ESP32 Pico custom PCB flashing error

jpfaguirre
Posts: 4
Joined: Fri Apr 03, 2020 2:58 pm

ESP32 Pico custom PCB flashing error

Postby jpfaguirre » Thu Jun 18, 2020 3:39 pm

I have developed a custom PCB board for a personal project which I had assembled in China via JLCPCB. I have problems programming the board via UART using a CP2102 board.

I have tested strapping pins:
* GPIO0: LOW (PCB pull-down)
* GPIO2: LOW (PCB pull-down)
* GPIO5: HIGH (internal pull-up)
* GPIO12: LOW (internal pull-down)
* GPIO15: HIGH (PCB pull-up)

When I try to program the ESP32 Pico I push the button connected to EN so it is LOW (measured with multimeter). I put a probe of my oscilloscope (Analog Discovery) in the TX pin of the ESP32 pico and it is always HIGH, except when I press the EN button. In this case I see high frequency noise (MHz) which makes me believe that the chip is not broken.

The schematics can be found in this image:
Image

I have tried powering it with the CP2102 board and also using a 12V 2A connected to the AMS1117-3.3 in my board. In both cases the results were the same.

Any ideas where the problem could be or what else could I test?

jwktje
Posts: 12
Joined: Wed Nov 21, 2018 11:54 am

Re: ESP32 Pico custom PCB flashing error

Postby jwktje » Mon Jun 22, 2020 5:17 pm

What error do you get when you try to flash it? And how are you flashing it? From ESP-IDF or Arduino IDE?

chegewara
Posts: 1180
Joined: Wed Jun 14, 2017 9:00 pm

Re: ESP32 Pico custom PCB flashing error

Postby chegewara » Mon Jun 22, 2020 8:14 pm

jpfaguirre wrote:GPIO12: LOW (internal pull-down)
It will do only if you burn efuse.
https://github.com/espressif/esptool/wi ... -Selection

jpfaguirre
Posts: 4
Joined: Fri Apr 03, 2020 2:58 pm

Re: ESP32 Pico custom PCB flashing error

Postby jpfaguirre » Wed Jul 01, 2020 7:00 pm

I tried flashing it both with ESP-IDF and Arduino. In both cases the error was timeout. When I reset putting IO0 to GND and pressing enable nothing is sent by the ESP32 via UART (nothing seen on serial terminal nor in the TX Pin using an oscilloscope).

mspider65
Posts: 4
Joined: Tue Jan 07, 2020 10:12 am

Re: ESP32 Pico custom PCB flashing error

Postby mspider65 » Tue Jul 07, 2020 11:34 am

Connect a terminal like putty and check if you are able to receive some text during boot process.
If not, it could be a problem of the GND PAD soldering. The GND pad footprint shoul not be solid but similar to the one in the following image.
Footprint.png
Footprint.png (14.41 KiB) Viewed 280 times


I had also a similar problem with JLPCB because JLPCB normally doesn't correct automatically footprint errors like this.

Who is online

Users browsing this forum: No registered users and 14 guests