CHAPTER 6 USB CONTROLLER
366 Preliminary User’s Manual S15543EJ1V0UM
6.7.3 Remote wake up
The Remote Wake Up sequence is shown below.
Figure 6-29. Remote Wake Up Sequence
VR4120A USBControllerHost PC
Receives the
data from
Sets RR bit (B it0)
in USB General
Mode Register Starts K-state
signaling
20 ms
10 ms
(1)
(2)
Stops K-state
signaling
(4)
(5)
Detects K-state
signaling.
Starts to
broadcast
RESUME signaling
(6)
Stops RESUME
signaling.
Executes EOP
signaling for only
2 bit-time
(7)
End processing
of Remote Wake
Up
(8)
Sets sendin g
Data to USB
(3)

µ

PD98502
other block
(1) Here, it is assumed that the USB is in the Suspend status. Data is received from other block.
(2) The VR4120A sets the RR bit (Bit 0) of the USB General Mode Register in order to switch the USB in the
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 VR4120A can continue to set transmit data for the USB. Specifically, the VR4120A prepares transmit data
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.