Intel 5400 Series manual Platform Environmental Control Interface Peci

Thermal/Mechanical Reference Design

smaller foot print and decreased sensitivity to noise. These DTS benefits will result in more accurate fan speed control and TCC activation.The DTS application in fan speed control will be discussed in more detail in Section 2.4.1.

2.2.3Platform Environmental Control Interface (PECI)

The PECI interface is designed specifically to convey system management information from the processor (initially, only thermal data from the Digital Thermal Sensor). It is a proprietary single wire bus between the processor and the chipset or other health monitoring device. The PECI specification provides a specific command set to discover, enumerate devices, and read the temperature. For an overview of the PECI interface, please refer to PECI Feature Set Overview. For more detailed information on PECI, please refer to Platform Environment Control Interface (PECI) Specification and Quad- Core Intel® Xeon® Processor 5400 Series Datasheet.

2.2.4Multiple Core Special Considerations

2.2.4.1Multiple Digital Thermal Sensor Operation

Each Quad-Core Intel® Xeon® Processor 5400 Series can have multiple Digital Thermal Sensors located on the die. Each die within the processor currently maps to a PECI domain. The Quad-Core Intel® Xeon® Processor 5400 Series contains two cores per die (domain) and two domains (die) per socket. BIOS will be responsible for detecting the proper processor type and providing the number of domains to the thermal management system. An external PECI device that is part of the thermal management system polls the processor domains for temperature information and currently receives the highest of the DTS output temperatures within each domain. Figure 2-5provides an illustration of the DTS domains for the Quad-Core Intel® Xeon® Processor 5400 Series.

Figure 2-5. DTS Domain for Quad-Core Intel® Xeon® Processor 5400 Series

Quad-Core Intel® Xeon® Processor 5400 Series TMDG 21