Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
59
Address Translation Unit (PCI-X)—Intel
®
81341 and 81342
Inbound and outbound ATU transactions are best described by the data flows used on
the PCI bus and the 81341 and 81342 internal bus during read and write operations.
The following sections describe read and write operations for inbound ATU transactions
(PCI to internal bus) and outbound transactions (internal bus to PCI).
Table 1.
ATU Command Support
PCI Command
Encoding
PCI Command
Type
PCI-X
Command
Type
Claimed on
Inbound
Transactions
on PCI Bus
Generated by
Outbound
Transactions
on PCI Bus
Valid Internal
Bus Command
0000
Interrupt
Acknowledge
Interrupt
Acknowledge
No
No
Reserved
0001
Special Cycle
Special Cycle
No
No
Reserved
0010
I/O Read
I/O Read
No
Yes
Reserved
0011
I/O Write
I/O Write
No
Yes
Reserved
0100
Reserved
Reserved
No
No
Reserved
0101
Reserved
Device ID
Message
No
No
Reserved
0110
Memory Read
Memory Read
DWORD
Yes
Yes
Read
0111
Memory Write
Memory Write
Yes
Yes
Write
1000
Reserved
Alias to Memory
Read Block
Yes
No
Read
1001
Reserved
Alias to Memory
Write Block
Yes
No
Write
1010
Configuration
Read
Configuration
Read
Yes
Yes
Read
1011
Configuration
Write
Configuration
Write
Yes
Yes
Write
1100
Memory Read
Multiple
Split Completion
Yes
Yes
Split Completion
1101
Dual Address
Cycle
Dual Address
Cycle
Yes
Yes
Reserved
1110
Memory Read
Line
Memory Read
Block
Yes
Yes
Read
1111
Memory Write
and Invalidate
Memory Write
Block
Yes
Yes
Write
Notes:
1.
PCI-X mode 2 only
2.
PCI-X mode only