ESP32 Forum

Dear All,

Thanks for your time to read this post. recently I designed a board with ESP32-WROOM-32E and to upload the sketch from Arduino to the module I used the FTDI module. Unfortunately by mistake I forgot to change the voltage jumper from 5V to 3.3V and I noticed after 2 attempts since the jumper is slightly hidden . After I change the state to 3.3V, funnily enough the sketch was uploaded successfully but for some reason, the ESP32 can't boot up. How I can check that the module is dead or not before I replace it?

Bummer. Depending on what got hooked up wrong and for how long, under what circumstances, etc. (Don't bother trying to explain...it won't matter) the damage can range from one pin that doesn't work (yay) that can just be unused or remapped away in software to damage that basically requires replacement of the chip/module.

These things are dirt cheap. Keep a couple on hand so when you do - even unintentionally - sacrifice one to the Electronics Gods - you don't get stuck. Time + postage probably costs more than a similar board costs these days.

If it is indeed a board you designed, consider this a learning opportunity on behalf of your customers/users and see if you can design aroundd this act. Perhaps a clamping zener of the "right" voltage and polarity in the right place might have saved this board - and the boards of your customers that also let dangling wires ruin their days, even if they don't yet know it. You can't design around every possible mishap, but a few nickels of protection can often save a lot of grief in product returns, RMAs, and more. Just like programmers should code defensively, hardware should try to survive casual misuse.

Thanks all. The issue is solved now. I plugged the esp32 to pc and noticed that brownout was detected. The pc usb current was not enough for my module. I put an external powersupply and it worked like a charm. Thanks for your kind help.