To start with Internal Block Diagram of Micro Controller, we have to know what a Micro-Controller is. A Micro controller is a special category of microprocessor that was intended for control activities rather for only crunching big numbers. Depending on their workability this type of microprocessor gained an identity of its own, and became called a microcontroller.
Like a microprocessor, a microcontroller needs to be able to compute, although not necessarily with only big numbers. But also it has other needs as well. The main features for which it so popular because it must have excellent input/output capability; it must be small, self-contained and low cost.
So work with Micro Controller we need to know Internal Block Diagram of Micro Controller which is shown in Figure bellow. Essentially, it contains a simple microprocessor core, along with all necessary data and program memory. To this it adds all the peripherals that allow it to do the interfacing it needs to do. These may include digital and analog input and output, or counting and timing elements.