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XMEGA A [MANUAL]
8077I–AVR–11/2012
The XMEGA A 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); up to four serial peripheral interfaces (SPIs); 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 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 XMEGA A 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.Block Diagram