FDC37B78X SMSC Corporation, FDC37B78X Datasheet - Page 152

• Manufacturer Part Number: FDC37B78X
• Description: Enhanced Super I/O Controller with ACPI Support/ Real Time Clock and Consumer IR
• Manufacturer: SMSC Corporation

ACPI/PME/SMI FEATURES
ACPI Features
The FDC37B78x supports ACPI as described in
this section.
ACPI Specification, Revision 1.0.
Legacy/ACPI Select Capability
This capability consists of an SMI/SCI switch
which is required in a system that supports both
legacy and ACPI power management models.
This is due to the fact that the system software
for legacy power management consists of the
SMI interrupt handler while for ACPI it consists
of the ACPI driver (SCI interrupt handler). This
support uses Logical Device A at 0x0A to hold
the address pointers to the ACPI power
management register block, PM1_BLK, which
consists of run-time registers. Included in the
PM1_BLK is an enable bit, SCI_EN, to allow the
SCI interrupt to be generated upon an enabled
SCI event. This SCI interrupt can be switched
out to the nPME/SCI pin or routed to one of the
parallel interrupts, IRQ11, or any Serial IRQ
frame. Note that the Serial IRQ is not available
under V
(open collector or push-pull) of the SCI is
selected through the IRQ MUX Register.
The software power management events (those
that generate an SMI in legacy mode and an
SCI in ACPI mode) are controlled by the
EN_SMI and SCI_EN bits. The SCI enable bit,
SCI_EN, is located in the PM1_CNTRL register,
bit 0.
EN_SMI, bit 7 of the SMI enable register 2, to
enable either SCI or SMI (or both). For legacy
power management, the EN_SMI bit is used; if
set, it routes the power management events to
the SMI interrupt logic.
management, the SCI_EN bit is used; if set, it
routes the power management events to the SCI
interrupt logic.
TR
This bit is used in conjunction with
power. The polarity and output type
These features comply with the
For ACPI power
152
Power Button With Override
The power button has a status and and enable
bit in the PM1_BLK of registers to provide an
SCI upon the button press. The power button
can also turn the system on and off through the
soft power management logic.
button also has an override event as required by
the ACPI specification.
Management Section. This override event is
described as follows: If the user presses the
power button for more than 4 seconds while the
system is in the working state, a hardware event
is generated and the system will transition to the
off state.
associated with this feature in the PM1_BLK
registers.
RTC Alarm
The ACPI specification requires that the RTC
alarm generate a hardware wake-up event from
the sleeping state. The RTC alarm event can be
enabled as both a PME and an SCI event
through bits in the PM1_BLK of registers. In
addition, the can also turn the system on due to
the
management logic.
There is a bit in the PME Enable Register and
the PME Status Register 1 to enable the RTC
alarm event as a nPME event and to read its
status.
generates an alarm event and is cleared by
writing a 1 to this bit (writing a 0 has no effect).
When the RTC generates an alarm event, the
RTC_PME_STS bit will be set.
RTC_PME_EN bit is set, an RTC PME power
management event will be generated.
For SCI, the RTC_STS and RTC_EN bits are in
the PM1_STS and PM1_EN registers.
RTC
The status bit is set when the RTC
There are status and enable bits
alarm
through
See The Soft Power
the
soft
The power
If the
power