The AVR Microcontroller: History and Features.?? Microprocessors (CPU) vs Microcontrollers (MCU) ???

The AVR Microcontroller: History and

Features

??? Microprocessors (CPU) vs Microcontrollers

(MCU) ???

CPU vs. MCU

Microprocessor No RAM, ROM, I/O Ports on chip itself e.g. Pentium (Intel), PowerPC (Motorola), Spark (SUN) Applications: Desktop, Laptop, workstations, Servers

Microcontroller Microprocessor, RAM, ROM, timers, I/O Ports on a single

chip. 8051(Intel), 68HC08 (Motorola), AVR (Atmel), Z8 (Zilog),

PIC (Microchip), ARM (Advanced RISC Machine). Application: TV Remote Control, video games, robots,

CPU vs. MCU

Most common MCU/CPU 8-bit MCU

AVR PIC 8051

16-bit MCU/CPU 8086/186/96/196 68HC12/16

32-bit MCU ARM PIC32

8-bit Microcontrollers

??? Embedded Systems ???

Embedded Systems An embedded system is controlled by its own

internal microprocessor (or microcontroller) as opposed to an external controller.

A PC is connected to various embedded products such as keyboard, printer, modem, disk controller, sound card, CD-ROM driver, mouse and so on.

a printer gets data and prints it. A mouse takes coordinates and sends to the PC.

Embedded Products Computing

PC Notebook Laptop Storage Color printer Laser printer Modem Cable modem Copier Scanner Digital camera

Cars Anti-lock breaks Air bags Engine Control Transmission

Control Climate control Collusion

avoidance Navigation Trip Computer Instrumentation Keyless entry

Communications Wire-line

Phone Cellular

Phones PDA Pager Fax machine Intercom

Cards Banking Electronic

Purse Social Security Tolls

Embedded Products Consumer

VCR, CD Video games DVD Player Stereo Smoke alarm Camera Remote Control Garage Door

Opener Security System

Consumer Toys Answering

machine Camcorder Musical

Instruments Sewing

Machine Exercise

equipment

Connectivity Cable TV Cable Modem Router Hub

Choosing a microcontroller Speed: What is the highest speed a microcontroller

supports? Packaging: Is it DIP (dual inline package) or a QFP

(quad flat package) or some other type? Power Consumption: Critical for battery powered

products. The amount of RAM and ROM on chip The number of timers and I/O pins on chip Cost per unite Availability of Compiler, Simulator, Debugger. Availability of chip in market

The AVR microcontroller Family The basic architecture of AVR was designed

by two students of Norwegian Institute of Technology (NTH), Alf-Egil Bogen and Vegard Wollan, and then was bought and developed by Atmel in 1996.

The AVR stands for Advanced Virtual RISC, or Alf and Vegard RISC.

The AVR is an 8-bit RISC single-chip microcontroller with Harvard architecture.

RISC and CISC CISC (Complex Instruction Set Computer)

A large number of instructions, typically from 100 to 250 instructions

Some instructions that perform specialized task and are used infrequently

A large variety of addressing modes, typically from 5 to 20 different modes

Variable-length instruction formats

RISC (Reduced Instruction Set Computer) Relatively few instructions Relatively few addressing modes Fixed-length, easily decoded instruction format

Harvard and von Neumann Architecture von Neumann (Princeton) architecture.

The same bus is used for accessing both the code and data Pentium Processor is based on von Neumann Architecture

Harvard architecture Separate buses are used for accessing the code and data

memory. That means that we need four sets of buses:

1. A set of data buses for carrying data into and out of the CPU,2. A set of address buses for accessing the data,3. A set of data buses for carrying code into the CPU, and4. An address bus for accessing the code

This is easy to implement inside an IC chip such as a microcontroller where both ROM code and data RAM are internal (on-chip) and distances are on the micron and millimeter scale

The AVR microcontroller Family

The Simplified view of an AVR Microcontroller

The AVR Family The AVR can be classified into four groups: Classic, Mega, Tiny,

and special purpose. Classic AVR (AT90Sxxxx)

This is the original AVR chip, which has been replaced by newer AVR chips. These are not recommended for new designs.

Mega AVR (ATmegaxxxx)These are powerful microcontrollers with more than 120 instructions and lots of different peripheral capabilities, which can be used in different designs. Some of their characteristics are as follows: Program memory: 4K to 256K bytes Package: 28 to 100 pins Extensive peripheral set Extended instruction set: They have rich instruction sets.

The AVR Family

The AVR Family Tiny AVR (ATtinyxxxx)

This group have less instructions and smaller packages in comparison to mega family. You can design systems with low costs and power consumptions using the Tiny AVRs. Some of their characteristics are as follows: Program memory: IK to 8K bytes Package: 8 to 28 pins Limited peripheral set Limited instruction set: The instruction sets are limited. For example,

some of them do not have the multiply instruction. Special purpose AVR

The ICs of this group can be considered as a subset of other groups, but their special capabilities are made for designing specific applications. Some of the special capabilities are: USB controller, CAN controller, LCD controller, Zigbee, Ethernet controller, FPGA, and advanced PWM.

The AVR Family

Embedded Systems

AVR different groups Classic AVR

e.g. AT90S2313, AT90S4433 Mega

e.g. ATmega8, ATmega32, ATmega128 Tiny

e.g. ATtiny13, ATtiny25 Special Purpose AVR

e.g. AT90PWM216,AT90USB1287

AVR different groups

AVR different groups

AVR different groups

Let’s get familiar with the AVR part numbersATmega128

ATtiny44

Atmel group Flash =128K

AtmelFlash =4K

AT90S4433

Atmel Classic group

Flash =4KTiny group