
58
Functional Operation
Chapter 3
AMD-8111 HyperTransport I/O Hub Data Sheet
24674
Rev. 3.00
April 2003
AMD Preliminary Information
Mechanical off (MOFF or ACPI G3 state).
MOFF is the state when only VDD_RTC is powered.
This can happen at any time, from any state, due to the loss of power to the AUX planes (e.g., a power
outage, the power supply is unplugged, or the power supply’s mechanical switch). When power is
applied to AUX, then the system transitions to either FON or SOFF.
Soft off (SOFF or ACPI G2/S5 states).
In the SOFF state, the system appears to the user to be off.
The AUX planes of the IC are powered, but the main supplies are not; RPWRON is Low to disable
power system DRAM. The system normally uses PWRBTN_L to transition from SOFF to FON.
Table 21 on page 59 lists all resume events that may cause a transition from SOFF to FON.
Suspend to disk (STD or ACPI S4 state).
The IC’s behavior in this state equivalent to SOFF.
Suspend to RAM (STR or ACPI S3 state).
In the STR state, the system’s context is stored in system
memory (which remains powered; RPWRON is High) and the main power supplies are shut off
(PWRON_L High). The behavior of the IC in the STR state is similar to SOFF; the main difference is
that RPWRON is asserted in STR.
Power on suspend (POS or ACPI S1 state).
All power planes to the IC are valid in POS. Signal
control during POS is specified by DevB:3x50. Table 21 on page 59 lists all resume events that may
cause a transition from POS to FON.
Stop Grant caches snoopable (C2).
In C2, the processor is placed into the Stop Grant state. Signal
control during C2 is specified by DevB:3x4F. It is expected that the processor’s cache may be
snooped while in this state. Table 21 on page 59 lists all resume events that may cause a transition
from C2 to FON.
Stop Grant caches not snoopable (C3).
In C3, the processor is placed into the Stop Grant state such
that the processor’s cache cannot be snooped; requests that result in snoops are resume events (see
PM04[BM_RLD]). Signal control during C3 is specified by DevB:3x4F. Table 21 on page 59 lists all
resume events that may cause a transition from C3 to FON.
Full on (FON or ACPI S0).
In FON, all the power planes are powered and the processor is not in the
Stop Grant state.
Figure 9 shows the system power state transitions.
Table 20.
System Power States
System Power State
VDD_IO,
VDD_CORE
On
On
On
On
Off
Off
Off
VDD_IOX,
VDD_COREX
On
On
On
On
On
On
Off
VDD_RTC
Full on (FON; S0)
C2
C3
Power on suspend (POS; S1)
Suspend to RAM (STR; S3)
Soft off (SOFF; S5); suspend to disk (STD; S4)
Mechanical off (MOFF; G3)
On
On
On
On
On
On
On