USB Host Controller
1552
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
29.2.4.21 HC Root Hub Status Register (HCRHSTATUS)
The HC root hub status register reports the USB host controller root hub status.
Figure 29-21. HC Root Hub Status Register (HCRHSTATUS) [address = FCF78B50h]
31
30
18
17
16
CRWE
Reserved
OCIC
LPSC
R/W-0
R-0
R/W-0
R/W-0
15
14
2
1
0
DRWE
Reserved
OCI
LPS
R/W-0
R-0
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value at reset
Table 29-23. HC Root Hub Status Register (HCRHSTATUS) Bit Field Descriptions
Bit
Field
Value
Description
31
CRWE
0-1
Clear remote wake-up enable
Write of 0 has no effect.
Write of 1 clears the device remote wake-up enable bit.
30-18
Reserved
0
Reserved
17
OCIC
Overcurrent indication change
This bit is automatically set when the overcurrent indicator bit changes.
0
Write of 0 has no effect.
1
Write of 1 clears this bit.
16
LPSC
Local power status change
0
Write of 0 has no effect.
1
Write of 1 sets the port power status bits for all ports if power switching mode is 0. A write of 1 sets
port power status bits for ports with their corresponding port power control mask bits cleared if
power switching mode is 1.
15
DRWE
Device remote wake-up enable
When 1, this bit enables a connect status change event to be treated as a resume event, which
causes a transition from USB suspend to USB resume state and sets the resume detected interrupt
status bit.
When 0, connect status change events do not cause a transition from USB suspend to USB
resume state and the resume detected interrupt is not changed.
0
Write of 0 has no effect.
1
Write of 1 sets the device remote wake-up enable bit.
14-2
Reserved
0
Reserved
1
OCI
Overcurrent indicator. This bit reports global overcurrent indication if global overcurrent reporting is
selected.
0
When 0, no overcurrent condition has been sensed.
1
When 1, this bit indicates that an overcurrent condition has been sensed.
0
LPS
Local power status
0
Write of 0 has no effect.
1
Write of 1 when in global power mode (power switching mode = 0), turns off power to all ports. If in
per-port power mode (power switching mode = 1), a write of 1 turns off power to those ports whose
corresponding port power control mask bit is 0.