ESP-WROOM-32 30-pin LED anomaly

[Phillip]

Greetings to all -

My question is this: I have six of these great 30-pin mcu's and the blue LED's all behave differently.

For instance, some mcu's will light these blue LED's when there is absolutely NO code reference to GPIO2. If I set -

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digitalWrite (blu_led, LOW)

in setup(), the blue LED will still light up. Yet, on other mcu's this blue LED is always off. If I run BLINK, the output is as expected.

This issue is not the end-of-the-world for me. I would just like to understand why these mcu's behave as they do with regard to these LED's.

Thank you.

[liaifat85]

From what you have written, the in-built LED of some ESP32 boards stays off when you run

Code: Select all

digitalWrite (blu_led, LOW);

If you run

Code: Select all

digitalWrite (blu_led, HIGH);

instead, do they turn on?
If yes, then these boards are different from the generic ones which have active low LEDs.
You can also check the questionable GPIO pins by connecting an external LED. The circuit diagram and code can be found here:
https://www.theengineeringprojects.com/ ... oteus.html

[Phillip]

@liaifat85

Thank you for your response to my query. I will try what you have suggested and report back.

Thanks again for your help.