Advanced Configuration and Power Interface Specification

ACPI Hardware Specification
Feature Name Description Programming Model
Power Button Override User sequence (press the power button
for 4 seconds) to turn off a hung system.
Real Time Clock Alarm Programmed time to wake the system. Optional Fixed Hardware Event a
Sleep/Wake Control
Logic
Embedded Controller
Interface
Legacy/ACPI Select
Lid switch
C1 Power State
C2 Power Control
C3 Power Control
Thermal Control
Device Power
Management
AC Adapter
Docking/device insertion
and removal
Logic used to transition the system
between the sleeping and working states.
ACPI Embedded Controller protocol and
interface, as described in Section 12,
“ACPI Embedded Controller Interface
Specification.”
Status bit that indicates the system is
using the legacy or ACPI power
management model (SCI_EN).
Button used to indicate whether the
system’s lid is open or closed (mobile
systems only).
Processor instruction to place the
processor into a low-power state.
Logic to place the processor into a C2
power state.
Logic to place the processor into a C3
power state.
Logic to generate thermal events at
specified trip points.
Control logic for switching between
different device power states.
Logic to detect the insertion and removal
of the AC adapter.
Logic to detect device insertion and
removal events.
Fixed Hardware Control and Event
Logic
Generic Hardware Event Logic, must
reside in the general-purpose register
block
Fixed Hardware Control Logic
Generic Hardware Event Feature
Processor ISA
Fixed Hardware Control Logic
Fixed Hardware Control Logic
Generic Hardware Event and Control
Logic (See description of thermal
logic in Section 3.10, “Thermal
Management.”)
Generic Hardware control logic
Generic Hardware event logic
Generic Hardware event logic
a. RTC wakeup alarm is required, the fixed hardware feature status bit is optional.
4.8 ACPI Register Model
ACPI hardware resides in one of six address spaces:
• System I/O
• System memory
• PCI configuration
• SMBus
• Embedded controller
• Functional Fixed Hardware
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