7.2. NVIC functional description

The NVIC supports up to 240 interrupts each with up to 256 levels of priority. You can change the priority of an interrupt dynamically. The NVIC and the processor core interface are closely coupled, to enable low-latency interrupt processing and efficient processing of late arriving interrupts. The NVIC maintains knowledge of the stacked, or nested, interrupts to enable tail-chaining of interrupts.

You can only fully access the NVIC from privileged mode, but you can cause interrupts to enter a pending state in user mode if you enable the Configuration and Control Register. Any other user mode access causes a bus fault.

You can access all NVIC registers using only word accesses. For more information on NVIC registers accessibility and their usage constraints, see the Arm®v7-M Architecture Reference Manual.

Processor exception handling is described in Exceptions.

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