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Thermal Specifications
6.3.2
PECI Specifications
6.3.2.1
PECI Device Address
The PECI register resides at address 30h.
6.3.2.2
PECI Command Support
The processor supports the PECI commands listed in
Table 6-4.
Supported PECI Command Functions and Codes
Command
Function
Ping()
GetTemp0()
6.3.2.3
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 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 damaging states. If the Host controller cannot complete a valid PECI
transactions of GetTemp0() with a given PECI device over 3 consecutive failed
transactions or a one second maximum specified interval, then it should take
appropriate actions to protect the corresponding device and/or other system
components from overheating. The host controller may also implement an alert to
software in the event of a critical or continuous fault condition.
6.3.2.4
PECI GetTemp0() Error Code Support
The error codes supported for the processor GetTemp() command are listed in
Table
6-5.
Table 6-5.
GetTemp0() Error Codes
Error Code
8000h
Datasheet
Code
N/A
This command targets a valid PECI device address followed by zero Write
Length and zero Read Length.
01h
Write Length: 1
Read Length: 2
Returns the temperature of the processor in Domain 0
General sensor error
Table
6-4.
Comments
Description
81
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