In computing, a programmable interrupt controller (PIC) is a device that is used to combine several sources of interrupt onto one or more CPU lines, while allowing priority levels to be assigned to its interrupt outputs. When the device has multiple interrupt outputs to assert, it asserts them in the order of their relative priority. Common modes of a PIC include hard priorities, rotating priorities, and cascading priorities. PICs often allow the cascading of their outputs to inputs between each other.