Intel 4 3.20 GHz BX80532PG3200F User Manual

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cause a noticeable performance loss, and in some cases may result in a T

C

 that exceeds the 

specified maximum temperature and may affect the long-term reliability of the processor. In 

addition, a thermal solution that is significantly under-designed may not be capable of cooling the 
processor even when the TCC is active continuously. Refer to the Intel

with 512-KB L2 Cache on 0.13 Micron Process Thermal Design Guidelines for information on 

designing a thermal solution.

The duty cycle for the TCC, when activated by the Thermal Monitor, is factory configured and 
cannot be modified. The Thermal Monitor does not require any additional hardware, software 
drivers, or interrupt handling routines.

The TCC may also be activated via On-Demand mode. If bit 4 of the ACPI Thermal Monitor 

Control Register is written to a 1, the TCC will be activated immediately independent of the 
processor temperature. When using On-Demand mode to activate the TCC, the duty cycle of the 
clock modulation is programmable via bits 3:1 of the same ACPI Thermal Monitor Control 
Register. In automatic mode, the duty cycle is fixed. However, 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 at the same time Automatic mode is enabled. However, if the 
system tries to enable the TCC via On-Demand mode at the same time automatic mode is enabled 

AND a high temperature condition exists, the duty cycle of the automatic mode will override the 
duty cycle selected by the On-Demand mode. 

An external signal, PROCHOT# (processor hot), is asserted when the processor detects that its 
temperature is at the thermal trip point. Bus snooping and interrupt latching are also active while 

the TCC is active. The temperature at which the thermal control circuit activates is not user 
configurable and is not software visible. 

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 automatically shuts down when the silicon has reached a temperature of approximately 
135 °C. At this point the system bus signal THERMTRIP# goes active and stays 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

CC

) must 

be removed within 0.5 seconds.