Intel LF80550KF0604M Data Sheet
Features
110
Dual-Core Intel® Xeon® Processor 7100 Series Datasheet
Checksums are automatically calculated and programmed by Intel. The first step in
calculating the checksum is to add each byte from the field to the next subsequent
byte. This result is then negated to provide the checksum.
calculating the checksum is to add each byte from the field to the next subsequent
byte. This result is then negated to provide the checksum.
Example: For a byte string of AA445Ch, the resulting checksum will be B6h.
AA = 10101010
44 = 01000100
5C = 0101100
AA + 44 + 5C = 01001010
Negate the sum: 10110101 +1 = 101101 (B6h)
7.4.5
Scratch EEPROM
Also available in the memory component on the processor SMBus is an EEPROM which
may be used for other data at the system or processor vendor’s discretion. The data in
this EEPROM, once programmed, can be write-protected by asserting the active-high
SM_WP signal. This signal has a weak pull-down (10 kΩ) to allow the EEPROM to be
may be used for other data at the system or processor vendor’s discretion. The data in
this EEPROM, once programmed, can be write-protected by asserting the active-high
SM_WP signal. This signal has a weak pull-down (10 kΩ) to allow the EEPROM to be
programmed in systems with no implementation of this signal. The Scratch EEPROM
resides in the upper half of the memory component (addresses 80 - FFh). The lower
half comprises the Processor Information ROM (addresses 00 - 7Fh), which is
permanently write-protected by Intel.
resides in the upper half of the memory component (addresses 80 - FFh). The lower
half comprises the Processor Information ROM (addresses 00 - 7Fh), which is
permanently write-protected by Intel.
7.4.6
SMBus Thermal Sensor
The processor’s SMBus thermal sensor provides a means of acquiring thermal data
from the processor’s two thermal diodes. The thermal sensor is composed of control
logic, SMBus interface logic, a precision analog-to-digital converter, and a single bank
of precision current sources. The A/D converter and the current source are muxed
between the two sensor channels. The sensor drives a small current through the p-n
junction for the thermal diodes located on the processor core. The forward bias voltage
generated across each thermal diode is sensed and the precision A/D converter derives
a byte of thermal reference data, or a “thermal byte reading.” The resolution of the
least significant bit of a thermal byte is 1° Celsius.
from the processor’s two thermal diodes. The thermal sensor is composed of control
logic, SMBus interface logic, a precision analog-to-digital converter, and a single bank
of precision current sources. The A/D converter and the current source are muxed
between the two sensor channels. The sensor drives a small current through the p-n
junction for the thermal diodes located on the processor core. The forward bias voltage
generated across each thermal diode is sensed and the precision A/D converter derives
a byte of thermal reference data, or a “thermal byte reading.” The resolution of the
least significant bit of a thermal byte is 1° Celsius.
The processor incorporates the SMBus thermal sensor onto the processor package.
Upper and lower thermal reference thresholds can be individually programmed for each
channel of the SMBus thermal sensor. Comparator circuits sample the register where
the single byte of thermal data (thermal byte reading) is stored. These circuits compare
the single-byte result against programmable threshold bytes. If enabled, the alert
signal on the processor SMBus (SM_ALERT#) will be asserted when the sensor detects
that either the high or low threshold is reached or crossed for each channel. Analysis of
SMBus thermal sensor data may be useful in detecting changes in the system
environment that may require attention.
Upper and lower thermal reference thresholds can be individually programmed for each
channel of the SMBus thermal sensor. Comparator circuits sample the register where
the single byte of thermal data (thermal byte reading) is stored. These circuits compare
the single-byte result against programmable threshold bytes. If enabled, the alert
signal on the processor SMBus (SM_ALERT#) will be asserted when the sensor detects
that either the high or low threshold is reached or crossed for each channel. Analysis of
SMBus thermal sensor data may be useful in detecting changes in the system
environment that may require attention.
The processor SMBus thermal sensor may be used to monitor long term temperature
trends, but can not be used to manage the short term temperature of the processor or
predict the activation of the thermal control circuit. As mentioned earlier, the
processor’s high thermal ramp rates make this infeasible. Refer to the thermal design
guidelines listed in
trends, but can not be used to manage the short term temperature of the processor or
predict the activation of the thermal control circuit. As mentioned earlier, the
processor’s high thermal ramp rates make this infeasible. Refer to the thermal design
guidelines listed in
for more details.
The SMBus thermal sensor feature in the processor cannot be used to measure T
CASE
.
The T
CASE
specification in
must be met regardless of the reading of the
processor's thermal sensor in order to ensure adequate cooling for the entire processor.
The SMBus thermal sensor feature is only available while V
The SMBus thermal sensor feature is only available while V
CC
and SM_VCC are at valid
levels and the processor is not in a low-power state.