A Single microcontroller can serve several peripherals. There are two methods by which
devices receive service from the microcontroller: interrupts and polling.
In the interrupt method, whenever any peripheral needs the microcontroller’s service, the
device notifies it by sending an interrupt signal. Upon receiving an interrupt signal, the
microcontroller stops whatever it is doing and serves the device. The program associated
with the interrupt is called the Interrupt Service Routine (ISR).
In polling, the microcontroller continuously monitors the status of several devices and serve
each of them as certain conditions are met. However, it is not an efficient use of the
microcontroller.
The most important reason why the interrupt method is preferable is that; the polling
method wastes much of the microcontroller’s time by polling devices that do not need
service.
