What is Micro Controller

A micro controller is an electronic device that generally consists of a microprocessor, a memory unit in the form of Random Access Memory (RAM) and Read Only Memory (ROM), various timers and input/output serial and parallel ports all integrated on a single chip. In some advanced micro controller systems, on chip ADC’s, DAC’s etc are also included. A few examples of microcontrollers available in the market today are: – Intel 8051, Motorola’s 6811, Zilog’s Z8 etc.


A microcontroller can be programmed to do a variety of functions according to the requirement of the system. These are mainly used in embedded systems where less computing power is required. The program to be executed is burnt on the on-chip ROM with the help of relevant computer software and a burner device.  The program written for a micro controller is generally in assembly language form using micro controller specific Op Codes and Operands.


As already mentioned above, the main area where micro controllers are used is of embedded systems. A couple of examples of these applications are:-

In micro controller based power supplies, the micro controller regularly monitors the output for any fluctuations and compensate for it by changing the frequency of switching MOSFET’s. By doing the same, the microcontroller can also provide a variety of user desired outputs. In traffic lights, the microcontroller controls the switching of lights by sending on/off signals to its port in accordance with the program burnt on it.

Besides these, the microcontrollers are used these days in a variety of systems such as printers, scanners, refrigerators, automatic railway crossings, remote controls etc.

The factors that determine the usability of a microcontroller for a specific application are:-

Speed and Availability Power Consumption Amount of on chip RAM and ROM and whether the microcontroller supports any addition of external memory. Number of I/O ports and on chip timers. Availability of Software for programming the specific microcontroller. Consideration of Cost per Unit of the specific micro controller because the embedded systems using this controller are usually manufactured on a large scale.

Then a question arises why a micro controller? Why not just use a general purpose micro processor instead along with external memory and timers. Well general purpose micro processors are much more powerful and are useful where high computing power is required. But in embedded systems, there is a need to only do some simple routine tasks and for this if micro processors are used, the system will become costly and much more power consuming. So the microcontroller chips containing small IBP’s i.e. itty-bitty processors are better suited for such applications.

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