Intel 6 SERIES CHIPSET - DATASHEET 01-2011 Datasheet page 517

LPC Interface Bridge Registers (D31:F0)
13.8.3.1 PM1_STS—Power Management 1 Status Register
I/O Address:
Default Value:
Lockable:
Power Well:
If bit 10 or 8 in this register is set, and the corresponding _EN bit is set in the PM1_EN
register, then the PCH will generate a Wake Event. Once back in an S0 state (or if
already in an S0 state when the event occurs), the PCH will also generate an SCI if the
SCI_EN bit is set, or an SMI# if the SCI_EN bit is not set.
Note: Bit 5 does not cause an SMI# or a wake event. Bit 0 does not cause a wake event but
can cause an SMI# or SCI.
Bit
15
14
13:12
Datasheet
PMBASE + 00h
Attribute:
0000h
No
Bits 0 7: Core,
–
Bits 12-15: Resume
Bit 11: RTC,
Bits 8 and 10: DSW
Wake Status (WAK_STS) — R/WC. This bit is not affected by hard resets caused by a
CF9 write, but is reset by RSMRST#.
0 = Software clears this bit by writing a 1 to it.
1 = Set by hardware when the system is in one of the sleep states (using the SLP_EN
bit) and an enabled wake event occurs. Upon setting this bit, the PCH will transition
the system to the ON state.
If the AFTERG3_EN bit is not set and a power failure (such as removed batteries)
occurs without the SLP_EN bit set, the system will return to an S0 state when power
returns, and the WAK_STS bit will not be set.
If the AFTERG3_EN bit is set and a power failure occurs without the SLP_EN bit having
been set, the system will go into an S5 state when power returns, and a subsequent
wake event will cause the WAK_STS bit to be set. Note that any subsequent wake event
would have to be caused by either a Power Button press, or an enabled wake event that
was preserved through the power failure (enable bit in the RTC well).
PCI Express Wake Status (PCIEXPWAK_STS) — R/WC.
0 = Software clears this bit by writing a 1 to it. If the WAKE# pin is still active during
the write or the PME message received indication has not been cleared in the root
port, then the bit will remain active (that is, all inputs to this bit are level-
sensitive).
1 = This bit is set by hardware to indicate that the system woke due to a PCI Express
wakeup event. This wakeup event can be caused by the PCI Express WAKE# pin
being active or receipt of a PCI Express PME message at a root port. This bit is set
only when one of these events causes the system to transition from a non-S0
system power state to the S0 system power state. This bit is set independent of the
state of the PCIEXP_WAKE_DIS bit.
NOTE: This bit does not itself cause a wake event or prevent entry to a sleeping state.
Thus, if the bit is 1 and the system is put into a sleeping state, the system will
not automatically wake.
Reserved
R/WC
Size: 16-bit
Usage: ACPI or Legacy
Description
517