Thermal/Mechanical Specifications and Design Guide 85
PECI Interface
7.1.4.11.1 Command Format
The RdPCIConfigLocal() format is as follows:
Write Length: 0x05
Read Length: 0x02 (byte), 0x03 (word), 0x05 (dword)
Command: 0xe1
Description: Returns the data maintained in the PCI configuration space within the
processor at the requested PCI configuration address. The Read Length dictates the
desired data return size. This command supports byte, word and dword responses as
well as a completion code. All command responses are prepended with a completion
code that includes additional pass/fail status information. Refer to Section 7.1.7.2 for
details regarding completion codes.
The 3-byte PCI configuration address and read data field defined in Figure 7-42 are
sent in standard PECI ordering with LSB first and MSB last.
7.1.4.11.2 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.
The PECI client response can also vary depending on the address and data. It will
respond with a passing completion code if it successfully submits the request to the
appropriate location and gets a response. Exactly what the receiving agent does with
the data or how it responds is up to that agent and is outside the scope of PECI 3.0.
Figure 7-42. RdPCIConfigLocal()
01 2 3
Byte #
FCS
12
7
9
Completion
Code
LSB PCI Configuration Address MSB
10
Write Length
0x05
LSB Data (1, 2 or 4 bytes) MSB
5
Cmd Code
0xe1
14
Read Length
{0x02,0x03,0x05}
68
Host ID[7:1] &
Retry[0]
Client Address
13
4
11
FCS
Byte
Definition
Table 7-14. RdPCIConfigLocal() Response Definition (Sheet 1 of 2)
Response Meaning
Bad FCS Electrical error
Abort FCS Invalid 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 appropriate.
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