SH7721 datasheet(851/1524 Pages) RENESAS

851 / 1524 page

Section 24

USB Host Controller (USBH)

Rev. 3.00 Jan. 18, 2008 Page 789 of 1458

REJ09B0033-0300

24.3.20

Hc Rh Descriptor B Register (USBHRDB)

USBHRDB is the second register of two registers describing the features of the root hub. These

bits are written during the initial setting so as to correspond to the system implementation. The

reset value is implementation specific.

Bit

Bit Name

Initial

Value

R/W

Description

31 to 16 PPCM15 to

PPCM0

All 0

R/W

Port Power Control Mask

This bit indicates that the port is influenced by the global

power-control command when the PSM bit in the

USBHRDA register is set. When this bit is set, the power

state of the port is affected by the power control at each

port (set/clear port power). When this bit is cleared, the

port is controlled by the global power switch (set/clear

global power). If the device is placed in the global

switching mode (PSM = 0), this bit is not valid.

Bit 31: Port#15 power mask

Bit 18: Port#2 power mask

Bit 17: Port#1 power mask

Bit 16: Reserved

Note:

Clear the NPS of the USBHRDA register so that

the power to all ports is OFF (Port Power Status =

0), then set this bit.

15 to 0

DR15 to

DR0

All 0

R/W

Device Removable

These bits are dedicated to the ports of the root hub.

When these bits are cleared, the set device becomes

removable. When these bits are set, do not remove the set

device.

Bit 15: Device affixed to Port#15

Bit 2: Device affixed to Port#2

Bit 1: Device affixed to Port#1

Bit 0: Reserved

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