at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 318

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

27.7.2
27.7.2.1
27.7.2.2
318
AT91SAM9G20 Preliminary
Interrupt Latencies
External Interrupt Edge Triggered Source
External Interrupt Level Sensitive Source
Global interrupt latencies depend on several parameters, including:
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 pro-
cessor. 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.
Figure 27-6.
Figure 27-7.
• 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.
External Interrupt Edge Triggered Source
External Interrupt Level Sensitive Source
(Negative Edge)
(Positive Edge)
IRQ or FIQ
IRQ or FIQ
nIRQ
MCK
nFIQ
(High Level)
(Low Level)
IRQ or FIQ
IRQ or FIQ
nIRQ
MCK
nFIQ
Maximum IRQ Latency = 4 Cycles
Maximum FIQ Latency = 4 Cycles
Latency = 3 Cycles
Latency = 3 cycles
Maximum IRQ
Maximum FIQ
6384B–ATARM–15-Dec-08