82801FB Datasheet, PDF (559/786 Pages) Intel Corporation – Intel I/O Controller Hub 6 (ICH6) Family

EHCI Controller Registers (D29:F7)
Bit
Description
Port Enabled/Disabled — R/W. Ports can only be enabled by the host controller as a part of the
reset and enable. Software cannot enable a port by writing a 1 to this bit. Ports can be disabled by
either a fault condition (disconnect event or other fault condition) or by host software. Note that the
2 ^{bit status does not change until the port state actually changes. There may be a delay in disabling or}
enabling a port due to other host controller and bus events.
0 = Disable
1 = Enable (Default)
Connect Status Change — R/WC. This bit indicates a change has occurred in the port’s Current
Connect Status. Software sets this bit to 0 by writing a 1 to it.
0 = No change (Default).
1 ^{1 = Change in Current Connect Status. The host controller sets this bit for all changes to the port}
device connect status, even if system software has not cleared an existing connect status
change. For example, the insertion status changes twice before system software has cleared
the changed condition, hub hardware will be “setting” an already-set bit (i.e., the bit will remain
set).
Current Connect Status — RO. This value reflects the current state of the port, and may not
correspond directly to the event that caused the Connect Status Change bit (Bit 1) to be set.
0
0 = No device is present. (Default)
1 = Device is present on port.
Intel^® I/O Controller Hub 6 (ICH6) Family Datasheet
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