Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
289
Address Translation Unit (PCI Express)—Intel
®
81341 and 81342
3.14
Root Complex Functionality
The ATU has the capability to operate as the Root Complex of the PCI Express
hierarchy.
When operating as a Root Complex, the ATU behaves as a single function device and
only claims transactions for the ATU function. This means that the BARs and control
signals from other internal functions are ignored and any PCI status updates are limited
to the ATU.
Note:
When an endpoint device transmits an upstream configuration cycle to the ATUE as a
Root Complex, the ATUE will discard the configuration cycle without sending a
completion.