9.3.3 Exiting a Low Energy Mode
A system in EM2 DeepSleep and EM3 Stop can be woken up to EM0 Active through regular interrupt requests from active peripherals.
Since state and RAM retention is available, the EFM32 is fully restored and can continue to operate as before it went into the Low
Energy Mode.
Wakeup from EM4 Hibernate or EM4 Shutoff is performed through reset. Wakeup from a specific module must be enabled en
EMU_EM4WUCONF.
Enabled interrupts that can cause wakeup from a low energy mode are shown in
Table 9.3 EMU Wakeup Triggers from Low Energy
. The wakeup triggers always return the EFM32 to EM0 Active/EM1 Sleep. Additionally, any reset source will return
to EM0 Active.
Table 9.3. EMU Wakeup Triggers from Low Energy Modes
Peripheral
Wakeup Trigger
EM2 Deep-
Sleep
EM3 Stop
EM4 Hiber-
nate
EM4 Shut-
off
LEUART (Low Energy Uart)
Receive / transmit
Yes
-
-
-
LETIMER
Any enabled interrupt
Yes
-
-
-
I
2
C
Receive address recognition
Yes
Yes
-
-
ACMP
Any enabled edge interrupt
Yes
Yes
-
-
PCNT
Any enabled interrupt
Yes
Yes
-
-
RTCC
Any enabled interrupt
Yes
Yes
Yes
VMON
Rising or falling edge on any moni-
tored power
Yes
Yes
Yes
-
TEMPCHANGE
Measured temperature outside the de-
fined limits
Yes
Yes
Yes
-
CRYOTIMER
Timeout
Yes
Yes
Yes
Yes
Pin Interrupts
Transition
Yes
Yes
Yes
Yes
Reset Pin
Assertion
Yes
Yes
Yes
Yes
Power
Cycle Off/On
Yes
Yes
Yes
Yes
1
When using an external clock
2
Corresponding bit in EMU_WUEN must be set.
3
Only available on a subset of the pins. Please refer to the Data Sheet for details.
EFM32JG1 Reference Manual
EMU - Energy Management Unit
silabs.com
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