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 1. Sleep Mode Activity Overview for
Peripherals
| Peripheral |
Active in Sleep Mode |
| Idle |
Standby |
Power-Down |
| CPU |
|
|
|
| RTC |
X |
X(1,2) |
X(2) |
| WDT |
X |
X |
X |
| BOD |
X |
X |
X |
| EVSYS |
X |
X |
X |
| CCL |
X |
X(1) |
|
| ACn |
| ADCn |
| TCBn |
| All other peripherals |
X |
|
|
Notes:
- 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.
Table 2. Sleep Mode Activity Overview for Clock
Sources
| Clock Source |
Active in Sleep Mode |
| Idle |
Standby |
Power-Down |
| Main Clock Source |
X |
X(1) |
|
| RTC Clock Source |
X |
X(1,2) |
X(2) |
| WDT Oscillator |
X |
X |
X |
| BOD Oscillator(3) |
X |
X |
X |
| CCL clock source |
X |
X(1) |
|
Notes:
- 1.For the clock source 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.The Sampled mode only.
Table 3. Sleep Mode Wake-Up Sources
| Wake-Up Source |
Active in Sleep Mode |
| Idle |
Standby |
Power-Down |
| PORT Pin interrupt |
X |
X |
X(1) |
| TWI Address Match interrupt |
X |
X |
X |
| BOD VLM interrupt |
X |
X |
X |
| CCL interrupts |
X |
X(2,3) |
X(3) |
| RTC interrupts |
X |
X(2,4) |
X(4) |
| USART interrupts |
X(5) |
X(6) |
- |
| TCAn interrupts |
X |
X(2) |
|
| TCBn interrupts |
| ADCn interrupts |
| ACn Compare interrupt |
| All other interrupts |
X |
- |
- |
Notes:
- 1.The I/O pin has to be configured according to Asynchronous Sensing Pin
Properties in the PORT section.
- 2.RUNSTDBY bit of the corresponding
peripheral must be set to enter an active state.
- 3.CCL can wake up the device if the path through LUTn is asynchronous
(FILTSEL=
0x0 and EDGEDET=0x0 in LUTnCTRLA
register).
- 4.In Standby sleep mode, only the RTC
functionality requires the RUNSTDBY to be set to enter an active state. In Power-Down
sleep mode, only the PIT functionality is available.
- 5.Start-of-Frame interrupt is only available in Standby Sleep Mode.
- 6.In Standby Sleep Mode only the Start-of-Frame interrupt will trigger Wake-Up
from USART.