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, 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.
- Power-Down
- BOD, WDT, and PIT (a component of the RTC) are active.
| Group | Peripheral | Active in Sleep Mode | |||
|---|---|---|---|---|---|
| Clock | Idle | Standby | Power-Down | ||
| Active Clock Domain | CPU | CLK_CPU | |||
| RTC | CLK_RTC | X | X(1) | X(2) | |
| ADCn/PTC | CLK_PER | X | X(1) | ||
| TCBn | CLK_PER | X | X(1) | ||
| BOD | CLK_BOR | X | X | X | |
| WDT | CLK_WDT | X | X | X | |
| All other peripherals | CLK_PER | X | |||
| Oscillators | Main clock source | X | X(1) | ||
| RTC clock source | X | X(1) | X(2) | ||
| WDT oscillator | X | X | X | ||
| Wake-Up Sources | PORT Pin interrupt | X | X | X | |
| TWI Address Match interrupt | X | X | X | ||
| USART Start-of-Frame interrupts | X | X(1) | |||
| ADC/PTC interrupts | X | X(1) | |||
| RTC interrupts | X | X(1) | X(2) | ||
| TCBn Capture interrupt | X | X(1) | |||
| All other interrupts | X | ||||
Note:
- The RUNSTBY bit of the corresponding peripheral must be set to enter the Active state.
- Only the PIT is available in the Power-Down sleep mode.