Microprocessor Chapter 1

7/28/2019 Microprocessor Chapter 1

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Introduction to

Microprocessor-basedSystems

EC304: Microprocessor Fundamental



What we are going to learn in this

session: What is a microprocessor.

History of microprocessors.

What is a microprocessor system.

Components inside the microprocessor system: Component description.

Function.

Arrangement.

Important terminology



Microprocessors



Microprocessor

A microprocessor is an electronic device thatconsists of millions (or billions) of transistors

packed into one IC. Its function is to execute instructions in the form

of programs, calculate and store its results.

Microprocessor requires only one chip to build acomplete system

Microprocessors are used widely in our everyday lives.



Everyday Items that use

Microprocessors



Microprocessor

µP is a complex, powerful device:

Able to process huge amounts of data.

Built using transistors etched on silicon die.

Needs external components to supportoperation.

Microcomputer system – support µPoperations.



Microprocessors Fabrication

1. Microprocessors aremanufactured by etchingtransistors into anempty silicon wafer.

2. The etching processis done in a clean roomusing machines.

3. Once proper leadsand connections areattached, the microprocessor

is ready to be used.



Microprocessor

The microprocessor can be used toperform complex operations by giving it

instructions. These instructions are called programs.

Programs are loaded into memory, and

are executed line-by line by themicroprocessor.



History of

Computers



Microprocessor and Computers

Since its invention in 1970s, themicroprocessor has undergone major

improvements. We can look at the history of

microprocessors by looking at computers

and how they have evolved over theyears.



History of Computers

Has undergone significant improvements:

4 generations until now.

Tied to development of electronics,semiconductors.




VacuumTube

Transistor IC Better ICtechnology

G1 G2 G3 G4




What’s next?

Conventional computing:

Advancements in semiconductor technology. Smaller, faster, less power.

More cores in one processor.

Unconventional computing: Quantum computer.

Chemical computer.

Molecular computer.




First Generation (1954-56):Vacuum Tubes as switches.

Magnetic drums as memory.Very big, unreliable, slow.

Examples:ENIAC (Electronic Numerical Integrator And Computer),UNIVAC (UNIVersal Automatic Computer).



First Generation Computers

Electronic Numerical Integrator and Computer (ENIAC)

Vacuum Tubes




Second Generation (1956-63):

After invention of transistors.

Smaller, faster, cheaper.

Limited to military and business use.



Second Generation Computers

Transistor circuit

Vacuum tube circuit



History of Microprocessors

Third Generation (1964-71):

After invention of Integrated Circuits (IC).

Many transistors can be packed into IC – birth of microprocessors.

Early microprocessors: Intel 8008, Intel 4004.

Medium Scale Integration (MSI) and LargeScale Integration (LSI) devices.



Early Intel Microprocessors



Third Generation Computers

L a p t o p

P C




Fourth Generation (1971-now):

Improvements in IC technology, µP design.

More transistors more processing power.

Very Large Scale Integration (VLSI).

Intel Montecito Itanium: 1 bln. transistors.

Reduced Instruction Set Computers (RISC).32, 64-Bit microprocessors.



Fourth Generation Computers



Comparison between Computer

GenerationsComputer Speed Memory Cost

UNIVAC(1st Gen.)

Pentium III(4th Gen.)

DEC PDP-8(3nd Gen.)

1.3 kHz

1 MHz

500 MHz

1MB

6 kB

128 MB

$1.6 million

$20,000

$700

$47,9001.4kBIBM 1401(2nd Gen.)

2.2 kHz



Microprocessor

Systems



Microprocessor Systems

Definition: A complete electronic system builtaround the microprocessor to support themicroprocessor operation.

May consist of CPU, memory, I/O (disk drives,keyboard, mouse), system bus, and supportingcircuitry.

CPU as the “brain” – controls actions of allcomponents.



