atxmega128a4-mu ATMEL Corporation, atxmega128a4-mu Datasheet - Page 5

• Manufacturer Part Number: atxmega128a4-mu
• Description: Atxmega16a4 8/16-bit Avr Xmega Microcontroller
• Manufacturer: ATMEL Corporation

6. AVR CPU
6.1
6.2
8069A–AVR–02/08
Features
Overview
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The XMEGA A4 uses an 8/16-bit AVR CPU. The main function of the CPU is to ensure correct
program execution. The CPU must therefore be able to access memories, perform calculations
and control peripherals. Interrupt handling is described in a separate section.
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Figure 6-1.
The AVR uses a Harvard architecture - with separate memories and buses for program and
data. Instructions in the program memory are executed with a single level pipeline. While one
instruction is being executed, the next instruction is pre-fetched from the program memory. This
concept enables instructions to be executed in every clock cycle. The program memory is In-
System Re-programmable Flash memory.
shows the CPU block diagram.
8/16-bit high performance AVR RISC Architecture
32x8-bit registers directly connected to the ALU
Stack in RAM
Stack Pointer accessible in I/O memory space
Direct addressing of up to 16M bytes of program and data memory.
True 16/24-bit access to 16/24-bit I/O registers
Support for 8-, 16- and 32-bit Aritmetic’s
Configuration Change Protection of system critical features.
– 139 instructions
– Hardware multiplier
MODULE 1
CPU block diagram
I/O
Instruction
Program
Program
Register
Memory
Counter
FLASH
MODULE n
I/O
MODULE n
Indirect Addressing
Direct Addressing
I/O
Instruction
DATA BUS
Decoder
SRAM
DATA BUS
Data
I/O LINES
EEPROM
CONTROL
Registers
STATUS/
Purpose
General
32 x 8
ALU
ATxmega A4
PMIC
Figure 6-1 on page
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