Intel E5240 EU80573KJ0806M Data Sheet

90

The Digital Thermal Sensor (DTS) provides an improved capability to monitor device 
hot spots, which inherently leads to more varying temperature readings over short time 
intervals. The DTS sample interval range can be modified, and a data filtering algorithm 
can be activated to help moderate this. The DTS sample interval range is 82us (default) 
to 20 ms (max). This value can be set in BIOS.

To reduce the sample rate requirements on PECI and improve thermal data stability vs. 
time the processor DTS also implements an averaging algorithm that filters the 
incoming data. This is an alpha-beta filter with coefficients of 0.5, and is expressed 
mathematically as: Current_filtered_temp = (Previous_filtered_temp / 2) + 
(new_sensor_temp / 2). This filtering algorithm is fixed and cannot be changed. It is on 
by default and can be turned off in BIOS.

Host controllers should utilize the min/max sample times to determine the appropriate 
sample rate based on the controller's fan control algorithm and targeted response rate. 
The key items to take into account when settling on a fan control algorithm are the DTS 
sample rate, whether the temperature filter is enabled, how often the PECI host will 
poll the processor for temperature data, and the rate at which fan speed is changed. 
Depending on the designer’s specific requirements the DTS sample rate and alpha-beta 
filter may have no effect on the fan control algorithm. 

The PECI device address for socket 0 is 0x30 and socket 1 is 0x31. Please note that 
each address also supports two domains (Domain0 and Domain1). For more 
information on PECI domains, please refer to the Platform Environment Control 
Interface (PECI) Specification.

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.