Signal Descriptions
50 Datasheet
6.9 Processor Power and Ground Supplies§ §
§ §
Table 6-14. Power and Ground Signals
Signal Name Description
VCC
Variable power supply for the processor cores, lowest level caches (LLC), ring
interface, and home agent. It is provided by a VRM/EVRD 12.0 compliant regulator
for each processor socket. The output voltage of this supply is selected by the
processor, using the serial voltage ID (SVID) bus.
Note: VCC has a Vboot setting of 0.0 V and is not included in the PWRGOOD
indication.
VCC_SENSE
VSS_VCC_SENSE
VCC_SENSE and VSS_VCC_SENSE provide an isolated, low impedance connection
to the processor core power and ground. These signals must be connected to the
voltage regulator feedback circuit that insures the output voltage (that is,
processor voltage) remains within specification.
VSA_SENSE
VSS_VSA_SENSE
VSA_SENSE and VSS_VSA_SENSE provide an isolated, low impedance connection
to the processor system agent (VSA) power plane. These signals must be
connected to the voltage regulator feedback circuit that insures the output voltage
(that is, processor voltage) remains within specification.
VTTD_SENSE
VSS_VTTD_SENSE
VTTD_SENSE and VSS_VTTD_SENSE provide an isolated, low impedance
connection to the processor I/O power plane. These signals must be connected to
the voltage regulator feedback circuit that insures the output voltage (that is,
processor voltage) remains within specification.
VCCD_01 and VCCD_23
Variable power supply for the processor system memory interface. These signals
are provided by two VRM/EVRD 12.0 compliant regulators per processor socket.
VCCD_01 and VCCD_23 are used for memory channels 0, 1, 2, and 3 respectively.
The valid voltage of this supply (1.50V or 1.35V) is configured by BIOS after
determining the operating voltages of the installed memory. VCCD_01 and
VCCD_23 will also be referred to as VCCD.
Note: The processor must be provided VCCD_01 and VCCD_23 for proper
operation, even in configurations where no memory is populated. A
VRM/EVRD 12.0 controller is recommended, but not required.
VCCPLL Fixed power supply (1.7V) for the processor phased lock loop (PLL).
VSA
Variable power supply for the processor system agent units. These include logic
(non-I/O) for the integrated I/O controller, the integrated memory controller
(IMC), and the Power Control Unit (PCU). The output voltage of this supply is
selected by the processor, using the serial voltage ID (SVID) bus.
Note: VSA has a Vboot setting of 0.9V.
VSS Processor ground node.
VTTA
VTTD
Combined fixed analog and digital power supply for I/O sections of the processor,
Direct Media Interface Gen 2 (DMI2) interface, and PCI Express* interface. These
signals will also be referred to as VTT.