The AVR Microcontroller: History and Features

??? Microprocessors (CPU) vs Microcontrollers (MCU) ???

CPU vs. MCU Microprocessor Microcontroller 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 16-bit MCU/CPU 32-bit MCU AVR PIC 8051 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 Cars Cards Communications 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 Consumer Connectivity 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: A set of data buses for carrying data into and out of the CPU, A set of address buses for accessing the data, A set of data buses for carrying code into the CPU, and 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 Mega Tiny Special Purpose 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 numbers ATmega128 Atmel group Flash =128K ATtiny44 AT90S4433 Atmel Flash =4K Atmel Tiny group Classic group Flash =4K