Intel
®
81341 and 81342—Messaging Unit
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
444
Order Number: 315037-002US
4.9.23
MU Base Address Register - MUBAR
MU Base Address Register (MUBAR) contains lower 32-bit of the 36-bit local memory
base address of the MU address space as depicted in
. For example, the MU
address space as viewed from Host I/O Interface. The MU base address is required to
be located on an 8-KByte boundary. The upper four-bits of the MU Base Address are
located in the MU Upper Address Register (MUBAR). Refer to
Base Address Register - MUUBAR”
. The MU always claim the entire 8 KBytes of the
internal bus address space relative to the MU Base Address Registers. The 8 KBytes
include the MU Registers, Index Registers, and MSI-X Data Structures. When the 8-
KByte MU Base Address Registers are programmed to overlap onto the DDR MCU
Memory space, the entire overlapped 8-KByte space is claimed by the MU - and not by
the DDR MCU. Overlapping the MU space onto the DDR MCU space is required when the
Index registers are required, because the Index registers are implemented using the
DDR Memory.
Note:
The default values of MUBAR/MUBAR are programmed to match the default values
programmed in the Inbound ATU Translate Value Register 0 - IATVR0/Inbound ATU
Upper Translate Value Register 0 - IAUTVR0. This allows the MU registers to be mapped
in the first 8-KByte of the PCI Window 0 Address space.
Table 287. MU Base Address Register - MUBAR
Bit
Default
Description
31:13
FF000H
MU Base Address - Local memory address of the MU (including MSI-X) registers as viewed from Host I/
O Interface. The MU occupies a 8-KByte space from Host I/O Interface.
12:00
000H
Reserved
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rv rv rv rv rv rv rv rv rv rv rv rv rv
na na na na na na na na na na na na na na na na na na na na na na na na na na na na na na na na
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
MUBAR
internal bus address offset
4084H