IDT Tsi310TM, User Manual

Page: 29 / 207

2. Bus Operation 29
Tsi310 User Manual
80B6020_MA001_05
As indicated in the previous tables, certain commands are not supported by the Tsi310:
• The bridge never initiates a transaction with a reserved command code and, as a target, the
bridge ignores reserved command codes.
• The bridge never initiates an interrupt acknowledge transaction and, as a target, the bridge
ignores interrupt acknowledge transactions. Interrupt acknowledge transactions are
expected to reside entirely on the primary bus closest to the host bridge.
• The bridge does not respond to special cycle transactions. To generate special cycle
transactions on other buses, either upstream or downstream, a Type 1 configuration
command must be used.
• The Tsi310’s response to Type 1 Configuration accesses on the secondary interface is
limited. The Tsi310 only responds to Type 1 configuration writes that get converted to
special cycles going upstream, as described in
Section 2.4.4 on page 42 .
Table 2: PCI-X Transactions
Command
Code Type of Transaction
Initiates as Master Responds as Target
Primary Secondary Primary Secondary
0000 Interrupt Acknowledge No No No No
0001 Special Cycle Yes Yes No No
0010 I/O Read Yes Yes Yes Yes
0011 I/O Write Yes Yes Yes Yes
0100 Reserved No No No No
0101 Reserved No No No No
0110 Memory Read Yes Yes Yes Yes
0111 Memory Write Yes Yes Yes Yes
1000 Alias to Memory Read Block No No Yes Yes
1001 Alias to Memory Write Block No No Yes Yes
1010 Configuration Read No Yes Yes Type 0
1011 Configuration Write Type 1 Yes Yes Yes
1100 Split Completion Yes Yes Yes Yes
1101 Dual Address Cycle Yes Yes Yes Yes
1110 Memory Read Block Yes Yes Yes Yes
1111 Memory Write Block Yes Yes Yes Yes