On-Demand Mode. Intel AT80571RG0601ML, AT80571RG0561ML

Thermal Specifications and Design Considerations

Figure 15.

Thermal Monitor 2 Frequency and Voltage Ordering

T

TM2

f

MAX

f

TM2

VID

VID

TM2

Temperature

Frequency

VID

5.2.3

PROCHOT#

The PROCHOT# signal is asserted when a high temperature situation is detected, regardless of whether Thermal Monitor or Thermal Monitor 2 is enabled.

It should be noted that the Thermal Monitor 2 TCC cannot be activated using the ondemand mode. The Thermal Monitor TCC, however, can be activated through the use of the on-demand mode.

On-Demand Mode

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 using 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 using 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 used in conjunction with the Thermal Monitor. If the system tries to enable On-

Demand mode at the same time the TCC is engaged, the factory configured duty cycle of the TCC will override the duty cycle selected by the On-Demand mode.

80 Datasheet