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Section 22 USB Function Module (USB)
(2)
Resume Operation from Up-Stream
When the USB bus enters the non-suspend state from the suspend state by resume signal output
from up-stream, processing should proceed as shown below.
USB function
USB cable connected
USB bus in suspend state
Resume interrupts is
requested from the
up-stream.
Suspend/resume
interrupt occurs.
(IFR2/SURSF = 1)
Start USB operating
clock oscillation
Rev. 1.00 Mar. 12, 2008 Page 868 of 1178
REJ09B0403-0100
RESUME
Figure 22.5 Resume Operation from Up-Stream
Yes
Software standby
Cancel software
standby mode
No
Oscillation stabilization
time has passed?
Yes
Cancel USB module stop
Clear SURSF in IFR2 to 0
Check if SURSS in IFR2 is
Set SURSE in IER2 to 1
Clear SSRSME in IER2 to 0
Return to normal state
Application
mode ?
No
No
USB module
stopped?
Yes
cleared to 0
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