Datasheet

Land Listing and Signal Descriptions
72 Datasheet
VCC Input
VCC are the power pins for the processor. The voltage supplied to
these pins is determined by the VID[7:0] pins.
VCCA Input
VCCA provides isolated power for internal PLLs on previous
generation processors. It may be left as a No-Connect on boards
supporting the Wolfdale processor.
VCCIOPLL Input
VCCIOPLL provides isolated power for internal processor FSB PLLs on
previous generation processors. It may be left as a No-Connect on
boards supporting the Wolfdale processor.
VCCPLL Input VCCPLL provides isolated power for internal processor FSB PLLs.
VCC_SENSE Output
VCC_SENSE is an isolated low impedance connection to processor
core power (V
CC
). It can be used to sense or measure voltage near
the silicon with little noise.
VCC_MB_
REGULATION
Output
This land is provided as a voltage regulator feedback sense point for
V
CC
. It is connected internally in the processor package to the sense
point land U27 as described in the Voltage Regulator-Down (VRD)
11.0 Processor Power Delivery Design Guidelines For Desktop
LGA775 Socket.
VID[7:0] Output
The VID (Voltage ID) signals are used to support automatic selection
of power supply voltages (V
CC
). Refer to the appropriate platform
design guide or the Voltage Regulator-Down (VRD) 11.0 Processor
Power Delivery Design Guidelines For Desktop LGA775 Socket for
more information. The voltage supply for these signals must be valid
before the VR can supply V
CC
to the processor. Conversely, the VR
output must be disabled until the voltage supply for the VID signals
becomes valid. The VID signals are needed to support the processor
voltage specification variations. See Table 2-1 for definitions of these
signals. The VR must supply the voltage that is requested by the
signals, or disable itself.
VID_SELECT Output
This land is tied high on the processor package and is used by the VR
to choose the proper VID table. Refer to the appropriate platform
design guide or the Voltage Regulator-Down (VRD) 11.0 Processor
Power Delivery Design Guidelines For Desktop LGA775 Socket for
more information.
VRDSEL Input
This input should be left as a no connect in order for the processor to
boot. The processor will not boot on legacy platforms where this land
is connected to V
SS
.
VSS Input
VSS are the ground pins for the processor and should be connected
to the system ground plane.
VSSA Input
VSSA provides isolated ground for internal PLLs on previous
generation processors. It may be left as a No-Connect on boards
supporting the Wolfdale processor.
VSS_SENSE Output
VSS_SENSE is an isolated low impedance connection to processor
core V
SS
. It can be used to sense or measure ground near the silicon
with little noise.
VSS_MB_
REGULATION
Output
This land is provided as a voltage regulator feedback sense point for
V
SS
. It is connected internally in the processor package to the sense
point land V27 as described in the Voltage Regulator-Down (VRD)
11.0 Processor Power Delivery Design Guidelines For Desktop
LGA775 Socket.
VTT Miscellaneous voltage supply.
Table 4-3. Signal Description (Sheet 9 of 10)
Name Type Description