 and 0V so you can choose when to upload new firmware or let it run normally.

- Fri Apr 24, 2020 9:47 am #86740

GPIO0 is sampled during start up after reset or power up to determine the start up mode of the ESP8266 (0 = serial upload new firmware, 1 = normal run).

If you have it permanently grounded then it will always be in upload mode and never run the real code on the ESP8266.

You probably want to put a push button switch between GPIO0 and 0V so you can choose when to upload new firmware or let it run normally.

Okay, so I set up a button for GPIO0, but the code isn't even able to upload at all, it keeps giving me the error. My understanding was that it needed to be grounded when I'm uploading code, but it gives the same error when the button is pushed, and when GPIO0 isn't connected at all.