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multiple choice questions (MCQs ) of 8085 microprocessor (AKTU )

Here I will give you Top- 100+ multiple choice question related to the 8085 microprocessor which will help in you college or university examinations, in your mid semester examination and in your upcoming AKTU examination .


31. When a peripheral is connected to the microprocessor in input/output mode, the data transfer takes place between

a.any register and I/O device

b.memory and I/O device

c.accumulator and I/O device

d.HL registerand I/O device

Answer. c

32. While execution of I/O instruction takes place, the 8-bit address of the port is placed on

a.lower address bus

b.higher address bus

c.data bus

d.lower as well as higher-order address bus

Answer. d

33. The length of a bus cycle in 8086/8088 is four clock cycles, T1, T2, T3, T4 and an indeterminate number of wait state clock cycles denoted by TW. The wait states are always inserted between

a.T1 and T2

b.T2 and T3

c.T3 and T4

d.T4 and T1

Answer. c 

34. Which one of the following circuits transmits two messages simultaneously in one direction?





Answer. b

35. A microprocessor is ALU

a.and control unit on a single chip

b.and memory on a single chip

c.register unit and I/O device on a single chip

d.register unit and control unit on a single chip

Answer. d

36. In Intel 8085 microprocessor, ALE signal is made high to

a.Enable the data bus to be used as low order address bus

b.To latch data D0— D7 from the data bus

c.To disable data bus

d.To achieve all the functions listed above

Answer. a

37. Which one of the following statements for Intel 8085 is correct?

a.Program counter (PC) specifies the address of the instruction last executed

b.PC specifies the address of the instruction being executed

c.PC specifies the address of the instruction be executed

d.PC specifies the number of instruction executed so far


38. What will be the contents of DE and HL register pairs respectively after the execution of the following ir:cnstructions?

a.LXIH, 2500 H

b.LXID, 0200 H



0200 H, 2500 H

0200 H, 2700 H

2500 H, 0200 H

2700 H, 0200 H

Answer. d

39. In 8085 microprocessor, the address for ‘TRAP’ interrupt is

a.0024 H

b.002C H

c.0034 H

d.003C H

Answer. a

40. A ‘DAD H” instruction is the same as shifting each bit by one position to the



c.left with a zero inserted in LSB position

d.right with a zero inserted in LSB position

Answer. c

41. When a program is being executed in an 8085 microprocessor, its program counter contains

a.the memory address as the instruction that is to be executed next

b.the memory address of the instruction that is being currently matched.

c.the total number of instructions in the program being executed.

d.the number of instructions in the current program that have already been executed.

Answer. a

42. Which of the following data transfer is not possible in microprocessor?

a.Memory to accumulator

b.Accumulator to memory

c.Memory to memory

d.I/O device to accumulator

Answer. c

43. LOADER is a program that

a.loads the memories and generates a hex file

b.loads the hex file and converts to the executable file

c.loads the COM file and generates the binary code

d.loads English like command and generates the binary code

Answer. b

44. Which of the following instructions is closest match to the instruction POP PC?





Answer. a

45. How many machine cycles are required by STA instruction?





Answer. c

46. Which of the following 8085 instruction will require maximum T-states for execution? 

a.XRI byte

b.STA address

c.CALL address

d.JMP address

Answer. c

47. In 8085 microprocessor, which mode of addressing does the instruction CMP M use?

a.Direct addressing

b.Register addressing

c.Indirect addressing

d.Immediate addressing

Answer. c

48. With reference to 8085 microprocessor, which of the following statements are correct?

1. INR is 1 byte instruction

2. OUT is 2 byte instruction

3. STA is 3 byte instruction

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

Answer. d

Explanation:- STA 4050H has 3 byte.

49. What is content of accumulator of 8085 microprocessor after the execution of XRI F0 H instruction?

a.Only the upper nibble of accumulator is complemented

b.Only the lower nibble is complemented

c.Only the upper nibble is reset to zero

d.Only the lower nibble is reset to zero

Answer. a

50. The 8085 programming manual says that it takes seven T states to fetch and execute the MOV instruction. If the system clock has a frequency of 2.5 MHz, how long is an instruction Cycle?

a.2.8 s


c.2.8 ns

d.2.8 μs

Answer. d

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Top-100 questions of 8085 microprocessor

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