Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
261
Address Translation Unit (PCI Express)—Intel
®
81341 and 81342
3.5
Messaging Unit
The Messaging Unit (MU) is used to transfer data between the PCI system and the
81341 and 81342 and notifies the respective system when new data arrives. The MU is
located on the south internal bus of the 81341 and 81342 and is accessed via the ATU.
The MU is described in
.
The PCI window for messaging transactions is the 8 Kbytes of the inbound translation
window defined by the Inbound ATU Base Address Register 0 (IABAR0) and the
Inbound ATU Limit Register 0 (IALR0).