EMBEDDED SYSTEMPresented by:IQBAL HUSSAIN

ELECTRONICS&COMMUNICATI0NFinal year

CONTENTS

WHAT IS AN EMBEDDED SYSTEM? Block Diagram of an Embedded System. WHAT’S A MICROCONTROLLER? INTERRUPTS ADDRESSING MODES. INTRODUCTION 8051 ASSEMBLY PROGRAMMING INTERFACING OF STEPPER MOTOR BY USING

8051 APPLICATI0N OF EMBEDDED SYSTEM

WHAT IS AN EMBEDDED SYSTEM?

“ An embedded system can be defined as those control systems which are designed either by microprocessor or microcontroller for a specific tasks. ” OR“ An embedded system is some combination of computer hardware & software, either fixed in capability or programmable, that is specifically designed for a particular kind of application device. ”

BLOCK DIAGRAM OF AN EMBEDDED SYSTEM

WHAT’S A MICROCONTROLLER?

A microcontroller is a computer-on-a-chip,

or, a single-chip computer. Micro suggests That the device is small, and controller tells that the device might be used to control objects, processes, or events. Another term to describe a microcontroller is embedded controller, because the microcontroller and its support circuits are often built into, or embedded in, the devices they control.

THE 8051 MICROCONTROLLER:

• The 8051 is the first microcontroller of the MCS-51 family introduced by Intel Corporation at the end of the 1970’s.

• The 8051 architecture contains the following:o 4K Bytes ROMo 128 Bytes RAMo two timer/counters (16 bit)o A serial porto 32 input/output porto Interrupt controllero 16 bit program counter(PC) and data pointer(DPTR)o 2 external and 3 internal interrupt sources Oscillator and clock circuitso 8 bit program status word(PSW)o 8 bit CPU with registers A and B etc.

Interrupts

Definition of ‘Interrupt:-“Event that disrupts the normal execution of a program and causes the execution of special instructions”.

types of interrupt

hardware software(RST0,….RST7) (TRAP,RST7.5,6.5,5.5,INTR)

VECTORED NONVECTORED

ADDRESSING MODES

An "addressing mode" refers to how you areaddressing a given memory location. Insummary, the addressing modes are asfollows. . . . Immediate Addressing Register Addressing Direct Addressing Indirect Addressing

INTRODUCTION 8051 ASSEMBLY PROGRAMMING

It was time that hardware-oriented to the core made compromise if they wanted to stay “in the game”. Namely, unlike other circuits which only need to be connected to other components and powered in order to be of any use, microcontrollers require to be programmed as well. Fortunately, they still didn't progress so far in their evolution, so that all microcontroller families “understand” only one language - machine language. That's a good thing. The bad one is that, even primitive, this language of zeros and ones can only be understood by microcontrollers and some of the experts working on its development. In order to bridge this gap between machine and humans, the first high-level programming language called Assembly language was created.

The main problem of remembering codes recognized as instructions by electronics was solved therefore, but another one, equally complicated to both us and “them”(microcontrollers) arose. This problem was also easily solved by means of the program for a PC called assembler and a simple device called programmer.

This program enables the PC to receive commands in the form of abbreviations and convert them unerringly into so called “executable file”. The moment of compiling a program into machine language is crucial as this file, called HEX file, represents a series of binary numbers understandable to microcontrollers only. The program written in assembly language cannot be executed practically unless this file is loaded into the microcontroller memory. This is the moment when the last link in the chain - the programmer - appears on the scene. It is a small device connected to a PC via some of the ports and has a socket for placing chip in.

RUNNING AN 8051 PROGRAMA

EDITORPROGRAM

ASSEMBLERPROGRAM

LINKERPROGRAM

OHPROGRAM

Myfile.asm

Myfile.objOther obj file

Myfile.lst

Myfile.hex

ABSOLUTE FILE

MS-DOS,NOTEPAD

STRUCTURE OF ASSEMBLY PROGRAM

{Label :} INSTRUCTION {; comments}

MNEMONICS OPERANDS

DESTINATION SOURCE

STEPPER MOTOR

A stepper motor is a widely used device that translates electrical pulses into mechanical movement

The stepper motor is used for position control in applications such as disk drivers, dot matrix printers, and robotics, etc.

Every stepper motor has a permanent magnet rotor (also called the shaft) surrounded by a stator .

The most common stepper motors have four stator windings that are paired with a center-tapped common.

This type of stepper motor is commonly referred to as a four-phase stepper motor

The center tap allows a change of current direction in each of two coils when a winding is grounded, thereby resulting in a polarity change of the stator.

The stepper motor discussed here has a total of 6 leads, 4 leads representing the four stator windings ,2 commons for the center tapped leads.

As the sequence of power is applied to each stator winding, the rotor will rotate.

STEPPER MOTER 4-STEP SEQUENCE

INTERFACING OF STEPPER MOTOR BY USING 8051

APPLICATI0N OF EMBEDDED SYSTEM

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1.AUTOMATIC CONTROLLING OF CARS

3.Product: NASA'sMars SojournerRover.

4.Product: Sony AiboERS-110 RoboticDog.

THANKS.

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