what is the need of a microprocessor when it is already built in a microcontroller?

Question

please specify in points

Answer 1

Do you mean why use a microprocessor instead of a microcontroller? Because the 'processor usually has more complex instruction sets, bigger (and therefore faster) ALUs, wider busses etc. This means they can do complicated tasks more quickly.

Or do you mean why have a 'controller and a 'processor on the same board? Because you want a 'processor for the reasons listed above, but also have some lesser tasks that you don't want to waste 'processor cycles on... e.g. you use a 'controller to handle hardware interfaces while the 'processor gets on with the hard work.

Answer 2

Why pay for all the bells and whistles in the micro-controller if you don't need them?