ESP32 Forum

Hi all,
I'm making my 8th ESP32-S3 based board and I was completely stumped by a problem I've never seen. The ESP-S3-WROOM-1 based board programs, but it's not running any code and it's not outputting anything on Serial.

After a lot of troubleshooting, I hooked up a serial dongle to the Serial output and I could see that the board goes straight into download mode like this:

ESP-ROM:esp32s3-20210327
Build:Mar 27 2021
rst:0x1 (POWERON),boot:0x0 (DOWNLOAD(USB/UART0))
waiting for download

It never runs any code. I searched and searched but could not find anyone with a similar problem, but wouldn't you know - it was my own fault and I'll share it here in case it can help others. I had swapped the resistor and capacitor on the boot button ( ). The resistor tied the boot button to GND, putting it into eternal BOOT mode.

Hope this helps others as it took me close to two hours until I found it

Note that you may want to remove the capacitor on GPIO0 entirely. Having a capacitor between GPIO0 and ground means GPIO0 will be low for a moment on power-up, meaning as soon as you apply power the ESP32C3 will boot up in download mode initially.

Thanks! That's good advice that I'll use!

In my case, this issue been solved only when I made two improvements:
1. Remove the capacitor on GPIO0 entirely
2. Attach external pullup resistor (5k1) on GPIO0