~: Embedded Systems :~

It will not be wrong if i would say for a man in a day of today's life he will be coming in touch with more then 5-10 different kind of embedded systems although he is completely unaware of that. Amazed !!!!!!.... But this is really true. Embedded systems are so much penetrated in human life that no one has ever imagine. Cell phones, PDAs, IPODs, TV, music systems, car or any other automobile, toys, virtual reality based games, refrigerators, ACs, washing machines, microwaves and almost all other home appliances are now equipped with either light or heavy embedded system. For the industries embedded system is vital part. Robotics, CNC machines, motion controllers, AC/DC drives, stepper motor controller, PLC based automation, sensors, rectifiers, invertors, etc all are very good example of embedded systems.  And how can we forget military, satellite and space applications? One can not imagine these applications without embedded systems. Missile technology, high explosive bombs, fighter planes, tanks, rocket technology, different satellites all these become possible because of embedded system.

So now when we have understood the importance of embedded systems in domestic as well as industrial applications, one will be curious to know what is this embedded system ?  In a wide sense Embedded system is a combination of software and hardware designed and programmed to perform one/more particular task(s). The hardware is designed for specific application and then software is embedded in this hardware to perform the task. Both software and hardware are dedicated to that particular application. The heart of the system is either processor or controller. Processor / controller may be general purpose or special purpose that controls whole system. There may be more then one processor/controller if system is complex. It may be possible that there is one general purpose processor / controller and one or more special purpose processors / controllers. For example in 3G (or 4G) cell phones there is one general purpose processor that handles user commands, memory and display etc. And there are special purpose processors like DSP for voice communication and network management, display controller to generate real and reach images on color LCD screen.

To get better idea of these systems let us understood this by some examples.

Example 1 - TV: - now a days TVs are coming with advance features like auto volume control, auto brightness and contras control etc. In auto volume control there is a set value of volume set by user. So the TV will always see the input audio signal strength and compare with this set value. If it doesn't match it will either increase or decrease it so volume will be automatically set. So when ever you change the channel in your TV you need not to change volume. In second feature there is a light sensor in TV that sees room light. It detects the room light and gives the signal to internal processor. Processor process the information and automatically adjust the brightness and contras to get the best viewing result.

Example 2 - AC: - The AC with automatic temperature control is another example of embedded system. Once the temperature is set by user to some value AC will try to keep this temperature in room. If the temp goes down then for some time the compressor will be off. Again when temp increases above specified limit compressor will be on.  

Example 3 - motion control: - if you want to see the example of any industrial application then motion control will the perfect one. The speed of AC/DC motor is kept constant using embedded system. The speed of motor is set depending upon application requirement. This set value is sensed by sensor and given to controller or processor. Now if the speed of motor changes suddenly then this value is feedback to controller/processor and it will compare the value with set one. Then it will increase or decrease the speed of motor to match it with set value.

Example 4 - missile technology: - most of surface to surface or air to surface missile have technology to automatically lock their target. Initially the co-ordinates, digital image, digital map is fed into the missile controller. The missile will automatically create its virtual path from source to destination. After launch it will continuous track its path and it will be continuously guided by GPS. If there is any deviation in set path then controller will again divert the missile to right path by making suitable corrections and taking guidance by GPS. Before final few minutes of explosion it will take a picture of target and compare it with digital image make final few correction to hit exact target and finally BOOM BOOM !!!!!!!!........It's always Bulls Eye.

Here I have illustrated some of the example which is purely industrial applications. In most of the manufacturing industries these kind of systems are always exists. I have used 89C51 micro-controller as main part. Embedded C is used to program micro-controller as in the industries assembly language is not so popular as embedded C. Micro vision keil(IDE) is used as cross compiler to provide integrated development environment (IDE). Keil provides the platform to to write the assembly language programs of many kind of controllers in standard C language. When you compile the program it will generate hex file that can be directly loaded into target controller. The latest version of keil supports almost all kind of controllers from Atmel, Dallas, Maxim, Phillips, Samsung, etc. If anyone is new voice and not familiar with keil then please first go through these links

introduction to keil

sample programs in keil

interfacing programs in keil