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SAM9G45 [DATASHEET]
6438K–ATARM–12-Feb-13
27. Advanced Interrupt Controller (AIC)
27.1
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 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.
27.2
Embedded Characteristics
Controls the interrupt lines (nIRQ and nFIQ) of the ARM Processor
Thirty-two individually maskable and vectored interrupt sources
– Source 0 is reserved for the Fast Interrupt Input (FIQ)
– Source 1 is reserved for system peripherals (PIT, RTT, PMC, DBGU, etc.)
– Programmable Edge-triggered or Level-sensitive Internal Sources
– Programmable Positive/Negative Edge-triggered or High/Low Level-sensitive
One External Sources plus the Fast Interrupt signal
8-level Priority Controller
– Drives the Normal Interrupt of the processor
– Handles priority of the interrupt sources 1 to 31
– Higher priority interrupts can be served during service of lower priority interrupt
Vectoring
– Optimizes Interrupt Service Routine Branch and Execution
– One 32-bit Vector Register per interrupt source
– Interrupt Vector Register reads the corresponding current Interrupt Vector
Protect Mode
– Easy debugging by preventing automatic operations when protect modes are enabled
Fast Forcing
– Permits redirecting any normal interrupt source on the Fast Interrupt of the processor