Specification Sheet
Interfaces
64 Intel
®
 Xeon
®
 Processor E5-1600/E5-2600/E5-4600 v2 Product Families 
Datasheet Volume One of Two
Note: The 2-byte MSR Address field and read data field defined in Figure 2-43 are sent in standard PECI 
ordering with LSB first and MSB last.
2.5.2.7.3 Supported Responses
The typical client response is a passing FCS, a passing Completion Code and valid data. 
Under some conditions, the client’
s response will indicate a failure.
2.5.2.7.4 RdIAMSR() Capabilities
The processor PECI client allows PECI RdIAMSR() access to the registers listed in 
T
a
ble 2-11. These registers pertain to the processor core and uncore error banks 
(machine check banks 0 through 19). Information on the exact number of accessible 
banks for the processor device may be obtained by reading the IA32_MCG_CAP[7:0] 
MSR (0x0179). This register may be alternatively read using a RDMSR RBIOS 
instruction. Please consult the Intel® Xeon® Processor E5 v2 Prodcut Family 
Specification Update for more information on the exact number of cores supported by a 
particular processor SKU. Any attempt to read processor MSRs that are not accessible 
over PECI or simply not implemented will result in a completion code of 0x90. 
Figure 2-43. RdIAMSR()
Table 2-10. RdIAMSR() Response Definition
Response Meaning
Bad FCS Electrical error
Abort FCS Illegal command formatting (mismatched RL/WL/Command Code)
CC: 0x40 Command passed, data is valid.
CC: 0x80 Response timeout. The processor was not able to generate the required response in a timely 
fashion. Retry is .
CC: 0x81 Response timeout. The processor is not able to allocate resources for servicing this command 
at this time. Retry is .
CC: 0x82 The processor hardware resources required to service this command are in a low power state. 
Retry may be after modification of PECI wake mode behavior if .
CC: 0x90 Unknown/Invalid/Illegal Request
CC: 0x91 PECI control hardware, firmware or associated logic error. The processor is unable to process 
the request.










