Microprocessors and Microcontrollers (3160914) MCQs

MCQs of 8051 Assembly Language Programming

Showing 1 to 10 out of 25 Questions
1 2 3
1.

“DJNZ R0, label” is ________ byte instruction.

(a)

2
(b)

3
(c)

1
(d)

0
Answer:

Option (a)

2.

 JZ, JNZ, instructions checked content of _______ register.

(a)

DPTR
(b)

B
(c)

A
(d)

PSW
Answer:

Option (c)

3.

When the call instruction is executed the topmost element of stack comes out to be

(a)

 the address where stack pointer starts
(b)

the address next to the call instruction
(c)

address of the call instruction
(d)

 next address of the stack pointer
Answer:

Option (b)

4.

 LCALL instruction takes

(a)

 2 bytes
(b)

4 bytes
(c)

3 bytes
(d)

1 bytes
Answer:

Option (c)

5.

 Are PUSH and POP instructions are a type of CALL instructions?

(a)

yes
(b)

no
(c)

none
(d)

cant say
Answer:

Option (b)

6.

What is the time taken by one machine cycle if crystal frequency is 20MHz?

(a)

1.085 micro seconds
(b)

0.60 micro seconds
(c)

 0.75 micro seconds
(d)

 1 micro seconds
Answer:

Option (b)

7.

Find the number of times the following loop will be executed

MOV R6,#200
BACK:MOV R5,#100
HERE:DJNZ R5, HERE
DJNZ R6,BACK
END

(a)

100
(b)

200
(c)

20000
(d)

2000
Answer:

Option (c)

8.

 What is the meaning of the instruction MOV A,05H?

(a)

 data 05H is stored in the accumulator
(b)

 fifth bit of accumulator is set to one
(c)

address 05H is stored in the accumulator
(d)

NONE
Answer:

Option (c)

9.

 Do the two instructions mean the same?

1) BACK:  DEC R0            
          JZ BACK
2) BACK:  DJNZ RO, BACK

(a)

YES
(b)

NO
(c)

CANT SAY
(d)

NONE
Answer:

Option (b)

10.

 When we add two numbers the destination address must always be.

(a)

 some immediate data
(b)

 any register
(c)

 accumulator
(d)

 memory
Answer:

Option (c)

Showing 1 to 10 out of 25 Questions
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