AT91SAM7A2-AI datasheet(92/369 Pages) ATMEL

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PRELIMINARY

AT91SAM7A2

6021A–ATARM–07/04

Generic Interrupt Controller (GIC)

Overview

The GIC is an 8-level priority, individually maskable, vectored interrupt controller. It can

substantially reduce the software and real time overhead in handling internal and exter-

nal interrupts.

The interrupt controller is connected to the nFIQ (fast interrupt request) and the nIRQ

(standard interrupt request) inputs of the ARM7TDMI processor (see Figure 45 below).

The processor's nFIQ line can only be asserted by the external fast interrupt request

input, FIQ. The nIRQ line can be asserted by all other internal and external interrupt

sources.

Figure 45. GIC Connection to Core

An 8-level priority encoder allows the user to define the priority between the different

nIRQ interrupt sources. The internal interrupt sources are programmed to be level sen-

sitive or edge triggered. The external interrupt sources can be programmed to be

positive or negative edge triggered or high or low level sensitive.

Internal Interrupt Source

(Peripherals)

External Interrupt IRQ[1:0]

External Interrupt FIQ

GIC

ARM7TDMI

Core

nIRQ

nFIQ

AMBA

Bridge

APB

ASB

AT91SAM7A2-AI Datasheet(PDF) 92 Page - ATMEL Corporation