There are a lot of development boards available consider for example the ESP32 DEV kit. On it there is a Boot button, and I have read during power if the button is pressed for a while the board will boot up differently, my question is how does the booting is now different from the normal power up?

New to the forum ignore the lingo..

 

Does this answer your question?

https://www.reddit.com/r/esp32/comments/elc8wp

 

Not really!!!

 

Not really!!!

That’s a link! Did you read the entire post? Click on the picture. I don’t know why it didn’t appear like a link.

 

Yes I read the post, but I am asking something else...

 

BY the way the transistor DTR and RTS was useful thanks!

 

What question was different? You asked:

during power if the button is pressed for a while the board will boot up differently, my question is how does the booting is now different from the normal power up?

The forum stated that:

bootloader code reads gpio0 (boot button, if fitted). If high, starts user code, if low, expects to load new sketch via serial port.

So depending on the circuit around the boot button, holding it down could send a low signal to the GPIO, and the ESP32 would load a new sketch. Not holding it would send a high signal, and the previously loaded code in the EDP32 would execute. Or vise versa.. I’m not familiar with the ESP32 specifically. I use other MCPs.