Nano: USB and V-in power at same time?

Hi, Some searching online and in the forum has left me confused about options. A circuit I built uses a 9v/500ma wallwart to power the Nano via the V-in pin, and also powers some always-on LEDs directly off the 9v line.

In order to troubleshoot the circuit, I'd like to hook up the USB to the port and debug using some print.Serial commands, while still keeping the 9v hooked up to the circuit in order to keep the LEDs on (they provide light to LDRs that I'm detecting with the Nano).

So, the basic question is: Can the Nano v3.0 be safely connected to via USB while it is also being powered on V-in?

Thanks, Peter

Yes ! It is designed for that. The wallwart will keep the Nano running at a good 5.0V. If the usb is plugged in, the usb power is not used in that case.