ESP32 Forum

Hi,

I use an ESP32-S3 super mini with the Arduino IDE on a Raspberry pi 5.

I could download several scripts after ensuring that the "USB CDC On boot" is enabled.

The last script that I downloaded (testing deep sleep mode) was successful, but after it, the serial port disappeared.

There is no way to have it back, this on different computers.

I did several tests by powering it with the BOOT and RESET Buttons depressed (all possible variations, BOOT first and RESET for a short time etc..) but nothing helps.

I also used a USB BUP (3v3) to connect directly the TX and RX pins (with TX on TX, RX on RX and TX on RX and RX on TX), this gain trying the BOOT / RESET trick.

No success, no reply from the ESP32

Should I consider that my devices as dead .....
(Note that RED LED GP48 is still ON and the Battery LED is still flashing).
.... or is it a way to reinitialise the ESP32 and recover from this situation

Thanks in advance

Robert

Disconnect the USB cable, press+hold the 'BOOT' button, reconnect the USB cable, wait for a second, then you can release the 'BOOT' button. The chip should now be in 'download mode' and accept new firmware via USB, and the PC should be able to initialize the USB COM port.

Note that light and deep sleep power down the USB peripheral of the ESP, breaking the USB connection to the PC. The connection then is usually only recoverable via power-cycling of the ESP.
If your application goes to sleep shortly after starting, you may have a hard time being quick enough to start flashing via USB after power up but before the USB 'disappears' again. (For that reason, when experimenting with firmware, I let my ESP code wait for a second or two at start up before it does anything else. In case "anything else" crashes quickly I have a few seconds to react after power up before it enters a 'crash-boot-loop'.)

OK,
Finally, I've got it!
The sequence to retrieve the Serial communication is to depress the BOOT button for a few seconds at power on.
However, each time I load a script with some deep sleep command(s), the Serial port disappears, and I have to enforce the BOOT sequence again.
I need to do more investigation to determine which statement is causing this problem.
Robert