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Microprocessor

Prepared by : Ala Eldin Abdallah Awouda .2Lecture No 1

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Course Layout:1. Technology and concepts of microprocessors.

2. Von-Neumann Model.

3. p families Intel (486, 386, Pentium).

4. Intel 8085 microprocessor (CPU) Architecture and Addressing

Modes ( register addressing, immediate addressing, direct addressing, register indirect addressing,based addressing, index addressing, based index addressing, string addressing, relative addressing,implied addressing , buses characteristics , main memory (addressing,organization, and architecture), Registers.

5. 8085 Pins, Signals, Bus Cycle, Address, and Data BusConcepts.

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Course Layout:

6. Assembly Language. Instruction Set and Instructions Format instruction, op-code, operands, encoding of instructions anddata, signed and unsigned conditional branch instruction,conditional jump affecting individual flags. Instruction format

7. Address space. The control structure of a stored programsequential, conditional, iteration, subroutines, stack, and data movement instructions (push/ pop, MOV), arithmetic and logicinstructions (shift, add, subtraction, comparison).

8. Instruction cycle: fetch, decode, fetch data, execute, and storeresult.

9. Assembler Dependent and Pseudo Instruction.

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Reference Book:

1. The 8088 and 8086 Microprocessors, Walter A.Triebel and Avtar Singh, Fourth Edition.

2. Microprocessors and Interfacing Programming andHardware, Douglas V. Hall, Second Edition

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Contents: 1. Introduction.

2. What is Computer ?. 3. What is Microprocessor ?.

4. What is CPU ?. 5. Operation Types in a Microprocessor.

6. Microprocessor interfacing.7. The Intel 8086 Microprocessor.

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Why??

A Microprocessor is great at solving problems, but if it cant communicate with the outside world, it is of little worth.

A Microcomputer performs a task by reading andexecuting the set of instructions written in itsmemory. This set of instructions, written in asequence, is called a program .

Each instruction in the program is a command, in binary, to the microprocessor to perform an operation.

Assembly language is low level language. 6/18/2013 Lecture No 1 7

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1-1 Introduction The Microprocessor is something like the heart of a computer. The microprocessor world become more complicated. The item processor was solely used for the central

processing unit ( CPU ) of the von-Neuman-model . The microprocessor can be programmed to perform

functions on given data by writing specific instructionsinto its memory .

The microprocessor reads one instruction at a time,matches it with its instruction set, and performs the datamanipulation specified. The result is either stored back into memory or displayed on an output device.

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1-2 What is Computer ???

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Computer Data Processing

Data Storage

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Major Components of aComputer

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Computer

CPU

MEMORY

I/O SYSTEMBUS

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1-3 What is Microprocessor ?

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CPU

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1-4 What is CPU ?

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Control Unit & Instruction Decoder

Arithmetic/Logic Unit

Registers

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Control Unit & Instruction

Decoder

Arithmetic/Logic Unit

RegistersTo decode instruction and

pass the necessary control signals to CU

To synchronize and control the

overall operation of the P system

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Control Unit & InstructionDecoder

Arithmetic/Logic Unit

Registers

To perform the arithmetic andlogical operations within the CPU

To perform shift and rotateoperations that may either bearithmetic or logical in nature

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Control Unit & Instruction

Decoder

Arithmetic/Logic Unit

Registers

Control and Status Registers User-Variable Registers

A set of internal storagelocations within the CPU

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Past Microprocessors ...

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1971: Intel 4004 - The first microprocessor on the market

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1-5 Operation Types in a Microprocessor

All of the operations of the microprocessor can beclassified into one of three:

- Microprocessor Initiated Operations.

- Internal Operations.- Peripheral Initiated Operations.

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Microprocessor InitiatedOperations

These are operations that the microprocessor itself starts.

These are usually one of four operations: Memory Read. Memory Write. I/O Write(Send data to an output device). I/O Read (Get data from an input device).

It is important to note that the microprocessor treats memory

and I/O devices the same way.6/18/2013 Lecture No 1 18

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Microprocessor Internal Operations

The microprocessor can perform a number of internaloperations such as:

1. Storing Data.

2. Logic Operations.3. Testing for Condition.

4. Arithmetic Operations.

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1-6 Microprocessor interfacing

A microprocessor communicates with other devicesusing some of its pins.

Processors software reads and writes a port just like a

register. Processor has one or more N-bit ports. Processor has address, data and control ports that

form a single bus.

Communication protocol is built into the processor. A single instruction carries out the read or write

protocol on the bus.

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1-7 The Intel 8086 Microprocessor

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1-8 Components of Intel 8086 Architecture

The components of Intel 8086 microprocessor are:

1. Buses.

2. Memory.

3. Registers.

4. I/O Units.

5. Control Unit (CU).

6. Arithmetic Logic Unit (ALU).

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1-9 Von NeumannArchitecture

Early computer programs were hard wired . To reprogram a computer mean to change the hardware switches manually , that took a long time with potential errors . The computer memory wasonly used for storing data .

Dr John von Neumann suggested in 1946 that data and programsshould be stored together in memory, it is now called VonNeumann architecture.

The von Neumann processor has been the foundation of computing from the start . In it the programs are fetched frommemory for executions by a central unit that is what we call theCPU. Basically programs and data are represented on memory inthe same way. The program is just data coded for specialmeaning.

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Cont

A computer design model that uses a processing unit and a single separate storage structure to hold both instructions anddata.

Named after mathematician and early computer scientist

John von Neumann .

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http://en.wikipedia.org/wiki/File:Von_Neumann_architecture.svghttp://en.wikipedia.org/wiki/File:JohnvonNeumann-LosAlamos.gif

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1-10 Components of Von Neumann Architecture

The components of Von-Neumann microprocessor are:

1. Arithmetic Logic Unit (ALU).

2. Control Unit (CU).

3. I/O Units.

4. Memory.

5. Buses.

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Cont Arithmetic Logic Unit (ALU) :

The ALU is where calculation and logical operations take place. Control Unit :

The control unit controls the operations of the memory , ALU ,and the input/output subsystem .

Input/Output:

The input subsystem accepts input data and the program fromoutside the computer; the output subsystem sends the result of

processing to the outside. Memory :

Memory is the storage area. It is where programs and data arestored during processing.

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STORED PROGRAM CONCEPT The von Neumann model states that the program must be

stored in memory . This is totally different from the architectureof early computers in which only the data were stored inmemory.

Both the data and programs should have the same format because they are stored in memory . They are, in fact, stored asbinary patterns (a sequence of 0s and 1s ) in memory.

SEQUENTIAL EXECUTION OF INSTRUCTIONS: A program in the von Neumann model is made of a finite

number of instructions. In this model, the control unit fetches one instruction from memory, interprets it, and then executes it.

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1-11 Von Neumann microprocessor

A Von Neumann microprocessor is a processor that follows this pattern:

1. Fetch: An instruction and the necessary data areobtained from memory .

2. Decode: The instruction and data are separated , andthe components and pathways required to execute

the instruction are activated.3. Execute: The instruction is performed , the data is

manipulated, and the results are stored.

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Cont The Execute is typically implemented by separating the task to:

1. Control : The control unit reads the instruction , andactivates the appropriate parts of the datapath .

2. Datapath: The datapath is the pathway that the data takes

through the microprocessor. As the data travels to different parts of the datapath, the command signals from the controlunit cause the data to be manipulated in specific ways,according to the instruction. The datapath consists of the

circuitry for transforming data and for storing temporarydata . It contains ALUs capable of transforming data throughoperations such as addition, subtraction, logical AND, OR,inverting, and shifting.

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