FW82801DBM S L6DN Intel, FW82801DBM S L6DN Datasheet - Page 217

• Manufacturer Part Number: FW82801DBM S L6DN
• Manufacturer: Intel

Specifications of FW82801DBM S L6DN

• Lead Free Status / RoHS Status: Not Compliant

5.17.8.1
Intel
®
Figure 5-20. Intel
82801DBM ICH4-M Datasheet
Port-Routing Logic
Integrated into the EHC functionality is port-routing logic, which performs the muxing between the
USB UHCI and USB EHCI host controllers. The ICH4 conceptually implements this logic as
described in Section 4.2 of the Enhanced Host Controller Interface (EHCI) for Universal Serial
Bus Specification. If a device is connected that is not capable of USB 2.0’s high-speed signaling
protocol or if the EHCI software drivers are not present as indicated by the Configured Flag, then
the USB UHCI Controller owns the port. Owning the port means that the differential output is
driven by the owner and the input stream is only visible to the owner. The host controller that is not
the owner of the port internally sees a disconnected port.
Note that the port-routing logic is the only block of logic within the ICH4 that observes the
physical (real) connect/disconnect information. The port status logic inside each of the host
controllers observes the electrical connect/disconnect information that is generated by the port-
routing logic.
Only the differential signal pairs are muxed/demuxed between the USB UHCI and USB EHCI host
controllers. The other USB functional signals are handled as follows:
The Port-Routing logic is implemented in the Suspend power well so that re-enumeration 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.
The ICH4 also allows the USB Debug Port traffic to be routed in and out of Port #0. When in this
mode, the Enhanced Host Controller is the owner of Port #0.
•
The Overcurrent inputs (OC#[5:0]) are directly routed to both controllers. An overcurrent
event is recorded in both controller’s status registers.
®
ICH4 USB Port Connections
Port 5
Port 4
Port 3
Port 2
Port 1
Port 0
Debug
Port
(D29:F2)
UHCI #3
EHCI (D29:F7)
(D29:F1)
UHCI #2
(D29:F0)
UHCI #1
Functional Description
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