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6.7.3 Remote wake up
The Remote Wake Up sequence is shown below.
V
4120A
R
R eceives the
(1)
data from
other block
Sets R R bit (Bit0)
(2)
in U SB G eneral
M ode R egister
Sets sending
(3)
D ata to U SB
(1) Here, it is assumed that the USB is in the Suspend status. Data is received from other block.
(2) The V
4120A sets the RR bit (Bit 0) of the USB General Mode Register in order to switch the USB in the
R
Suspend status to the Resume status.
(3) Once the RR bit of the USB General Mode Register has been set, USB Controller starts K-state Signaling for
the USB.
(4) The V
4120A can continue to set transmit data for the USB. Specifically, the V
R
in system memory, then writes data into the USB Command Register (Address: 1000_1040H) and the USB
Command Extension Register (Address: 1000_1044H).
(5) USB Controller continues K-state Signaling for 5 ms, then terminates the signaling.
(6) The Host PC, upon receiving the K-state Signaling, broadcasts RESUME signaling. This RESUME signaling
continues for a minimum of 20 ms.
(7) Once at least 20 ms have elapsed, the Host PC terminates RESUME Signaling, then issues EOP Signaling for
a 2 bit-time duration.
(8) As a result of this sequence, Remote Wake Up is terminated, and the transaction being performed by the USB
is restarted.
366
CHAPTER 6 USB CONTROLLER
Figure 6-29. Remote Wake Up Sequence
U S B
C ontroller
Starts K-state
(4)
signaling
10 m s
Stops K-state
(5)
signaling
µ
P D 98502
Preliminary User's Manual S15543EJ1V0UM
H ost P C
D etects K-state
(6)
signaling.
Starts to
broadcast
R ESU M E signaling
20 m s
Stops R ESUM E
(7)
signaling.
Executes EO P
signaling for only
2 bit-tim e
(8)
End processing
of R em ote W ak e
U p
4120A prepares transmit data
R
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