Intel Xeon 7130N LF80550KF0878M Data Sheet
Product codes
LF80550KF0878M
Features
84
Dual-Core Intel
®
Xeon
®
Processor 7000 Series Datasheet
Note:
Writing to a read-command register or reading from a write-command register will produce invalid
results.
results.
The default command after reset is to a reserved value (00h). After reset, Receive Byte SMBus
packets will return invalid data until another command is sent to the thermal sensor.
packets will return invalid data until another command is sent to the thermal sensor.
7.4.6
SMBus Thermal Sensor Registers
7.4.6.1
Temperature Value Registers
Once the SMBus thermal sensor reads a processor thermal diode, it performs an analog to digital
conversion and stores the data in a temperature value register. The supported range is 0 to
+127 decimal and is expressed as an eight-bit number representing temperature in degrees Celsius.
This eight-bit value consists of seven bits of data and a sign bit (MSB) where the sign is always
positive (sign = 0) and is shown in
conversion and stores the data in a temperature value register. The supported range is 0 to
+127 decimal and is expressed as an eight-bit number representing temperature in degrees Celsius.
This eight-bit value consists of seven bits of data and a sign bit (MSB) where the sign is always
positive (sign = 0) and is shown in
. The values shown are also used to program the
Thermal Limit Registers.
The values of these registers should be treated as saturating values. Values above 127 are
represented at 127 decimal, and values of zero and below may be represented as 0 to -127 decimal.
If the device returns a value where the sign bit is set (1) and the data is 000_0000 through
111_1110, the temperature should be interpreted as 0° Celsius.
represented at 127 decimal, and values of zero and below may be represented as 0 to -127 decimal.
If the device returns a value where the sign bit is set (1) and the data is 000_0000 through
111_1110, the temperature should be interpreted as 0° Celsius.
7.4.6.2
Thermal Limit Registers
The SMBus thermal sensor has high and low Thermal Limit Registers for each channel. These
registers allow the user to define high and low limits for the processor core thermal diode readings.
The encoding for these registers is the same as for the thermal reference registers shown in
registers allow the user to define high and low limits for the processor core thermal diode readings.
The encoding for these registers is the same as for the thermal reference registers shown in
. If either processor thermal diode reading equals or exceeds one of these limits, then the
alarm bit (R1HIGH, R1LOW, R2HIGH, or R2LOW) in the Thermal Sensor Status Register is
triggered.
triggered.
7.4.6.3
Status Registers
indicates which, if any, thermal value
thresholds for the processor core thermal diode have been exceeded. It also indicates whether a
conversion is in progress or an open circuit has been detected in either processor core thermal
diode connection. Once set, alarm bits stay set until they are cleared by a Status Register read. A
successful read to the Status Register will clear any alarm bits that may have been set (unless the
conversion is in progress or an open circuit has been detected in either processor core thermal
diode connection. Once set, alarm bits stay set until they are cleared by a Status Register read. A
successful read to the Status Register will clear any alarm bits that may have been set (unless the
Table 7-11. Temperature Value Register Encoding
Temperature
(°C)
Register Value
(binary)
+127
0 111 1111
+126
0 111 1110
+100
0 110 0100
+50
0 011 0010
+25
0 001 1001
+1
0 000 0001
0
0 000 0000