Who knows if the 4.3V is a correct value, no value is correct.
3.3V? Ahh the magic of Voltage Regulators ....
such can be used to prevent other components from frying.
One should not be measuring across TX to RX
- So put another $120 in the jar to buy a new one when your
experiments will eventually cause the death of this one.
So electronics knowledge is prerequisite.
- such electronic devices may not be so forgiving.
Nextion is closed source, like an Apple iPhone, not all is told.
What is publically available is in the Data Sheet for your model.
Which model is that?
there are infact three 7.0" versions.
This is the model NX8048T070. No information about uart working voltage levels. Should be 5v since the power is 5v?
There is info about this, written in black and white.
Voltage is something that if not correct can kill your electronics.
There is a lower limit and a higher limit, and a typical
This is NEVER "oh I guess might be X.XV"
Guesses can, and will, kill your electronic devices
Always look up what the limits and tolerances are
you MAY be lucky enough to see the Magic white smoke
(but usually such smoke happens so quick you only smell it after)
But this is not the place for electronics classes.
as told earlier - electronics knowledge is prerequisite.