Allwinner A20 - Page 695

A20 User Manual (Revision 1.2) Copyright © 2013 Allwinner Technology Co., Ltd. All Rights Reserved. Page 695 / 812
2
R/W
R/W
0x0
set at the end of the port reset or when the HC is placed in the
USBRESUME state. If an upstream resume is in progress, it
should propagate to the HC.
0
port is not suspended
1
port is suspended
(write)SetPortSuspend
The HCD sets the PortSuspendStatus bit by writing a ‘1’ to this
bit. Writing a ‘0’ has no effect. If CurrentConnectStatus is cleared,
this write does not set PortSuspendStatus; instead it sets
ConnectStatusChange. This informs the driver that it attempted
to suspend a disconnected port.
1
R/W
R/W
0x0
(read)PortEnableStatus
This bit indicates whether the port is enabled or disabled. The Root
Hub may clear this bit when an overcurrent condition, disconnect
event, switched-off power, or operational bus error such as babble
is detected. This change also causes PortEnabledStatusChange
to be set. HCD sets this bit by writing SetPortEnable and clears it
by writing ClearPortEnable. This bit cannot be set when
CurrentConnectStatus is cleared. This bit is also set, if not
already, at the completion of a port reset when
ResetStatusChange is set or port suspend when
SuspendStatusChange is set.
0
port is disabled
1
port is enabled
(write)SetPortEnable
The HCD sets PortEnableStatus by writing a ‘1’. Writing a ‘0’ has
no effect. If CurrentConnectStatus is cleared, this write does not
set PortEnableStatus, but instead sets ConnectStatusChange.
This informs the driver that it attempted to enable a disconnected
Port.
0
R/W
R/W
0x0
(read)CurrentConnectStatus
This bit reflects the current state of the downstream port.
0
No device connected
1
Device connected
(write)ClearPortEnable
The HCD writes a ‘1’ to clear the PortEnableStatus bit. Writing ‘0’
has no effect. The CurrentConnectStatus is not affected by any
write.
Note: This bit is always read ‘1’ when the attached device is
nonremovalble(DviceRemoveable[NumberDownstreamPort]).