Functional Description
5.19.8.3
Device Disconnects
The Enhanced Host Controller Interface Specification for Universal Serial Bus, Revision
1.0 describes the details of handling Device Connects in Section 4.2. There are three
general scenarios that are summarized below.
1. Configure Flag = 0 and the device is disconnected
— In this case, the UHC is the owner of the port both before and after the
disconnect occurs. The EHC (except for the port-routing logic) never sees a
device attached. The UHCI driver handles disconnection process.
2. Configure Flag = 1 and a full-speed/low-speed-capable Device is disconnected
— In this case, the UHC is the owner of the port before the disconnect occurs. The
disconnect is reported by the UHC and serviced by the associated UHCI driver.
The port-routing logic in the EHC cluster forces the Port Owner bit to 0,
indicating that the EHC owns the unconnected port.
3. Configure Flag = 1 and a high-speed-capable Device is disconnected
— In this case, the EHC is the owner of the port before, and remains the owner
after, the disconnect occurs. The EHCI hardware and driver handle the
disconnection process. The UHC never sees a device attached.
5.19.8.4
Effect of Resets on Port-Routing Logic
As mentioned above, the Port Routing logic is implemented in the suspend power well
so that remuneration and re-mapping of the USB ports is not required following
entering and exiting a system sleep state in which the core power is turned off.
Reset Event
Effect on Configure Flag
Effect on Port Owner Bits
Suspend Well Reset
Core Well Reset
D3-to-D0 Reset
HCRESET
cleared (0)
no effect
set (1)
no effect
no effect
set (1)
no effect
cleared (0)
5.19.9
USB 2.0 Legacy Keyboard Operation
The ICH10 must support the possibility of a keyboard downstream from either a full-
speed/low-speed or a high-speed port. The description of the legacy keyboard support
is unchanged from USB 1.1 (See Section 5.18.8).
The EHC provides the basic ability to generate SMIs on an interrupt event, along with
more sophisticated control of the generation of SMIs.
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Datasheet
INTEL [ INTEL ]
