95
Thermal Specifications
should utilize the relative temperature value delivered over PECI in conjunction with the
T
CONTROL
MSR value to control or optimize fan speeds.
Figure 6-9
shows a conceptual
fan control diagram using PECI temperatures.
The relative temperature value reported over PECI represents the data below the onset
of thermal control circuit (TCC) activation as needed by PROCHOT# assertions. As the
temperature approaches TCC activation, the PECI value approaches zero. TCC activates
at a PECI count of zero.
6.3.1.2
Processor Thermal Data Sample Rate and Filtering
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.
Figure 6-9. Conceptual Fan Control Diagram of PECI-based Platforms
Fan Speed
(RPM )
(not intended to depict actual implementation)
M ax
M in
Temperature
PECI = -10
PECI = -20
TCC Activation
Temperature
T
CONTROL
Setting
PECI = 0
Fan Speed
(RPM )
(not intended to depict actual implementation)
M ax
M in
Temperature
PECI = -10
PECI = -20
TCC Activation
Temperature
T
CONTROL
Setting
PECI = 0
Summary of Contents for E5420 - CPU XEON QUAD CORE 2.50GHZ FSB1333MHZ 12M LGA771 HALOGEN FREE TRAY
Page 1: ...318589 005 Quad Core Intel Xeon Processor 5400 Series Datasheet August 2008 ...
Page 8: ...8 Quad Core Intel Xeon Processor 5400 Series Datasheet ...
Page 14: ...14 ...
Page 106: ...Boxed Processor Specifications 106 Figure 8 4 Top Side Board Keepout Zones Part 1 ...
Page 107: ...107 Boxed Processor Specifications Figure 8 5 Top Side Board Keepout Zones Part 2 ...
Page 108: ...Boxed Processor Specifications 108 Figure 8 6 Bottom Side Board Keepout Zones ...
Page 109: ...109 Boxed Processor Specifications Figure 8 7 Board Mounting Hole Keepout Zones ...
Page 110: ...Boxed Processor Specifications 110 Figure 8 8 Volumetric Height Keep Ins ...