Usb Device Resume Register (Udrr) - Hitachi H8S/2215 Series Hardware Manual

15.3.4

USB Device Resume Register (UDRR)

UDRR indicates remote wakeup according to the host enable/disable state and enables or disables
remote wakeup of the USB modules in the suspend state.
Bit Bit Name Initial Value R/W
7 to 2 — 0
1 RWUPs 0
0 DVR 0
Rev. 3.0, 10/02, page 450 of 686
Description
R Reserved
These bits are always read as 0 and cannot be
modified.
R Remote Wakeup Status
Indicates the enabled or disabled state of remote
wakeup by the host. This bit is a status bit and cannot
be written to. If the remote wakeup from the host is
disabled by Device_Remote_Wakeup through the
Set_Feature/Clear _Feature request, this bit is cleared
to 0. If the remote wakeup is enabled, this bit is set to
1.
0: Remote wakeup disabled state
1: Remote wakeup enabled state
W Device Resume
Cancels suspend state (remote wakeup execution).
This bit can be written to 1 and is always read as 0.
Before executing remote wakeup, software standby
mode or USB module stop mode must be cancelled to
provide a clock for the USB module.
0: Performs no operation
1: Cancels suspend state (executes remote wakeup)