at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 8

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

4.
4.1
4.2
8
AVR CPU Core
Introduction
Architectural Overview
AT90PWM81
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 calcula-
tions, control peripherals, and handle interrupts.
Figure 4-1.
In order to maximize performance and parallelism, 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 pipelining. While one instruction is being executed, the next instruction is pre-fetched from the pro-
gram memory. This concept enables instructions to be executed in every clock cycle. The program
memory is In-System Reprogrammable Flash memory.
Control Lines
Instruction
Instruction
Program
Memory
Decoder
Register
Block Diagram of the AVR Architecture
Flash
Program
Counter
and Control
EEPROM
Registrers
I/O Lines
Purpose
General
SRAM
Data Bus 8-bit
Status
32 x 8
Data
ALU
I/O Module 2
Comparator
I/O Module1
I/O Module n
Watchdog
Interrupt
Timer
Analog
Unit
Unit
SPI
7734M–AVR–03/10