SAM7S256_14 Datasheet, PDF (161/775 Pages) ATMEL Corporation – ARM-based Flash MCU

23. Advanced Interrupt Controller (AIC)
23.1
Overview
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 pro-
cessor. Inputs of the AIC are either internal peripheral interrupts or external 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.
23.2 Block Diagram
Figure 23-1. Block Diagram
FIQ
IRQ0-IRQn
Embedded
Pe_Erip_mh_be_era_dlE_dE_ed
P_Eer_mip_bhe_er_da_dl _ed
Peripheral
AIC
Up to
Thirty-two
Sources
ARM
Processor
nFIQ
nIRQ
APB
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
161