I'm working on a project using a Nano inside an enclosure. Power comes in via an external USB power supply connected to a USB breakout board, like this SparkFun USB Mini-B Breakout. Within the enclosure I'll run VCC and GND wires from the breakout to a (male) USB connector, in turn plugged into the Nano's USB socket.
I'm happy not having the ability to reprogram the Nano without opening the enclosure, and in fact would like to be able to power it from a laptop without it detecting the device and trying to install drivers. So I'm not planning on running a "mini USB cable" within the enclosure -- I'm not carrying D+, D- or ID to the Nano.
My question is, what should I do with the D+/D-/ID pins on the USB breakout board?
- Nothing, let them float? It won't look like a USB device is in the box anyway.
- Connect them to ground?