LPC1768 cannot detect U-Disk unplug !!

[lpcware]

Content originally posted in LPCWare by ruanlin on Wed Apr 10 00:40:15 MST 2013

hi everybody
I use "Example_MassStorageHost" in nxpUsbLib v0.98.
I change nothing.
I can see the first 512 bytes in the terminal window.
Then,I unplug the U-Disk and plug it again.There is noting in the terminal window.
I print the "USB_HostState[FlashDisk_MS_Interface.Config.PortNumber]" in the terminal window.It doesn't change when I unplug the U-Disk.
What's wrong here??
Thank you