USB Host Controller Registers
14-27
Universal Serial Bus Host
The HC root hub B register defines several aspects of the USB host controller
root hub functionality.
Table 14–21. HC Root Hub B Register (HcRhDescriptorB)
Bit
Name
Description
Type
Reset
Value
31–16
PPCM
Port power control mask
Each bit defines whether a corresponding downstream port
has port power controlled by the global power control. If set,
per-port power control is implemented for the corresponding
port. If clear, global power control is implemented for the
corresponding port.
PPCM bit 0 is reserved.
PPCM bit 1 is the port power control mask for downstream
port 1.
PPCM bit 2 is the port power control mask for downstream
port 2.
PPCM bit 3 is the port power control mask for downstream
port 3.
PPCM bits 4 through 15 are reserved.
OMAP5910 does not provide connections from the USB host
controller to pins to provide external port power switching.
Systems that implement port power switching must use other
mechanisms to control port power.
R/W
0x0000
15–0
DR
Device removable
Each bit defines whether a corresponding downstream port
has a removable or nonremovable device. A cleared bit
indicates the corresponding port may have a removable
device attached. A set bit indicates that the corresponding
port has a nonremovable device attached.
DR bit 0 is reserved.
DR bit 1 is the device removable bit for downstream port 1.
DR bit 2 is the device removable bit for downstream port 2.
DR bit 3 is the device removable bit for downstream port 3.
DR bits 4 through 15 are reserved.
R/W
0x0000