Difference between Maskable and Non-Maskable Interrupts

Usually, an interrupt is defined as an event that happened by an element other than the processor. It notifies the CPU of an external event that needs immediate attention. Interrupts are categorized into mainly two types: maskable and non-maskable. The maskable interrupt is an interrupt that the CPU may ignore. A non-maskable interrupt may not be ignored and is designated for certain crucial events.

In this article, you will learn about the difference between Maskable and Non-Maskable Interrupts. But before discussing the differences, you must know about the Maskable and Non-Maskable Interrupts.

What is Maskable Interrupt?

A hardware interrupt that could be ignored by setting a bit in the interrupt mask register's (IMR) bit-mask is referred to as a maskable interrupt. The microprocessor may suppress or ignore maskable interrupts, and the interruptions are either edge-triggered, level-triggered, or both. Some common instances of maskable interrupts include the RST6.5, RST7.5, and RST5.5 of the 8085 microprocessor.

What is Non-Maskable Interrupt?

Non-Maskable Interrupts are defined as interrupts that cannot be disabled or ignored by CPU instructions and usually indicate a non-recoverable hardware issue. When response time is crucial, or it is impossible to turn off standard system processes, non-maskable interrupts can be helpful.

This type of interrupt is used in modern computer systems to handle non-recoverable problems that require quick attention. As a result, it is impossible to mask these interrupts in the system's normal operation. In addition, the internal system chipset errors, data corruption errors on the system, memory errors, and peripheral bus errors are some instances of such interrupts. Debugging also aids in the diagnosis and correction of code flaws. In such cases, the non-maskable interrupt may run an interrupt handler, which transfers control to a dedicated monitor program.

Key differences between Maskable and Non-Maskable Interrupts

Here, you will learn about the various key differences between the Maskable and Non-Maskable Interrupts. Some main differences between Maskable and Non-Maskable Interrupts are as follows:

1. Maskable interrupts are those that may be accepted or ignored by the CPU based on their priority. In contrast, the CPU must accept the non-maskable interrupts.
2. A hardware interrupt that could be ignored by setting a bit in the interrupt mask register's (IMR) bit-mask is referred to as a maskable interrupt. In contrast, the non-maskable interrupts are hardware interrupts that don't have a bit-mask and can't be ignored.
3. The maskable interrupt aids in the management of low-priority jobs. On the other hand, the non-maskable interrupt aids in the management of high-priority jobs.
4. Maskable interrupts are mainly used to communicate with peripheral devices. On the other hand, non-maskable interrupts are utilized for emergency purposes, such as power outages or smoke detectors.
5. When a maskable interrupt happens, it may be handled after the current instruction is executed. On the other hand, when non-maskable interrupts happen, the current instructions and status are saved in the stack to allow the processor to manage the interrupt.
6. The RST6.5, RST7.5, and RST5.5 of the 8085 microprocessor are some common instances of maskable interrupts. On the other hand, the Trap of the 8085 microprocessor is an instance of a non-maskable interrupt.

Head-to-head comparison between Maskable and Non-Maskable Interrupts

Here, you will learn about the head-to-head comparison between the Maskable and Non-Maskable Interrupts. Some main differences between the Maskable and Non-Maskable Interrupts are as follows:

Conclusion

Interrupts are important events that need the CPU's attention, and Maskable interruptions are those that the CPU may accept or reject. In contrast, the non-maskable interrupts are those that the CPU has to accept