Cirrus Logic EP93xx User Manual

Page 473

DS785UM1

11-33

Universal Serial Bus Host Controller

EP93xx User’s Guide

PES:

(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.

PSS:

(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 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.