don't know if this is a bug or it suppose to work this way, but if I connect power/ground pins of my 3.2 nextion to arduino mega, everything works fine. but, if I connect external power to nextion, i don't have the communication between the two.
it is kinda weird.. on arduino reset buttno, my nextion refresh screen.. but i cant receive/send anything over serial.. but if i connect my nextion power/ground directly, it is ok.. i tried unstable/stable library-es, also no library examples.. it behaves the same.. also, i tried on my arduino uno.. also the same results..
is it normal behaviour? what to do if i cannot get enough power from my arduino?
(bigger nextion, lots of other hardware connected, etc.)
sorry if this is noob question.. i'm kinda new in this type of hardware..
You have to connect GND of your external power supply to GND of Arduino.
It is clear that the problem is due to improper ground.
Please review your setup or circuit and connect the ground properly.
You should use the ground of your main supply.
If the problem still exists then please share your setup here.