Intel Xeon Processor with 800 MHz System Bus Thermal/Mechanical Design Guide

Intel® Xeon™ Processor with 800 MHz System Bus Thermal/Mechanical Design Guidelines 79
Processor Thermal Management Logic and Thermal Monitor Features
F.1.7.2 THERMTRIP# Signal Pin
In the event of a catastrophic cooling failure, the processor will automatically shut down when the
silicon temperature has reached its operating limit. At this point the system bus signal
THERMTRIP# signal goes active and power must be removed from the processor. THERMTRIP#
stays active until RESET# has been initiated. THERMTRIP# activation is independent of
processor activity and does not generate any bus cycles.
F.1.7.3 FORCEPR# Signal Pin
The Intel Xeon Processor with 800 MHz System Bus provides a means for system hardware to
force activation of the TCC. One possible usage model would be to use this capability to protect
the voltage regulator from overheating in order to avoid a catastrophic shutdown. Refer to the
appropriate platform design guidelines and voltage regulator design guidelines for implementation
details. The use of the FORCEPR# signal pin requires that BIOS code enable the signal’s
recognition via an MSR.
F.1.8 Cooling System Failure Warning
If desired, the system may be designed to cool the maximum processor power. In this situation, it
may be useful to use the PROCHOT# signal as an indication of cooling system failure. Messages
could be sent to the system administrator to warn of the cooling failure, while the TCC would allow
the system to continue functioning or allow a graceful system shutdown. If no thermal
management action is taken, the silicon temperature may exceed the operating limits, causing
THERMTRIP# to activate and shut down the processor. Regardless of the system design
requirements or thermal solution ability, the Thermal Monitor feature must still be enabled to
ensure proper processor operation.
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