Three different sleep modes can be enabled to reduce power consumption.
Idle
| The CPU stops executing code, resulting in reduced power consumption.
All peripherals are running, and all interrupt sources can wake the device.
|
Standby
| All high-frequency clocks are stopped apart from any peripheral or clock that
are enabled to run in Standby sleep mode. This is enabled by writing the
corresponding RUNSTDBY bit to ‘1 ’. The power consumption is
dependent on the enabled functionality.
A subset of interrupt sources can wake the device(1).
|
Power-Down
| All high-frequency clocks are stopped, resulting in a power consumption lower
than the Idle sleep mode.
A subset of the peripherals are running, and a subset of interrupt sources can
wake the device(1).
|
Note:
- 1.Refer to the Sleep Mode
Activity tables for further information.
Refer to the Wake-up Time section for information on how the wake-up time is
affected by the different sleep modes.
Table 1. Sleep Mode Activity Overview for
Peripherals
Clock |
Peripheral |
Active in Sleep Mode |
Idle |
Standby |
Power-Down |
CLK_CPU |
CPU |
- |
- |
- |
CLK_RTC |
RTC |
X |
X(1,2) |
X(2) |
CLK_WDT |
WDT |
X |
X |
X |
CLK_BOD(3) |
BOD |
X |
X |
X |
(4) |
CCL |
X |
X(1) |
- |
CLK_PER |
ADCn |
X |
X(1) |
- |
TCAn |
TCBn |
All other peripherals |
X |
- |
- |
Notes:
- 1.Set the RUNSTDBY bit of the
corresponding peripheral to enter an active state.
- 2.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.
- 3.Sampled mode only.
- 4.The clock domain depends on the clock
source selected for CCL.
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.Write the RUNSTDBY bit of the corresponding peripheral to enter an
active state.
- 2.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.
- 3.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 must be configured
according to Asynchronous Sensing Pin Properties in the PORT section.
- 2.Set the RUNSTDBY bit of the corresponding peripheral 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.