Data Sheet

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Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
23. EVSYS – Event System
23.1 Overview
The Event System (EVSYS) allows autonomous, low-latency and configurable communication between peripherals.
Several peripherals can be configured to emit and/or respond to signals known as events. The exact condition to
generate an event, or the action taken upon receiving an event, is specific to each module. Peripherals that respond to
events are called event users. Peripherals that emit events are called event generators. A peripheral can have one or
more event generators and can have one or more event users.
Communication is made without CPU intervention and without consuming system resources such as bus or RAM
bandwidth. This reduces the load on the CPU and other system resources, compared to a traditional interrupt-based
system.
23.2 Features
z System for direct peripheral-to-peripheral communication and signaling
z 12 configurable event channels, where each channel can:
z Be connected to any event generator
z Provide a pure asynchronous, resynchronized or synchronous path
z 74 event generators
z 29 event users
z Configurable edge detector
z Peripherals can be event generators, event users or both
z SleepWalking and interrupt generation while operating in sleep modes
z Software event generation
z Each event user can choose which event channel to connect to