Datasheet

Datasheet 29
Electrical Specifications
2.7.3.1 Platform Environment Control Interface (PECI) DC Specifications
PECI is an Intel proprietary one-wire interface that provides a communication channel
between Intel processors, chipsets, and external thermal monitoring devices. The
processor contains Digital Thermal Sensors (DTS) distributed throughout die. These
sensors are implemented as analog-to-digital converters calibrated at the factory for
reasonable accuracy to provide a digital representation of relative processor
temperature. PECI provides an interface to relay the highest DTS temperature within a
die to external management devices for thermal/fan speed control. More detailed
information may be found in the Platform Environment Control Interface (PECI)
Specification.
.
Table 14. PECI DC Electrical Limits
Symbol Definition and Conditions Min Max Units Notes
1
NOTES:
1. V
TT
supplies the PECI interface. PECI behavior does not affect V
TT
min/max specifications. Refer to Table 4 for
V
TT
specifications.
V
in
Input Voltage Range -0.15 V
TT
V
V
hysteresis
Hysteresis 0.1 * V
TT
—V
2
2. The leakage specification applies to powered devices on the PECI bus.
V
n
Negative-edge threshold voltage 0.275 * V
TT
0.500 * V
TT
V
V
p
Positive-edge threshold voltage 0.550 * V
TT
0.725 * V
TT
V
I
source
High level output source
(V
OH
= 0.75 * V
TT)
-6.0 N/A mA
I
sink
Low level output sink
(V
OL
= 0.25 * V
TT
)
0.5 1.0 mA
I
leak+
High impedance state leakage to V
TT
N/A 50 µA
3
3. The input buffers use a Schmitt-triggered input design for improved noise immunity.
4. One node is counted for each client and one node for the system host. Extended trace lengths might appear
as additional nodes.
I
leak-
High impedance leakage to GND N/A 10 µA 3
C
bus
Bus capacitance per node N/A 10 pF 4
V
noise
Signal noise immunity above 300
MHz
0.1 * V
TT
—V
p-p