Intel L7555 AT80604004875AA User Manual

Intel® Xeon® Processor 7500 Datasheet, Volume 1

145

The PECI client is available on all processors, and positive identification of the PECI 
revision number can be achieved by issuing the GetDIB() command. Please refer to 

 for details on GetDIB response formatting.

The PECI client assumes a default base address of 0x30. There are three SKT_ID# 
strapping pins that are used to strap each PECI socket to a different node ID (in 
addition to defining the processor's socket ID). Since SKT_ID# is active low, strapping 
a pin to ground results in value of 1 for that bit of the client ID, and strapping to Vio 
results in a value of 0 for that bit. Intel® Xeon® processor 7500 series client addresses 
can therefore be strapped for values 0x30 through 0x37. These package pin straps are 
evaluated at the assertion of VCCPWRGOOD.

The client address may not be changed after VCCPWRGOOD assertion, until the next 
power cycle on the processor. Removal of a processor from its socket or tri-stating a 
processor in a MP configuration will have no impact to the remaining non-tri-stated 
PECI client address.

The Intel® Xeon® processor 7500 series PECI client is fully functional under all core 
and package C-states. Support for package C-states is a function of processor SKU and 
platform capabilities.

Because the Intel® Xeon® processor 7500 series takes aggressive power savings 
actions under the deepest C-states, PECI requests may have an impact to platform 
power. The impact is documented below:

• Ping(), GetDIB(), GetTemp() and MbxGet() have no measurable impact on 

processor power under C-states.

• MbxSend(), PCIConfigRd() and PCIConfigWr() usage under package C-states may 

result in increased power consumption because the processor must temporarily 
return to a C0 state in order to execute the request. The exact power impact of a 

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