Thermal Specifications and Design Considerations
88 Dual-Core Intel® Xeon® Processor 3000 Series Datasheet
5.4.2 PECI Specifications
5.4.2.1 PECI Device Address
The PECI device address for socket 0 is 30h and socket 1 resides at 31h. Note that each
address also supports two domains (Domain 0 and Domain 1). For more information on
PECI domains, refer to the Platform Environment Control Interface Specification.
5.4.2.2 PECI Command Support
PECI command support is covered in detail in the Platform Environment Control
Interface Specification. Refer to this document for details on supported PECI command
function and codes.
5.4.2.3 PECI Fault Handling Requirements
PECI is largely a fault tolerant interface, including noise immunity and error checking
improvements over other comparable industry standard interfaces. The PECI client is
as reliable as the device that it is embedded in, and thus given operating conditions
that fall under the specification, the PECI will always respond to requests and the
protocol itself can be relied upon to detect any transmission failures. There are,
however, certain scenarios where the PECI is know to be unresponsive.
Prior to a power on RESET# and during RESET# assertion, PECI is not ensured to
provide reliable thermal data. System designs should implement a default power-on
condition that ensures proper processor operation during the time frame when reliable
data is not available via PECI.
To protect platforms from potential operational or safety issues due to an abnormal
condition on PECI, the Host controller should take action to protect the system from
possible damaging states. It is recommended that the PECI host controller take
appropriate action to protect the client processor device if valid temperature readings
have not been obtained in response to three consecutive gettemp()s or for a one
second time interval. The host controller may also implement an alert to software in the
event of a critical or continuous fault condition.
5.4.2.4 PECI GetTemp0() Error Code Support
The error codes supported for the processor GetTemp() command are listed in Table 8.
Table 8. GetTemp0() Error Codes
Error Code Description
8000h General sensor error
8002h
Sensor is operational, but has detected a temperature below its operational
range (underflow).
