Chapter 2 Introduction To Microprocessor

7/28/2019 Chapter 2 Introduction To Microprocessor

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CHAPTER 2 :

INTRODUCTION TO

MICROPROCESSOR


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At the end of the class,

U should be able :

1) Illustrate internal architecture of

microprocessor

2) Describe fetch and execute cycle

3) Identify trends in microprocessor technology

4) State families of microprocessor

5) Illustrate the programmers model of 680006) Identify features of 68000 microprocessor

7) Illustrate hardware connection of 68000


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INTERNAL STRUCTURE OF

MICROPROCESSOR

MC68000


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Arithmetic Logic Unit (ALU) section:

Performs variety of arithmetic and logic

operations on data, such as addition,

subtraction, AND, OR, EX-OR, shifting,

incrementing, and decrementing.

The more advanced MPU have ALUs that can

do multiplication and divisions.


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Registers section:

These internal registers serve as temporary data

storage, before, in progress and after the process

done by ALU. Data transfer within these registers

is much faster as compared to the memory.

This section contains various registers (inside the

MPU), each of which performs a special function.

These registers are: general purpose registersarray, accumulator, instruction register, program

counter, and flag register.


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Control and timing section:

The main function is to fetch instruction codes from

program memory.

Then decode (interpret) them, to generate into

necessary control signals from MPU Then to execute the instructions.

This section also generates timing and control signals

(eg. R/W clock), that are needed by external RAM,ROM, and I/O devices.


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BASIC OPERATION OF

MICROPROCESSOR

FETCH AND EXECUTE CYCLES


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OPERATION OFCOMPUTERSYSTEM

How a computer system works?

Before a computer system is switched ON, CPU and RAMstore no data. ROM permanently stores a short programfor initializing the computer system.

When the computer is switched ON, CPU will READ

data/program that stored in ROM, two tasks is performed :


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Devices that are readily connected to the computer will be

reset to a standby mode.

System programs from permanent storage will betransferred to the RAM.

System program will display instructions to guide

the user to proceed accordingly


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Fetch and execute cycles

3) Microprocessor

continue the next

instruction.

1) Microprocessor fetch instructionrepresenting the signal carried

by the address bus.

2) Microprocessor

execute the instruction.

START

Fetch (next)Instruction

ExecuteInstruction

STOPYes

No Isit a HALT

instruction?


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Example

a.) Add two data which are stored in memory

at address 0001 and 0002.

b.) Store the result in the memory at address

0003.

Show the above process in terms of fetch and

execute cycles.


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solution


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Within the fetch cy cle, there are two operations or sub-cycles,

i.e. Read and write.

READ CYCLE

CPU sends a signal via control bus. If the bus is

busy, CPU is put on Wait state.

If the bus is free, CPU will place instruction addresson the address bus.

This address will be decoded or translated by the

circuitry in the memory or I/O interface.

Finally the data at that specific address is obtained,and is placed on the data bus.


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READ CYCLE


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Location 00Location 01Location 02

Location 03Location 0400011000

Location FELocation FF

Address

decoder

control

8 bits

8 bit Address

bus

8 bit data

bus

selectData to CPU

0001100000000101

RD

WR

Reading frommemorymemoryMicroprocessor

issues addresssignal to memory

through address bus

Address decoder

decoded the addressand activates aselect line

Microprocessor

sends a Read signalto memory

The control circuit in

memory initiates aread action

Data at location05H is placedonto the databus and read bymicroprocessor


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WRITE CYCLE

Write cycle enables CPU sends data to the memory o

I/O devices.

CPU will send a signal (request to write) to the control

bus.If the data bus is free, the data is placed on the data

bus, whereas the location address will be placed on th

address bus.

CPU will then send the data to the destination with

respect to the address.


