Interrupt Technology Guide

The Interrupt platform service provides an interface to the kernel +and device drivers to associate interrupt with an Interrupt Service +Routine (ISR). There are three levels of interrupt management:

+ Key concepts

Interrupt: An interrupt is a hardware or a software event that may need +to be serviced. An example of a hardware interrupt is a key press +.
Interrupt ID: The unique ID of an interrupt source. The interrupt ID are +defined by the developers creating ASSP and variant.
Spurious interrupts: Interrupts not associated with an Interrupt Service Routine +are called the spurious interrupts. The spurious interrupts are handled +by a spurious interrupt handler which is only used for debugging.
ISR: An Interrupt Service Routine (ISR ) is the function to handle +an interrupt. ISR is not a class member. ISR provides the minimum +processing such as storing data that may not be available later and +requests a DFC for further processing.
Interrupt priority: The Interrupt platform service allows developers to set a priority +for each interrupt source. The meaning of the priority value depends +on the hardware and the baseport implementation.
Interrupt dispatch: When an interrupt is received by the system, it calls the associated +ISR. This is called interrupt dispatch. The interrupt dispatch is +provided by the implementation of the interrupt class +in the ASSP layer.
ISR table: The table that maps the interrupt ID and the associated ISR. +The ISR table is implemented by the developers creating the baseport +variant.
Binding: The process of associating an interrupt ID with an ISR. Unbinding +removes the association.
Chained interrupts: The output of a low priority interrupt controller is provided +as an input to a higher priority interrupt controller.

Pseudo-interrupts: Pseudo-interrupts correspond to multiple interrupt sources +sharing a single input to an interrupt controller but requiring separate +ISRs to service them. The ISRs cannot all be bound to the single real +interrupt and are therefore bound to the pseudo-interrupt instead.

IRQs and FIQs: An IRQ (interrupt request) is the signal generated by an item +of hardware or software to request an interrupt from the processor. +An FIQ (fast IRQ) is an IRQ with high priority on systems +which support prioritization of requests.