1. UNIT I

2. EMBEDDED SYSTEM It 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.

3. Gen. Computing systems Embedded systems 1. Combination of generic h/w and a gen. OS 2. Will have an OS 3. Apps are alterable 4. Performance is the key factor 5. 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 altered 4. Performance, power requirements, memory usage (and other app specific req) are the factors. 5. Time critical

4. CLASSIFICATION OF ES: BASED ON GENERATION BASED ON COMPLEXITY & PERFORMANCE GENERATION: 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.

5. 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.

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

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

8. Major Application Areas 1. Consumer electronics 2. Household appliances 3. Home automation & security systems 4. Automotive industry 5. Telecom 6. Computer peripherals 7. Healthcare 8. Measurements & Instrumentations 9. Banking & Retail 10. Card Readers.

9. Purpose of ES 1. Data collection/storage/Representation 2. Data communication 3. Data (signal) processing 4. Monitoring 5. Control 6. Application Specific Interface.

10. 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.

11. 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.

12. 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)

13. Data (Signal) Processing ES with signal processing functionalities are used In appln like speech coding, synthesis etc. Eg.Digital Hearing aid.

14. 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.

15. 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.

16. 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.

17. 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.

18. 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 µ p.

19. The µ p 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 µ p 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.

20. Ms.Sarita B Assistant Professor SIES,Sion(West).