ESP32 Forum

Posted: **Sun Feb 04, 2024 10:17 pm**

I am in the process of bringing up a custom board with an ESP32-WROOM-32D chip on the board. I have run into a problem that I am having trouble solving. I am able to flash a sample program into the chip and the program runs fine, but then when attempting to flash the chip again, it is unable to connect to the chip. If I try to use esptool to erase flash I get the following response:

Code: Select all

(esptoolenv) D:\ESP>esptool -c ESP32 -p COM3 erase_flash
esptool.py v4.7.0
Serial port COM3
Connecting......................................

A fatal error occurred: Failed to connect to ESP32: No serial data received.
For troubleshooting steps visit: https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html

This problem has occurred on two dev boards, one that I programmed using a sample program via platformIO in VSCode and another board that I programmed using the Arduino IDE.

Before I programmed the boards I verified that pressing the reset and enable buttons on my board put the board into waiting for download mode, and was able to repeat that process numerous times. After programming, the buttons have no effect and the board simple refuses to go into waiting for download mode.

Is there something special that I have to do to setup for programming an ESP32 chip with 32Mb of flash? When programming the board with the Arduino IDE I used the DOIT ESP32 DEVKIT V1 board profile.

Thanks in advance.

Posted: **Thu Feb 08, 2024 2:51 am**

For anyone else that might have had this problem. I re-installed the driver for the CH340C usb bridge to serial chip that I am using and also removed a capacitor that was across the boot switch and that seems to have fixed the issue.

esptool is now able to get control of the chip and I was able to erase the flash memory and fetch the chip id, etc.

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