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8.5
USB 2.0 EHCI Host Controller Support
The 8 available USB ports are provided by a USB 2.0 Rate Matching Hub (RMH) integrated within the Intel
controller is connected to the hub as shown below. The Hub convert low and full-speed traffic into high-speed traffic. When the RMHs are
enabled, they will appear to software like an external hub is connected to Port 0 of the EHCI controller. In addition, port 1 of the RMH is
multiplexed with Port 1 of the EHCI controller and is able to bypass the RMH for use as the Debug Port. The hub operates like any USB 2.0
Discrete Hub and will consume one tier of hubs allowed by the USB 2.0 Spec. A maximum of four additional non-root hubs can be supported
on any of the PCH USB Ports. The RMH will report the following Vendor ID = 8087h and Product ID = 8000h.
Routing Diagram
Internal Port:
Ports swapped on revision C.x and later
to support Debug Port on COM Express Port 0
COM Express Port:
Copyright © 2013 congatec AG
EHCI #1
EHCI #1
EHCI #1
USB 2.0 Rate Matching Hub
Port 0
Port 1
Port 2
Port 3
{
Port 0
Port 1
Port 2
Port 3
TU87m12
®
Port 4
Port 5
Port 6
Port 7
Port 4
Port 5
Port 6
Port 7
8 Series PCH-LP . The EHCI
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