• Skip to main content
  • Skip to primary sidebar

RNTLab.com

The Ultimate Shortcut to Learn Electronics and Programming with Open Source Hardware and Software

  • Courses
  • Forum
    • Forum
    • Ask Question
  • Shop
  • Account
  • Blog
  • Login

Error uploading sketch on ESP32

Q&A Forum › Category: ESP32 › Error uploading sketch on ESP32
0 Vote Up Vote Down
Olivier Emery asked 7 years ago

Just a comment on the troubleshooting guide: the error “A fatal error occurred: “Failed to connect to ESP32: Timed out… Connecting…” can also happen when uploading code while a module using RX/TX is connected (in my case it was a LoRa module). The solution is to unplug the Vcc cable of the module before uploading the sketch (or use SoftwareSerial for the module for a long term solution). It took me a while to figure it out so it may be useful to add that to the troubleshooting guide.
 
Best, Oli
“

Question Tags: esp32 arduino sketch upload problem
3 Answers
0 Vote Up Vote Down
Rui Santos Staff answered 7 years ago

Thank you Olivier! That’s definitely true, you need to keep the ESP32 in flashing/uploading mode. Otherwise it fails to upload a new sketch. 
Regards,
Rui

0 Vote Up Vote Down
book1 answered 6 years ago

4. A fatal error occurred: “Failed to connect to ESP32: Timed out… Connecting…” from https://rntlab.com/module-1/esp32-troubleshooting-guide/

I also have an ESP32 with this problem which I have seen on other devices. Placed a 2.2uF 50v Cap (value selected because I had one on breadboard) from the EN pin to the GND pin and now loads without requiring the Enable PB. Think it has to do with keeping the enable input low a little longer for the data transfer to start.
Steve WA3RTC

0 Vote Up Vote Down
Rui Santos Staff answered 6 years ago

Exactly, that’s how to solve the problem permanently with an ESP32 dev board that has that behavior. I have a dedicated guide on that subject: [SOLVED] Failed to connect to ESP32: Timed out waiting for packet header

Primary Sidebar

Login to Ask or Answer Questions

This Forum is private and it’s only available for members enrolled in our Courses.

Login »

Latest Course Updates

  • [eBook Updated] Learn Raspberry Pi Pico/Pico W with MicroPython eBook – Version 1.2 May 26, 2025
  • [New Edition] Build ESP32-CAM Projects eBook – 2nd Edition April 16, 2025

You must be logged in to view this content.

Contact Support - Refunds - Privacy - Terms - MakerAdvisor.com - Member Login

Copyright © 2013-2025 · RandomNerdTutorials.com · All Rights Reserved

Insert/edit link

Enter the destination URL

Or link to existing content

    No search term specified. Showing recent items. Search or use up and down arrow keys to select an item.