AMD-762 Advanced Micro Devices, AMD-762 Datasheet - Page 35

• Manufacturer Part Number: AMD-762
• Description: System Controller
• Manufacturer: Advanced Micro Devices

24416C—December 2001
33-MHz PCI Bus
Figure 7.
Chapter 2
Generator
Clock
33 MHz
100/133 MHz
66 MHz
66 MHz
System Clocking with 66-MHz PCI Primary Bus
33 MHz
33-MHz PCI Clocks
AGP Slot
The AMD-762 system cont roller provides the three 66-MHz
clocks required for the Southbridge and the two PCI bus slots
in this mode. If a 33-MHz-only card is inserted in one of the
66-MHz PCI slots, then the M66EN signal is deasserted, which
causes the AMD-762 system controller to drive 33 MHz on the
PCI_66CLK[2:0] pins.
The 66-MHz PCI mode is illustrated in Figure 7.
An alternate mode of PCI bus operation is illustrated in Figure
8 on page 24, and simply supports a standard 33-MHz PCI
Southbridge and up to seven PCI slots.
In this mode, all PCI devices operate at 33 MHz and clocking is
provided by the motherboard clock generator chip.
Preliminary Information
Functional Operation
PCI_66CLK[0]
SYSCLK
AGPCLK
PCICLK
AMD-762™ System Controller
AMD-768™ Peripheral
32-bit, 33-MHz PCI Bus Slots
Bus Controller
Northbridge
AMD-762™ System Controller Data Sheet
CLKOUT[1]n
CLKOUT[2]n
CLKOUT[3]n
PCI_66CLK[2]
PCI_66CLK[1]
CLKOUT[0]n
64-bit, 66-MHz
PCI Bus Slots
DDR DIMMs
23