1. About the Manual
This document contains in-depth documentation of all peripherals and modules available for the
AVR 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 and
peripherals available and their absolute memory addresses refer to the device datasheets.
When several instances of one peripheral such as a PORT exist in one device, each instance of
a module will have a unique name, such as PORTA, PORTB etc. Register, bit names are unique
within one module.
For more details on applied use and code examples for all peripherals and modules, refer to the
XMEGA A 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 of the most important features and a short overview describing the module. The
remaining section describes the features and functions in more details.
The register description sections list all registers, and describe each bit/flag and its 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 Configu-
ration and a short description. The Group Configuration refer to the defined configuration name
used in the XMEGA A and 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 mod-
A comprehensive set of development tools, application notes and datasheets are available for
download on http://www.atmel.com/avr.
1.3 Recommended Reading
• XMEGA A Device Datasheets
• XMEGA Application Notes
This manual only contains general modules and peripheral descriptions. The XMEGA A device
datasheet contains device specific information. The XMEGA application notes contain example
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
XMEGA, and AVR1900 - Getting started with ATxmega128A1 application notes.