What is embedded system?
An Embedded System is a combination of computer hardware and software, and perhaps additional mechanical or other parts, designed to perform a specific function. An embedded system is a microcontroller-based, software driven, reliable, real-time control system, autonomous, or human or network interactive, operating on diverse physical variables and in diverse environments and sold into a competitive and cost conscious market. An embedded system is not a computer system that is used primarily for processing, not a software system on PC or UNIX, not a traditional business or scientific application. High-end embedded & lower end embedded systems. High-end embedded system - Generally 32, 64 Bit Controllers used with OS. Examples Personal Digital Assistant and Mobile phones etc .Lower end embedded systems - Generally 8,16 Bit Controllers used with an minimal operating systems and hardware layout designed for the specific purpose.
SYSTEM DESIGN CALLS:
Embedded system design calls on many disciplines
Figure 1(a): Embedded system design calls
EMBEDDED SYSTEM DESIGN CYCLE
Figure.1(b): “V Diagram”
Characteristics of Embedded System
* An embedded system is any computer system hidden inside a product other than a computer. * They will encounter a number of difficulties when writing embedded system software in addition to those we encounter when we write applications. * Throughput – Our system may need to handle a lot of data in a short period of time. * Response–Our system may need to react to events quickly. * Testability–Setting up equipment to test embedded software can be difficult. * Reliability – embedded systems must be able to handle any situation without human intervention. * Memory space – Memory is limited on embedded systems, and you must make the software and the data fit into whatever memory exists. * Program installation – you will need special tools to get your software into embedded systems. * Power consumption – Portable systems must run on battery power, and the software in these systems must conserve power. * Cost – Reducing the cost of the hardware is a concern in many embedded system projects; software often operates on hardware that is barely adequate for the job.
1) Military and aerospace embedded software applications. 2) Communication Applications.
3) Industrial automation and process control software.
4) Mastering the complexity of applications.
5) Reduction of product design time.
6) Real time processing of ever increasing amounts of data. 7) Intelligent, autonomous sensors.
* Real Time Systems.
* RTS is one which has to respond to events within a specified deadline. * A right answer after the dead line is a wrong answer.
* Hard Real Time Systems
* Soft Real Time System
HARD REAL TIME SYSTEM
* "Hard" real-time systems have very narrow response time. * Example: Nuclear power system, Cardiac pacemaker.
SOFT REAL TIME SYSTEM
* "Soft" real-time systems have reduced constrains on "lateness" but still must operate very quickly and repeatable. 2. BLOCK DIAGRAM
Figure 2: Block Diagram
3. HARDWARE REQUIREMENTS
1. POWER SUPPLY
2. MICROCONTROLLER (AT89S52/AT89C51)
3. PUSH BUTTONS