What is the difference between the microprocessor and micro controller?

A microprocessor typically refers specifically to the device/component whose job it is to fetch commands, interpret the command opcodes, and execute the commands. In a modern microprocessor, this basically means the ALU, the register set, instruction pipeline, and the microprocessor control circuitry to perform the Von-neumann "fetch-decode-execute" cycle. One generalization is that microprocessors require an external bus and discreet memory devices to interface with (separate from internal registers, and whatever built in caching memory the microprocessor contains). Microcontrollers - on the other hand, are more generalized devices which contain a microprocessor, a main system bus, ram, ROM/flash, and typically a set of other devices such as a programmable interrupt controller, analog/digital converters, any number of general purpose IO devices, communications interfaces, etc... So... microprocessors are the things that actually compute/calculate the work, and microcontrollers are devices which contain a microprocessor and a bunch of other integrated devices one might need when writing firmware. Microcontrollers are not exclusively stand-alone devices as they need external circuitry to do things like bias their timing circuitry, provide power regulation, perform filtering and noise bypassing, etc... read less

To answer this in layman's terms:- Microprocessor is a term used to describe a digital device that is exclusively used to perform computation involving multiple steps, typically, execute instructions that are stored in the memory and which can be programmed . Micro controller on the other hand is a term that is used to describe a programmable device that is primarily used to control a physical system. A microprocessor is an Integrated Circuit (IC) which has only the Central Processing Unit (CPU) inside it. They lack Random Access Memory (RAM), Read Only Memory (ROM), and other peripherals on the chip. To deploy a microprocessor in a system, the above-mentioned peripherals are required to be connected. The Intel Pentium series, i3, i5, Cortex A8 are popular microprocessors which find their applications in desktop PC’s, Laptops, notepads etc. Unlike microprocessors, micro controllers possess a CPU along with RAM, ROM, and other peripherals on the same chip. Therefore, it is also termed as a mini computer. Though the size of RAM and ROM and the processing power is far less as compared to an actual computer, it meets all the characteristics of a complete computer. Popular microcontrollers in the market are 8051, STM32, PIC32, Arduino, ATMEL etc. read less