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User avatar
By Dame Lyngdoh
#82226 Problem
Using the Arduino UNO board with the ESP8266 module with an empty sketch without calling any of the WiFi related functions produces an error during upload. Specifically during connection to the ESP module.

Board Setup/Connection
I have an Arduino UNO board, an ESP8266EX board and a level shifter (for 5V to 3.3V shift).
The connection is as follows:
Arduino UNO - ESP8266
  • Digital Pin 0 (RX) - RX
  • Digital Pin 1 (TX) - TX
  • Gnd - Gnd
  • 3.3V - VCC
  • 3.3V - CH_EN
In between Digital Pins 0 and 1 of the Arduino Board and the ESP8266 board, I have used the level shift board as the pins from the Arduino board give out a 5V output but the TX/RX pins of the ESP8266 board operate till a 3.3V.
The Arduino UNO board is connected to my laptop (running the Arduino IDE) via the USB interface.

I followed the instructions in, the instruction within the repository for installation. After installation, I restarted the Arduino IDE 1.8.9 and selected the board (from Tools -> Board -> Generic ESP8266 Module (Under ESP8266 Boards 2.6.0 - DEV section).

Hardware: ESP8266
Core Version: 2.6.0-dev
Development Env: Arduino IDE
Operating System: Windows 8.1 64x

Settings in IDE
Module: Generic ESP8266 Module
Flash Mode: DOUT compitable
Flash Size: 1MB no SPIFFS
lwip Variant: v2 Lower Memory
Reset Method: ck
Flash Frequency: 40Mhz
CPU Frequency: 80Mhz
Upload Using: SERIAL
Upload Speed: 115200

Code: Select allvoid setup() { }
void loop() { }

Debug Messages v2.6
2.6 v2.6
Serial port COM4
Connecting........_____....._____....._____....._____....._____....._____.....____Traceback (most recent call last):
File "D:\Applications\Arduino\hardware\esp8266com\esp8266/tools/", line 25, in <module>
File "D:/Applications/Arduino/hardware/esp8266com/esp8266/tools/esptool\", line 2653, in main
File "D:/Applications/Arduino/hardware/esp8266com/esp8266/tools/esptool\", line 468, in connect
raise FatalError('Failed to connect to %s: %s' % (self.CHIP_NAME, last_error))
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header

Additional Information
I tried the following actions:
  • grounding the GPIO0 pin of the ESP8266
  • connecting the GPIO1 pin to HIGH (VCC)
  • swapping TX/RX connections between the boards
but none of them produced and positive results.
User avatar
By QuickFix
#82263 Get yourself a NodeMCU or Wemos (both cost only $2.50 or so) or buy at least a proper USB -> UART convertor if you insist in using an ESP-01 (assuming you're using the worst module the entire internet advises people to use) and stop trying to get it to work using the Arduino-route if you don't know what your doing.
(Hint: you'll have to remove the Atmel controler on the Arduino board prior to using the board's USB-UART convertor). :idea: