Intel Pentium III Processor/840, Manual, Page: 34 / 151

3-10 Intel
®
Pentium
®
III Processor/840 Development Kit Manual
Theory of Operation
3.4 Power Management Features
Two power management modes are supported with a BIOS option: Advanced Configuration and
Power Interface (ACPI 1.0) or Advanced Power Management (APM 1.2).
3.4.1 ACPI 1.0 Support
The evaluation board will support the ACPI 1.0 specification with the following features:
•
Single power/sleep button user model (Normal switch depress (< 2 s) puts system in sleep
mode, 4 seconds or greater switch depress turns system off)
•
OS can turn system off (Soft Off feature)
•
Suspend all devices that support power down modes
•
Fan control for thermals and quiet operation (speeds = On/Off)
•
Supports ACPI S0, S1, S3, S5 System States, no S4 Suspend to disk, no S2 for dual-processor
designs
3.4.2 ACPI 1.0 System States and Power States
Note: All possible ACPI system states are listed in Table 3-3. Shaded states are not supported on the
Pentium
III processor/840 evaluation board.
Table 3-3. ACPI 1.0 System States and Power States
Global States Sleep States CPU States Device States
Targeted System
Power
G0/S0-working
state
N/A C0-working D0-working state
Full power> Depends
on system config.
G1-sleeping state S1-CPU stopped C1-stop grant
D1,D2,D3-device
specification specific
5W<power<30W
G1-sleeping
state
†
S2-Power on suspend
C2-clock
stopped
D2,D3-device
specification specified
Not supported
G1-sleeping state
S3-Suspend to RAM.
Context saved to disk.
No power
D3-no power except
for wake-up logic
5W<power
††
G1-sleeping
state
†
S4BIOS-Suspend to
disk. Context saved to
disk.
No power
D3-no power except
for wake-up logic
Not supported
G2/S5
S5-soft off. Context
not saved. Cold boot
is required.
No power
D3-no power except
for wake-up logic
5W<power
††
G3-mechanical
off. The power
supply cord is
unplugged from
the system.
No power to the
system.
No power
D3-no power. No
power for wake-up
logic, except when
provided by a battery
or external source.
No power to the
system so that service
can be performed.
† Not supported on the evaluation board.
†† Assumes limited number of wake-up devices.