Intel 220 LE80557RE009512 Ficha De Dados

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Datasheet

The Thermal Monitor feature helps control the processor temperature by activating the 

thermal control circuit (TCC) when the processor silicon reaches its maximum operating 

temperature. The TCC reduces processor power consumption by modulating (starting 

and stopping) the internal processor core clocks. The Thermal Monitor feature must 

be enabled for the processor to be operating within specifications. The 

temperature at which Thermal Monitor activates the thermal control circuit is not user 

configurable and is not software visible. Bus traffic is snooped in the normal manner, 

and interrupt requests are latched (and serviced during the time that the clocks are on) 

while the TCC is active.

When the Thermal Monitor feature is enabled, and a high temperature situation exists 

(i.e., TCC is active), the clocks will be modulated by alternately turning the clocks off 

and on at a duty cycle specific to the processor (typically 30–50%). Clocks often will 

not be off for more than 3.0 microseconds when the TCC is active. Cycle times are 

processor speed dependent and will decrease as processor core frequencies increase. A 

small amount of hysteresis has been included to prevent rapid active/inactive 

transitions of the TCC when the processor temperature is near its maximum operating 

temperature. Once the temperature has dropped below the maximum operating 

temperature, and the hysteresis timer has expired, the TCC goes inactive and clock 

modulation ceases.

With a properly designed and characterized thermal solution, it is anticipated that the 

TCC would only be activated for very short periods of time when running the most 

power intensive applications. The processor performance impact due to these brief 

periods of TCC activation is expected to be so minor that it would be immeasurable. An 

under-designed thermal solution that is not able to prevent excessive activation of the 

TCC in the anticipated ambient environment may cause a noticeable performance loss, 

and in some cases may result in a T

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 that exceeds the specified maximum temperature 

and may affect the long-term reliability of the processor. In addition, a thermal solution 

that is significantly under-designed may not be capable of cooling the processor even 

when the TCC is active continuously. Refer to the Intel

®

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Sequence Thermal and Mechanical Design Guidelines for information on designing a 

thermal solution.

The duty cycle for the TCC, when activated by the Thermal Monitor, is factory 

configured and cannot be modified. The Thermal Monitor does not require any 

additional hardware, software drivers, or interrupt handling routines.

The processor provides an auxiliary mechanism that allows system software to force 

the processor to reduce its power consumption. This mechanism is referred to as “On-

Demand” mode and is distinct from the Thermal Monitor feature. On-Demand mode is 

intended as a means to reduce system level power consumption. Systems using the 

processor must not rely on software usage of this mechanism to limit the processor 

temperature.

If bit 4 of the ACPI P_CNT Control Register (located in the processor 

IA32_THERM_CONTROL MSR) is written to a '1', the processor will immediately reduce 

its power consumption via modulation (starting and stopping) of the internal core clock, 

independent of the processor temperature. When using On-Demand mode, the duty 

cycle of the clock modulation is programmable via bits 3:1 of the same ACPI P_CNT 

Control Register. In On-Demand mode, the duty cycle can be programmed from 12.5% 

on/87.5% off, to 87.5% on/12.5% off in 12.5% increments. On-Demand mode may be