
16
XMEGA C3 [DATASHEET]
8492F–AVR–07/2013
8.
Event System
8.1
Features
System for direct peripheral-to-peripheral communication and signaling
Peripherals can directly send, receive, and react to peripheral events
CPU independent operation
100% predictable signal timing
Short and guaranteed response time
Four event channels for up to four different and parallel signal routing configurations
Events can be sent and/or used by most peripherals, clock system, and software
Additional functions include
Quadrature decoders
Digital filtering of I/O pin state
Works in active mode and idle sleep mode
8.2
Overview
The event system enables direct peripheral-to-peripheral communication and signaling. It allows a change in one
peripheral’s state to automatically trigger actions in other peripherals. It is designed to provide a predictable system for
short and predictable response times between peripherals. It allows for autonomous peripheral control and interaction
without the use of interrupts, and CPU, and is thus a powerful tool for reducing the complexity, size and execution time of
application code. It also allows for synchronized timing of actions in several peripheral modules.
A change in a peripheral’s state is referred to as an event, and usually corresponds to the peripheral’s interrupt
conditions. Events can be directly passed to other peripherals using a dedicated routing network called the event routing
network. How events are routed and used by the peripherals is configured in software.
Figure 8-1 on page 16 shows a basic diagram of all connected peripherals. The event system can directly connect
together analog to digital converter, analog comparators, I/O port pins, the real-time counter, timer/counters, IR
communication module (IRCOM), and USB interface. Events can also be generated from software and the peripheral
clock.
Figure 8-1.
Event system overview and connected peripherals.
The event routing network consists of four software-configurable multiplexers that control how events are routed and
routing latency is two peripheral clock cycles. The event system works in both active mode and idle sleep mode.
Timer /
Counters
USB
ADC
Real Time
Counter
Port pins
CPU /
Software
IRCOM
Event Routing Network
Event
System
Controller
clkPER
Prescaler
AC