Microprocessors And Microcontroller

By: Dr. Attiya Baqai

Semester : 4th , 5th (TL, ES) Assistant Professor,

Course Code : ES256 , ES313 Department of

Electronics, MUET.

Internal block diagram of CPU

Internal organisation of Computer

Architectures of Computers

CISC ◉Emphasis on hardware ◉ Includes multi- clock complex instructions ◉ Memory to memory: “LOAD” and “STORE” incorporated in instructions ◉Small code sizes, high cycles per second

RISC ◉Emphasis on software ◉ Single-clock, reduced instruction only ◉Register to register: “LOAD” and “STORE are independent instructions ◉ Low cycles per second, large code sizes ◉Spend more transistors on memory registers

Architectures of Computers

Difference; Microprocessor & Microcntroller

General

Purpose

Micro

processor

RAM ROM Timer

Serial

COM

Port

IO

Port

Data BUS

Address BUS

Control BUS

CPU RAM ROM

I/O Timer Serial

Port

General Purpose Microprocessors

Microcontrollers

Difference; Microprocessor & Microcntroller

Difference

Hardware Architecture Applications Instruction set

Microcontroller ◉Microcontrollers are found in small, minimum-component designs performing control oriented activities.

◉microcontrollers are used to perform specialized single tasks.

Applications

Microprocessor ◉Microprocessors are suited to processing information in computer systems ◉Microprocessors are which designed to be very general to perform any number of tasks (programs)

Microcontroller ◉On chip circuitry of CPU, limited amount of RAM & ROM,I/O ports, timers, ADC, built in interrupt system etc. ◉Small in size, occupy less space, cheap in price. ◉Microcontrollers usually must have low-power requirements 0.5 - 1 W

Hardware Architecture

Microprocessor ◉Microprocessors do not have such devices on chip. Designer have to connect them externally for microprocessor based embedded system. ◉bulkier and more expensive. ◉10 - 50 W for general purpose desktop CPUs.

Microcontroller ◉Microcontrollers have instructions to set and clear individual bits and perform other bit oriented operations.

◉The instructions must be extremely compact with the majority implemented in a single byte.

Instruction set

Microprocessor ◉Microprocessor instruction sets are processing intensive implying they have powerful addressing modes with instructions for operations on large volume of data. ◉Instructions operate on nibbles, bytes, words or even double words.

An Embedded system Uses a microprocessor (or microcontroller) to do one and only one task.

Technology for Embedded System

Embedded systems are controlled by one or more main processing cores that are typically either

◉Microcontrollers

◉Microprocessors

◉Digital Signal Processors (DSP)

◉FPGA’s

A short list of Embedded Systems Anti-lock brakes Auto-focus cameras

Automatic teller machines

Automatic toll systems

Automatic transmission

Avionic systems

Battery chargers

Camcorders

Cell phones

Cell-phone base stations

Cordless phones

Cruise control

Video game consoles

Digital cameras

Disk drives

Electronic card readers

Electronic instruments

Electronic toys/games

Factory control

Fax machines

Fingerprint identifiers

Home security systems

Life-support systems

Washers and dryers

Modems

MPEG decoders

Network cards

Network switches/routers

On-board navigation

Pagers

Photocopiers

Point-of-sale systems

Portable video games

Printers

Satellite phones

Scanners

Smart ovens/dishwashers

Speech recognizers

Stereo systems

Teleconferencing systems

Televisions

Temperature controllers

Theft tracking systems

TV set-top boxes

VCR’s, DVD players

Most common 8 bit Microcontrollers

◉ INTEL’s 8051

◉ Free Scale Semiconductor’s (Motorola) 68HC08/68HC11

◉ Atmel’s AVR

◉ Zilog’s Z8

◉ Microchip Technology PIC 16X

◉ Phillips/ Signatics

Criteria for choosing a Microcontroller

◉ Must meet the task efficiently and cost effectively. The analysis may include: o Speed o Packaging o Power consumption o Amount of RAM and ROM on chip o Number of I/Os o Number of Timers o How easy is it to upgrade to higher performance and/or lower power

consumption versions. o Cost per unit

Criteria for choosing a Microcontroller

◉ How easy it is to develop products around it. Key considerations include: o Availability of an assembler, debugger, o a code efficient C language compiler o emulator o technical support ◉Should be readily available in needed quantities both now and in future.

AVR family Overview

◉Classic AVR-e.g. AT90S2313, AT90S4433

◉Mega e.g. ATmega8, ATmega32, ATmega128

◉Tiny e.g. ATtiny13, ATtiny25

◉Special Purpose AVR-e.g. AT90PWM216,AT90USB1287

Classic AVR (AT90Sxxxx)

mega AVR (ATmegaxxxx)

Tiny AVR (ATtinyxxxx)

Special Purpose AVR

AVR IC Packages

AVR Part Numbers ATmega128

ATtiny44

Atmel group Flash =128K

Atmel Flash =4K

AT90S4433

Atmel Classic group Flash =4K

Tiny group

Comparison of different microcontrollers

AVR On Chip ROM Size & Address Space

AVR’s CPU

PROGRAM

ROM

PortsOSC

Timers

Other

Peripherals

Program

BusData

Bus

RAM

I/O

PINS

EEPROM

Interrupt

Unit

General

Purpose

Registers

CPU

data busaddress bus

control busData

Bus

AVR CPU and Memory space

$0000

$0001

$0020

General

purpose

RAM

(SRAM)

R0

R1

R2

$001F

$005F

R31

...

TWBR

TWSR

SPH

SREG

...

General

Purpose

Registers

Standard I/O

Registers

$00

$01

$3E

$3F

$0060

...

...

Data Address

Space

I/O Address

...

8 bit

$FFFF

CPU PC

ALU

registers

R1

R0

R15

R2

…

R16

R17

…

R30

R31 Instruction Register

Instruction decoder

SREG: I T H S V N C Z

Data Memory with Extended I/O

Data Memory size

Any questions ?

Thanks!