Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Datenbogen

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SAM9M10 [DATASHEET]

6355F–ATARM–12-Mar-13

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, resynchroniza-
tion 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.

 External Interrupt Edge Triggered Source

 External Interrupt Level Sensitive Source

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