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42
Intel
82865G/82865GV GMCH Datasheet
Signal Description
2.8
RCOMP, VREF, VSWING Signals
NOTE:
1. Reference the
Intel
865G/865GV/865PE/865P Chipset Platform Design Guide
for platform design
information.
Signal Name
Type
Description
HDVREF
I
Host Data Reference Voltage:
This signal is the reference voltage input for
the data signals of the Host AGTL+ interface.
HDRCOMP
I/O
CMOS
Host RCOMP:
HDRCOMP is used to calibrate the Host AGTL+ I/O buffers.
HDSWING
I
Host Voltage Swing:
These signals provide a reference voltage used by the
FSB RCOMP circuit.
SMVREF_A
I
Memory Reference Voltage for Channel A:
SMVREF_A is the reference
voltage input for system memory Interface. This signal is tied internally to
SMVREF_B. Thus, only one of these signals needs to be the SMVREF and
the other should be decoupled.
SMXRCOMPVOL
I
Memory RCOMP for Channel A:
This signal is used to Calibrate VOL.
SMXRCOMPVOH
I
Memory RCOMP for Channel A
: This signal is used to Calibrate VOH.
SMXRCOMP
I/O
CMOS
Memory RCOMP for Channel A:
This signal is used to calibrate the memory
I/O buffers.
SMVREF_B
I
Memory Reference Voltage for Channel B:
SMVREF_B is the reference
voltage input for System Memory Interface. This signal is tied internally to
SMVREF_A. Thus, only one of these signals needs to be the SMVREF and
the other should be decoupled.
SMYRCOMPVOL
I
Memory RCOMP for Channel B
: This signal is used to Calibrate VOL.
SMYRCOMPVOH
I
Memory RCOMP for Channel B
: This signal is used to Calibrate VOH.
SMYRCOMP
I/O
CMOS
Memory RCOMP for Channel B:
This signal is used to calibrate the memory
I/O buffers.
GVREF
I
AGP Reference:
The reference voltage for the AGP/DVO I/O buffers is
0.75 V.
GVSWING
I
AGP Voltage Swing
: This signal provides a reference voltage for GRCOMP
in AGP mode.
GRCOMP/
DVOBCRCOMP
I/O
CMOS
Compensation for AGP/DVOB:
This signal is used to calibrate the AGP/
DVO buffers. This signal should be connected to ground through a 43
pull-
up resistor to VDDQ
HI_VREF
I
HI Reference:
HI_VREF is the reference voltage input for the hub interface.
HI_RCOMP
I/O
CMOS
Compensation for HI:
This signal is used to calibrate the hub interface I/O
buffers.
HI_SWING
I
HI Voltage Swing:
This signal provides a reference voltage used by the
HI_RCOMP circuit.
CI_VREF
I
CSA Reference:
CI_VREF is the reference voltage input for the CSA
interface.
CI_RCOMP
I/O
CMOS
Compensation for CSA:
This signal is used to calibrate the CSA I/O buffers.
CI_SWING
I
CSA Voltage Swing:
This signal provides a reference voltage used by the
CI_RCOMP circuit.