5 High Priority Interrupt Vector

When a higher interrupt priority is required over what is already defined, one interrupt vector can be assigned priority level 1. That interrupt will have priority over all level 0 interrupts and has the ability to interrupt an ongoing level 0 interrupt handler.

All interrupt sources are by default assigned level 0 priority, except for Non-Maskable Interrupts (NMI). These are the only interrupts that have higher priority than the level 1 interrupt. For more info see the Non-Maskable Interrupts chapter.