Microprocessor System - PC

ROM

Keyboard Mouse HDD

Floppy RAM

CD-ROMSupporting

CircuitryCPU



Microprocessor System - Calculator

Keypad

Memory

Power Supply LCD DisplayCPU



Block Diagram

CPU(Microproc

essor)

MEMORY

Primary:

RAMROM

Secondary:

Floppy

CDROM

Etc.

I/O

Interface

I/ODevices

Data Bus

Address Bus

Control Bus

Unidirect ional :

Signals flow in

one direction.

Bidirect ional :

Signals flow in

both direction

(one at a time).



System Bus

A µP-based system consists of manycomponents:

CPU.Memory.

I/O: disk drives, keyboard, mouse.

System Bus.

All components communicate using System Bus.



System Bus

Communication “highway” for all

components.

A group of wires is called bus. Contains:

Data bus:

Address bus.

Control bus:.



System Bus – Data Bus

Bidirectional (2 ways) bus.

Transfer data to/from the CPU

CPU

R/WControlsignal is

READ

Input

(from

Memory or

I/O devices)

Data bus

CPU

R/WControl

signal is

WRITE

Output

(to Memory

or I/O

devices)

Data bus



Example:Motorolla 68000 microprocessor has 8 bits data bus,

thus: Data size n = 8 bits,

Data lines/bus are labelled Dn : D0, D1, ….. D6, D7

The size of data bus is determined by the number of lines (bits) which is also called data size .



System Bus – Address Bus

Single direction (unidirectional/1 way) bus

Transfer the address data code to memory

or devices.

CPU

Memory

I/O

Devices

CPU to other

elementsADDRESS BUS



Example: Motorolla 68000 has 16 bits of address bus:

n = 16 bits (Size of address bus)

Address bus is labelled An : A0, A1, ….. A14, A15 216 = 65536

CPU can handle or address 65536 single cells (each cell has 8 bits datasize) of memory.



In other words, 16 bit address lines canrepresent 65536 memory location

0 to 65535 locations, addressed as 0000hto FFFFh

16 address lines, then the size of thememory is equal to 216 = 64Kbyte.





1 Kilo = 210 = 1024

1 Mega = 220 = 1024 K

1 Giga = 230 = 1024 M

2n

= RAM size/size of memory



Example 1

8-bit address bus

Address bus labeled A0, A1,………..A7

Memory location 28 = 256

Address 00h to FFh

Size of the memory 28 = 256 byte



Example 2

32-bit address bus

Address bus labeled A0, A1,………..A31

Memory location 232 = 4,294,967,296

Address 00000000h to FFFFFFFFh

Size of the memory 232 = 22 . 230 = 4GB



System bus – Control Bus

Control all the activities of the elements.

Regulate information transfer, interrupts,

error signals. Ensures that only one IC is active at a time

to avoid a bus conflict caused by two IC’s

writing different data to the same bus.



The CPU

“Master” of all components.

Silicon chip that works as “heart” of the

system Job:

Receive instruction from memory to

implement a task.Perform calculations (may use math co-

processor).

Control bus operations.

CPU



The CPU

CPU consists of:

ALU (Arithmetic/Logic Unit):

Performs arithmetic/ logic computations.

CU (Control and Timing Unit):

Responsible to retrieve instructions, analyze, thenexecute.

Control unitRegisters:

Fast internal storage.

Used to temporarily store addresses, data,

processor status.



Memory

Stores instructions/programs and data for CPU.

Each memory location given uniqueaddress.

CPU refers to address to access.

Types:Read-Only Memory (ROM).

Random-Access Memory (RAM).

Memory



RAM, ROM and NVM

Memory NVM

RAM

ROM

Stores start-upinstructions and critical

system data andvariables.

Stores general dataand applications



ROM

Read-Only Memory:

Data can be read, but cannot be written (read-only).

Contents stay without power (non-volatile). Usually contains basic start-up instructions, data.

Stores data permanently without the presence of power supply but with very limited capacity.

