User manual
...the world's most energy friendly microcontrollers
2012-04-24 - Giant Gecko Family - d0053_Rev0.96 112
www.energymicro.com
Table 10.3. EMU Wakeup Triggers from Low Energy Modes
Peripheral Wakeup Trigger EM0
1
EM1
2
EM2
2
EM3
2
EM4
2
RTC Any enabled interrupt - Yes Yes Yes
3
-
USART Receive / transmit - Yes - - -
UART Receive / transmit - Yes - - -
LEUART Receive / transmit - Yes Yes - -
LESENSE Any enabled interrupt - Yes Yes Yes
3
-
I
2
C Any enabled interrupt - Yes - - -
I
2
C Receive address recognition - Yes Yes Yes -
TIMER Any enabled interrupt - Yes - - -
LETIMER Any enabled interrupt - Yes Yes Yes
3
-
CMU Any enabled interrupt - Yes - - -
DMA Any enabled interrupt - Yes - - -
MSC Any enabled interrupt - Yes - - -
DAC Any enabled interrupt - Yes - - -
ADC Any enabled interrupt - Yes - - -
AES Any enabled interrupt - Yes - - -
PCNT Any enabled interrupt - Yes Yes Yes
4
-
LCD Any enabled interrupt - Yes Yes - -
ACMP Any enabled edge interrupt - Yes Yes Yes -
VCMP Any enabled edge interrupt - Yes Yes Yes -
Pin interrupts Asynchronous - Yes Yes Yes -
Pin Reset - Yes Yes Yes Yes
EM4 wakeup on supported
pins
Asynchronous - - - - Yes
Backup RTC Any enabled interrupt Yes Yes Yes Yes Yes
Power Cycle Off/On Yes Yes Yes Yes
1
Energy Mode 0/Active Mode
2
Energy mode 1/2/3/4
3
When the 1 kHz ULFRCO is selected
4
When using an external clock
10.3.4 Backup power domain
10.3.4.1 Introduction
The EFM32GG has the possibility to be partly powered by a backup battery. The backup power input,
BU_VIN, is connected to a power domain in the EFM32GG containing the Backup RTC and 512 bytes
of data retention, available in all energy modes. Figure 10.3 (p. 113) shows an overview of the backup
powering scheme. During normal operation, the entire chip is powered by the main power supply. If the
main power supply drains out and the Backup mode functionality is enabled, the system enters a low
energy mode, equivalent to EM4, and automatically switches over to the backup power supply.