introduction to embedded system

SUBMITTED BY:NITEESH KUMAR[EI 3rd YEAR]ROLL No.-0903532017

04/12/23 1niteesh kumar(BBDIT)

WHAT IS AN EMBEDDED SYSTEM?

A special purpose computer that can perform a single or few functionalities .

Functionalities is done by dedicated HW & SW with limited resources.

On average, a person is interacts with 100s of embedded system on daily basis.

Embedded system are of high diversity.

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BLOCK DIAGRAM

CPU

MEMORY

A/D

SENSOR HUMAN INTERFACE

D/A ACTUATORS

LCD

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EMBEDDED SYSTEM CONSIST OF:

An EMBEDDED SYSTEM consist of:

Hardware Software

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HARDWARE

The physical components of a system.

Ex.- CPU MEMORY SENSOR

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A TO D CONVERTORD TO A CONVERTORACTUATORSLCD

CONTINUE…

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CPU The central processing unit (CPU) is the

portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system.

It is similar to the BRAIN. Performs arithmetic , control and I/O

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CPU STRUCTURE

Registers Internal bus

Address Bus

Data Bus

Control Bus

CU : Control Unit ALU: Arithmetic Logic

Control

CU

REGISTERS

INTERNALBUS

ALU

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REGISTERS

Temporal storage inside the CPU Flip-flop and latches

A register can be:A general purpose register

Carry out program or data processing

A control registerControl the program or CPU

A status/flag registerShow the current status of CPU

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ALU

Carries on:Arithmatic operations

+,-,/…..

Logic operationAND,OR ,SHIFT,etc

Operates and store results in general registers

Store operation status status/flag registers carry occurrence,overflow occurance, etc.

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CONTROL UNIT

Control the internal flow to fetch,decode and execute instructions

INSTRUCTIONS

INSTRUCTION REGISTER

INSTRUCTION REGISTER

INSTRUCTION DECODER

INSTRUCTION DECODER

CONTROL SIGNAL

GENERATOR

PROGRAM COUNTERPROGRAM COUNTER

MEMORYDEVICE

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MEMORY

• They are used store data and instructions

• They can divided into :Volatile memory

When power is off, content are lost

Non volatile memoryWhen power is off, content are preserved

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CLASSIFICATION

MEMORIESMEMORIES

NON-VOLATILENON-VOLATILE

VOLATILEVOLATILE

SRAMSRAM

DRAMDRAM

E2PROME2PROM

NAND FLASHNAND FLASH

NOR FLASHNOR FLASH

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PROCESSOR IN EMBEDDED

In EMBEDDED SYSTEMS we use microprocessor or microcontroller IC

MICROCONTROLLER is widely used because it :

Consume less power

Reduce complexity

Internal memory

Internal timer/counter

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MICROPROCESSOR

A microprocessor incorporates the functions of a computer's central processing unit (CPU) on a single integrated circuit

Ex- intel 8085,8086,Z80 etc.

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The features of INTEL 8085 are :

It is an 8 bit processor.

It is a single chip N-MOS device with 40 pins.

THE 8085 µP

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CONTINUE….

It has multiplexed address and data bus.(AD0-AD7).

It works on 5 Volt dc power supply. The maximum clock frequency is 3 MHz

while minimum frequency is 500kHz. It provides 74 instructions with 5 different

addressing modes.

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CPUGeneral-Purpose Micro-

processor

RAM ROM I/O Port

TimerSerial COM Port

Data Bus

Address Bus

General-Purpose Microprocessor System

CPU for Computers No RAM, ROM, I/O on CPU chip itself Example--Intel’s x86: 8086,8088,80386,80486, Pentium

Many chips on mother board

GENERAL PURPOSE µP

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8085 IC

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PIN DIAGRAM

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AD0-AD7: Multiplexed Address and data lines.

A8-A15: Tri-stated higher order address lines.

ALE: Address latch enable is an output signal. It goes high when operation is started by processor .

S0,S1: These are the status signals used to indicate type of operation.

RD¯: Read is active low input signal used to read data from I/O device or memory.

WR¯: Write is an active low output signal used write data on memory or an I/O device.

PIN DESCRIPTION

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READY: This an output signal used to check the status of output device. If it is low, µP will WAIT until it is high.

