Event-Driven Processor Programming

Almost since computers were invented, interrupts have been a common programming method to deal with real-time tasks. An interrupt causes a processor to stop the running task, and to execute an interrupt handler instead. The interrupt handler determines the cause of the interrupt, responds to the interrupt, whereupon control is restored to the original task. A simple example is an interrupt from a UART (a serial port) stating that a character has been received, and the interrupt handler will take the character from the UART and store it in a queue in memory for use by the main task.