11.3.2.1 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 (component of the RTC) are active.
The only wake-up sources are the pin change interrupt and TWI address match.
Table 11-2. Sleep Mode Activity Overview
Group Peripheral Active in Sleep Mode
Clock Idle Standby Power Down
Active Clock Domain CPU CLK_CPU
Peripherals CLK_PER X
RTC CLK_RTC X X*
ADC/PTC CLK_PER X X*
PIT (RTC) CLK_RTC X X X
WDT CLK_WDT X X X
Oscillators Main Clock Source X X*
RTC Clock Source X X*
WDT Oscillator X X X
Wake-Up Sources INTn and pin change X X X
TWI address match X X X
Periodic Interrupt Timer X X X
UART start of frame X X*
ADC/PTC window X X*
RTC interrupt X X*
All other interrupts X
Note:
  • X means active. X* indicates that the RUNSTBY bit of the corresponding peripheral must be set to enter active state.