A microprocessor by itself is not a computer. To be functional, the microprocessor must be connected to other ICs that provide the memory and I/O capability. A microcontroller is a computer on a single IC, designed specifically for control applications. It consists of a microprocessor, memory (RAM and ROM), I/O ports and can have additional features such as ADCs/DACs and timers. Having a complete controller on a single chip allows the hardware design to be simple and very low-cost. Microcontrollers are used in industrial applications as well as home appliances as embedded controllers because the controller is physically located in the equipment being controlled.
Related: Microcontrollers in Industrial Control
A key difference between microprocessors and microcontrollers is that microprocessors are designed to be used in microcomputers where greater speed and larger word size are the driving requirements, while microcontrollers are evolving toward reduced chip count by integrating more hardware functions on the chip.
One more difference between microprocessors and microcontrollers is about the instruction set. The microprocessor tends to be rich in instructions dealing with moving data into and out memory. The microcontroller has fewer memory-move instructions and more bit-handling instructions. The basis for the fewer memory-move instructions in a microcontroller is typically due to the fact that it has a small amount of RAM. The additional bit-handling instructions are used in control applications, for instance, in a control system; each separate bit of a parallel output word might control a different device, such as a motor or indicator light. The bit-handling instructions allow the software to turn one device easily on or off without affecting the others.
Also Read: Microprocessors In Mechatronics Systems
