Datasheet

24.6.3 Interrupts
The EVSYS has the following interrupt sources:
• Overrun Channel n (OVRn): for details, refer to The Overrun Channel n Interrupt section.
• Event Detected Channel n (EVDn): for details, refer to The Event Detected Channel n Interrupt
section.
These interrupts events are asynchronous wake-up sources. See Sleep Mode Controller.
Each interrupt source has an interrupt flag which is in the Interrupt Flag Status and Clear (INTFLAG)
register. The flag is set when the interrupt is issued. Each interrupt event can be individually enabled by
setting a ‘1’ to the corresponding bit in the Interrupt Enable Set (INTENSET) register, and disabled by
setting a ‘1’ to the corresponding bit in the Interrupt Enable Clear (INTENCLR) register. An interrupt event
is generated when the interrupt flag is set and the corresponding interrupt is enabled. The interrupt event
works until the interrupt flag is cleared, the interrupt is disabled, or the Event System is reset. See
INTFLAG for details on how to clear interrupt flags.
All interrupt events from the peripheral are ORed together on system level to generate one combined
interrupt request to the NVIC. Refer to the Nested Vector Interrupt Controller for details. The event user
must read the INTFLAG register to determine what the interrupt condition is.
Note that interrupts must be globally enabled for interrupt requests to be generated. Refer to Nested
Vector Interrupt Controller for details.
Related Links
11.2 Nested Vector Interrupt Controller
16.6.1.3 Sleep Mode Controller
24.6.3.1 The Overrun Channel n Interrupt
The Overrun Channel n interrupt flag in the Interrupt Flag Status and Clear register (CHINTFLAGn.OVR)
will be set, and the optional interrupt will be generated in the following cases:
• One or more event users on channel n is not ready when there is a new event.
• An event occurs when the previous event on channel m has not been handled by all event users
connected to that channel.
The flag will only be set when using resynchronized paths. In the case of asynchronous path, the
CHINTFLAGn.OVR is always read as zero.
Related Links
11.2 Nested Vector Interrupt Controller
24.6.3.2 The Event Detected Channel n Interrupt
The Event Detected Channel n interrupt flag in the Interrupt Flag Status and Clear register
(CHINTFLAGn.EVD) is set when an event coming from the event generator configured on channel n is
detected.
The flag will only be set when using a resynchronized path. In the case of asynchronous path, the
CHINTFLAGn.EVD is always zero.
Related Links
11.2 Nested Vector Interrupt Controller
24.6.4 Sleep Mode Operation
The EVSYS can generate interrupts to wake up the device from any sleep mode.
SAM D21 Family
EVSYS – Event System
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 443