Samsung S5PC100, Руководство пользователя

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S5PC100 USER’S MANUAL (REV1.0) USB HOST CONTROLLER
8.9-33
5.2.20 USB HcRhDescriptorB Register (UHCRHDB, Address = 0xED40_004C)
The UHC Root Hub Descriptor B register is the second register of two describing the characteristics of the root
hub. These fields are written during initialization to correspond with the system implementation. Only bits 1, 2, 17,
and 18 are writable; all other bits always read as 0.
Table 8.9-20 UHCRHDB Bit Definitions
UHCRHDB Bit Description R/W Reset Value
PPCM [31:16] PortPowerControlMask
Each bit in this field indicates if a port is affected by a global
power control command when power switching mode
(UHCRHDA[PSM]) is set. If this bit (UHCRHDB[PPCM]) is
set, the port power state is affected only by perport power
control (Set/Clear Port Power). If cleared, the port is
controlled by the global power switch (Set/Clear Global
Power). If the device is configured to global switching mode
(UHCRHDA[PSM] = 0), this field is not valid. Bit 17
corresponds to ganged-power mask on port 1, and bit 18
corresponds to ganged-power mask on port 2, and bit 19
corresponds to ganged-power mask on port 3. Bits 31 to 20,
and bit 16 are not used.
bit 16: Unused, always reads as 0
bit 17: Ganged-power mask on port 1
bit 18: Ganged-power mask on port 2
bits 19
–
31: Unused, always reads as 0
R/W
DR [15:0] DeviceNotRemovable
Each bit is dedicated to a port of the root hub. If cleared, the
attached device is removable; if set, it is not removable. Bit 1
refers to port 1, bit 2 refers to port 2, and bit 3 refers to port
3. Bits 15
–
4 and bit 0 are unused. If set, this bit forces the
corresponding Port Status register current
connection status bit (UHCRHPS1/2[CSC]) to 1.
bit 0: Unused, always reads as 0
bit 1: 1 if device attached to port 1 is not removable
bit 2: 1 if device attached to port 2 is not removable
bits 3
–
15: Unused, always reads as 0
R/W