AU Solved Paper - 71777 - set 12

AU Solved Paper - 71777

May - 2017

Microprocessors & Microcontrollers

Semester-V (EEE) - Regulation 2013

Time: Three hours]

[Maximum Marks: 100

Answer ALL questions.

PART A - (10 × 2 = 20 Marks)

Q.1 Why data bus is bi-directional ?

Ans. : In microprocessor systems, data is transferred from memory input/output devices to the CPU and also from CPU to memory or input/output : devices. Thus, data bus is bi-directional.

Q.2 List out the machine cycles of 8085 microprocessor.

(Refer Two Marks Q.5 of Chapter 5)

Q.3 Write an 8085 program to swap lower and higher nibble of the contents of accumulator.

Ans :

RLC

RLC

RLC

RLC

Q.4 List different instruction formats. (Refer section 2.7)

Q.5 Classify the addressing modes of 8051 microcontroller. (Refer section 15.1)

Q.6 List any four special function registers. (Refer Two Marks Q.4 of Chapter 14)

Q.7 What are the modes of 8254 timer ? (Refer Two Marks Q.1 of Chapter 10)

Q.8 What is meant by cascading in 8259? (Refer Two Marks Q.3 of Chapter 9)

Q.9 Explain the function of DJNZ instruction. (Refer section 15.8.2)

Q.10 What is meant by bit oriented instructions? (Refer section 15.6)

PART B - (5 × 16 = 80 Marks)

Q.11 a) i) Explain the interrupt structure of 8085 microprocessor. (Refer section 4.2)

[8]

ii) With pin diagram explain 8085 microprocessor. (Refer section 1.3) [8]

OR

b) i) Explain the registers of 8085 microprocessor. (Refer section 1.2.1) [8]

ii) What is meant by memory interfacing? Explain with an example. (Refer section 6.4) [8]

Q.12 a) i) Explain the addressing modes of 8085 microprocessor. (Refer section 2.3) [8]

ii) Write an 8085 assembly language program to divide an 8 bit number by another 8 bit number. [8]

Ans. :

MVI A, Dividend ; Load dividend

MVI B, Divisor  ; Load divisor

MVI C, 00H  ; Quotient = 0

BACK : SUB B  ; Subtract divisor

JC  SKIP

INR C  ; Incremental quotient

JMP BACK  ; Repeat

ADD B  ; Restore remainder in A register

HLT ; Stop

This program gives quotient in C register and remainder in A register.

OR

b) i) Write an 8085 assembly language program to find the largest among 'N' number where the value of N should be stored in 4200 and the array of elements from 4201. Store the result in 4300 ?

(Refer similar program: Lab Experiment 3.1.6) [8]

ii) What is meant by subroutine? Explain how the stack is affected while calling a subroutine program. (Refer section 2.2.6) [8]

Q. 13 a) Explain timer modes of 8051 microcontroller. (Refer section 16.4)

 [16]

OR

b) Explain the architecture of 8051 microcontroller with a block diagram. (Refer section 14.3) [16]

Q.14 a) Explain the functioning of 8255 programmable peripheral interface and its modes. (Refer section 8.4) [16]

OR

b) Explain the working of 8237 as a DMA controller and its command registers and their functions. (Not in new syllabus) [16]

Q.15 a) Explain the stepper motor control using 8051 and write an assembly language program for running the stepper motor in clockwise direction. (Refer section 17.4) [16]

OR

b) Explain the closed loop control of a servo motor using 8051 with a neat diagram. (Not in new syllabus)  [16]