In the memory-stick branch

The program is the demo that STM32F4 is the host, writing a file to portable disk

Steps:
    1. Plug in the disk
    2. Observe the LEDs
        RED On    -> disk is attached
        Green On  -> file system is mounted
        Orange On -> open the directory of the usb disk
        Blue On   -> Complete writing the signautre
    3. All LEDs are turned off when the device is disconnected

Developer's Note : http://kvzhao.blogspot.tw/2013/12/stm32f407-usb-filesystem-dev-notes.html