Bit of a noob question (sorry if it's been asked before)...
I have an Arduino Mega driving an LED matrix display that needs more power than my computer's USB port can supply. At the moment I'm running them both off a separate 2A 5V supply. (I'm powering the Arduino via it's 5v and GND pins)
Is it safe to also connect the USB port for programming and serial communications while the external 5V supply is also connected? At the moment I'm disconnecting everything before I plug in the USB to update the sketch.
The documentation for the Mega says it will pick the supply automatically, obviously I don't want it to draw power from the computer, just pass data back and forth.