Allwinner A20 - Page 694

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8
R/W
R/W
0x0
is determined by PowerSwitchingMode and
PortPortControlMask[NumberDownstreamPort]. In global
switching mode(PowerSwitchingMode=0), only
Set/ClearGlobalPower controls
this bit. In per-port power switching (PowerSwitchingMode=1), if
the PortPowerControlMask[NDP] bit for the port is set, only
Set/ClearPortPower commands are enabled. If the mask is not
set, only Set/ClearGlobalPower commands are enabled. When
port power is disabled, CurrentConnectStatus,
PortEnableStatus, PortSuspendStatus, and PortResetStatus
should be reset.
0
port power is off
1
port power is on
(write)SetPortPower
The HCD writes a ‘1’ to set the PortPowerStatus bit. Writing a ‘0’
has no effect.
Note: This bit is always reads ‘1b’ if power switching is not
supported.
7:5
Reserved
4
R/W
R/W
0x0
(read)PortResetStatus
When this bit is set by a write to SetPortReset, port reset signaling
is asserted. When reset is completed, this bit is cleared when
PortResetStatusChange is set. This bit cannot be set if
CurrentConnectStatus is cleared.
0
port reset signal is not active
1
port reset signal is active
(write)SetPortReset
The HCD sets the port reset signaling by writing a ‘1’ to this bit.
Writing a ‘0’ has no effect. If CurrentConnectStatus is cleared,
this write does not set PortResetStatus, but instead sets
ConnectStatusChange. This informs the driver that it attempted
to reset a disconnected port.
3
R/W
R/W
0x0
(read)PortOverCurrentIndicator
This bit is only valid when the Root Hub is configured in such a way
that overcurrent conditions are reported on a per-port basis. If
per-port overcurrent reporting is not supported, this bit is set to 0. If
cleared, all power operations are normal for this port. If set, an
overcurrent condition exists on this port. This bit always reflects the
overcurrent input signal.
0
no overcurrent condition.
1
overcurrent condition detected.
(write)ClearSuspendStatus
The HCD writes a ‘1’ to initiate a resume. Writing a ‘0’ has no
effect. A resume is initiated only if PortSuspendStatus is set.
(read)PortSuspendStatus
This bit indicates the port is suspended or in the resume sequence.
It is set by a SetSuspendState write and cleared when
PortSuspendStatusChange is set at the end of the resume
interval. This bit cannot be set if CurrentConnectStatus is
cleared. This bit is also cleared when PortResetStatusChange is