IDT Switch Operation
Routing
PES12N3 User Manual
4 - 3
June 7, 2006
Notes
Each header credit is allocated 20 bytes (3 double doublewords) in a FIFO regardless of whether or not
a credit represents 16 or 20 bytes. Each posted and completion data credit is allocated 16 bytes (2 double
doublewords) in a FIFO. Non-posted data credits are allocated 8 bytes (one double doubleword). Two
header and data credits are reserved in each FIFO for TLPs generated by the switch (e.g., configuration
read completions).
The header and data flow control credits advertised may be configured on a per port basis via the Flow
Control Credit Posted Configuration (FCPTCFG), Flow Control Credit Non-Posted Configuration
(FCNPCFG) and Flow Control Credit Completion Configuration (FCCPCFG) registers. These registers may
only be modified using the serial EEPROM or during initialization via the SMBus when the RSTHALT bit is
set in the PA_SWCTL register. Modifying these registers in a running system produces undefined results.
Routing
The PES12N3 supports routing of all transaction types defined in the PCIe specification. This includes
routing using in specification defined transactions as well as those that may be used in vendor defined
messages and in future revisions of the PCIe specifications.
Specifically, the PES12N3 supports the following type of routing:
–
Address routing with 32-bit or 64-bit format
–
ID based routing using bus, device and function numbers.
–
Implicit routing utilizing
Route to root
Broadcast from root
Local - terminate at receiver
Gathered and routed to root
–
A summary of TLP types that use the above routing methods is provided in Table 4.3.
Flow Control
Category
Default
Advertised
Credits
Notes
Posted Header
30 credits
Each credit represents 20 bytes (i.e., 5 doublewords) for a max-
imum of 600 bytes
Posted Data
204 credits
Each credit represents 16 bytes (i.e., 4 doublewords) for a max-
imum of 3264 bytes
Non-Posted Header
30 credits
Each credit represents 20 bytes (i.e., 5 doublewords) for a max-
imum of 600 bytes
Non-Posted Data
30 credits
Each credit represents 16 bytes (i.e., 4 doublewords) for a max-
imum of 480 bytes (note that non-posted data is assumed to
consists of only one doubleword per header)
Completion Header
30 credits
Each credit represents 16 bytes (i.e., 4 doublewords) for a max-
imum of 480 bytes
Completion Data
204 credits
Each credit represents 16 bytes (i.e., 4 doublewords) for a max-
imum of 3264 bytes
Table 4.2 PES12N3 Advertised Flow Control Credits
Summary of Contents for 89HPES12N3
Page 10: ...IDT Table of Contents PES12N3 User Manual iv June 7 2006 Notes...
Page 14: ...IDT List of Figures PES12N3 User Manual viii June 7 2006 Notes...
Page 36: ...IDT Clocking Reset and Initialization Reset PES12N3 User Manual 2 8 June 7 2006 Notes...
Page 40: ...IDT Link Operation Slot Power Limit Support PES12N3 User Manual 3 4 June 7 2006 Notes...
Page 50: ...IDT Switch Operation Switch Core Errors PES12N3 User Manual 4 10 June 7 2006 Notes...
Page 54: ...IDT Power Management Active State Power Management PES12N3 User Manual 5 4 June 7 2006 Notes...
Page 62: ...IDT Hot Plug and Hot Swap Hot Swap PES12N3 User Manual 6 8 June 7 2006 Notes...
Page 78: ...IDT SMBus Interfaces Slave SMBus Interface PES12N3 User Manual 7 16 June 7 2006 Notes...
Page 148: ...IDT Test and Debug SerDes Test Clock PES12N3 User Manual 10 6 June 7 2006...
Page 158: ...IDT JTAG Boundary Scan Usage Considerations PES12N3 User Manual 11 10 June 7 2006 Notes...
