ATXMEGA384C3_14 Datasheet, PDF (8/125 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA C3 Microcontroller

6. AVR CPU
6.1 Features
• 8/16-bit, high-performance Atmel AVR RISC CPU
– 142 instructions
– Hardware multiplier
• 32x8-bit registers directly connected to the ALU
• Stack in RAM
• Stack pointer accessible in I/O memory space
• Direct addressing of up to 16MB of program memory and 16MB of data memory
• True 16/24-bit access to 16/24-bit I/O registers
• Efficient support for 8-, 16-, and 32-bit arithmetic
• Configuration change protection of system-critical features
6.2 Overview
All Atmel AVR XMEGA devices use the 8/16-bit AVR CPU. The main function of the CPU is to execute the code and
perform all calculations. The CPU is able to access memories, perform calculations, control peripherals, and execute the
program in the flash memory. Interrupt handling is described in a separate section, refer to “Interrupts and Programmable
Multilevel Interrupt Controller” on page 26.
6.3 Architectural Overview
In order to maximize performance and parallelism, the AVR CPU uses a Harvard architecture with separate memories
and buses for program and data. Instructions in the program memory are executed with single-level pipelining. While one
instruction is being executed, the next instruction is pre-fetched from the program memory. This enables instructions to
be executed on every clock cycle. For details of all AVR instructions, refer to http://www.atmel.com/avr.
Figure 6-1. Block Diagram of the AVR CPU Architecture
The arithmetic logic unit (ALU) supports arithmetic and logic operations between registers or between a constant and a
register. Single-register operations can also be executed in the ALU. After an arithmetic operation, the status register is
updated to reflect information about the result of the operation.
XMEGA C3 [DATASHEET]
8
Atmel-8361F-AVR-ATxmega384C3-Datasheet–11/2014