TRAP: It is an Edge triggered highest priority , non mask able interrupt. After TRAP, restart occurs and execution starts from address 0024H.

RST 5.5,6.5,7.5: These are maskable interrupts and have low priority than TRAP.

INTR¯&INTA: INTR is a interrupt request signal after which µP generates INTA or interrupt acknowledge signal.

IO/M¯: This is output pin or signal used to indicate whether 8085 is working in I/O mode(IO/M¯=1) or Memory mode(IO/M¯=0 ).

CONTINUE….

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HOLD&HLDA: HOLD is an input signal .When µP receives HOLD signal it completes current machine cycle and stops executing next instruction. In response to HOLD µP generates HLDA that is HOLD Acknowledge signal.

RESET IN¯: This is input signal. When RESET IN¯ is low µp restarts and starts executing from location 0000H.

SID: Serial input data is input pin used to accept serial 1 bit data .

X1 & X2 : These are clock input signals and are connected to external LC,or RC circuit. These are divide by two so if 6 MHz is connected to X1X2, the operating frequency becomes 3 MHz

VCC & VSS: Power supply VCC=+ -5Volt& VSS=-GND reference.

CONTINUE….

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ARCHITECHTURE

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MICROCONTROLLER

A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals

Ex- intel 8051,ATMEL,MOTOROLA,etc.

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Microcontroller

RAM ROM

I/O Port

TimerSerial COM Port

CPU

A smaller computer. On-chip RAM, ROM, I/O ports... Example:- Motorola’s 6811, Intel’s 8051

and PIC 16X

A single chip

MICROCONTROLLER

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

8051 IC

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8051 IC

The 8051 family characteristics: 4K Bytes ROM 128 Bytes RAM two timer/counters (16 bit)A serial port 32 input/output port Interrupt controller

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INTERNAL ARCHITECHTURE

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Ground

Voltage Supply

(+5V)

PIN DIAGRAM

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Port 0 from Pin-39 to Pin-32

An 8-bit open drain bidirectional port.

DUAL FUNCTION

Used to access both data and address

CONTINUE….

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Port 1 fromPin-1 to pin-8

8-bit bidirectional I/O port with internal pull-ups

CONTINUE….

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Port 2 fromPin-21 to pin-28

Used to access address and I/O

CONTINUE….

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Port 3 from Pin-10 to Pin-17

P3.0 : RxD(serial input port)P3.1 :TxD (serial output port)P3.2 :INT0 (external interrupt 0)P3.3 :INT1 (external interrupt 1)P3.4 :T0 (timer 0 external input)P3.5 :T1 (timer 1 external input)P3.6 :WR (external data memory write strobe)P3.7 :RD (external data memory read strobe)

CONTINUE….

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crystal

reset

External memory

Add. Latch enable

Program Store Enable

CONTINUE….

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SENSOR

A sensor (also called detectors) is a device that measures a measurable attribute and converts it into a signal which can be read by an observer or by an instrument.

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TYPES

Electric current, electric potential, magnetic

Optical, light  Pressure  Force, density, level Thermal, heat, temperature

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EXAMPLES

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IR SENSOR

An object reflects,transmits, and emits

energy, as shownin the diagram.

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REQUIREMENT

To detect & differentiate between two contrasting surfaces

Generally, black & white Small & attachable Operates at +5V and also gives output in TTL

(0V/5V) Configurable

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Reflects most of the incident light

Absorbs almost of the incident light

Photodiode(detector)

Photodiode(detector)

WORKING

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Hurray! I‘ve found

whiteI think I am on black

surface

CONTINUE….

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LINE FOLLOWER

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CKT. DIAGRAM

3.5V

4V

5V

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CONTINUE….