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WRITE CYCLE


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Location 00Location 01Location 02

Location 0300011000

Location FELocation FF

Address

decoder

control

8 bits

8 bit Address

bus

8 bit databus

select

data bus

00000100

RD

WR

Microprocessorissues addresssignal to memorythrough address bus

Address decoderdecoded the addressand activates a

select line

Microprocessor

sends a write signalto memory

01110000

00100000

The control circuit in

memory initiates aread action

Data sent bymicroprocessorthrough the databus

00100000


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Evolution of microprocessor between Intel and

Motorola


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TAHUN/PENGELUAR INTEL MOTOROLA

1971 4004,4 Bit,2000 Transistor,

108 KHZ

1972 8008, 8bit

1974 8080, 8 bit1977 8085, 8 bit

1978 8086, 16 bit, 29000

trqansistor, 2 MHz

1979 8088, 8 bit tetapi strktur

dalaman sama dengan 8086

68000, bas data dalaman 32

bit, bas data luaran 16 bit

1982 80286, 32 bit, 275 000

transistor, 16-20 MHz

1984 68020, bas data dan alamat 32bit

1985 80386, 32 bit, 1.2 juta

transistor, 25-66 MHZ

1989 80486, 32 bit, 1.2 juta

transistor, 25-66 MHz

68040

1993 Pentium, 4 bit, 3.1 juta

transistor, 60-166 MHZ

1994 68060, 16 bit

1995 Pentium Overdrive & PentiumPro150, 166, 180 dan 200 MHz

1997 Pentium II, 300 MHz, 7.5 juta

transistor

1999 Intel Celeron

1999 Pentium III pada 800Eb Mhz,

866 Mhz, 933 Mhz, 1B Ghz

dan 1.13 Ghz

2000 Pentium IV, 400 Mhz


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Mc68000 family summary


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Register Set of MC68000

Programmers model of the 68000


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The working element of a microprocessor is the

internal registers, where raw data and addresses to

be stored, moved around and transferred to be

processed in the ALU. The MC68000 is an internal 32-bit processor,

meaning that each register has 32 bits and the

processor can perform arithmetic and logic

operations on 32-bit operands.


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Programmers model of the 68000


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DATA REGISTER

8 data registers namely D0 D7

Used to hold data temporarily for the use in

processing.

Each registers can be accessed for byte

operands (0-7), word operands (0-15 bits) or

long-word operands (0-31 bits).

Function:

Used to store information within the 68k

microprocessor itself.


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ADDRESS REGISTER

A0 - A7

Address register are not provided for storage of data for processing.

Instead, they are meant to store address information

Although every registers contain 32 bits, only the lower 24 bits are used to

access memory. Therefore, the address range is 2

24

(16M) byte.

Function:

Used to store the location where data can be founded outside the processor. Ex:

external memory chip. A7 usually is used to execute subroutine.


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STACK POINTER (SP)

Address register A7 also serves as SP either

supervisor stack pointer (SSP) or the user

stack pointer (USP), depending on the

supervisor bit in the status register.

Used to save the program counter when

branching to a subroutine.


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STATUS REGISTER (SR)

The status register (SR) has 16 bits and is divided into

the system byte and user byte.

The user byte contains five condition flags. The

remaining 3 bits are not used and remain zero. The condition flags contain information on the result

of the last processor operation. The setting can be

tested by conditional branch instructions.


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PIN CONFIGURATION OF

MICROPROCESSOR CHIP


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Mc68000 features

32 bit data and address registers

16 bit data bus

24 bit address bus

14 addressing modes

Memory-mapped input-output

Program counter

56 instructions

5 main data types


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Clock speeds : 4 MHz to 12.5 MHz

7 interrupt levels

synchronous and asynchronous data transfer


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TUTORIAL What are the two major microprocessor

manufacturers? How many data registers are in the

MC68000?

How many address registers are in theMC68000?

What is the size of data registers in MC68000?

What is the total number of data bus lines inMC68000?

What is the total number of address bus lines

?

Chapter 2 Introduction To Microprocessor

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