6. Bridging > Transaction Ordering
56
PEB383 User Manual
July 25, 2011
Integrated Device Technology, Inc.
Confidential - NDA Required
6.10
Transaction Ordering
defines the transaction ordering rules that are followed by the PEB383. These rules apply
uniformly to all types of transactions, including Memory, I/O, Configurations, and Messages.
In the table, the columns represent a first received transaction while the rows represent a subsequently
received transaction. Each table entry indicates the ordering relationship between the two transactions.
The table entries are defined as follows:
•
Yes – The second transaction is allowed to pass the first transaction.
•
No – The second transaction is not allowed to pass the first transaction.
The PEB383 does not allow a posted transaction to pass another posted transaction even if the relaxed
ordering attribute bit is set. However, the device allows a Read completion with the relaxed ordering
attribute bit set to pass a posted transaction.
Table entries with 1) and 2) are defined as follows:
1.
Indicates the ordering relationship when the relaxed ordering attribute bit is clear in the second
transaction header information.
2.
Indicates the ordering relationship when the relaxed ordering attribute bit is set in the second
transaction header information.
Table 12: Transaction Ordering
Posted Request
Non-Posted Request
Completion
Can Row Pass Column?
Memory Write or
Message
Request
Read Request
I/O or
Configuration
Write Request
Read Completion
I/O or
Configuration
Write Completion
Posted
Request
Memory Write
or Message
Request
1) No
2) No
Yes
Yes
1) Yes
2) Yes
1) Yes
2) Yes
Non-Posted
Request
Read Request
No
Yes
Yes
Yes
Yes
I/O or
Configuration
No
Yes
Yes
Yes
Yes
Complet
ion
Read
Completion
1) No
2) Yes
Yes
Yes
1) Yes
2) Yes
Yes
I/O or
Configuration
Write
Completion
No
Yes
Yes
Yes
Yes