Intel 6 SERIES CHIPSET - DATASHEET 01-2011 Datasheet page 536

Bit
BIOSWR_STS — R/WC.
0 = Software clears this bit by writing a 1 to it.
1 = PCH sets this bit and generates and SMI# to indicate an invalid attempt to write to
8
NOTE: On write cycles attempted to the 4 MB lower alias to the BIOS space, the
NEWCENTURY_STS — R/WC. This bit is in the RTC well.
0 = Cleared by writing a 1 to the bit position or by RTCRST# going active.
1 = This bit is set when the Year byte (RTC I/O space, index offset 09h) rolls over from
NOTE: The NEWCENTURY_STS bit is not valid when the RTC battery is first installed (or
7
The NEWCENTURY_STS bit may take up to 3 RTC clocks for the bit to be cleared after a
1 is written to the bit to clear it. After writing a 1 to this bit, software should not exit the
SMI handler until verifying that the bit has actually been cleared. This will ensure that
the SMI is not re-entered.
6:4 Reserved
TIMEOUT — R/WC.
3
0 = Software clears this bit by writing a 1 to it.
1 = Set by PCH to indicate that the SMI was caused by the TCO timer reaching 0.
TCO_INT_STS — R/WC.
0 = Software clears this bit by writing a 1 to it.
2
1 = SMI handler caused the interrupt by writing to the TCO_DAT_OUT register
SW_TCO_SMI — R/WC.
0 = Software clears this bit by writing a 1 to it.
1
1 = Software caused an SMI# by writing to the TCO_DAT_IN register (TCOBASE +
NMI2SMI_STS — RO.
0 = Cleared by clearing the associated NMI status bit.
0
1 = Set by the PCH when an SMI# occurs because an event occurred that would
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the BIOS. This occurs when either:
a) The BIOSWP bit is changed from 0 to 1 and the BLD bit is also set, or
b) any write is attempted to the BIOS and the BIOSWP bit is also set.
BIOSWR_STS will not be set.
99 to 00. Setting this bit will cause an SMI# (but not a wake event).
when RTC power has not been maintained). Software can determine if RTC
power has not been maintained by checking the RTC_PWR_STS bit
(D31:F0:A4h, bit 2), or by other means (such as a checksum on RTC RAM). If
RTC power is determined to have not been maintained, BIOS should set the
time to a valid value and then clear the NEWCENTURY_STS bit.
(TCOBASE + 03h).
02h).
otherwise have caused an NMI (because NMI2SMI_EN is set).
LPC Interface Bridge Registers (D31:F0)
Description
Datasheet