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2012
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6.5
USB 2.0 EHCI Host Controller Support
The Intel
®
CG82NM10 (NM10) PCH supports up to eight USB ports. The 8 available USB ports are shared between 1 EHCI host controller
and the 4 UHCI host controllers.
The muxing between the UHCI and EHCI host controllers is performed by the port-routing logic integrated into the EHC functionality. If a device
not capable of USB 2.0 high-speed signalling is connected or if the EHCI software drivers are not present,then the 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.
The Intel
®
CG82NM10 (NM10) PCH 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.
Routing Diagram
UHCI #3
(D29:F3)
Debug
Port
Enhanced Host Controller Logic
UHCI #2
(D29:F2)
UHCI #1
(D29:F1)
UHCI #0
(D29:F0)
Port 7
Port 6
Port 5
Port 4
Port 3
Port 2
Port 1
Port 0
