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XMEGA AU [MANUAL]
8331F–AVR–04/2013
2. Overview
The AVR XMEGA AU 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 Atmel AVR XMEGA AU 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.
The Atmel AVR XMEGA AU devices provide the following features: in-system programmable flash with read-while-write
capabilities; internal EEPROM and SRAM; four-channel DMA controller; eight-channel event system and programmable
multilevel interrupt controller; up to 78 general purpose I/O lines; 16- or 32-bit real-time counter (RTC); up to eight
flexible, 16-bit timer/counters with capture, compare and PWM modes; up to eight USARTs; up to four I2C and SMBUS
compatible two-wire serial interfaces (TWIs); one full-speed USB 2.0 interface; up to four serial peripheral interfaces
(SPIs); CRC module; AES and DES cryptographic engine; up to two 16-channel, 12-bit ADCs with programmable gain;
up to two 2-channel, 12-bit DACs; up to four analog comparators with window mode; programmable watchdog timer with
separate internal oscillator; accurate internal oscillators with PLL and prescaler; and programmable brown-out detection.
The program and debug interface (PDI), a fast, two-pin interface for programming and debugging, is available. Selected
devices also have an IEEE std. 1149.1 compliant JTAG interface, and this can also be used for on-chip debug and
programming.
The Atmel AVR XMEGA devices have five software selectable power saving modes. The idle mode stops the CPU while
allowing the SRAM, DMA controller, event system, interrupt controller, and all peripherals to continue functioning. The
power-down mode saves the SRAM and register contents, but stops the oscillators, disabling all other functions until the
next TWI, USB resume, or pin-change interrupt, or reset. In power-save mode, the asynchronous real-time counter
continues to run, allowing the application to maintain a timer base while the rest of the device is sleeping. In standby
mode, the external crystal oscillator keeps running while the rest of the device is sleeping. This allows very fast startup
from the external crystal, combined with low power consumption. In extended standby mode, both the main oscillator and
the asynchronous timer continue to run. To further reduce power consumption, the peripheral clock to each individual
peripheral can optionally be stopped in active mode and idle sleep mode.
The devices are manufactured using Atmel high-density, nonvolatile memory technology. The program flash memory can
be reprogrammed in-system through the PDI or JTAG interfaces. A boot loader running in the device can use any
interface to download the application program to the flash memory. The boot loader software in the boot flash section will
continue to run while the application flash section is updated, providing true read-while-write operation. By combining an
8/16-bit RISC CPU with In-system, self-programmable flash, the Atmel AVR XMEGA is a powerful microcontroller family
that provides a highly flexible and cost effective solution for many embedded applications.
The Atmel AVR XMEGA AU devices are supported with a full suite of program and system development tools, including
C compilers, macro assemblers, program debugger/simulators, programmers, and evaluation kits.