micro intro 1 lecture 1

7/27/2019 Micro Intro 1 Lecture 1

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Basic Processor Architecture andIntroduction to 8085

1

Ramesh BhakthavatchaluDepartment of ECE

EC312 - Microprocessors

[email protected]


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WELCOME

wORLD oF miCRoProCEssoRS


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Foundation

What is a Digital Signal? Basic Blocks of Digital

Systems

Decoder, Encoder, MUX,DEMUX, Flip Flop,


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Foundation What is a Digital Signal?

Add slides from Digital


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Foundation Basic Blocks of Digital

Systems

Design


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Foundation Decoder, Encoder, MUX,

DEMUX, Flip Flop,

Design


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Computer A computer is a machine

It processes information according to alist ofinstructions.

form) and software (instructions).

The information that is processed is

called data.


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Computer Parts & Peripherals

CPU + Memory


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Computer - PC

The hardware has 4 parts.

CPU Controller / Manager of the System

Memory Stores instructions and data

I/O Devices Keyboard, Monitor, etc.

System bus Connects all above.

The Software has 2 parts

An operating system base (windows, etc)

Application software (MS office, matlab,

etc.)


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Computer - Simple diagram


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Computer

(Memory)CPU = ALU + CU

(Output)Monitor

PROCESS

RESULTS

PROGRAMS/DATA

Output devices can be monitor(CRT, LCD), projector, printer,etc.

MICROPROCESSOR

(Input)Keyboard

COMMANDS

Input devices can be KB, Mouse,scanner, barcode reader,sensors, etc


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CPU

The Central Processing Unit (CPU)

executes the sequence of stored instructions

called programs.

The information to be processed is received

from Input devices or Memory. The entire computer system operation

including controlling all the devices and allcomputations involved are performed by

the CPU.


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Microprocessor (P)

CPU has 3 units:- Arithmetic Logic Unit(ALU), Control Unit (CU) and Register Array.

ALU CU REG.

A CPU inside a single chip is called aMicroprocessor (uP).

MICROPROCESSORARRAY


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Microcomputer - PC

Any computer which uses a

microprocessor as its CPU

(central processing unit) is

called a microcomputer.

All personal computers (PC)we see everyday are microcomputers.

Alternately, we can say, any devicewhich works as CPU of a microcomputer

is called a microprocessor.


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Classification of Computers

1.Large Computers

Large, general purpose, multi user, multi

tasking Perform complex scientific and engineering

calculation, handling records for large

v . Supercomputer, Mainframe

2.Medium Size Computer (Mid range)

Minicomputer Slower, smaller memory capacity than

mainframe (ex: IBM AS 400 (1970s))


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3. Microcomputer

All Personal Computers (1970s ..)

Work Stations

Classification of Computers

Single board

Single chip microcomputer uC-Microcontrollers Embedded Systems


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Microcomputer - PC

Microcomputer is a microprocessor based

system. It includes the following:

- Microprocessor, Input/Output and Memory Components are connected through a

communication path called a bus

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How we can differentiate microcomputer anda microprocessor?

uP is one component of the microcomputer

The CPU functions of the microcomputerare performed by the uP

The term peripherals is used for I/O devices.


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uP based System Architecture

(Microcomputer)


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that reads binary instruction from a storagedevice called memory,

accepts binary data as input and

process data according to the instructions,and provides results as output.

Microprocessor

multipurpose, programmable, clock driven, register-based electronic device

Manufactured by using LSI or VLSI technology Operation is similar to human brain

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How we can differentiate CPU & uP ?

The ALU + CU of a microcomputer is

called as CPU. (Central Processing Unit)

CPU is implemented on one or more

Microprocessor

circuit boards to perform the computingfunctions

When CPU is made on a single chip uP it is called as microprocessor

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ALU :- Perform various computing functions

such as arithmetic operations (Addition &

Subtraction) and logic operations(AND/OR/EXOR) etc.

Re ister Arra :- Store data tem oraril durin

Microprocessor

execution of a program and are accessible tothe user through an instruction

Control Unit :- Provides necessary timing and

control signals to all the operations. Controls

the flow of data b/w uP, memory and

peripherals.21


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The typical processor system consists of:

CPU (central processing unit)

ALU (arithmetic-logic unit) Control Logic Registers, etc

Microprocessor

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Input / Output interfaces

Interconnections between these units:

Address Bus Data Bus Control Bus


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Communication path between the uP and

peripherals

Group of wires to carry bits

System Bus

All peripherals share the same bus

uP communicates with only one

peripheral at a time

Timing is provided by the CU of the uP.


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System Bus

address bus: carries theaddress (or) points the locationwithin the memory that isein accesse

data bus: carries the datavalue being communicated

control bus: describes theaction on the address and

data buses24


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CPU-Core of the processor, whereinstructions are executed

High-level language:

= + Assembly language:add r1 r2 r3 Machine language:0001001010111010101

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Problems

"There is only one group of

people who don't haveproblems and they're all dead.

Problems are a sign of life.So the more problems you

have, the more alive you are."

- Norman Vincent Peale26


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Memory

Place where instructions and data

are stored

Organized in arrays of locations

addresses each storin one b te 8

bits) in general

A readoperation to a particular

location (address) always returns thelast value stored in that location

(address)27


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Memory stores binary information as instruction and

data in 2 sections

Read only Memory (ROM) Program in ROM can only be read, not altered.

Memory

Read/Write Memory (RAM Random Access

Mem.)

User Memory

Stores user program & data

Information stored can be easily read and altered


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Consider the monitor program, generally

stored in ROM

This program interprets the information

entered throu h a ke board and

Memory

provides equivalent binary to the uP.

