Rainbow Electronics AT91CAP9S250A - Manual (Page 383)

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6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
30. Advanced Interrupt Controller (AIC)
30.1 Description
The Advanced Interrupt Controller (AIC) is an 8-level priority, individually maskable, vectored
interrupt controller, providing handling of up to thirty-two interrupt sources. It is designed to
substantially reduce the software and real-time overhead in handling internal and external
interrupts.
The AIC drives the nFIQ (fast interrupt request) and the nIRQ (standard interrupt request)
inputs of an ARM processor. Inputs of the AIC are either internal peripheral interrupts or exter-
nal interrupts coming from the product's pins.
The 8-level Priority Controller allows the user to define the priority for each interrupt source,
thus permitting higher priority interrupts to be serviced even if a lower priority interrupt is being
treated.
Internal interrupt sources can be programmed to be level sensitive or edge triggered. External
interrupt sources can be programmed to be positive-edge or negative-edge triggered or high-
level or low-level sensitive.
The fast forcing feature redirects any internal or external interrupt source to provide a fast
interrupt rather than a normal interrupt.