ATXMEGA128B1 Datasheet, PDF (16/138 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA B1 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 routings and 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 9-1 on page 17 shows a basic diagram of all connected peripherals. The event system can directly connect
together analog and digital converters, 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.
XMEGA B1 [DATASHEET] 16
8330C–AVR–07/2012