Datasheet

Intel
®
Xeon
®
Processor C5500/C3500 Series
February 2010 Datasheet, Volume 1
Order Number: 323103-001 71
Interfaces
PECI-based access to DRAM thermal readings and throttling control coefficients provide
a means for Board Management Controllers (BMCs) or other platform management
devices to feed hints into on-die memory controller throttling algorithms. These control
coefficients are accessible using PCI configuration space writes via PECI reference are
documented in Section 2.2.2.5.
2.2.1.2 Platform Manageability
PECI allows full read access to error and status monitoring registers within the
processor’s PCI configuration space. It also provides insight into thermal monitoring
functions such as TCC activation timers and thermal error logs.
2.2.1.3 Processor Interface Tuning and Diagnostics
The processor Intel
®
IBIST allows for in-field diagnostic capabilities in Intel
®
QuickPath
Interconnect and memory controller interfaces. PECI provides a port to execute these
diagnostics via its PCI Configuration read and write capabilities.
2.2.2 Client Command Suite
2.2.2.1 Ping()
Ping() is a required message for all PECI devices. This message is used to enumerate
devices or determine if a device has been removed, been powered-off, etc. A Ping()
sent to a device address always returns a non-zero Write FCS if the device at the
targeted address is able to respond.
2.2.2.1.1 Command Format
The Ping() format is as follows:
Write Length: 0
Read Length: 0
An example Ping() command to PECI device address 0x30 is shown below.
Figure 12. Ping()
Byte #
Byte
Definition
0
Client Address
1
Write Length
0x00
2
Read Length
0x00
3
FCS
Figure 13. Ping() Example
Byte #
Byte
Definition
0
0x30
1
0x00
2
0x00
3
0xe1