4.3 About Code Examples
This documentation contains simple code examples that briefly show how to use various parts of
the device. These code examples assume that the part specific header file is included before
compilation. Be aware that not all C compiler vendors include bit definitions in the header file
and interrupt handling in C is compiler dependent. Please confirm with the C compiler documen-
tation for more details.
4.4 AVR CPU Core
4.4.1
Introduction
This section discusses the AVR core architecture in general. The main function of the CPU core
is to ensure correct program execution. The CPU must therefore be able to access memories,
perform calculations, control peripherals, and handle interrupts.
4.4.2 Architectural Overview
Figure 4-2. Block Diagram of the AVR Architecture
Data Bus 8-bit
Flash
program
memory
Instruction
register
Instruction
decoder
Control lines
Program
counter
Status
and control
32 × 8
general
purpose
registers
ALU
DATA
SRAM
EEPROM
I/O lines
Interrupt
unit
SPI
unit
Watchdog
timer
Analog
comparator
I/O Module 1
I/O Module 2
I/O Module n
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