NMI stands for Non-Maskable Interrupt, and it is a term commonly used in computer science and electronics. An NMI is an interrupt signal that cannot be ignored or disabled by the processor. When an NMI occurs, it interrupts the normal execution of the processor, forcing it to respond to the interrupt immediately.
NMIs are typically used for critical or time-sensitive events that require immediate attention from the processor. Common examples of events that may trigger an NMI include power failures, system resets, hardware malfunctions, or other types of critical errors.
Unlike regular interrupt signals, which can be masked or disabled by the processor's interrupt enable or mask bits, an NMI cannot be ignored. This is because NMIs are usually reserved for vital system functions that must always be handled. Therefore, even if the processor is in a state where it cannot or should not respond to regular interrupts, it must still process the NMI.
Upon receiving an NMI, the processor halts its current execution and takes the appropriate action based on the nature of the interrupt. This can involve executing a specific interrupt service routine (ISR) designed to handle the NMI, performing a system reset, or triggering other emergency procedures to prevent data loss or system failure.
In summary, an NMI is a non-maskable interrupt that cannot be disabled or ignored by the processor. It is used for critical events that require immediate attention and overrides any ongoing processes.
