ATXMEGA384C3_14 Datasheet, PDF (17/125 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA C3 Microcontroller

9. Event System
9.1 Features
• System for direct peripheral-to-peripheral communication and signaling
• Peripherals can directly send, receive, and react to peripheral events
– CPU and DMA controller 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
9.2 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, CPU, or DMA controller 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 on page 17 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. It can also be used to trigger DMA transactions (DMA controller). Events can also
be generated from software and the peripheral clock.
Figure 9-1. Event System Overview and Connected Peripherals
CPU /
Software
DMA
Controller
ADC
AC
Event Routing Network
Event
System
Controller
clk_PER
Prescaler
Real Time
Counter
Timer /
Counters
USB
Port pins
IRCOM
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.
XMEGA C3 [DATASHEET]
17
Atmel-8361F-AVR-ATxmega384C3-Datasheet–11/2014