UGC NET CSE | December 2015 | Part 3 | Question: 3

Question

Which of the following $8085$ microprocessor hardware interrupt has the lowest priority?

• A. RST $6.5$
• B. RST $7.5$
• C. TRAP
• D. INTR

Answer 1

Answer is D     INTR

Hardware interrupts: The 8085 microprocessor has five hardware interrupt inputs (five pins). They are TRAP, RST 7.5, RST 6.5, RST 5.5, and INTR in the decreasing order of priority. If two or more interrupts go high at the same time, the 8085 will service them on priority basis.

TRAP	RST 7.5	RST 6.5	RST 5.5	INTR
Edge triggered & Level triggered	Edge triggered	Level triggered	Level triggered	Level triggered
Non maskable. It can be masked only by resetting microprocessor.	Maskable. DI instruction.	Maskable. DI and SIM instructions.	Maskable. DI and SIM instructions.	Maskable. DI and SIM instructions.
0024 H	003C H	0034 H	002C H	Not vectored