Content originally posted in LPCWare by Ex-Zero on Sun Feb 20 13:40:42 MST 2011
1. Yes!! No Ground, no Fun :)
2. AFAIR working without FET requires a lot disconnecting and reconnecting...
User manual:
5.6 SoftConnect
The connection to the USB is accomplished by bringing USB_DP (for a full-speed device) HIGH through a 1.5 kOhm pull-up resistor. The SoftConnect feature can be used to allow software to finish its initialization sequence before deciding to establish connection to the USB. Re-initialization of the USB bus connection can also be performed without having to unplug the cable.