I'm designing a PCB with 3 Atmel ATmega16U4-AU micro-controllers on it.
I will be programming them through SPI.
Therefore, I will not be using D+ and D- ports on the USB interface. Then how do I deal with those pins.
Leave them unconnected?
Or Connect them to three different usb ports? (This way looks stupid. I don't want so many usb ports on the PCB)