Thermal/Mechanical Reference Design
above, the
TCASE_MAX value of a specific solution can be calculated at TDP. Once this point is determined, the line can be extended to Power (P) = 0W representing the Thermal
Profile of the specific solution. If that line stays at or below the Thermal Profile specification, then that particular solution is deemed as a compliant solution.
2.2.6TCONTROL Definition
TCONTROL can be described as a trigger point for fan speed control implementation. The processor TCONTROL value provided by the Digital Thermal Sensor is relative and no longer absolute. The TCONTROL value is now defined as a relative value to the TCC activation set point (i.e. PECI Count = 0), as indicated by PROCHOT#. Figure
depicts the interaction between the TCONTROL value and Digital Thermal Sensor value.
Figure 2-8. TCONTROL Value and Digital Thermal Sensor Value Interaction
Digital Thermal Sensor Temperature
0
Tcontrol = -5
-10 Temperature
Time
The value for TCONTROL is calibrated in manufacturing and configured for each processor individually. For the
(IA32_TEMPERATURE_TARGET MSR).
Note: There is no TCONTROL_BASE value to sum as previously required on legacy processors. The fan speed control device only needs to read the TOFFSET MSR and compare this to the DTS value from the PECI interface. The equation for calculating TCONTROL is:
Equation 2-2.TCONTROL = -TOFFSET
Where:
TOFFSET = A
IA32_TEMPERATURE_TARGET MSR. This is a static and a unique value. Refer to the RS - Wolfdale Processor Family BIOS Writer’s Guide (BWG) for further details.
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