Datasheet

Section 14 Universal Serial Bus (USB)
Rev.7.00 Dec. 24, 2008 Page 500 of 698
REJ09B0074-0700
(3) USB Cable Disconnection (When USB module stop or power-down mode is not used)
If the USB cable enters the disconnection state from the connection state in an application (self
powered) where USB module stop or power-down mode is not used, perform the operation as
shown in figure 14.5. In bus-powered mode, the power is automatically turned off when the
USB cable is disconnected and the following processing is not required.
Disconnect the USB cable
VBUS interrupt occurs
USB function
Firmware
Reset the UDC core
Clear VBUSi in UIFR3 to 0
Check if VBUSs in UIFR3
is cleared to 0
Cancel D + pull-up by
port 36 (P36)
Wait for USB cable connection
Reset the UDC core
Write UDCRST in UCTLR to 1
*
*
EXIRQx
Note:
VBUS interrupts in the USB module cannot be detected in power-down mode
or in the USB module stop state.
Figure 14.5 USB Cable Disconnection
(When USB Module Stop or Power-Down Mode Is not Used)