Thermal Specifications
trends and not instantaneous readings. Therefore, PECI supports a configurable low-
pass temperature filtering function. By default, this filter results in a thermal reading
that is a moving average of 256 samples taken at approximately 1msec intervals. This
filter’s depth, or smoothing factor, may be configured to between 1 sample and 1024
samples, in powers of 2. See the following equation for reference where the
configurable variable is ‘X’.
TN = TN-1 + 1/2X * (TSAMPLE - TN-1
)
Refer to Section 6.3.2.6.6 for the definition of the thermal configuration command.
6.3.6.4
Reserved Values
Several values well out of the operational range are reserved to signal temperature
sensor errors. These are summarized in the following table:
Table 6-19. Error Codes and Descriptions
Error Code
Description
0x8000
General Sensor Error (GSE)
6.3.7
Client Management
Power-up Sequencing
6.3.7.1
The PECI client is fully reset during processor RESET_N assertion. This means that any
transactions on the bus will be completely ignored, and the host will read the response
from the client as all zeroes. After processor RESET_N deassertion, the Intel Xeon
Processor E7-8800/4800/2800 Product Families processor PECI client is operational
enough to participate in timing negotiations and respond with reasonable data.
However, the client data is not guaranteed to be fully populated until approximately
500 µS after processor RESET_N is deasserted. Until that time, data may not be ready
for all commands. Note that PECI commands may time out frequently during boot. The
client responses to each command are as follows:
Table 6-20. PECI Client Response During Power-Up (During ‘Data Not Ready’)
Command
Ping()
Response
Fully functional
Fully functional
GetDIB()
GetTemp()
PCIConfigRd()
PCIConfigWr()
MbxSend()
MbxGet()
Client responds with a ‘hot’ reading, or 0x0000
Fully functional
Fully functional
Fully functional
Client responds with Abort FCS (if MbxSend() has been previously issued)
In the event that the processor is tri-stated using power-on-configuration controls, the
PECI client will also be tri-stated. Processor tri-state controls are described in
Chapter 7.
Datasheet Volume 1 of 2
141
INTEL [ INTEL ]
