The microcontroller has a memory Jerryd Bayless Jersey , inputoutput, and processor all placed in a single integrated circuit. Microcontrollers do a lot of operations through programs. Any program will have its normal logical flow. An interrupt will change or stop the normal logical flow of the program. A sequence of steps are executed as part of the interrupt. Then the microcontroller resumes its normal sequence of events. An engineer taking the Professional Engineering Exam will be well versed with the concept of interrupts in microcontrollers.