The monitor programs monitors the

Hex Key and stores data in R/W

memory29


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No of address lines and memory size

Assume each location can store 1 byte

2 power 3 = 8 locations

2 ower 5 =32 locations

Memory Structure

2 power 10 = 1024 locations = 1 KB

2 power 20 = 1024 KB = 1MB

2 power 30 = 1024 MB = 1 GB

2 power 40 = 1024 GB = 1 TB


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Memory Architecture

Von Neumann

Architecture

Embedded processors are constructed into 2 mainarchitecture

instructions and

data from same

memory

Limits operating

bandwidth


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Harvard Architecture

Two separatememory spaces for

Memory Architecture

Increases throughput

Different program

and data bus widthsare possible

Ex: PIC uController.


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Input/Output :-

Also known as peripherals

Communicating with the outside world through I/O

In uts devices :- ke board switches ADC

I/O Device (Peripherals)

Transfer binary information from outside world to

the uP

Output devices:- LED, LCD, CRT, Video screen(monitor), XY Plotter, Magnetic Tape, DAC

Transfer data from uP to the outside world33


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I/O Device (Peripherals)

Enable uP system to interact with the world Device interface (a.k.a. controller or adapter)

hardware connects actual device to bus

like memory that can be accessed over thebus.

Readsmay not return last value written

Writesmay have side effects Enable some

operations of peripherals.


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Fetch, Decode, Execute

uP fetches the first instruction from the memory

Decodes it

Execute the instruction

Microprocessor - Working

ses e sys em us o e c e ns ruc on an a a

from the memory in the entire process

Uses registers to store data temporarily

Performs the computing function in the ALU

Sends out the result in binary using the same bus lines

to the o/p.


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Word - No: of bits uP recognizes and process at a time

Machine Language

uP communicates and operates in 0s & 1s instruction in binary language

Assembly language

Some Definitions

Programmer writes the program in English words Symbolic code for each instruction, called mnemonics

Assembler

Program that translates the mnemonics entered from

the keyboard into the corresponding binary machine

codes of the uP36


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- CPU is stand-alone

- RAM, ROM, I/O, timerare separate

- Designer can decide on the

- CPU, RAM, ROM, I/Oand timer are all on asingle chip

- Fixed amount of on-chip

MicroprocessorMicroprocessorMicroprocessorMicroprocessor v/sv/sv/sv/s MicrocontrollerMicrocontrollerMicrocontrollerMicrocontroller

amount o ,

and I/O ports.

- Versatile Applications

- General-purpose

- Ex. 8085,8086 mp,Motorola 6800, Intels

8086, etc.

- For applications inwhich cost, power andspace are critical

- Single-purpose- Ex. 8051, PIC mc,Motorola MCs, Phillips,etc.


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8085 Microprocessor Architecture

Now we will examine these components more closelyby using the Intel 8085 microprocessor architecture

as an example:

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The 8085 Bus Structure

The 8-bit 8085 CPU (or MPU Micro Processing Unit)communicates with the other units using a 16-bit address

bus, an 8-bit data bus and a control bus.

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Address Bus

Consists of 16 address lines: A0 A15

Operates in unidirectional mode: The addressbits are always sent from the MPU to peripheral

devices, not reverse.

16 address lines are capable of addressing atotal of 216 = 65,536 (64k) memory locations.

Address locations: 0000 (hex) FFFF (hex)


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What is the last address of

a 4K memory starting ataddress 2000H? (December

Answer : 2FFFH


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What is the last address of

a 3K memory starting ataddress 31FFH?

Answer : _____H


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Data Bus

Consists of 8 data lines: D0 D7

Operates in bidirectional mode: The data bits aresent from the MPU to peripheral devices, as wellas from the eri heral devices to the MPU.

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Data range: 00 (hex) FF (hex)

Control Bus

Consists of various lines carrying the controlsignals such as read / write enable, flag bits.


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The 8085: CPU Internal Structure

The internal architecture of the 8085 CPU iscapable of performing the following operations:

Store 8-bit data (Registers, Accumulator)

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Test for conditions (IF / THEN)

Sequence the execution of instructions

Store temporary data in RAM during execution


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The 8085: Registers

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Registers

Six general purpose 8-bit registers: B, C, D, E, H, L

They can also be combined as register pairs toperform 16-bit operations: BC, DE, HL

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Registers are programmable (data load, move, etc.)

Accumulator

Single 8-bit register that is part of the ALU !

Used for arithmetic / logic operations the result isalways stored in the accumulator.


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Flag Bits

Indicate the result of condition tests.

Carry, Zero, Sign, Parity, etc.

Conditional o erations IF / THEN are executed

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based on the condition of these flag bits.Program Counter (PC)

Contains the memory address (16 bits) of the

instruction that will be executed in the next step.

Stack Pointer (SP)


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Example: Memory Read Operation

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Example: Instruction Fetch Operation

All instructions (program steps) are stored in memory.

To run a program, the individual instructions mustbe read from the memory in sequence, and executed.

Program counter puts the 16-bit memory address of the

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instruction on the address bus

Control unit sends the Memory Read Enable signal toaccess the memory

The 8-bit instruction stored in memory is placed on the data

bus and transferred to the instruction decoder

Instruction is decoded and executed


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Ready is an input signal

E l I t ti F t h O ti


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8085 Functional Block Diagram


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8085 Functional Block Diagram

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Q & A


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Q & A

Teacher : Tell me 1000 words

in English without using thealphabet a.

Student: Zero, One, Two,

Three,Four,...Nine Ninty

Nine.58


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DISCUSSION


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Upcoming Topics

Assembly language Instructions set of 8085

Simple Programs

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THANK YOU

micro intro 1 lecture 1

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