Intel QX9775 EU80574XL088N Data Sheet

80

voltage transition back to the normal system operating point. Transition of the VID code 

will occur first, in order to insure proper operation once the processor reaches its 

normal operating frequency. Refer to 

 for an illustration of this ordering.

The PROCHOT# signal is asserted when a high temperature situation is detected, 

regardless of whether Thermal Monitor 1 or Thermal Monitor 2 is enabled.

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 1 and Thermal Monitor 2 

features. 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 

IA32_CLOCK_MODULATION MSR is set 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 

IA32_CLOCK_MODULATION MSR. 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; however, 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.

An external signal, PROCHOT# (processor hot) is asserted when the processor die 

temperature of any processor cores reaches its factory configured trip point. If Thermal 

Monitor is enabled (note that Thermal Monitor must be enabled for the processor to be 

operating within specification), the TCC will be active when PROCHOT# is asserted. The 

processor can be configured to generate an interrupt upon the assertion or de-

assertion of PROCHOT#. Refer to the Intel

Developer’s Manual for specific register and programming details.

Vcc

Temperature

V

NOM

Frequency

Time

f

TM2

f

MAX

T

TM2

V

TM2

T(hysterisis)

Vcc

Temperature

V

NOM

Frequency

Time

f

TM2

f

MAX

T

TM2

V

TM2

T(hysterisis)