Electrical Specifications
90 Datasheet, Volume 1
7.11 Platform Environmental Control Interface (PECI) DC Specifications
PECI is an Intel proprietary interface that provides a communication channel between
Intel processors and chipset components to external thermal monitoring devices. The
processor contains a Digital Thermal Sensor (DTS) that reports a relative die
temperature as an offset from Thermal Control Circuit (TCC) activation temperature.
Temperature sensors located throughout the die are implemented as analog-to-digital
converters calibrated at the factory. PECI provides an interface for external devices to
read the DTS temperature for thermal management and fan speed control. More
detailed information may be found in the Platform Environment Control Interface
(PECI) Specification.

7.11.1 PECI Bus Architecture

The PECI architecture based on wired OR bus which the clients (as processor PECI)
can pull up high (with strong drive).
The idle state on the bus is near zero.
Figure 7-1 demonstrates PECI design and connectivity, while the host/originator can be
3rd party PECI host, and one of the PECI clients is the processor PECI device.
Figure 7-1. Example for PECI Host-Clients Connection
VTT
Q1
nX
Q2
1X CPECI
<10 pF / Node
VTT
Q3
nX
PECI ClientHost / Originator
Additional PECI
Clients
PECI