pc87317vul National Semiconductor Corporation, pc87317vul Datasheet - Page 60

• Manufacturer Part Number: pc87317vul
• Description: Pc87317vul/pc97317vul Superi/o Plug And Play Compatible With Acpi Compliant Controller/extender
• Manufacturer: National Semiconductor Corporation

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events, or to power down in an orderly, controlled manner.
The APC assumes the function of the physical power supply
On/Off switch, which is replaced by a momentary switch
that enables the user to signal requests for power-state
changes to the APC.
The APC device is powered at all times that external AC
power or battery backup power are connected to the RTC
device. This is true even though the PC may be switched off
or disconnected from the external AC power outlet, in which
case the APC device is active but does not activate system
power. The APC device controls the power state of the en-
tire PC system in response to various events (including the
power-on or power-off switch event).
WARNING:
The APC function produces four output signals:
ONCTL: The ONCTL signal is intended to activate or deac-
tivate the system power supply.
The ONCTL’s value depends on the following:
POR: The APC generates a Power-Off-Request (POR) (as
an interrupt request signal) in response to various “Power
Off events”, including the “Switch Off event” generated
when the power switch is manually toggled. This enables
various user-selectable choices of system response when
returning from a power Failure, or a software controlled exit
procedure (analogous to the autoexec.bat startup pro-
cedure in DOS operating systems) with automatic activation
of preprogrammed features such as system status backup,
system activity logging, file closing and backup, remote
communications termination, print completion, etc.
SCI: The APC meets ACPI requirements, with additional
optional features (see “ACPI Compliance” below). An SCI
interrupt is generated to send ACPI-relevant notifications to
the host operating system. (See “The SCI Signal” on page
69.)
LED: The APC supplies a programmable LED signal output
that may directly drive an external LED to indicate system
status under various power states (See TABLE 4-7 "LED
signal outputs" on page 68).
NOTE: The APC can distinguish between two events of the
same type if a minimum time of 2.5 periods of the 32Khz
clock passed between their arrivals. Thus, if the APC de-
tects an event, and another event of the same nature occurs
once again in less than 70us from the previous event, the
APC might not detect the second event, i.e., the event will
be lost.
The APC device does not function if the 32.768 KHz os-
cillator is not running.
the ONCTL signal - to activate the system power supply
the Power-Off-Request (POR) - an interrupt request
signal designed to enable software-controlled power
off activity
the SCI interrupt request - to comply with ACPI speci-
fications for system power management.
The LED signal - to drive an external LED status indicator
External events
Programmable parameter settings
The system’s state when an external event occurs
The state of the system’s power supply.
Real-Time Clock (RTC) and Advanced Power Control (APC) (Logical Device 2)
60
ACPI Compliance
The PC87317 supports all the minimum requirements of the
ACPI spec (Rev 1.0):
The following optional features are also supported:
Several programmable General Purpose Power Manage-
ments events may be utilized to wake-up the system or to
generate interrupts, as listed in “General Purpose Power
Management Events” on page 68. The module includes a
Power Management timer that can generate interrupt re-
quests.
TABLE 4-4 "APC Control and Status Register List" lists the
registers used for Automatic Power Supply Control (APC) in
the PC87317VUL.
The ACPI Fixed Registers include four groups of registers,
as listed below.
TABLE 4-4. APC Control and Status Register List
Power Management Timer.
Power Button.
Real Time Clock Alarm.
Suspend modes via software emulation.
Plug-and-Play SCI.
Global Lock mechanism.
General Purpose events.
Day-of-Month Alarm.
Century byte.
Index
4Ah
4Bh
4Ch
4Dh
4Eh
40h
41h
49h
42h
47h
4Fh
50h
51h
43h
44h
45h
46h
48h
Mnemonic
MADDR
DADDR
CADDR
APCR1
APCR2
APCR3
APCR4
APCR5
APCR6
APCR7
APSR1
APSR
WDW
WDM
RLR
WM
WC
WY
APC Control Register 1
APC Control Register 2
APC Control Register 3
APC Control Register 4
APC Control Register 5
APC Control Register 6
APC Control Register 7
APC Status Register
APC Status Register 1
RAM Lock Register
Day-of-Month Alarm Address
Register
Month Alarm Address Register
Century Address Register
Wake up Day of Week
Wake up Date of Month
Wake up Month
Wake up Year
Wake up Century
Description