9.2.2 NMI Channels

One or more Non Maskable Interrupt (NMI) channels are provided within each physical External Interrupt Controller module, allowing a single physical pin of the device to fire a single NMI interrupt in response to a particular edge or level stimulus. An NMI cannot, as the name suggests, be disabled in firmware and will take precedence over any in-progress interrupt sources.

NMIs can be used to implement critical device features such as forced software reset or other functionality where the action should be executed in preference to all other running code with a minimum amount of latency.