A micro controller differs from a microprocessor in many ways. The first and most important difference is its functionality. In order the microprocessor may be used, other components such as memory or components for data transfer must be added to it. Even though the microprocessor is considered to be a powerful computer machine, the weak point is that it is not adjusted to communication to peripheral environment.
Simply, in order to communicate with peripheral environment, the microprocessor must use specialized circuits added as external chips. It means in short that microprocessors are the pure heart of the computers. That is how it was when they appeared and the same is now.
On the other hand, the micro-controller is designed to be all of that in one. No other specialized external components are needed for its application because all necessary circuits which otherwise belong to peripherals are already built into it. It in any case saves the time and space needed to design a device.
