ISRO2017-20

Question

Which interrupt in $8085$ Microprocessor is unmaskable?

1. $\textsf{RST 5.5}$
2. $\textsf{RST 7.5}$
3. $\textsf{TRAP}$
4. Both (a) and (b)

Answer 1

There are five interrupt input TRAP,RST 75,SRT 65,RST 55 and IWTR.

TRAP is a nonmaskable interrupt, that is, it cannot be disabled by an instruction

RST75,65,55 and INTR are maskable interrupt i.e. they can be enabled or disabled by software.

http://gradestack.com/Microprocessors-and/Interrupts-of-8085/Classification-Of/19314-3912-38133-study-wtw

Ans. (c) TRAP

Comments

Any suggestion to remember these interrupts?

Answer 2

Interrupts are the signals generated by the external devices to request the microprocessor to perform a ask. There are 5 interrupt signals. Given low priority to high is
1. INTR
2. RST 5.5
3. RST 6.5
4. RST 7.5
5. TRAP
Maskable Interrupts: They can be enabled or disabled by software INTR,RST 5.5,RST 6.5 and RST 7.5
Un maskable Interrupts: TRAP