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XMEGA A [MANUAL]
8077I–AVR–11/2012
1.
About the Manual
This document contains in-depth documentation of all peripherals and modules available for the XMEGA A
microcontroller family. All features are documented on a functional level and described in a general sense. All peripherals
and modules described in this manual may not be present in all XMEGA A devices.
For all device-specific information such as characterization data, memory sizes, modules, peripherals available and their
absolute memory addresses, refer to the device datasheets. When several instances of a peripheral exists in one device,
each instance will have a unique name. For example each port module (PORT) have unique name, such as PORTA,
PORTB, etc. Register and bit names are unique within one module instance.
For more details on applied use and code examples for peripherals and modules, refer to the Atmel AVR XMEGA
specific application notes available from http://www.atmel.com/avr.
1.1
Reading the Manual
The main sections describe the various modules and peripherals. Each section contains a short feature list and overview
describing the module. The remaining section describes the features and functions in more detail.
The register description sections list all registers and describe each register, bit and flag with their function. This includes
details on how to set up and enable various features in the module. When multiple bits are needed for a configuration
setting, these are grouped together in a bit group. The possible bit group configurations are listed for all bit groups
together with their associated Group Configuration and a short description. The Group Configuration refers to the defined
configuration name used in the Atmel AVR XMEGA assembler header files and application note source code.
The register summary sections list the internal register map for each module type.
The interrupt vector summary sections list the interrupt vectors and offset address for each module type.
1.2
Resources
A comprehensive set of development tools, application notes, and datasheets are available for download from
1.3
Recommended Reading
XMEGA A device datasheets
XMEGA application notes
This manual contains general modules and peripheral descriptions. The AVR XMEGA A device datasheets con-
tains the device-specific information. The XMEGA application notes and AVR Software Framework contain exam-
ple code and show applied use of the modules and peripherals.
For new users, it is recommended to read the AVR1000 - Getting Started Writing C Code for Atmel XMEGA, and
AVR1900 - Getting Started with Atmel ATxmega128A1 application notes.
2.
Overview
The XMEGA A microcontrollers is a family of low-power, high-performance, and peripheral-rich CMOS 8/16-bit
microcontrollers based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock
cycle, the XMEGA A devices achieve throughputs approaching one million instructions per second (MIPS) per
megahertz, allowing the system designer to optimize power consumption versus processing speed.
The AVR CPU combines a rich instruction set with 32 general purpose working registers. All 32 registers are directly
connected to the arithmetic logic unit (ALU), allowing two independent registers to be accessed in a single instruction,
executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs many times
faster than conventional single-accumulator or CISC based microcontrollers.