Sleep Modes

The SAM devices have several sleep modes. The sleep mode controls which clock systems on the device will remain enabled or disabled when the device enters a low power sleep mode. Table 1 lists the clock settings of the different sleep modes.

Table 1. SAM Device Sleep Modes

Sleep mode

System clock

CPU clock

AHB/AHB clock

GCLK clocks

Oscillators (ONDEMAND = 0)

Oscillators (ONDEMAND = 1)

Regulator mode

RAM mode

Idle

Run

Stop

Run if requested

Run

Run

Run if requested

Normal

Normal

Standby

Stop

Stop

Run if requested

Run if requested

Run if requested or RUNSTDBY = 1

Run if requested

Low pwer

Low pwer

Backup

Stop

Stop

Stop

Stop

Stop

Stop

Backup

Off

Off

Off

Off

Off

Off

Off

Off

Off

Off

Before entering device sleep, one of the available sleep modes must be set. The device will automatically wake up in response to an interrupt being generated or upon any other sleep mode exit condition.

Some peripheral clocks will remain enabled during sleep, depending on their configuration. If desired, the modules can remain clocked during sleep to allow them continue to operate while other parts of the system are powered down to save power.