Datasheet
Table Of Contents
- Features
- 1. Ordering Information
- 2. Pinout/Block Diagram
- 3. Overview
- 4. Resources
- 5. Capacitive touch sensing
- 6. AVR CPU
- 7. Memories
- 8. Event System
- 9. System Clock and Clock options
- 9.1 Features
- 9.2 Overview
- 9.3 Clock Sources
- 9.3.1 32kHz Ultra Low Power Internal Oscillator
- 9.3.2 32.768kHz Calibrated Internal Oscillator
- 9.3.3 32.768kHz Crystal Oscillator
- 9.3.4 0.4 - 16MHz Crystal Oscillator
- 9.3.5 2MHz Run-time Calibrated Internal Oscillator
- 9.3.6 32MHz Run-time Calibrated Internal Oscillator
- 9.3.7 External Clock Sources
- 9.3.8 PLL with 1x-31x Multiplication Factor
- 10. Power Management and Sleep Modes
- 11. System Control and Reset
- 12. WDT – Watchdog Timer
- 13. Interrupts and Programmable Multilevel Interrupt Controller
- 14. I/O Ports
- 15. TC0/1 – 16-bit Timer/Counter Type 0 and 1
- 16. TC2 – Timer/Counter Type 2
- 17. AWeX – Advanced Waveform Extension
- 18. Hi-Res – High Resolution Extension
- 19. RTC – 16-bit Real-Time Counter
- 20. USB – Universal Serial Bus Interface
- 21. TWI – Two-Wire Interface
- 22. SPI – Serial Peripheral Interface
- 23. USART
- 24. IRCOM – IR Communication Module
- 25. CRC – Cyclic Redundancy Check Generator
- 26. ADC – 12-bit Analog to Digital Converter
- 27. AC – Analog Comparator
- 28. Programming and Debugging
- 29. Pinout and Pin Functions
- 30. Peripheral Module Address Map
- 31. Instruction Set Summary
- 32. Packaging information
- 33. Electrical Characteristics TBD
- 34. Typical Characteristics TBD
- 35. Errata
- 36. Datasheet Revision History
- Table of Contents
16
8493A–AVR–02/12
XMEGA C4
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 independant 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 inter-
rupts, 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 ded-
icated 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 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.
Events can also be generated from software and the peripheral clock.