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2.9
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.
2.9.1
DC Characteristics
The PECI interface operates at a nominal voltage set by V
specifications shown in
interface supply. V
devices will operate at the V
system. For specific nominal V
Table 2-5.
PECI DC Electrical Limits
Symbol
V
in
V
hysteresis
V
n
V
p
I
source
I
sink
I
leak+
I
leak-
C
bus
V
noise
Notes:
1.
V
supplies the PECI interface. PECI behavior does not affect V
TTD
2.
The leakage specification applies to powered devices on the PECI bus.
20
Table 2-5
is used with devices normally operating from a V
nominal levels will vary between processor families. All PECI
TTD
level determined by the processor installed in the
TTD
levels, refer to
TTD
Definition and Conditions
Input Voltage Range
Hysteresis
Negative-edge threshold voltage
Positive-edge threshold voltage
High level output source
(V
= 0.75 * V
)
OH
TTD
Low level output sink
(V
= 0.25 * V
)
OL
TTD
High impedance state leakage to V
(V
= V
)
leak
OL
High impedance leakage to GND
(V
= V
)
leak
OH
Bus capacitance per node
Signal noise immunity above 300 MHz
. The set of DC electrical
TTD
Table
2-7.
Min
-0.150
0.1 * V
TTD
0.275 * V
0.500 * V
TTD
0.550 * V
0.725 * V
TTD
-6.0
0.5
TTD
N/A
N/A
N/A
0.1 * V
TTD
min/max specifications.
TTD
Electrical Specifications
TTD
1
Max
Units
Notes
V
V
TTD
N/A
V
V
TTD
V
TTD
N/A
mA
1.0
mA
100
µA
2
100
µA
2
10
pF
N/A
V
p-p
Datasheet
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