Atmel Evaluation Kit AT91SAM9X35-EK AT91SAM9X35-EK Data Sheet

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SAM9X35 [DATASHEET]

11055E–ATARM–10-Mar-2014

Global interrupt latencies depend on several parameters, including:



The time the software masks the interrupts.



Occurrence, either at the processor level or at the AIC level.



The execution time of the instruction in progress when the interrupt occurs.



The treatment of higher priority interrupts and the resynchronization of the hardware signals.

This section addresses only the hardware resynchronizations. It gives details of the latency times between the event on
an external interrupt leading in a valid interrupt (edge or level) or the assertion of an internal interrupt source and the
assertion of the nIRQ or nFIQ line on the processor. The resynchronization time depends on the programming of the
interrupt source and on its type (internal or external). For the standard interrupt, resynchronization times are given
assuming there is no higher priority in progress.

The PIO Controller multiplexing has no effect on the interrupt latencies of the external interrupt sources.

Maximum FIQ Latency = 4 Cycles

Maximum IRQ Latency = 4 Cycles

nFIQ

nIRQ

MCK

IRQ or FIQ

(Positive Edge)

IRQ or FIQ

(Negative Edge)

Maximum IRQ

Latency = 3 Cycles

Maximum FIQ

Latency = 3 cycles

MCK

IRQ or FIQ

(High Level)

IRQ or FIQ

(Low Level)

nIRQ

nFIQ