18
XMEGA D3 [DATASHEET]
Atmel-8134N-ATxmega32D3-64D3-128D3-192D3-256D3-384D3_datasheet–03/2014
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 or CPU resources, 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 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, and IR communication module
(IRCOM). 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
used. These are called event channels, and allow for up to four parallel event routing configurations. The maximum
routing latency is two peripheral clock cycles. The event system works in both active mode and idle sleep mode.
Timer /
Counters
ADC
Real Time
Counter
Port pins
CPU /
Software
IRCOM
Event Routing Network
Event
System
Controller
clkPER
Prescaler
AC