Datasheet

Datasheet 73
Land Listing and Signal Descriptions
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TMS Input
TMS (Test Mode Select) is a JTAG specification support signal used by debug
tools.
TRDY# Input
TRDY# (Target Ready) is asserted by the target to indicate that it is ready to
receive a write or implicit writeback data transfer. TRDY# must connect the
appropriate pins/lands of all FSB agents.
TRST# Input
TRST# (Test Reset) resets the Test Access Port (TAP) logic. TRST# must be
driven low during power on Reset. Refer to the eXtended Debug Port: Debug
Port Design Guide for UP and DP Platforms for complete implementation
details.
VCC Input
VCC are the power pins for the processor. The voltage supplied to these pins is
determined by the VID[5:0] pins.
VCCA Input VCCA provides isolated power for the internal processor core PLLs.
VCCIOPLL Input VCCIOPLL
provides isolated power for internal processor FSB PLLs.
VCCPLL Input VCCPLL is available for compatibility with future processors.
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) 10.1 Design Guide for Desktop
Socket 775.
VID[5:0] Output
VID[5:0] (Voltage ID) signals are used to support automatic selection of power
supply voltages (V
CC
). These are open drain signals that are driven by the
processor and must be pulled up on the motherboard. Refer to the Voltage
Regulator-Down (VRD) 10.1 Design Guide for Desktop Socket 775 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.
VSS Input
VSS are the ground lands for the processor and should be connected to the
system ground plane.
VSSA Input VSSA is the isolated ground for internal PLLs.
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) 10.1 Design Guide for Desktop
Socket 775.
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.
VTTPWRGD Input
The processor requires this input to determine that the V
TT
voltages are stable
and within specification.
Table 4-3. Signal Description (Sheet 8 of 8)
Name Type Description