Datasheet

Section 22 USB Function Module (USB)
Rev. 2.00 Aug. 20, 2008 Page 865 of 1198
REJ09B0403-0200
22.5.3 Suspend and Resume Operations
(1) Suspend Operation
When the USB bus enters the suspend state from the non-suspend state, processing should proceed
as shown below.
USB cable connected
Bus idle of 3 ms or
more occurs
Suspend/resume
interrupt occurs
(IFR2/SURSF = 1)
USBINT2
USBINT3
Remote
wakeup enabled?
(CTLR/RWUPS = 1?)
Clear SURSF in IFR2 to 0
Check if SURSS in IFR2
is set to 1
Clear SURSE in IER2 to 0
Wait for suspend/
resume interrupt
Ye s
Ye s
No
No
Enter software
standby mode
Check remote-wakeup
function enabled
System needs to
enter power-down
mode?
Check remote-wakeup
function disabled
Ye s
No
Need to enter
software standby
mode?
USB function
Application
Set SURSE in IER2 to 1
Set SSRSME in IER2 to 1 Clear SSRSME in IER2 to 0
USB module stop
Figure 22.4 Suspend Operation