In ARM Cortex-M microcontrollers, interrupt prioritization is a critical feature for real-time embedded systems. The system uses a Nested Vectored Interrupt Controller (NVIC) to manage interrupt requests. The NVIC enables interrupts to be prioritized dynamically and efficiently.

Interrupts in ARM Cortex-M cores are assigned priority levels, which range from 0 (highest priority) to 255 (lowest priority). These priorities are configured using a 4-bit field in the interrupt control registers, allowing developers to assign different priorities to various interrupt sources. The NVIC uses these priorities to determine which interrupt should be serviced first when multiple interrupts occur simultaneously.

When an interrupt request is triggered, the NVIC checks the priority of the pending interrupt against the priority of the currently executing code. If the pending interrupt has a higher priority than the executing code, the processor will suspend its current operation and jump to the interrupt service routine (ISR). If the priority is lower, the interrupt is held off until the processor becomes available.

In addition to this basic priority mechanism, ARM Cortex-M cores also support preemption and nesting. Preemption occurs when a higher-priority interrupt interrupts the service of a lower-priority interrupt, ensuring that critical tasks are addressed first. The NVIC also supports tail-chaining, where multiple interrupts can be handled in quick succession without returning to the main program flow in between.

Additionally, ARM Cortex-M microcontrollers allow for the configuration of interrupt priorities with finer granularity through the use of the "priority group" field, which separates the interrupt priority into two parts: a preemption priority and a subpriority. This allows more flexibility in managing interrupt priorities.

For those pursuing an embedded system certification course, understanding interrupt prioritization is fundamental, as it ensures real-time, efficient handling of critical tasks in embedded applications.