Intel
82801BA ICH2 Datasheet
9-55
LPC Interface Bridge Registers (D31:F0)
9.8.1.2
GEN_PMCON_2—General PM Configuration 2 Register (PM—D31:F0)
Offset Address:
Default Value:
Lockable:
A2h
00h
No
Attribute:
Size:
Usage:
Power Well:
R/WC
16-bit
ACPI, Legacy
Resume
9.8.1.3
GEN_PMCON_3—General PM Configuration 3 Register (PM—D31:F0)
Offset Address:
Default Value:
Lockable:
A4h
00h
No
Attribute:
Size:
Usage:
Power Well:
R/W
8-bit
ACPI, Legacy
RTC
Bit
Description
7:2
Reserved.
1
CPU Power Failure (CPUPWR_FLR)
—R/WC.
0 = Software clears this bit by writing a 1 to the bit position.
1 = Indicates that the VRMPWRGD signal from the processor’s VRM went low.
0
PWROK Failure (PWROK_FLR)
—R/WC.
0 = Software clears this bit by writing a 1 to the bit position, or when the system goes into a G3
state.
1 = This bit will be set any time PWROK goes low, when the system was in S0 or S1 state. The bit
will be cleared only by software by writing a 1 to this bit or when the system goes to a G3 state.
Note: Traditional designs have a reset button logically ANDed with the PWROK signal from the
power supply and the processor’s voltage regulator module. If this is done with the ICH2, the
PWROK_FLR bit will be set. The ICH2 treats this internally as if the RSMRST# signal had
gone active. However, it is not treated as a full power failure. If PWROK goes inactive and
then active (but RSMRST# stays high), then the ICH2 will reboot (regardless of the state of
the AFTERG3 bit). If the RSMRST# signal also goes low before PWROK goes high, then this
is a full power failure and the reboot policy is controlled by the AFTERG3 bit.
Bit
Description
7:3
Reserved.
2
RTC Power Status (RTC_PWR_STS)
—R/WC.
0 = Software clears this bit by writing a 0 to the bit position.
1 = Indicates that the RTC battery was removed or failed. This bit is set when RTCRST# signal is
low.
Note: Clearing CMOS in an ICH-based platform can be done by using a jumper on RTCRST# or
GPI, or using SAFEMODE strap. Implementations should not attempt to clear CMOS by using
a jumper to pull VccRTC low.
1
Power Failure (PWR_FLR)
—R/WC. This bit is in the RTC well, and is not cleared by any type of
reset except RTCRST#.
0 = Indicates that the trickle current has not failed since the last time the bit was cleared. Software
clears this bit by writing a 1 to the bit position.
1 = Indicates that the trickle current (from the main battery or trickle supply) was removed or failed.
Note: Clearing CMOS in an ICH-based platform can be done by using a jumper on RTCRST# or
GPI, or using SAFEMODE strap. Implementations should not attempt to clear CMOS by using
a jumper to pull VccRTC low.
0
After G3 State Select (AFTERG3_EN)
—R/W. Determines what state to go to when power is re-
applied after a power failure (G3 state). This bit is in the RTC well and is not cleared by any type of
reset except writes to CF9h or RTCRST#.
0 = System will return to S0 state (boot) after power is re-applied.
1 = System will return to the S5 state (except if it was in S4, in which case it will return to S4). In the
S5 state, the only enabled wake event is the Power Button or any enabled wake event that was
preserved through the power failure.
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