22-10-2014, 03:27 PM
Abstracts: A USB flash drive is a USB device that contains flash memory that PCs and other USB hosts can access in the same way as other drive. Every USB communication is between a host and a device. The host contains host controller hardware and manages communications on the bus. The device contains device-controller hardware and responds to communications from the host. Host hardware and code are more complex than device hardware and code. PCs contain host controllers and thus can communicate with USB devices, including flash drives. Most microcontrollers with USB support contain device controllers. A microcontroller that wants to access flash drives or other USB devices must have a host controller embedded in the microcontroller or accessed on a separate chip. This concept of Host microcontroller is used here.