Intel Quad-core Intel Xeon DP L5335 Active BX80563L5335A Data Sheet

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Quad-Core Intel® Xeon® Processor 5300 Series Datasheet

PECI command support is covered in detail in Platform Environment Control Interface 
Specification. Please refer to this document for details on supported PECI command 
function and codes

PECI is largely a fault tolerant interface, including noise immunity and error checking 
improvements over other compatible industry standard interfaces. The PECI client is as 
reliable as the device that it is embedded within, and thus given operating conditions 
that fall under the specification, the PECI client will always respond to requests and the 
protocol itself can be relied upon to detect any transmission failures. There are, 
however, certain scenarios where PECI is known to be unresponsive.

Prior to a power on RESET# and during RESET# assertion, PECI is not guaranteed 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 PECI host controller should take action to protect the system 
from possible damage. 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 PECI host controller may also implement an alert to software 
in the event of a critical or continuous fault condition.

The error codes supported for the processor GetTemp0() and GetTemp1() command 
are listed in 

 below:

0x8000

General sensor error

0x8002

Sensor is operational, but has detected a temperature below its operational range 

(underflow).