Freescale Semiconductor TWR-MCF52259-Ethenet User Manual page 124

USB On-the-Go: Introduction to USB
What is it?
TM
By 2001, there was a proliferation of peripheral devices
that could be interconnected and pass data to each other.
Because of this interaction of peripheral devices, the USB
Group saw the need for a USB device to sometimes act
as a device and sometimes act as the host. From that
need came the USB On-the-Go specification.