HS_USB2.0 host
RM0082
458/844
Doc ID 018672 Rev 1
22.6.49 HcRhPortStatus[1:NDP]
register
The HcRhPortStatus[1:NDP] register is used to control and report port events on a per-port
basis. NumberDownstreamPorts represents the number of HcRhPortStatus registers that
are implemented in hardware. The lower word is used to reflect the port status, whereas the
upper word reflects the status change bits. Some status bits are implemented with special
write behavior (see below). If a transaction (token through handshake) is in progress when a
write to change port status occurs, the resulting port status change must be postponed until
the transaction completes. Reserved bits should always be written '0'.
[16]
LPSC
0b
R/W
R
(read) LocalPowerStatusChange
The Root Hub does not support the local power status
feature; thus, this bit is always read as ‘0’.(write)
SetGlobalPower In global power mode
(PowerSwitchingMode=0), This bit is written to ‘1’ to turn
on power to all ports (clear PortPowerStatus). In per-port
power mode, it sets PortPowerStatus only on ports whose
PortPowerControlMask bit is not set. Writing a ‘0’ has no
effect.
[15]
DRWE
0b
R/W
R
(read) DeviceRemoteWakeupEnable
This bit enables a ConnectStatusChange bit as a resume
event, causing a USBSUSPEND to USBRESUME state
transition and setting the ResumeDetected interrupt.
0 = ConnectStatusChange is not a remote wakeup event.
1 = ConnectStatusChange is a remote wakeup event.
(write) SetRemoteWakeupEnable
Writing a '1' sets DeviceRemoveWakeupEnable. Writing a
'0' has no effect.
[14:02]
Reserved
[01]
OCI
0b
R
R/W
OverCurrentIndicator
This bit reports overcurrent conditions when the global
reporting is implemented. When set, an overcurrent
condition exists. When cleared, all power operations are
normal. If per-port overcurrent protection is implemented
this bit is always ‘0’
[00]
LPS
0b
R/W
R
(read) LocalPowerStatus
The Root Hub does not support the local power status
feature; thus, this bit is always read as ‘0’.
(write) ClearGlobalPower In global power mode
(PowerSwitchingMode=0), This bit is written to ‘1’ to turn
off power to all ports (clear PortPowerStatus). In per-port
power mode, it clears PortPowerStatus only on ports
whose PortPowerControlMask bit is not set. Writing a ‘0’
has no effect.
Table 386.
HcRhStatus register bit assignments (continued)
Bits
Name
Reset
Read/Write
Description
HCD
HC