SleepWalking is the capability for a device to temporarily wake up clocks for a peripheral to perform a task without waking up the CPU from Standby mode. At the end of the sleepwalking task, the device can either be woken up by an interrupt (from a peripheral involved in SleepWalking) or enter again into Standby mode. In this device, SleepWalking is supported only on GCLK clocks by using the on-demand clock principle of the clock sources.
In Standby mode, when SleepWalking is ongoing, the performance level used to execute the sleepwalking task is the current configured performance level (used in Active mode), and the main voltage regulator used to execute the SleepWalking task is the selected regulator used in Active mode (LDO or Buck converter).
These are illustrated in the figure below.