Intel D525 AU80610006225AA User Manual
Product codes
AU80610006225AA
Datasheet
63
Thermal Specifications and Design Considerations
7.1.3
Digital Thermal Sensor
The processor also contains an on die Digital Thermal Sensor (DTS) that can be read
via an MSR (no I/O interface). Each core of the processor will have a unique digital
thermal sensor whose temperature is accessible via the processor MSRs. The DTS is the
preferred method of reading the processor die temperature since it can be located
much closer to the hottest portions of the die and can thus more accurately track the
die temperature and potential activation of processor core clock modulation via the
Thermal Monitor. The DTS is only valid while the processor is in the normal operating
state (the Normal package level low power state).
via an MSR (no I/O interface). Each core of the processor will have a unique digital
thermal sensor whose temperature is accessible via the processor MSRs. The DTS is the
preferred method of reading the processor die temperature since it can be located
much closer to the hottest portions of the die and can thus more accurately track the
die temperature and potential activation of processor core clock modulation via the
Thermal Monitor. The DTS is only valid while the processor is in the normal operating
state (the Normal package level low power state).
Unlike traditional thermal devices, the DTS will output a temperature relative to the
maximum supported operating temperature of the processor (T
maximum supported operating temperature of the processor (T
J_max
). It is the
responsibility of software to convert the relative temperature to an absolute
temperature. The temperature returned by the DTS will always be at or below T
temperature. The temperature returned by the DTS will always be at or below T
J_max
.
Catastrophic temperature conditions are detectable via an Out Of Spec status bit. This
bit is also part of the DTS MSR. When this bit is set, the processor is operating out of
specification and immediate shutdown of the system should occur. The processor
operation and code execution is not ensured once the activation of the Out of Spec
status bit is set.
bit is also part of the DTS MSR. When this bit is set, the processor is operating out of
specification and immediate shutdown of the system should occur. The processor
operation and code execution is not ensured once the activation of the Out of Spec
status bit is set.
The DTS-relative temperature readout corresponds to the Thermal Monitor 1(TM1)
trigger point. When the DTS indicates maximum processor core temperature has been
reached, the TM1 hardware thermal control mechanism will activate. The DTS and TM1
temperature may not correspond to the thermal diode reading since the thermal diode
is located in a separate portion of the die and thermal gradient between the individual
core DTS. Additionally, the thermal gradient from DTS to thermal diode can vary
substantially due to changes in processor power, mechanical and thermal attach, and
software application. The system designer is required to use the DTS to ensure proper
operation of the processor within its temperature operating specifications.
trigger point. When the DTS indicates maximum processor core temperature has been
reached, the TM1 hardware thermal control mechanism will activate. The DTS and TM1
temperature may not correspond to the thermal diode reading since the thermal diode
is located in a separate portion of the die and thermal gradient between the individual
core DTS. Additionally, the thermal gradient from DTS to thermal diode can vary
substantially due to changes in processor power, mechanical and thermal attach, and
software application. The system designer is required to use the DTS to ensure proper
operation of the processor within its temperature operating specifications.
Changes to the temperature can be detected via two programmable thresholds located
in the processor MSRs. These thresholds have the capability of generating interrupts
via the core's local APIC. Refer to the Intel® 64 and IA-32 Architectures Software
Developer's Manuals for specific register and programming details.
in the processor MSRs. These thresholds have the capability of generating interrupts
via the core's local APIC. Refer to the Intel® 64 and IA-32 Architectures Software
Developer's Manuals for specific register and programming details.
Note:
The Digital Thermal Sensor (DTS) accuracy is in the order of -5°C to +10°C around
100°C. I deteriorates to -10°C to +15°C at 50°C. The DTS temperature reading
saturates at some temperature below 50°C. Any DTS reading below 50°C should be
considered to indicate only a temperature below 50°C and not a specific temperature.
External thermal sensor with “BJT” model is required to read thermal diode
temperature if more accurate temperature reading is needed.
100°C. I deteriorates to -10°C to +15°C at 50°C. The DTS temperature reading
saturates at some temperature below 50°C. Any DTS reading below 50°C should be
considered to indicate only a temperature below 50°C and not a specific temperature.
External thermal sensor with “BJT” model is required to read thermal diode
temperature if more accurate temperature reading is needed.
7.1.4
Out of Specification Detection
Overheat detection is performed by monitoring the processor temperature and
temperature gradient. This feature is intended for graceful shut down before the
THERMTRIP# is activated. If the processor’s TM1 is triggered and the temperature
temperature gradient. This feature is intended for graceful shut down before the
THERMTRIP# is activated. If the processor’s TM1 is triggered and the temperature