ESP32 Forum

Hello everyone,

I have made a custom board using ESP32-WROOM32D module to develop simple BLE keypad.
You can find schematic here:
https://drive.google.com/file/d/1hOGqtG ... sp=sharing
I am facing an issue while powering ON the boards.
Board boots successfully when I am powering it from computer USB supply.
Board boots successfully when I am powering it from 5V USB Adapter.
Board boots successfully when I disconnect and reconnect micro USB.
Board does not boot when I unplug from main supply and plug again 5V Adapter.
Please have a look at the video demonstration for more clarification:
https://drive.google.com/file/d/1GjApi8 ... UEqB_/view

Please share your valuable feedback and thoughts.

Thanks for your time.

I would suggest ties (up or down, whatever..) on EN etc.
My main tact would however be to ask how you differ from reference circuits (EVB etc) and then ask why? Its easier to track changes from accepted norms & only you can quickly identify the full set of changes ...

If you haven't already, suggest indeed to follow the hardware reference / Wroom datasheet and connect to EN a 10K pullup plus an 100nF capacitor to ground

Checked again & seems quite close to the EVB reference including 0.1uF and pull ups. Difference between 1K n 10K on one of the resistor sets but otherwise the same. Fraid this one seems quite detailed ...

Possibly the bulk output cap in the 5V adapter is to blame... it may make the voltage either ramp down or ramp up too slowly. In this case, you could switching out the 1K/100nF combo on the EN pin for e.g. an 10K/1uF combo. If that doesn't help, a voltage monitor IC should.

Thanks Sprite, that would be a strong candidate.
The schematics have gone now but I do not remember seeing a supervisor - which usually means trouble!

Thank you for all the suggestions. I found one the schematic from esspressif the link: https://dl.espressif.com/dl/schematics/ ... V2_sch.pdf
which was having both the 10uF and 0.1uF at CP2102 VBUS pin. So I connected both. I have prepared another design with removing extra capacitors and given for fabrication. Let me check if the issue still persists.