Editing Microcontroller (section)

=== Interrupts ===
Microcontrollers must provide [[Real-time computing|real-time]] (predictable, though not necessarily fast) response to events in the embedded system they are controlling. When certain events occur, an [[interrupt]] system can signal the processor to suspend processing the current instruction sequence and to begin an [[interrupt service routine]] (ISR, or "interrupt handler") which will perform any processing required based on the source of the interrupt, before returning to the original instruction sequence. Possible interrupt sources are device-dependent and often include events such as an internal timer overflow, completing an analog-to-digital conversion, a logic-level change on an input such as from a button being pressed, and data received on a communication link. Where power consumption is important as in battery devices, interrupts may also wake a microcontroller from a low-power sleep state where the processor is halted until required to do something by a peripheral event.