Intel i3-4360T CM8064601481958 User Manual

A corner case exists for PROCHOT# configured as a bi-directional signal that can

cause several milliseconds of delay to a system assertion of PROCHOT# when the

output function is asserted.

As an output, PROCHOT# (Processor Hot) will go active when the processor

temperature monitoring sensor detects that one or more cores has reached its

maximum safe operating temperature. This indicates that the processor Thermal

Control Circuit (TCC) has been activated, if enabled. As an input, assertion of

PROCHOT# by the system will activate the TCC for all cores. TCC activation when

PROCHOT# is asserted by the system will result in the processor immediately

transitioning to the minimum frequency and corresponding voltage (using Frequency

control). Clock modulation is not activated in this case. The TCC will remain active

until the system de-asserts PROCHOT#.

Use of PROCHOT# in input or bi-directional mode can allow VR thermal designs to

target maximum sustained current instead of maximum current. Systems should still

provide proper cooling for the Voltage Regulator (VR), and rely on PROCHOT# only as

a backup in case of system cooling failure. The system thermal design should allow

the power delivery circuitry to operate within its temperature specification even while

the processor is operating at its Thermal Design Power.

Regardless of whether or not Adaptive Thermal Monitor is enabled, in the event of a

catastrophic cooling failure, the processor will automatically shut down when the

silicon has reached an elevated temperature (refer to the THERMTRIP# definition in 

 on page 92). THERMTRIP# activation is

independent of processor activity. The temperature at which THERMTRIP# asserts is

not user configurable and is not software visible.

Each processor execution core has an on-die Digital Thermal Sensor (DTS) that

detects the core's instantaneous temperature. The DTS is the preferred method of

monitoring processor die temperature because:
•

It is located near the hottest portions of the die.

•

It can accurately track the die temperature and ensure that the Adaptive Thermal

Monitor is not excessively activated.

Temperature values from the DTS can be retrieved through:
•

A software interface using processor Model Specific Register (MSR).

•

 on page 37.

When temperature is retrieved by the processor MSR, it is the instantaneous

temperature of the given core. When temperature is retrieved using PECI, it is the

average of the highest DTS temperature in the package over a 256 ms time window.

Intel recommends using the PECI reported temperature for platform thermal control

that benefits from averaging, such as fan speed control. The average DTS

temperature may not be a good indicator of package Adaptive Thermal Monitor

activation or rapid increases in temperature that triggers the Out of Specification

status bit within the PACKAGE_THERM_STATUS MSR 1B1h and IA32_THERM_STATUS

MSR 19Ch.

Desktop 4th Generation Intel

®

 Core

™

 Processor Family, Desktop Intel

®

 Pentium

®

 Processor Family, and Desktop Intel

®

 Celeron

®

Processor Family

July 2014

Datasheet – Volume 1 of 2

Order No.: 328897-009

81