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82801AA and 82801AB Datasheet
2-7
Signal Description
2.8
Power Management Interface
Table 2-8. Power Management Interface Signals
Name
Type
Description
THRM#
I
Thermal Alarm:
Active low signal generated by external hardware to start the
Hardware clock throttling mode. Can also generate an SMI# or an SCI.
SLP_S3#
/
GPIO[24]
O
S3 Sleep Control:
Power plane control. The signal is used to shut power off to all
non-critical systems when in S3 (Suspend To RAM) state. It can be used as General
Purpose Output if STR is not supported.
SLP_S5#
O
S5 Sleep Control:
Power plane control. The signal is used to shut power off to all
non-critical systems when in the S4 (Suspend To Disk) or S5 (Soft Off) states.
PWROK
I
Power OK:
When asserted, PWROK is an indication to the ICH that core power and
PCICLK have been stable for at least 1 ms. PWROK can be driven asynchronously.
When PWROK is negated, the ICH asserts PCIRST#.
PWRBTN#
I
Power Button:
The Power Button will cause SMI# or SCI to indicate a system
request to go to a sleep state. If the system is already in a sleep state, this signal will
cause a wake event. If PWRBTN# is pressed for more than 4 seconds, this will cause
an unconditional transition (power button override) to the S5 state with only the
PWRBTN# available as a wake event. Override will occur, even if the system is in the
S1-S4 states.
RI#
I
Ring Indicate:
From the modem interface. Can be enabled as a wake event and this
is preserved across power failures.
RSMRST#
I
Resume Well Reset:
Used for resetting the resume power plane logic.
SUS_STAT#
/
GPIO[25]
O
Suspend Status:
This signal is asserted by the ICH to indicate that the system will
be entering a low power state soon. This can be monitored by devices with memory
that need to switch from normal refresh to suspend refresh mode. It can also be used
by other peripherals as an indication that they should isolate their outputs that may
be going to powered-off planes. This signal is called LPCPD# on the LPC Interface.
NOTE:
Can be used as General Purpose Output if external logic does not require
this signal.
SUSCLK
/
GPIO[26]
(82801AA
only)
O
Suspend Clock (82801AA only):
Output of the RTC generator circuit to use by
other chips for refresh clock.
NOTES:
1. Can be used as General Purpose Output if external logic does not require this
signal.
2. GPIO[26] is a non-muliplexed signal on the ICH0 (82801AB).