what would be the correct capacitance on EN for serial upload to work?

[ZinggJM]

I have just received several ESP32 WROOM and ESP32 WROVER boards that time out on program upload over USB. Hitting the Boot button during upload helps.
I see in esptool.py near line 400 that this issue is addressed, but don't really understand it.

I am quite sure that I am not the only one suffering from low cost Chinese ESP32 boards with this issue. So I dare to ask if there is a workaround, or what capacitance should be added to EN.

Thank you for any help!

[lbernstone]

Espressif has reference designs at https://www.espressif.com/en/support/download/documents/development-board
This forum is for issues with the arduino code base. General questions belong at esp32.com

[ZinggJM]

@lbernstone,

Thank you for your answer. It doesn't help me much, but I will try adding a capacitor according to the reference design.

But I still think this is the correct place to raise this issue, as the fix for issue #136 doesn't seem to cope with recent ESP32 boards. I don't think so many boards have defective transistors in the RTS DTR reset/boot circuit. I believe you will hear more about ESP32 boards with this issue being thrown on the market actually.

Jean-Marc

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[ZinggJM]

Maybe the title of the issue is wrong. But I think it is still an issue, if I have to push the Boot button for successful program upload from the Arduino IDE.
One of the ESP32 board that shows the issue is not a nonname, it is a ESP32 DEVKIT V1 from www.doit.am, available e.g. from: https://www.aliexpress.com/item/4000165144198.html
I assume the board has a newer SILABS CP2102 that doesn't work with the tricks in the phyton code for upload?
And this is not the only ESP32 board that has this issue.

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[karls0]

I recently bought two ESP32-boards from OLIMEX and had problems uploading. It was very strange, since it worked the first time, but never again ??? After googling around for quite some time, I found your solution.
DanKoloff from Olimex gave me some tips too, but it was a capacitor at EN that helped. From curiosity I tested different caps, diffent resistors and the two Olimex-boards plus a AZ-delivery ESP32-Dev which I had bought the week before.
You can find the table of my tests at
OLIMEX/ESP32-POE#11
Regards, Karl

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