Interrupts are special events that require immediate attention. They cause the processor to cease the running task to serve a special task for which the interrupt [[wysiwyg_imageupload::]]event had occurred. After the special task is over, the processor resumes performing the original task.The processor can also serve these events by polling method. But polling is an inefficient technique as compared to interrupts. In the polling method, the processor has to continuously wait for the event signal. Thus it always remains busy using extra resources. To understand the difference between polling and interrupts well, refer introductory paragraphs of 8051 Interrupts.Following is an example to illustrate the interrupts better. Suppose a programmer wants to make a real time watch which shows ambient temperature as well. The programmer has to use two internal peripherals of the controller, namely, a Timer and an ADC channel. Consider this project without using interrupt : the programmer has to take care of both peripherals one by one continuously by polling them. This is not an efficient way of programming.