ATXMEGA128A4U-AU Datasheet, PDF (16/121 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA A4U Microcontroller

XMEGA A4U
9. Event System
9.1 Features
9.2 Overview
• 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
• 8 Event Channels for up to 8 different and parallel signal routines 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 change
• Works in Active mode and Idle sleep mode
The Event System is system for direct peripheral to peripheral communication and signaling. It
enables the possibility for a change in one peripheral to automatically trigger actions in others
peripherals. It is designed for having a predictable system for short and guaranteed response
time between peripherals. It is simple and powerful since it allows for autonomous peripheral
control and interaction without use of interrupts, CPU or DMA Controller resources. It also
enables synchronized timing of actions in several peripheral modules.
The change in a peripheral is referred to as an event, and is it usually the same as the interrupt
conditions for the peripheral. These 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 other peripherals is configured in software.
Figure 9-1 on page 17 shows a basic block diagram of all connected peripherals. The Event
System can directly connect together Analog and Digital converters, Analog Comparators, I/O
ports pins, the Real-time Counter, Timer/Counters, IR Communication Module (IRCOM), and
USB. It can also be used to trigger DMA transactions (DMA Controller). Events can also be gen-
erated from software and the Peripheral Clock.
16
8387A–AVR–07/11