ESP32 Forum

Hej all,

I desinged my own PCB based on ESP32-WROOM32E-H4. The schematic should be the same as on https://docs.espressif.com/projects/esp ... vkitc.html (ESP32-DevKitC V4 schematics (PDF)).
I use the USB bridge chip: CP2102N-A02-GQFN24R. As I see it my design and the reference linked above only differ in the boot button.

On the ESP module:
IO 17 21 pulled down
IO 35 sensor output ~ 2 V
IO 26 / 27 CAN bus chip
IO 18 19 23 5 SPI bus chip
rest left open.

In Windows device manager I can see the USB bridge on COM12. Driver installed, working fine.
In Arduino IDE or VSCode I can choose COM12.
On the oscilloscope I can see:
- a data stream arriving at the ESP module pins.
- EN and IO0 going low and high

Arduino IDE says:
esptool.py v4.2.1
Serial port COM12
Connecting....................................
A fatal error occurred: Failed to connect to ESP32: No serial data received.

VSCode says:
esptool.py v3.1
Serial port COM12
Connecting........_____....._____....._____....._____....._____....._____....._____

A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
*** [upload] Error 2


What is wrong? Auto boot circuit? Wrong capacities?
Connecting IO0 manually to GND with a cable dont work as well.

The bought DevKit works perfectly by the way. Without pressing any buttons.

Best regards


My schematics for the USB connection: