Intel E5-4603 BX80621E54603 User Manual
Product codes
BX80621E54603
Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families
77
Datasheet Volume One
Temperature readings from the processor are always negative in a 2’s complement
format, and imply an offset from the processor T
jmax
(PECI = 0). For example, if the
processor T
jmax
is 100°C, a PECI thermal reading of -10 implies that the processor is
running at approximately 10°C below T
jmax
or at 90°C. PECI temperature readings are
not reliable at temperatures above T
jmax
since the processor is outside its operating
range and hence, PECI temperature readings are never positive.
The changes in PECI data counts are approximately linear in relation to changes in
temperature in degrees centigrade. A change of ‘1’ in the PECI count represents
temperature in degrees centigrade. A change of ‘1’ in the PECI count represents
roughly a temperature change of 1 degree centigrade. This linearity is approximate and
cannot be guaranteed over the entire range of PECI temperatures, especially as the
offset from the maximum PECI temperature (zero) increases.
offset from the maximum PECI temperature (zero) increases.
2.5.7.3
Temperature Filtering
The processor digital thermal sensor (DTS) provides an improved capability to monitor
device hot spots, which inherently leads to more varying temperature readings over
device hot spots, which inherently leads to more varying temperature readings over
short time intervals. Coupled with the fact that typical fan speed controllers may only
read temperatures at 4Hz, it is necessary for the thermal readings to reflect thermal
trends and not instantaneous readings. Therefore, PECI supports a configurable low-
trends and not instantaneous readings. Therefore, PECI supports a configurable low-
pass temperature filtering function that is expressed by the equation:
T
N
= (1-α) * T
N-1
+ α * T
SAMPLE
where
T
N
and
T
N-1
are the current and previous averaged PECI temperature values
respectively,
T
SAMPLE
is the current PECI temperature sample value and the variable
‘α’ = 1/2
X
, where ‘X’ is the ‘Thermal Averaging Constant’ that is programmable as
.
2.5.7.4
Reserved Values
Several values well out of the operational range are reserved to signal temperature
sensor errors. These are summarized in
.
§
Table 2-24. Error Codes and Descriptions
Error Code
Description
0x8000
General Sensor Error (GSE)
0x8001
Reserved
0x8002
Sensor is operational, but has detected a temperature below its operational range
(underflow)
0x8003-0x81ff
Reserved