![Intel 413808 I/O Developer'S Manual Download Page 257](http://html1.mh-extra.com/html/intel/413808-i-o/413808-i-o_developers-manual_2072039257.webp)
Intel
®
413808 and 413812 I/O Controllers in TPER Mode
October 2007
Developer’s Manual
Order Number: 317805-001US
257
Address Translation Unit (PCI Express)—Intel
®
413808 and 413812
3.5
Messaging Unit
The Messaging Unit (MU) is used to transfer data between the PCI system and the
4138xx and notifies the respective system when new data arrives. The MU is located on
the south internal bus of the 4138xx and is accessed via the ATU. The MU is described
in
Chapter 4.0, “Messaging Unit”
.
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).