Question

Question 9 (6 marks) Question 9.1 (3 marks) What is the difference between maskable and non-maskable interrupts? Question 9.2 (3 marks) Give an example of a situation when it would be preferable to use a maskable interrupt.

Answer 1

The most important difference in between the maskable and non maskable interrupts is that non maskable interrupts must be serviced wherever introduced (or)commanded & maskable interrupts can be masked (or) ignored rightarrow A maskable interrupt is one that we can ignore by setting (or clearing) a bit in an interrupt control register. Typically our processor might allow multiple interrupt sources but our design only requires some of them. We would mask off the unused interrupts so that noise on these lines does not cause problems Example: RST6.5, RST7.5, RST5.5, of 8085 are maskable interrupts. rightarrow Non maskable interrupts do not get gated by the interrupts control register they always interrupts, no matter what state your processor is in. Typically these are used for critical (or)total conditions, (or) for system reset functions Example: TRAP of 8085 microprocessor (highest priority interrupt)