Hi Steve.
Are you sure that you’ve uploaded the code? There is an option in the IDE to run the code. That’s probably what you did (run is different than upload).
Can you describe the process you did to upload codE?
Regards,
Sara

Hi Sara
Thanks for responding.
Having got as far as Module 6 in
MicroPython_Programming_with_ESP32_and_ESP8266_V1_2.pdf using an ESP8266
I am taking a second run through the book (or at least trying to) using an ESP32.
Using Thonny 3.3.5 on a Pi4.
The only way I have found to upload code to the ESP32 (or for that matter to the 8266) is under the save command – where you get the option to either “save to this computer” OR “save to device”.
Image below shows code saved on device:
https://www.dropbox.com/s/r98i9sakx4wpx4h/Thonny_2.jpg?dl=0
BUT
I can only get the code to run using the “Run current script” button
https://www.dropbox.com/s/p1n9enoq25ic3j1/Thonny_1.jpg?dl=0

My last image shows the text displayed in the Shell (on Thonny) when I hit the EN button on the device.
Pressing the BOOT button has no effect.
The code is definitely saved on the device – it’s still resident in memory after cycling the power.
I hope this gives you enough information to come back to me with some suggestions
Regards
Steve

Hi again.
Are you saving your code with the name “pwm_pot_esp32.py”?
The file should be called main.py.
(Otherwise, it won’t run unless a main.py or a boot.py file calls it).
Is that your issue?
Regards,
Sara

Yes
That was my issue.
That’s what I call “Learning the Hard Way”.
Obvious when I stop to think!.
Thanks
Steve

Great!
I’m glad we found the issue.
I’ll mark this issue as resolved, if you need further help, you just need to open a new question in our forum.
Regards,
Sara