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8331B–AVR–03/12
Atmel AVR XMEGA AU
2.
Overview
The AVR XMEGA AU microcontrollers is a family of low-power, high-performance, and periph-
eral-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 reg-
isters 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 conven-
tional 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 control-
ler; 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 I
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C 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 inter-
nal 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 debug-
ging, 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 control-
ler, 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 asynchro-
nous 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.