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, and all interrupt sources can wake 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.
Power-Down
BOD, WDT, and PIT (a component of the RTC) are active.
The only wake-up sources are the pin change interrupt, PIT, VLM, TWI address match, and CCL.
Table 11-1. Sleep Mode Activity Overview for Peripherals
PeripheralActive in Sleep Mode
IdleStandbyPower-Down
CPU---
RTCXX(1,2)X(2)
WDTXXX
BODXXX
EVSYSXXX
CCLXX(1)-
ACnXX(1)-
ADCn/PTC(3)XX(1)-
DACnXX(1)-
TCBnXX(1)-
All other peripheralsX--
Note:
  1. For the peripheral to run in Standby sleep mode, the RUNSTDBY bit of the corresponding peripheral must be set.

  2. In Standby sleep mode, only the RTC functionality requires the RUNSTDBY bit to be set.
    In Power-Down sleep mode, only the PIT functionality is available.

  3. PTC is only available in devices with 8 KB Flash.
Table 11-2. Sleep Mode Activity Overview for Clock Sources
Clock SourceActive in Sleep Mode
IdleStandbyPower-Down
Main clock sourceXX(1)-
RTC clock sourceXX(1,2)X(2)
WDT oscillatorXXX
BOD oscillator(3)XXX
CCL clock sourceXX(1)-
TCD clock sourceX--
Note:
  1. For the clock source to run in Standby sleep mode, the RUNSTDBY bit of the requesting peripheral must be set.

  2. In Standby sleep mode, only the RTC functionality requires the RUNSTDBY bit to be set.
    In Power-Down sleep mode, only the PIT functionality is available.

  3. The Sampled mode only.
Table 11-3. Sleep Mode Wake-up Sources
Wake-up SourcesActive in Sleep Mode
IdleStandbyPower-Down
PORT Pin interruptXXX(1)
BOD VLM interruptsXXX
RTC interruptsXX(2,3)X(3)
TWIn Address Match interruptXXX
USARTn Start-of-Frame interruptsXX-
ADCn/PTC(4) interruptsXX-
TCBn Capture interruptXX-
All other interruptsX--
Note:
  1. The I/O pin must be configured according to Asynchronous Sensing Pin Properties in the PORT section.
  2. For the peripheral to run in Standby sleep mode, the RUNSTDBY bit of the corresponding peripheral must be set.

  3. In Standby sleep mode, only the RTC functionality requires the RUNSTDBY bit to be set.
    In Power-Down sleep mode, only the PIT functionality is available.

  4. PTC is only available in devices with 8 KB Flash.