Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
387
Address Translation Unit (PCI Express)—Intel
®
81341 and 81342
3.16.103 Outbound Configuration Cycle Data Register - OCCDR
The Outbound Configuration Cycle Data Register is used to initiate a configuration read
or write transaction on the PCI Express Link. The register is logical rather than physical
meaning that it is an address not a register. The Intel XScale
®
processor reads or
writes the data registers memory-mapped address to initiate the configuration
transaction on the PCI Express Link with the address found in the OCCAR. For a
configuration write, the data is latched from the internal bus and forwarded directly to
the ONPQ. For a read, the data is returned directly from the ICPLDQ to the Intel
XScale
®
processor and is never actually entered into the data register (which does not
physically exist).
The OCCDR is only visible from 81341 and 81342 internal bus address space and
appears as a reserved value within the ATU configuration space.
Note:
This register does not physically exist and reads from the PCI domain returns ‘0’.
Table 237. Outbound Configuration Cycle Data Register - OCCDR
Bit
Default
Description
31:00 0000 0000H Configuration Cycle Data - These bits define the data used during an outbound configuration read or
write transaction.
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
rw
ro
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Internal Bus Address Offset
+330H