An Embedded System is defined as a system that has Embedded software and computer hardware,which makes it a system dedicated for an application or a product or constitute as a large part of a system.
It is a system where a Micro-controller or Micro-processor based programmable system is embedded in a larger system.An Embedded System is expected to respond and monitor to External environment using Sensors and Actuators.
If you look around your world you will find a number of items which will classify as an example of an Embedded System -from TV Remotes,Washing Machines,ATM Card,Music Systems to Sophisticated Systems like Mobiles,LAN Systems,Security Products and Defence equipments!
HOW IT IS DIFFERENT FROM A GENERAL PURPOSE SYSTEM
- Embedded Systems use Micro-Controllers while General Purpose Systems use Micro-Processors.
- They use ROM or Flash Memory instead of Primary and Secondary Memory.
- They use Buttons,Switches and Display Units as Input/Output Interface.
- They require a Real Time Operating System for scheduling of tasks which enables finishing of tasks within their Deadline.
CHARACTERISTICS OF AN EMBEDDED SYSTEM
- It performs Real-Time Operations.Such operations need to be fulfilled within a specified deadline.
- It only performs a Dedicated set of Functions.
- It requires Lesser Power and requires Restricted Memory.
- It incurs Low Manufacturing Costs and major cost of it is required in Application dependent Processor.
EMBEDDED HARDWARE UNITS IN A SYSTEM
CLASSIFICATION OF EMBEDDED SYSTEMS
1.Small Scale Embedded Systems
It has little hardware and software complexities and involve board-level designs.It is designed with a single 8-bit or 16-bit Microcontroller.
Examples-Washing Machine,Cooking Machine,CD Drives,Printer,Photocopy Machine,TV Remote etc.
2.Medium Scale Embedded Systems
It is designed using a 16-bit or 32-bit Microcontroller or a Digital Signal Processor or RISC Processor. It requires a Real Time Operating system for scheduling of tasks
For Example-Routers,Switches,Bridges,Video Games,SIM Card,Video Games etc.
3.Sophisticated Embedded Systems
It is designed using 32 or 64 bit RISCs.It may require modern development tools or SOC(System-on-Chip).
For Example-Mobiles,Tablets,Wireless LANs,High speed Networking components ,Real-time Video,High speed Security Products etc.