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Microprocessor – INTERVIEW QUESTIONS

Published on Aug 17 2009 // 8085 Tutorials

16.How many interrupts are there in 8085?

Ans:– There are 12 interrupts in 8085.

17.What is clock frequency for 8085?

Ans:– 3 MHz is the maximum clock frequency for 8085.

18.What is the RST for the TRAP?

Ans:– RST 4.5 is called as TRAP.

19.In 8085 which is called as High order / Low order Register?

Ans:– Flag is called as Low order register & Accumulator is called as High order Register.

20.What are input & output devices?

Ans:– Keyboards, Floppy disk are the examples of input devices. Printer, LED / LCD display, CRT Monitor are the examples of output devices.


21.Can an RC circuit be used as clock source for 8085?

Ans:– Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal.

22.Why crystal is a preferred clock source?

Ans:– Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.

23.Which interrupt is not level-sensitive in 8085?

Ans:– RST 7.5 is a raising edge-triggering interrupt.

24.What does Quality factor mean?

Ans:– The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.

25.What are level-triggering interrupt?

Ans:– RST 6.5 & RST 5.5 are level-triggering interrupts.


26.What is meant by Maskable interrupts?

Ans:– An interrupt that can be turned off by the programmer is known as Maskable interrupt.

27.What is Non-Maskable interrupts?

Ans:- An interrupt which can be never be turned off (ie.disabled) is known as Non-Maskable interrupt.

28.Which interrupts are generally used for critical events?

Ans:– Non-Maskable interrupts are used in critical events. Such as Power failure, Emergency, Shut off etc.,

29.Give examples for Maskable interrupts?

Ans:– RST 7.5, RST6.5, RST5.5 are Maskable interrupts

30.Give example for Non-Maskable interrupts?

Ans:– Trap is known as Non-Maskable interrupts, which is used in emergency condition.

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