SH7727 Datasheet, PDF (820/1109 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

Section 24 USB HOST Module
Register: HcRhDescriptorA
Bits
Reset
R/W
9
1
R/W
8
0
R/W
7–0
02h
R
Offset: 48–4B
Description
NoPowerSwitching (NPS)
This bit selects whether the power switching is supported or
ports are always power-supplied. This bit is implementation
specific. When this bit is cleared, Power-SwitchingMode
specifies the global/port switching.
0: Ports can be power-switched.
1: Ports are always powered on when the host controller is
powered on. (initial value)
Note: Because the initial value is 1, first clear this bit (write 0
with the HCD) to enable power switching of the port.
PowerSwitchingMode (PSM)
This bit specifies how the power switching of the root-hub port
is controlled. This bit is implementation specific. This bit is valid
only when the NoPowerSwitching bit is cleared.
0: All ports are simultaneously power-supplied. (initial value)
1: Each port is power-supplied individually. In this mode, the
port power is controlled with either of global/port switching.
When the PortPowerControlMask bit is set, the port is
reacted only to the port-power command (set/clear port
power). When the port mask is cleared, the port is controlled
only by the global power-switch (set/clear global power).
NumberDownstreamPorts (NDP)
These bits specify the number of downstream ports supported
by the root hub. These bits are implementation specific.
In the SH7727 their value is H'2.
Rev. 5.00 Dec 12, 2005 page 748 of 1034
REJ09B0254-0500