Functional Description
168 Datasheet
5.13.7.3 Exiting Sleep States
Sleep states (S1–S5) are exited based on Wake events. The Wake events forces the
system to a full on state (S0), although some non-critical subsystems might still be
shut off and have to be brought back manually. For example, the hard disk may be shut
off during a sleep state and have to be enabled using a GPIO pin before it can be used.
Upon exit from the PCH-controlled Sleep states, the WAK_STS bit is set. The possible
causes of Wake Events (and their restrictions) are shown in Table 5-29.
Note: (Mobile Only) If the BATLOW# signal is asserted, the PCH does not attempt to wake
from an S1–S5 state, even if the power button is pressed. This prevents the system
from waking when the battery power is insufficient to wake the system. Wake events
that occur while BATLOW# is asserted are latched by the PCH, and the system wakes
after BATLOW# is deasserted.
Table 5-28. Sleep Types
Sleep Type Comment
S1
System lowers the processor’s power consumption. No snooping is possible in this
state.
S3
The PCH asserts SLP_S3#. The SLP_S3# signal controls the power to non-critical
circuits. Power is only retained to devices needed to wake from this sleeping
state, as well as to the memory.
S4
The PCH asserts SLP_S3# and SLP_S4#. The SLP_S4# signal shuts off the power
to the memory subsystem. Only devices needed to wake from this state should be
powered.
S5 The PCH asserts SLP_S3#, SLP_S4# and SLP_S5#.
Table 5-29. Causes of Wake Events (Sheet 1 of 2)
Cause How Enabled
Wake from
S1, Sx
Wake from
Deep S4/S5
Wake from
S1, Sx After
Power Loss
(Note 1)
Wake from
“Reset”
Types
(Note 2)
RTC Alarm
Set RTC_EN bit in PM1_EN
register.
YY Y
Power Button
Always enabled as Wake
event.
YY YY
GPI[15:0]
GPE0_EN register
NOTE: GPIs that are in the
core well are not
capable of waking the
system from sleep
states when the core
well is not powered.
Y
GPIO27
Set GP27_EN in GPE0_EN
Register.
YY YY
LAN
Will use PME#. Wake enable
set with LAN logic.
YY
RI#
Set RI_EN bit in GPE0_EN
register.
YY
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