Intel E5400 AT80571PG0682ML Data Sheet

Datasheet

83

The PECI register resides at address 30h. 

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.

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 assured 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 using 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 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 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 GetTemp() command are listed in 

:

8000h

General sensor error

8002h

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