ESP32-WROOM-DA internal LED, serial: pick one

technology

Starting out with a ESP32-WROOM-DA it might be tempting to make the internal LED blink. Turns out it is trickier than thought. Of course one needs to pick the correct board, otherwise you might see:

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00

But even after that it might be that the LED does not blink if you use a different PIN ID than 1 – lots of examples are around with 2,4, 13 etc


A common way debug is to output something to the serial port. Which works, UNLESS you use PIN ID 1 to turn the LED on or OFF. In which case the serial output turns into gibberish.

No big deal, but can be confusing.