AMD-762 Advanced Micro Devices, AMD-762 Datasheet - Page 39

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

24416C—December 2001
2.6.1
2.6.2
2.6.3
Chapter 2
Throttling with STPCLK# Assertion
Full-On (C0)
Halt (C1)
The AMD-762 system controller supports the following power
states :
1. ACPI C0 full-on
2. ACPI C1 Halt
3. ACPI S1 power-on suspend
4. ACPI S3 suspend to RAM
Th e s e p owe r s t a t e s a r e d e s cr i b e d i n f u r t h e r d e t a i l i n
subsequent paragraphs.
In this state, the AMD-762 system controller is fully operational,
all clock trees are running, all voltage planes are enabled, and the
AMD-762 system controller provides normal refresh to DRAM.
If the AMD-762 system controller detects a Halt special cycle
from either of the processors, the Halt state (C1) is entered and
t he Halt special cycle is driven on the PCI bus. No further
activity is required. The processor buses remain connected and
the memory remains in normal refresh mode.
The AMD-762 system controller supports clock throttling via
assertion of the processor ’s STPCLK# pin. If the AMD-762
system controller has detected a Stop Grant special cycle from
the processor, the AMD-762 system controller waits for a Stop
Grant from the second processor (if installed), then the Stop
Grant special cycle is driven on the PCI bus. If the Stop Grant
disconnect bit is set (Dev 0:F0:0x60), when the Stop Grant
special cycle state is received, and there is no probe traffic, the
AMD-762 system con t rolle r disconnects the processor and
places system memory into self-refresh mode before passing
t h e specia l cycle to the PCI Bus. If the AMD-762 syst em
controller detects a PCI DMA master transaction that needs a
snoop, then the processors are connected, DRAM is taken out
of self-refresh mode, and the probe cycle(s) are initiated on the
AMD Athlon processor system buses. If the processors do not
start any non-NOP AMD Athlon processor system bus cycles
Preliminary Information
Functional Operation
AMD-762™ System Controller Data Sheet
27