3.5V

2.5V 0V

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A TO D CONVERTER

An analog-to-digital converter (abbreviated ADC, A/D or A to D) is a device that converts a continuous quantity to a discrete time digital representation

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SAR ADC

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An 8-level ADC coding scheme

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D TO A CONVERTER

A digital-to-analog converter (DAC or D-to-A) is a device that converts a digital (usually binary) code to an analog signal(current , voltage, or electric charge)

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BLOCK DIAGRAM

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OUTPUT

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ACUATORS

An actuator is a type of motor for moving or controlling a mechanism or system. It is operated by a source of energy, usually in the form of an electric current, hydraulic fluid pressure or pneumatic pressure, and converts that energy into some kind of motion

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ActuatorsActuators

RotationalRotational LinearLinear

PneumaticsPneumaticsDC MotorsDC Motors Stepper MotorsStepper Motors

GearedGeared RC ServoRC Servo BipolarBipolarUnipolarUnipolar

ArtificialMusclesArtificialMuscles

HydraulicsHydraulics

TYPES

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DC MOTOR

A DC motor is an electric motor that runs on direct current (DC) electricity. DC motors were used to run machinery

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DC ELECTRIC MOTOR

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DC GEARED

Reliable, sturdy & relatively powerful

A major actuator in robotics

Easy to use Available in

various shapes and sizes

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INSIDE DC GEARED

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DC SERVO

A servomotor is a motor which forms part of a servomechanism. The servomotor is paired with some type of encoder to provide position/speed feedback

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SERVO

Remote Controlled Servo (RC Servo)

Used mostly in RC aeroplanes and cars

Needs PWM signal to control its position

Cannot rotate more than 180 degrees

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Signal Conditioning

(Analog/Digital)Driver

GearedMotor

POT

Basic Operation of a RC Servo Motor

RC Servo Motor

Vcc

Gnd

PWMControl Signal

SERVO CONTROL

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INSIDE SERVO

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STEPPER MOTOR

• A stepper motor (or step motor) is a brushless DC electric motor that can divide a full rotation into a large number of steps. The motor's position can be controlled precisely without any feedback mechanism

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1 2 3 4

1 0 0 0

0 1 0 0

0 0 1 0

0 0 0 1

Truth table

CLOCKWISE ROTATION

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UNIPOLAR STEPPER

FULL STEPPING

(wave drive)

a,b 1a 1b 1c 1d

0 1 0 0 0

0 1 1 1 0

0 1 1 1 0

0 0 0 0 1

cw

ccw

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BIPOLAR STEPPER

Construction is similar to unipolars but without the center taps

Current flows in both directions

Highest Torque Complex driving

circuitry

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IDENTIFYING STEPPER

Unipolar Steppers• Mostly have 5 to 6 wires• There are always 1 or 2

commons

Bipolar Steppers• Always have 4 wires• No commons

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PNEUMATIC

Powerful Complicated Expensive Bulky

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DC motors are always preffered over stepper motors

There are many things which we can do with our DC motor when interfaced with microcontroller

MOTOR INTERFACING

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CONTINUE….

For example: we can control the speed of motor we can control the direction of rotation we can also do encoding of the rotation

made by DC motor i.e. keeping track of how many turns are made by our motors etc.

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CONTINUE….

Usually H-bridge is preferred way of interfacing a DC motor.

L293D is most used H-Bridge driver IC.

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IC L293D

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WORKING

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M

+Vcc

GNDniteesh kumar(BBDIT)

LCD

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PIN CONFIGURATION

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PIN DESCRIPTION

Connections JP1 Pins 1 - 8 Description JP1 Pins 9 -16 Description

Pin1 Ground Pin9 D2 (Not Used)

Pin2 VCC (+5) Pin10 D3 (Not Used)

Pin3 Contrast Pin11 D4 Pin4 Data/Command (R/S) Pin12 D5 Pin5 Read/Write (W) Pin13 D6 Pin6 Enable (E1) Pin14 D7 Pin7 D0 (Not Used) Pin15 VCC (LEDSV+)

Pin8 D1 (Not Used) Pin16 Ground

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Software’sSoftware’s UsedUsed

Kiel µVision Top View Simulator

Express PCB

SOFTWARE

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EXAMPELS

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APPLICATIONS

Industrial automation Electronics application and consumer

device Communication application Biomedical application Mobile phone Digital camera Robots04/12/23 78niteesh kumar(BBDIT)

APPLICATIONS

Point of sales terminals Automatic Chocolate Vending Machine Stepper motor controllers for a robotics

system Washing or cooking system Multitasking Toys Microcontroller- based single or multi-

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APPLICATIONS

digital panel meter for voltage, current, resistance and frequency

Keyboard controller

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QUESTION

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