I am going to power up my GPS-RTK board but before I do that I have to make sure the following power supply question (Of course I have read the GPS-RTK2 Hookup Guide but unfortunately it has not given answer)
The board can be powered via USB and/or 5 Volt external power supply.
What happen if external power (5Volt) is connected, then I connect USB cable which also supply 5 Volt?
Is there a built in logics in the modul to prevent problem when both (USB 5 Volt and external 5 Volt) are connected in the same time?
Is it safe to use the module with external 5 Volt power then during that connect USB cable?
I have asked the above question from SparkFun Support too, then I got answer:
“This board does not have any built-in logic to switch power depending on the source. You will only want to apply a single source of power (USB, 5V or regulated 3.3V) to the board at any given time. Providing power via USB and one of the other options will damage the board.”
So it is EXTREMELY IMPORTANT to use ONLY a single power source in a time!
E.g. if you use the board with an external 5 Volt power supply then you connect the USB cable may that DEMAGEs your board!
You MUST use either USB ONLY or external ONLY power source in a given time!
Since this kind of information is not present in SparkFun’s “hookup guide” I suggested them to include this in the document.
I’ve looked at the schematic for that board. Connecting two power sources is highly unlikely to damage the board. Everything important is on the other side of the 3.3V regulator. It might, however, damage one of the sources.