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USB Controller Module
HcRhDescriptorB register
Address: 9010 104C
The HcRhDescriptorB register is the second of two registers describing the
characteristics of the root hub. These fields are written during initialization to
correspond with the system implementation. Reset values are implementation-
specific.
Register bit assignment
Bits Access Mnemonic Reset Description
D31:16 R/W PPCM IS PortPowerControlMask
Each bit indicates whether a port is affected by a global
control command when PowerSwitchingMode (see
"HcRhDescriptorA register" on page 753) is set.
When set, the port’s power state is affected only by per-
port power control (Set/ClearPortPower).
When cleared, the port is controlled by the global power
switch (Set/ClearGlobalPower).
If the device is configured to global switching mode
(PowerSwitchingMode=0), this field is not valid.
Bit 0: Reserved
Bit 1: Ganged-power mask on port #1
Bit 2: Ganged-power mask on port #2
...
Bit 15: Ganged-power mask on port #15
Table 442: HcRhDesdcriptorB register
13121110987654321015 14
31 29 28 27 26 25 24 23 22 21 20 19 18 17 1630
PortPowerControlMask (PPCM)
DeviceRemovable (DR)