Embedded Systems

   EMBEDDED SYSTEMS:

A system is an arrangement in which all its unit assemble work together according to a set of rules. It can also be defined as a way of working, organizing or doing one or many tasks according to a fixed plan. For example, a watch is a time displaying system. Its components follow a set of rules to show time. If one of its parts fails, the watch will stop working. So we can say, in a system, all its sub-components depend on each other.

"Embedded system" as its name suggests, Embedded means something that is attached to another thing. An embedded system can be thought of as a computer hardware system having software embedded in it. An embedded system can be an independent system or it can be a part of a large system. An embedded system is a micro-controller or microprocessor based system which is designed to perform a specific task. For example, a fire alarm is an embedded system; it will sense only smoke.

Embedded system is the combination of hardware, software, and RTOS(Real Time Operating System). Eg: Air Conditioner, Refrigerator, Washing Machine, etc., Since it is a system, the machine will start(output on) when we give the input( when we switch on the machine) but it is not only included current but, it also comprises of hardware (i.e., machine components), software( the machine is programmed to function), RTOS( to connect h/w + s/w). Hence, these are called an Embedded system. Generally, OS[Operating System] is used to connect our hardware system with user-interface i.e. , software.

Since Embedded system is the combination of h/w and s/w, RTOS is used to merge it.

So finally equation will be like:

Embedded system= h/w + s/w + RTOS.

Flight Deck Systems

So questions may arises, Do all embedded systems have an operating system?

The answer is 'Not Often'.

An operating system is often not required, even if you are using a “middleware” stack like TCP/IP, USB or a file system.

Sometimes chips are just too small — for example, you’re never going to fit an OS on the , with only 256 12-bit words of flash and 16 bytes of RAM.

When one thinks of operating systems for micros, Linux comes to mind but it is not really suited for most embedded systems because standard Linux is not real-time, and it requires a fast 32-bit processor with a Memory Management Unit (MMU) and many MBs of memory.

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Most Real-time Operating Systems(RTOS) that we already mentioned for embedded devices are not a full OS in the sense that Linux is; they may provide only task scheduling, Inter-Process Communication (IPC), synchronization timing and interrupt services — essentially the "kernel" only. They don’t include all the utilities and user programs because they are designed to be used by a dedicated application, instead of users that are logged in.

Where simply in Electronics world Embedded systems is combination of “hardware and software” i.e. an electronic system that has a computer software that is embedded in a computer hardware. A hardware platform is generally a micro controller or microprocessor in which the program is dumped. The hardware has its own software. They are either Machine code (hex code) or Programming code ( C, C++ code).

For example, take 8051 controller. Here we embed program into it and it performs the task as per the program instructions. One things to note on is that majority of current generation's embedded system are are build up off with microcontroller rather than microprocessor the reason is simple that is in case of microprocessor it get connected with external IO devices / memory devices as well as several other peripheral devices. While in case of microcontroller, all this external peripheral devices get connected with microprocessor and customised on a single board.

Most people confuse General purpose system (GPS) with Embedded system (ES) . A GPS does multiple tasks. Take example, Laptop. Here we can do multiple things at a time( Watch video, write mail, etc) . But an Embedded system is destined to do a single particular task. Take example, Pace Maker. This device keeps monitoring heart beat, so when heart pump goes slow, it takes counter acting action and make heart beat come back to normal condition.

Here are some major points of Embedded system to know.

• All Embedded System are single function. i.e have single objective.
  Real Time performance i.e if input given at any unpredictable time, the system perform action without any delay.
  Multirate. Take example Camera. It can be color, Black & white or motion. Here all these supported for a particular camera action. So an Embedded system have Multiple rate operation.

• So Before the end of the article I want to mentioned one main advantage of embedded system:

• The main advantage of embedded systems is the decentralization of processing power. So instead of one central processor that handles all tasks, you have many embedded processors running in parallel. This system is scaleable and has better performance than a system based on the central processor.