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 .

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71. Carry flag is not affected after the execution of

a.ADD B

b.SBB B

c.INR B

d.ORA B

Answer. c

72. The contents of the Program Counter (PC), when the microprocessor is reading from 2FFF H memory location, will be

a.2FFE H

b.2FFF H

c.3000 H

d.3001 H

Answer. c

73. If the HLT instruction of an Intel 8085A microprocessor is executed

a.the microprocessor is disconnected from the system bus till the RESET is pressed.

b.the microprocessor halts the execution of the program and returns to the monitor.

c.the microprocessor enters into a HALT state and the buses are tri-stated.

d.the microprocessor reloads the program counter from the locations 0024 H and 0025 H.

Answer. c

74. The stack pointer of an 8085 A microprocessor contains ABCD H.

1.PUSH PSW

2.XTHL

3.PUSH D

4.JMP EC75 H

At the end of the execution of the above instructions, what would be the content of the stack pointer?

a.ABCB H

b.ABCA H

c.ABC9 H

d.ABC8 H

Answer. c

75. In an Intel 8085 A, what is the content of the Instruction Register (IR)?

a.Op-code for the instruction being executed

b.Operand for the instruction being executed

c.Op-code for the instruction to be executed next

d.Operand for the instruction to be executed next

Answer. a

76. The content of the Program Counter of an intel 8085A microprocessor specifies which one of the following?

a.The address of the instruction being executed

b.The address of the instruction executed earlier

c.The address of the next instruction to be executed

d.The number of instructions executed so far

Answer. c

77. Which one of the following statement does not describe property/characteristic of a stack pointer register in 8085 microprocessor?

a.It points to the top of the stack.

b.It is UP/DOWN counter

c.It is automatically initialized to 0000 H on power-on

d.It is a 16-bit register

Answer. c

78. Which one of the following instructions is a 3-byte instruction?

a.MVI A

b.LDAX B

c.JMP 2050 H

d.MOV A,M

Answer. c

79. In 8085, the DAA instruction is used for

a.Direct Address Accumulator

b.Double Add Accumulator

c.Decimal Adjust Accumulator

d.Direct Access Accumulator

Answer. c

80. When an 8086 executes an INT type instruction, it?

a.Resets both IF and TF flags

b.Resets all flags

c.Sets both IF and TF

d.Resets the CF and TF

Answer. a

81. How many times will the following loop be executed?

   LXI B, 0010 H

LOOP: DCX B

MOV A, B

ORA C

JNZ LOOP

Select the correct answer using the code given below:

a.10

b.100

c.16

d.15

Answer. c

82. On execution of the following segment 0f instructions in sequence

MVI A, 91H

XRI 91 H

Which one of the following is correct?

a.Content of accumulator is 00 H. Carry, Auxiliary Carry and Zero flag set to 0, 1 and 0, respectively.

b.Content of accumulator is 91 H. Carry, Auxiliary Carry and Zero flag set to 0, 0 and 1, respectively.

c.Content of accumulator is 00 H. Carry, Auxiliary Carry and Zero flag set to 0, 0 and 1, respectively.

d.Content of accumulator is 91 H. Carry, Auxiliary Carry and Zero flag set to 0, 1 and 0, respectively.

Answer. c

83. Consider the following statements:

1. Indirect addressing is not possible for mapped I/O port addresses

2. Pointers can not be used to access memory-mapped I/O addresses

3. Fewer machine instructions can be used with I/O mapped I/O addressing as compared to memory mapped I/O addressing

4. With an 8085 microprocessor, one can access at the most 512 devices with unique addresses using I/O mapped I/O addressing

Which of these statements are correct?

a.1, 2 and 3

b.2 and 4

c.3 and 4

d.1 and 3

Answer. d

84. The contents of memory locations 2000 H, 2001 H and 2002 H are AAH, BBH and CCH respectively. What are the contents of H and L registers after executing the following instructions in sequence?

LXI H, 2001 H

LHLD 2001 H

Select the correct answer using the codes given below:

a.Contents of H and L registers are 20 H and 01 H, respectively

b.Contents of H and L registers are AAH and BBH, respectively

c.Contents of H and L registers are BBH and CCH, respectively

d.Contents of H and L registers are CCH and BBH, respectively

Answer. d

85. The following sequences of instructions are executed by an 8085 microprocessor:

1000        LXI SP, 27FF

1003        CALL 1006

1006        POPH

What are the contents of the stack pointer (SP) and the HL register pair on completion of execution of these instructions?

a.SP = 27 FF, HL = 1003

b.SP = 27 FD, HL = 1003

c.SP = 27 FF, HL = 1006

d.SP = 27 FD, HL = 1006

Answer. c

86. INR instruction of 8085 does not affect carry flag. Which of the following is correct about INR instruction?

a.Overflow cannot be detected

b.Overflow can be detected

c.If a programme requires overflow to be detected, ADD instruction should be used instead of INR

d.It can be used to increase the contents of the BC register pair

Answer. c

87. Consider the following 8085 instructions:

ANA A, ORA A, XRA A, SUB A, CMP A.

Now, consider the following statements:

1. All are arithmetic and logic instructions

2. All cause the accumulator to be cleared irrespective of its original contents

3. All reset the carry flag

4. All of them are 1-byte instructions

Which of these statements is/are correct?

a.1, 2, 3 and 4

b.2 only

c.1, 2 and 4

d.1,3 and 4

Answer. d

88. Consider the program given below, which transfer a block of data from one place in memory to another:

       MVI C, 0B H

       LXI H, 2400 H

       LXI D, 3400 H

    L1: MOV A, M

       STAX D

       INR L

       INR E

       DCR C

       JNZ L1

What is the total number of memory accesses (including instruction fetches) carried out?

a.118

b.140

c.98

d.108

Answer. a

89. Consider the following statements about register indirect addressing:

1. It helps in writing code that executes faster

2. It helps in writing compact code

3. It allows reuse of memory CPU data transfer instruction

4. It is essential for stack operations

Which of these statements are correct?

a.1, 3 and 4

b.1, 2 and 4

c.2,3 and 4

d.1,2 and 3

Answer. b

90. Which one of the following 8085 assembly language instructions does not affect the contents of the accumulator?

a.CMA

b.CMP B

c.DAA

d.ADD B

Answer. b


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Top-100 questions of 8085 microprocessor


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