User Guide

Datasheet, Volume 1 of 2 85
Thermal Management
active as long as the package temperature remains at its specified limit. Therefore, the
Adaptive Thermal Monitor will continue to reduce the package frequency and voltage
until the TCC is de-activated.
Tj
MAX
is factory calibrated and is not user configurable. The default value is software
visible in the TEMPERATURE_TARGET (0x1A2) MSR, bits [23:16].
The Adaptive Thermal Monitor does not require any additional hardware, software
drivers, or interrupt handling routines. It is not intended as a mechanism to maintain
processor thermal control to PL1 = TDP. The system design should provide a thermal
solution that can maintain normal operation when PL1 = TDP within the intended usage
range.
Adaptive Thermal Monitor protection is always enabled.
5.1.5.1.1 TCC Activation Offset
TCC Activation Offset can be set as an offset from the maximum allowed component
temperature to lower the onset of TCC and Adaptive Thermal Monitor. In addition, the
processor has added an optional time window (Tau) to manage processor performance
at the TCC Activation offset value via an EWMA (Exponential Weighted Moving Average)
of temperature.
TCC Activation Offset with Tau=0
An offset (degrees Celsius) can be written to the TEMPERATURE_TARGET (0x1A2) MSR,
bits [29:24], the offset value will be subtracted from the value found in bits [23:16].
When the time window (Tau) is set to zero, there will be no averaging, the offset, will
be subtracted from the Tj
MAX
value and used as a new max temperature set point for
Adaptive Thermal Monitoring. This will have the same behavior as in prior products to
have TCC activation and Adaptive Thermal Monitor to occur at this lower target silicon
temperature.
If enabled, the offset should be set lower than any other passive protection such as
ACPI _PSV trip points
TCC Activation Offset with Tau
To manage the processor with the EWMA (Exponential Weighted Moving Average) of
temperature, an offset (degrees Celsius) is written to the TEMPERATURE_TARGET
(0x1A2) MSR, bits [29:24], and the time window (Tau) is written to the
TEMPERATURE_TARGET (0x1A2) MSR [6:0]. The Offset value will be subtracted from
the value found in bits [23:16] and be the temperature.
The processor will manage to this average temperature by adjusting the frequency of
the various domains. The instantaneous Tj can briefly exceed the average temperature.
The magnitude and duration of the overshoot is managed by the time window value
(Tau).
This averaged temperature thermal management mechanism is in addition, and not
instead of Tj
MAX
thermal management. That is, whether the TCC activation offset is 0 or
not, TCC Activation will occur at Tj
MAX
.