30.
EVSYS – Event System
30.1. Overview
The Event System (EVSYS) allows autonomous, low-latency and configurable communication between
peripherals.
Several peripherals can be configured to generate 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 peripheral.
Peripherals that respond to events are called event users. Peripherals that generate 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.
30.2. Features
•
8 configurable event channels, where each channel can:
–
Be connected to any event generator.
–
Provide a pure asynchronous, resynchronized or synchronous path
•
69 event generators.
•
31 event users.
•
Configurable edge detector.
•
Peripherals can be event generators, event users, or both.
•
SleepWalking and interrupt for operation in sleep modes.
•
Software event generation.
•
Each event user can choose which channel to respond to.
30.3. Block Diagram
Figure 30-1. Event System Block Diagram
USER x+1
Event Channel m
Event Channel 1
Event Channel 0
USER x
D Q
R
Synchronized Path
Asynchronous Path
Edge Detector
CHANNEL0.EDGSEL
CHANNEL0.PATH
EVT
D
Q
R
D
Q
R
D
Q
R
Resynchronized Path
D Q
R
D Q
R
D Q
R
SWEVT.CHANNEL0
PERIPHERAL n
PERIPHERAL0
CHANNEL0.EVGEN
USER.CHANNELx
Channel_EVT_0
EVT ACK
Channel_EVT_m
Clock Request [m:0]
To Peripheral x
Peripheral x
GCLK_EVSYS_0
SleepWalking
Detector
Event Acknowledge
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