EMBEDDED SYSTEMSUNIT I

EMBEDDED SYSTEMIt is an electrical/electro-mechanical system

designed to perform a specific function.It is a combination of hardware and software

(majorly , firmware).Eg. Washing machines, microwaves, elevators

etc.

Gen. Computing systems Embedded systems

1. Combination of generic h/w and a gen. OS

2. Will have an OS3. Apps are alterable4. Performance is the key

factor5. Response requirements

are not time crictical

1. Combination of special purpose h/w and (or)embedded OS

2. may or may not contain an OS.

3. Cannot be altered4. Performance, power

requirements, memory usage (and other app specific req) are the factors.

5. Time critical

CLASSIFICATION OF ES:BASED ON GENERATION BASED ON COMPLEXITY & PERFORMANCEGENERATION:

FIRST GEN:8 bit microprocessor (8085) & 4 bit microcontrollers. Simple hardware circuits with firmware developed in assembly code.

SECOND GEN: built around 16 bit microprocessors and 8 or 16 bit micro controllers. More complex & powerful . Embedded OS.

THIRD GEN:32 bit microprocessors & 16 bit microcontrollers. App specific and domain specific like DSP.

FOURTH GEN:System on Chips(SOC) , reconfigurable processors , multi core processors.

Classification (Complexity & Performance)SMALL-SCALE ES: Simple in application needs, Requirements are not time critical Low performance & Low cost 8 bit processor. Eg. Electronic toyMEDIUM-SCALE ES:Highly complex hardware & software .Medium performance 16 or 32 bit µp.They usually contain an embedded operating

system for functioning.

LARGE-SCALE ES:Highly complex hardware & software.32 or 64 bit processorsThey are used in Mission critical

applications.

Major Application Areas1. Consumer electronics2. Household appliances3. Home automation & security systems4. Automotive industry5. Telecom6. Computer peripherals7. Healthcare8. Measurements & Instrumentations9. Banking & Retail10. Card Readers.

Purpose of ES1. Data collection/storage/Representation2. Data communication3. Data (signal) processing4. Monitoring5. Control6. Application Specific Interface.

DATA COLLECTION / STORAGE/REPRESENTATION

Performs acquisition of data from the external world.

Usually done for storage, analysis, manipulation and transmission.

Can be text, voice, image , video , electrical etc.

Can be analog or digital data Depending on type of data, it is converted

from analog to digital (A/D converters). The collected data maybe stored directly in

the system or maybe transmitted to another system.

Eg.images are captured They maybe saved in

the memory of the camera.

It can also be presented to the user through an LCD unit.

Data Communication• Embedded terminal

maybe used to transfer data from one system to another , remotely.

• It can be done either by wire-line transmission & wire-less medium.

• Wire-less medium offers cheaper connectivity solutions.

• They can incorporate wireless modules (Bluetooth ,WiFi) or wired modules (USB, TCP/IP)

Data (Signal) Processing• ES with signal processing

functionalities are used In appln like speech coding , synthesis etc.

• Eg.Digital Hearing aid.

Monitoring • Specially designed for

monitoring purpose.• Majority of embedded

products in medical domain come under Monitoring.

• They determine the state of some variables which are input.

• It does not have any control over those variables.

Control • ES with control functionalities force their control

over some variables according to the changes in the input.

• It must contain both sensors and actuators.• Sensors are connected to the input . • The actuators are connected to the output port.• They vary the output according to the variation

in the output.

• Eg.Air-conditioner• The sensors is the room

temperature sensing element & a hand-held unit for feeding the desired temperature.

• The air compressor unit is the actuator.

• The compressor is controlled according to the current room temperature and the desired room temperature set by the user.

Application specific User Interface• They are ES with App

Spc. User Interface like buttons, keypads ,lights etc.

• Eg. Mobile Phone• The user interface is

provided through keypad, LCD(graphical), speaker, vibration alert.

• Eg.Smart Running Shoes.• The adaptive cushioning provided by the shoes

has shock-absorbing characteristics & is customised for each user & also on the running type,pace,body weight and running surface.

• The shoe has a magnetic sensing system to measure cushioning level which is adjusted via a DSP unit that controls a motor-driven cable system

• About 1000 readings/sec are taking & relayed to the shoes µp .

• The µp is positioned under the arch of the shoe.

• It runs an algorithm that compares the compression msgs received and decides whether the shoe is soft or too firm.

• Then the shoes µp commands the micro motor in mid foot which lengthen or shortens a cable secured to the walls of a plastic cushioning element.

• The goal is for the runner not to feel sudden changes .

+ LED lights confirm that the electronics are working fine.

Ms.Sarita BAssistant ProfessorSIES ,Sion(West).