Thermal Specifications and Design Considerations
An external signal, PROCHOT# (processor hot) is asserted when the processor die temperature has
reached its thermal limit. If the TCC is enabled (note that the TCC must be enabled for the
processor to be operating within spec), TCC will be active when the PROCHOT# signal is active.
The temperature at which the thermal control circuit activates is not user configurable and is not
software visible. Bus snooping and interrupt latching are active while the TCC is active.
Besides the thermal sensor and TCC, the thermal monitor feature also includes one ACPI register,
performance monitoring logic, bits in three model specific registers (MSR), and one I/O pin
(PROCHOT#). All are available to monitor and control the state of the thermal monitor feature.
Thermal monitor can be configured to generate an interrupt upon the assertion or de-assertion of
PROCHOT#.
If automatic mode is disabled the processor will be operating out of specification. Regardless of
enabling of the automatic or On-Demand modes, in the event of a catastrophic cooling failure, the
processor will automatically shut down when the silicon has reached a temperature of
approximately 135 °C. At this point the system bus signal THERMTRIP# will go active and stay
active until RESET# has been initiated. THERMTRIP# activation is independent of processor
activity and does not generate any bus cycles. If THERMTRIP# is asserted, processor core voltage
(V ) must be removed within the timeframe defined in Table 22.
CC
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Mobile Intel Pentium 4 Processor-M Datasheet
INTEL [ INTEL ]
