Intel Q9400S Data Sheet - Page 73

Table 4-3., Signal Description, Sheet 10 of 10

Page 73 highlights

Land Listing and Signal Descriptions Table 4-3. Signal Description (Sheet 10 of 10) Name Type Description VID[7:0] VID_SELECT VRDSEL VSS VSSA VSS_SENSE VSS_MB_ REGULATION VTT VTT_OUT_LEFT VTT_OUT_RIGHT VTT_SEL Output Output Input Input Input Output Output Output Output The VID (Voltage ID) signals are used to support automatic selection of power supply voltages (VCC). Refer to the Voltage Regulator Design Guide for more information. The voltage supply for these signals must be valid before the VR can supply VCC 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. This land is tied high on the processor package and is used by the VR to choose the proper VID table. Refer to the Voltage Regulator Design Guide for more information. 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 VSS. VSS are the ground pins for the processor and should be connected to the system ground plane. VSSA provides isolated ground for internal PLLs on previous generation processors. It may be left as a No-Connect on boards supporting the processor. VSS_SENSE is an isolated low impedance connection to processor core VSS. It can be used to sense or measure ground near the silicon with little noise. This land is provided as a voltage regulator feedback sense point for VSS. It is connected internally in the processor package to the sense point land V27 as described in the Voltage Regulator Design Guide. Miscellaneous voltage supply. The VTT_OUT_LEFT and VTT_OUT_RIGHT signals are included to provide a voltage supply for some signals that require termination to VTT on the motherboard. The VTT_SEL signal is used to select the correct VTT voltage level for the processor. This land is connected internally in the package to VSS. § Datasheet 73

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Datasheet
73
Land Listing and Signal Descriptions
ยง
VID[7:0]
Output
The VID (Voltage ID) signals are used to support automatic
selection of power supply voltages (V
CC
). Refer to the Voltage
Regulator Design Guide 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 Voltage Regulator
Design Guide
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 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 Design
Guide.
VTT
Miscellaneous voltage supply.
VTT_OUT_LEFT
VTT_OUT_RIGHT
Output
The VTT_OUT_LEFT and VTT_OUT_RIGHT signals are included to
provide a voltage supply for some signals that require termination
to V
TT
on the motherboard.
VTT_SEL
Output
The VTT_SEL signal is used to select the correct V
TT
voltage level
for the processor. This land is connected internally in the package
to V
SS
.
Table 4-3.
Signal Description
(Sheet 10 of 10)
Name
Type
Description