Two Marks Questions with Answers

Two Marks Questions with Answers

 

Q.1 What is the time taken to execute MUL instruction in 8031?

(Refer section 15.5.4)

Q.2 Give the PSW setting for making register bank 2 as default register bank in 8051 microcontroller ?

(Refer program 15.10.9)

Q.3 What is the operation carried out when 8051 executes the instruction MOVC A, @ A + DPTR ?

(Refer section 15.3.2)

Q.4 Name any four bit manipulation instructions in microcontroller 8051.

(Refer section 15.6)

Q.5 How can you perform multiplication using 8051 microcontroller ?

(Refer section 16.5.4)

Q.6 Write the I/O related instructions in microcontroller 8051.

(Refer section 16.3)

 

Q.7 What is output of the program ?

MOV R0, A

XRL A, #3FH

XRL A, R0

Ans. : The contents of A register will be 3FH and contents of RO will be the initial contents of A.

 

Q.8 Explain about the instruction DJNZ.

(Refer section 15.8.2)

Q.9 Write an 8051 program to divide two 8-bit numbers.

(Refer program 15.10.10)       

Q.10  What are the uses of LCALL and LJUMP instructions of 8051?

(Refer section 15.8)

Q.11  List the different types of 8051 instructions.

(Refer sections 15.2, 15.3, 15.4 and 15.5) 

Q.12  What are the various operations performed by boolean variable instructions of 8051 ?

(Refer section 15.6)       

 

Q.13 Explain DJNZ instructions of Intel 8051 microcontroller ?

Ans. : 1 DJNZ Rn, rel : Decrement the content of the register Rn and jump if not zero.

2. DJNZ direct, rel : Decrement the content of direct 8-bit address and jump if not zero.

 

Q.14  Write a program using 8051 assembly language to change the data 55H stored in the lower byte of the data pointer register to AAH using rotate instruction.

Ans.  MOV DPL, #55H

MOV A, DPL

RL A

 

Q.15  Specify the single instruction, which clears the most significant bit of B register of 8051, without affecting the remaining bits.

Ans. :          Single instruction, which clears the most significant bit of B register of 8051, without affecting the remaining bit is CLR B.7.

 

Q.16  Explain the contents of the accumulator after the execution of the following program segments :

MOV A, #3CH

MOV R4, #66H

ANL A, R4

Ans :

A = 3C

R4 = 66

A = 24

 

Q.17  Write a program to load accumulator A, DPH and DPL with 30H.

Ans. :         

MOV A, #30

MOV DPH, A

MOV DPL, A

 

Q.18  Write a program to subtract the contents of R1 of BankO from the contents of R0 of Bank2.

Ans. :         

MOV PSW, #10

MOV A, R0

MOV PSW, #00

SUBB A, R1

 

Q.19  List the 8051 instructions that affect the overflow flag.

Ans. :          ADD, ADDC, DIV, MUL, SUBB

 

Q.20  List the 8051 instructions that always clear the carry flag.

Ans. :          CLR C, DIV, MUL

 

Q.21  List the 8051 instructions that affect all the flags.

Ans. :          ADD, ADDC and SUBB

 

Q.22  What are the addressing modes supported by 8051 ?

Ans. :          The addressing modes supported by 8051 are :

1. Register addressing   

2. Direct byte addressing        

3. Register indirect

4. Immediate

5. Register specific

6. Index

 

Q.23  What does the mnemonics "LCALL" and "ACALL" stand for ?

(Refer section 15.8.3)

Q.24  Give an example for DA instruction of 8051 microcontroller.

(Refer section 15.5.5)

Q.25  State the functions performed by JBC and CJNE instructions in 8051 microcontroller.

(Refer section 15.8.2)

Q.26  Write an 8051 assembly language program to clear the accumulator and add 3 to the accumulator 10 times.

(Refer example 15.10.24)

Q.27  What is the operation of the given 8051 microcontroller instructions : XRL A, direct ?

(Refer section 15.4)

Q.28  Write a program to find 2's complement using 8051.

(Refer program 15.10.6)

Q.29  Mention any four data transfer instructions of 8051 microcontroller.

(Refer section 15.3)

Q.30  Can single bit of a port be accessed in 8051 ? If yes, how ? Give an example.

(Refer section 15.6)

 

 

University Questions with Answers (Long Answered Questions)

 

(Regulation 2008)

May-11

Q.1 Explain the data transfer instructions and program control instructions of 8051 microcontroller.

(Refer sections 15.3 and 15.8)         [8]

Q.2 Write an assembly language program based on 8051 microcontroller instruction set to perform four arithmetic operations on 2, 8 bit data.

(Refer programs 15.10.4, 15.10.8, 15.10.10 and 15.10.11) [8]

Dec.-11

Q.3 Explain the different addressing modes in 8051 in detail.

(Refer section 15.1) [8]

Dec.-12

Q.4 Write an 8051 assembly language program to copy the valule 55h into RAM memory locations 40h to 45h using register indirect addressing with a loop.

(Refer program 15.10.23) [8]

May-13               

Q.5 Explain the different addressing modes of 8051 microcontroller.

(Refer section 15.1) [8]

Dec.-13                

Q.6 Explain the different addressing modes of 8051 microcontroller.

(Refer section 15.1) [16]

May-14

Q.7 Explain the different operand addressing modes in 8051 microcontroller with examples.

(Refer section 16.1) [16]

 

(Regulation 2013)

May-16

Q.8 Explain the different addressing modes of 8051 microcontroller.

(Refer section 15.1) [8]

Dec.-17

Q.9    Explain the different types of instructions used in 8051 microcontroller.

(Refer sections 16.2 to 15.8)   [13]

Dec.-18

Q.10  Explain the various bit manipulation instructions in 8051 with examples.

(Refer section 15.6)       [13]