12.3.2.1 Sleep Modes

In addition to Active mode, there are three different sleep modes, with decreasing power consumption and functionality.

Idle
The CPU stops executing code, no peripherals are disabled.
All interrupt sources can wake-up the device.
Standby
The user can configure peripherals to be enabled or not, using the respective RUNSTBY bit. This means that the power consumption is highly dependent on what functionality is enabled, and thus may vary between the Idle and Power-Down levels.
SleepWalking is available for the ADC module.
The wake-up sources are pin interrupts, TWI address match, UART Start-of-Frame interrupt (if USART is enabled to run in Standby), ADC window interrupt (if PTC enabled to run in Standby), RTC interrupt (if RTC enabled to run in Standby), and TCB interrupt.
Power-Down
Only the WDT and the PIT (a component of the RTC) are active.
The only wake-up sources are the pin change interrupt and TWI address match.
Table 12-2. Sleep Mode Activity Overview
GroupPeripheralActive in Sleep Mode
ClockIdleStandbyPower-Down
Active Clock DomainCPUCLK_CPU
PeripheralsCLK_PERX
RTCCLK_RTCXX*
ADC/PTCCLK_PERXX*
PIT (RTC)CLK_RTCXXX
WDTCLK_WDTXXX
OscillatorsMain Clock SourceXX*
RTC Clock SourceXX*
WDT OscillatorXXX
Wake-Up SourcesINTn and Pin ChangeXXX
TWI Address MatchXXX
Periodic Interrupt TimerXXX
UART Start-of-FrameXX*
ADC/PTC WindowXX*
RTC InterruptXX*
All other InterruptsX
Note:
  • X means active. X* indicates that the RUNSTBY bit of the corresponding peripheral must be set to enter the active state.