I don't know if my arduino UNO is broken, I havent done something "dangerous" lately. I made a simple code for read A0 A1 and A2 connecting them to 5V or 3.3V, then print it in Serial but I always get the same value from all them, it seems like they are in the same node. Also when I press the RESET button, they start with nothing connected they return a high value that decrease with the time.
with nothing connected they return a high value that decrease with the time.
What were you expecting for a floating input?
connecting them to 5V or 3.3V, then print it in Serial but I always get the same value from all them
Again, if they're all connected to the same voltage, what did you expect them to read?