Intel Mobile Intel Pentium 4 RH80532GC021512 User Manual
Product codes
RH80532GC021512
Intel
®
Pentium
®
4 Processor in the 423-pin Package
79
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 at 50% on, 50% off, 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 50% duty cycle of the automatic
mode will override the duty cycle selected by the On-Demand mode.
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 at 50% on, 50% off, 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 50% 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 any time the TCC is active (either in
Automatic or On-Demand mode). 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.
Automatic or On-Demand mode). 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 thermal control circuit, the Thermal Monitor feature also includes
one ACPI register, one performance counter register, 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# (i.e. upon the activation/deactivation of TCC).
one ACPI register, one performance counter register, 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# (i.e. upon the activation/deactivation of TCC).
If automatic mode is disabled the processor will be operating out of specification and cannot be
guaranteed to provide reliable results. 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 the processor has cooled down and
RESET# has been initiated. THERMTRIP# activation is independent of processor activity and
does not generate any bus cycles.
guaranteed to provide reliable results. 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 the processor has cooled down and
RESET# has been initiated. THERMTRIP# activation is independent of processor activity and
does not generate any bus cycles.
7.3.1
Thermal Diode
The Pentium 4 processor incorporates an on-die thermal diode. A thermal sensor located on the
system board may monitor the die temperature of the Pentium 4 processor for thermal
management/long term die temperature change purposes. Table 35 and Table 36 provide the diode
parameter and interface specifications. This thermal diode is separate from the Thermal Monitor’s
thermal sensor and cannot be used to predict the behavior of the Thermal Monitor.
system board may monitor the die temperature of the Pentium 4 processor for thermal
management/long term die temperature change purposes. Table 35 and Table 36 provide the diode
parameter and interface specifications. This thermal diode is separate from the Thermal Monitor’s
thermal sensor and cannot be used to predict the behavior of the Thermal Monitor.
NOTES:
1. Not 100% tested. Specified by design characterization.
2. Intel does not support or recommend operation of the thermal diode under reverse bias.
3. At room temperature with a forward bias of 630 mV.
4. n_ideality is the diode ideality factor parameter, as represented by the diode equation:
2. Intel does not support or recommend operation of the thermal diode under reverse bias.
3. At room temperature with a forward bias of 630 mV.
4. n_ideality is the diode ideality factor parameter, as represented by the diode equation:
I=Io(e (Vd*q)/(nkT) - 1).
Table 35. Thermal Diode Parameters
Symbol
Min
Typ
Max
Unit
Notes
1
I
forward bias
5
450
uA
2
n_ideality
0.9933
1.0045
1.0368
3, 4