AMD-762 Datasheet, PDF (105/122 Pages) Advanced Micro Devices – System Controller

24416C—December 2001
Preliminary Information
AMD-762™ System Controller Data Sheet
Table 34. Signal Descriptions (Continued)
Signal
ROM_SCK
Type
Description
SIP ROM Clock
This pin provides the clock output to an optional serial ROM or microcontroller when used
for loading the SIP parameters for the AMD Athlon processor. This function is required
B only for cases when SIP parameters are required that are different than those supplied by
the AMD-762™ system controller.
This pin must be pulled Low when using the internal SIP ROM table on the AMD-762
system controller or pulled High to use the external ROM.
VSS
VDD_CORE
VDD_PCI
VDD_AGP
AVDD
AGP_CAL and
AGP_CAL#
P0_CAL and
P0_CAL#
AGP_VREF
AGP_VREF4x
REF_5V
P0_VREF
DDR_REF
S_CLKREF
CPU_VCORE
SI_VSS and SI_VDD
VSS/VDD, I/O Pad and Voltage Reference, and Compensation Pins
VSS
AMD-762 system controller VDD pins, 2.5 Vdc.
VDD for PCI I/O cells, 3.3 Vdc.
This pin functions as VDD for AGP I/O cells, and can be 1.5 Vdc or 3.3 Vdc as determined by
TYPEDET# pin on the motherboard. The motherboard drives this input to 1.5 Vdc when the
TYPEDT# pin is asserted Low by an AGP card or 3.3 Vdc when the TYPEDET# pin is High.
Separately filtered 2.5 Vdc for analog PLL circuitry.
Compensation pads for matching impedance of motherboard AGP traces.
Compensation pads for matching impedance of motherboard AMD Athlon system bus
traces.
Voltage reference for 3.3 Vdc AGP I/O cells.
Voltage reference for 1.5 Vdc AGP I/O cells.
Voltage reference to support 5 Vdc PCI signalling.
AMD Athlon system bus I/O voltage reference.
DDR I/O voltage reference.
System clock reference voltage.
Voltage for push-pull I/O pads.
Connected to the AMD-762 system controller VSS and VDD_CORE planes. These are
intended only for signal integrity testing and should be connected to the motherboard VSS
and VDD_CORE planes, respectively.
Chapter 7
Signal Descriptions
93