Contents hard-wired during manufacturing.Newer versions can be reprogrammed:

PROM: Fuse & anti-fuse.

EPROM: UV light.

EEPROM: Electrical current.



ROM Examples

Quartz Window

EEPROM Programmer

EPROM



RAM

Random Access Memory.

Contents can be read and written.

Loses data without electrical power (volatile). Advantages:

Programs can be loaded and reloaded.

Larger capacity.

Disadvantages:

Requires power, refresh cycles.



RAM vs. ROM

Computer isturned on

CPU looks for instructions frommemory

RAM is still empty

because the computer has just been started.

CPU loadsinstructionsfrom ROM.



RAM vs. ROM

ROM only has basicfunctions to start the computer.

RAM loads moreadvanced functions, suchas the OS.



RAM vs. ROM

RAM (Random AccessMemory)

Volatile

Temporary storage wherethe information will lose

when power off. Read&Write

Flexible for being read or written via software

Operation

RAM is the main memoryof the computer that holdsthe programs andinformation beingprocessed. Usually is usedto stored temporary data.

ROM (Read Only Memory)

Non-Volatile

Retain data even withabsence of power.

Read

Can be read, but not write.

ROMs are programed once(with assistance of hardware)

Operation

It is used by the computer to get started from power on (boot up). It includes

BIOS (basic input/outputsystem)



Control and Timing Unit Timing

Synchronizes all components in the system.

All components refer to the clock timing for operations.

Generates square waves at constant intervals.

Crystal oscillator + timing circuitry.

Higher clock speed allow computers to function

faster .



Crystal Oscillator

Symbol

Equivalent Circuit

Sample



I/O

Input/Output.

Connects µP with external devices:

Add functionality to µP. Interfaces with µP using ports.

Examples:

Keyboard.

Mouse.

Display monitor.





Important

Terminology



Data Size

The capacity of a microprocessor is normally referred tohow many bi ts of data can be handled at one time, or what is the memory size

Data size is a mean of measure to determine how muchdata can be stored in a single cell of memory.

Size of single cell in the memory.

Data type : Bit (B)

Nibble

Word (W)

Longword (L)



Example

A single cell sized 1 bit can store either logic-0 or logic-1. In other word, two different situations can be stored or represented. Thusthe range of data is 0 – 1.

Data size: n = 1

Data capacity : 2n = 21 = 2

Range : 0 – 1

A single cell sized 4 bit (Nibble) can store 16 possible situations.

Data size: n = 4

Data capacity : 2n = 24 = 16

Range : 0 - 15







Try This Question

A single cell sized 1 bit can store either logic 0or logic 1. In other words, two differentsituations can be stored or represented.Determine the following features of a singlecell sized 32-bits.



i) Data type = ?

ii) Data size, n = ?

iii) Data capacity = ?

iv) Range = ?



68000 Data

Organization



Byte View (.B)



Word View (.W)



Longword View



Conclusion



Conclusion

µP is a complex, powerful device:

Able to process huge amounts of data.

µP-based systems provide supporting circuitry tosupport µP functions.

Long history, advancements along withtechnology.

Executes instructions from memory in endlessloop.



Tutorial



Tutorial

Name the 4 computer generations and thetechnological breakthroughs that caused

them to happen. Draw the microprocessor system for a PC

and explain the functions of each

component in the system. List the three major parts of a CPU



Tutorial

What are the three most basiccomponents that are required in any

microprocessor system? What is the function of the memory?

List the two general types of memory.

Explain the difference between RAM andROM.



Is the address bus unidirectional or bidirectional?

Is the data bus unidirectional or bidirectional?

What is the two main facts to determine

the capacity of a microprocessor? What is the definition of data size?



The Motorolla 68000 has 16 bits of address bus:

What is the address size?

How to label the address bus?How many single cells of memory can be

addressed?

The Motorolla 68000 microprocessor has 8 bitsdata bus;

What is the data size and how to label thedata bus?



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Microprocessor Chapter 1