307013-003 Datasheet, PDF (213/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

Functional Description
5.20.8.2
5.20.8.3
Device Connects
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 four
general scenarios that are summarized below.
1. Configure Flag = 0 and a full-speed/low-speed-only Device is connected
— In this case, the UHC is the owner of the port both before and after the connect
occurs. The EHC (except for the port-routing logic) does not see the connect
occur. The UHCI driver handles the connection and initialization process.
2. Configure Flag = 0 and a high-speed-capable Device is connected
— In this case, the UHC is the owner of the port both before and after the connect
occurs. The EHC (except for the port-routing logic) not see the connect occur.
The UHCI driver handles the connection and initialization process. Since the
UHC does not perform the high-speed chirp handshake, the device operates in
compatible mode.
3. Configure Flag = 1 and a full-speed/low-speed-only Device is connected
— In this case, the EHC is the owner of the port before the connect occurs. The
EHCI driver handles the connection and performs the port reset. After the reset
process completes, the EHC hardware has cleared (not set) the Port Enable bit
in the EHC’s PORTSC register. The EHCI driver then writes a 1 to the Port Owner
bit in the same register, causing the UHC to see a connect event and the EHC to
see an “electrical” disconnect event. The UHCI driver and hardware handle the
connection and initialization process from that point on. The EHCI driver and
hardware handle the perceived disconnect.
4. Configure Flag = 1 and a high-speed-capable Device is connected
— In this case, the EHC is the owner of the port before, and remains the owner
after, the connect occurs. The EHCI driver handles the connection and performs
the port reset. After the reset process completes, the EHC hardware has set the
Port Enable bit in the EHC’s PORTSC register. The port is functional at this point.
The UHC continues to see an unconnected port.
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) not see 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 does not see a device attached.
Intel ^® ICH7 Family Datasheet
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