Intel Itanium 2 Processor manual Thermal Features, Thermal Alert

5Thermal Specifications

This chapter provides a description of the thermal features relating to the Itanium 2 processor.

5.1Thermal Features

The Itanium 2 processor has an internal thermal circuit which senses when a certain temperature is reached on the processor core. This circuit is used for controlling various thermal states. In addition, an on-chip thermal diode is available for use by the thermal sensing device on the Itanium 2 processor. Figure 5-1shows the relationship between temperature, time, and the thermal alert, enhanced thermal management (ETM), and thermal trip points.

Note: Figure 5-1is not intended to show a linear relationship in time or temperature as a processor's thermal state advances from one state to the next state when the cooling solution fails to control the processor temperature, as this is affected by many factors such as cooling solution performance degradation and processor workload variations.

Figure 5-1. Itanium® 2 Processor Thermal Features

Temperature

5.1.1Thermal Alert

ETM Thermal Trip

Thermal Alert

Time

000653b

THRMALERT# is a programmable thermal alert signal which is part of the Itanium 2 processor system management feature. THRMALERT# is asserted when the measured temperature from the processor thermal diode equals or exceeds the temperature threshold data programmed in the high temp (THIGH) or low temp (TLOW) registers on the sensor. Intel recommends using the upper temperature reference byte listed in the Processor Information ROM when programming the THIGH register (see Chapter 6 for more details). This signal can be used by the platform to implement thermal regulation features such as generating an external interrupt to tell the operating system that the processor core die temperature is increasing.

Datasheet 75