For those of you attempting to build USB devices I put together some Launchpad examples as well as a lab type walkthrough of how to create custom devices (mainly HID)
1) Examples ported to the Launchpad - Mouse, Keyboard, Composite
2) Updated HID header file with additional device and usage types
3) A new device type called usbdhidcustom - This allows you to make new devices with minimal code changes
4) A complete document in lab type format where you build a volume control device, a gamepad and a keyboard + mouse
5) Completed projects to go with the labs
Single cable. There is a switch between the two ports the switches which USB port is used for power. By default the device ships with the switch set to debug. Switch it the other way and it will pull power from the device port instead so you only need one cable for power and device interface.