What is NVIC in ARM Cortex?

Answer:

The Nested Vector Interrupt Controller (NVIC) in the Cortex-M processor family is an example of an interrupt controller with extremely flexible interrupt priority management. It enables programmable priority levels, automatic nested interrupt support, along with support for multiple interrupt masking, whilst still being very easy to use by the programmer.

The Cortex-M3 and Cortex-M4 processors the NVIC supports up to 240 interrupt inputs, with 8 up to 256 programmable priority levels