22.6.4 Sleep Mode Operation
The EVSYS can generate interrupts to wake up the device from any sleep mode.
Some event generators can generate an event when the system clock is stopped. The generic clock (GCLK_EVSYS_CHANNELx) for this channel will be restarted if the channel uses a synchronized path or a resynchronized path, without waking the system from sleep. The clock remains active only as long as necessary to handle the event. After the event has been handled, the clock will be turned off and the system will remain in the original sleep mode. This is known as SleepWalking. When an asynchronous path is used, there is no need for the clock to be activated for the event to be propagated to the user.
On a software reset, all registers are set to their reset values and any ongoing events are canceled.