CS2252 Microprocessor And Microcontrollers All Units Question Bank

Anna University , Chennai


Cs2252 –  Microprocessor And Microcontrollers


PART-A(2 Marks)

1. What is Microprocessor? Give the power supply & clock frequency of 8085

2. What are the functions of an accumulator?

3. List the 16 – bit registers of 8085 microprocessor

4. List few applications of microprocessor-based system

5. List the allowed register pairs of 8085

6. Mention the purpose of SID and SOD lines

7. What is an Opcode?

8. What is the function of IO/M signal in the 8085?

9. What is an Operand?

10. How many operations are there in the instruction set of 8085

11. List out the five categories of the 8085 instructions. Give examples of the instructions for each group

12. Explain the difference between a JMP instruction and CALL instruction

13. . Explain the purpose of the I/O instructions IN and OUT.

14. What is the difference between the shift and rotate instructions?

15. How many address lines in a 4096 x 8 EPROM CHIP?

16. What are the control signals used for DMA operation

17. What is meant by Wait State?

18. List the four instructions which control the interrupt structure of the 8085 microprocessor.

19. What is meant by polling?

20. What is meant by interrupt?

21. Explain priority interrupts of 8085.

22. What is a microcomputer?

23. What is the signal classification of 8085

24. What are operations performed on data in 8085

25. Steps involved to fetch a byte in 8085

26. How many interrupts does 8085 have, mention them

27. Basic concepts in memory interfacing

28. Define instruction cycle, ma chine cycle and T-state

29. What is an instruction?

30. What is the use of ALE

31. How many machine cycles does 8085 have, mention them

32. Explain the signals HOLD, READY and SID

33. Mention the categories of instruction and give two examples for each category

34. Explain LDA, STA and DAA instructions

35. Explain the different instruction formats with examples

36. What is the use of addressing modes, mention the different types

37. What is the use of bi-directional buffers?

38. Give the register organization of 8085

39. Define stack and explain stack related instructions

40. Why do we use XRA A instruction

41. Compare CALL and PUSH instruction

42. What is Microcontroller and Microcomputer

43. Define Flags

44. How does the microprocessor differentiate between data and instruction.

PART-B(8 Marks)

1.  Explain the pin diagram of 8085.

2.  Explain  the  requirement  of  a  program  counter,stack  pointer  and  status  flags  in  the architecture of 8085 microprocessor.

3. Explain the memory mapped i/o addressing scheme.

4. Draw and explain the timing diagram of memory read cycle.

5. Draw and explain the timing diagram of memory write cycle with example.

6. Draw and explain the timing diagram of opcode fetch cycle.

7. Assume that the accumulator contents data bytes 88 hand instruction MOV C, A 4FH is fetched. List the steps decoding and executing the instruction.

8. Draw the functional block diagram of 8085 microprocessor and explain.

9. Write a Program to Perform the following functions and verify the output steps:

a. Load the number 5CH in register D

b. Load the number 9E H in register C

c. Increment the Contents of register C by one.

d. Add the contents of register C and D and Display the sum at output port1.

10.  Write  an  assembly  language  program  to  find  out  the  largest  number  from  a  given unordered array of 8 bit numbers, stored in the locations starting from a known address.

.11. Explain 8085 Stack in detail.

12. Write a 8085 ALP to generate a accurate time delay of 100ms.

13. Write 8085 assembly language program to SORT an array of 10 bytes in Descending order.

14. Explain 8085 stack in detail


1.Explain the architecture of microprocessors 8085.

2.Explain the direct addressing modes and indirect addressing modes of 8085 with example.

3.With suitable examples explain 8085 instruction set in detail.

4. With suitable examples explain 8085 addressing modes in detail


PART-A(2 Marks)

1. How do 8086 interrupts occur

2. What are the 8086 interrupt types

3. What is interrupt service routine

4. Define BIOS

5. Explain PUBLIC

6. Explain DUP

7. Compare Procedure & Macro

8. What is the purpose of segment registers in 8086?

9. Define pipelining?

10. Discuss the function of instruction queue in 8086?

11. What is the maximum memory size that can be addressed by 8086?

12. What is the function of the signal in 8086?

13. What are the predefined interrupts in 8086?

14. What are the different flag available in status register of 8086?

15. List the various addressing modes present in 8086?

16. How single stepping can be done in 8086?

17. State the significance of LOCK signal in 8086?

18. What are the functions of bus interface unit (BIU) in 8086?

19. What is the clock frequency of 8086?

20. What are the two modes of operations present in 8086?

21. Explain the process control instructions

22. Explain REPEAT-UNTIL statements

23. What is multiprogramming

24. Differentiate between absolute and linear select decoding?

25. What are the three classifications of 8086 interrupts?

26. What are the functions of status pins in 8086?

PART-B(8 Marks)

1.Write a 8086 ALP to convert an 8 bit binary number into equivalent gray code.

2. Explain the function of all the pins of 8086 Processor.

3. Write a 8086 ALP to sort an array of ten bytes in ascending order. Add comments to your


4. Explain the function of various flags of 8086 microprocessor.

5. Explain the function of unsigned multiplication and Division instructions in 8086 with suitable examples.

6. Describe the functional units present and their functions in BIU and EU of 8086.

7. Write 8086 assembly language program to perform the following a. To move a string of words from offset 1000h to offset 6000h. The Length of the string is 0Ch.

b. To add an array of bytes. The array contains 50bytes.


1.Describe Intel 8086 Microprocessor Architecture

2.Describe any five addressing modes of 8086 with suitable examples


PART-A(2 Marks)

1. What are the configurations used for physical interconnections?

2. What is Closely Coupled Configuration?

3. What is Loosely Coupled Configuration

4. What is a data amplifier?

5. What are the different inter connection topologies?

6. Give the instruction set of 8087?

7. What are the different data types commonly used.

8. Write the advantages of loosely coupled system over tightly coupled systems?

9. Define Coprocessor.

10. Explain the different methods of data transfer possible between MPU and I/O.

11. What is the main use of I/O processor.

12. Difference between Loosely and Tightly Coupled Configuration

13. What is the need of Co-processors? Give an example.

14. What are the drawbacks of using tightly Coupled Configuration.

15. What are the major blocks available in 8089 architecture.

16. explain how CPU communicate with IOP.

17. What are the advantages of using 8087 Numeric Data Processor.

PART-B(8 Marks)

1. Explain briefly about loosely Coupled Configuration.

2. Explain briefly about tightly coupled configuration.

3. Explain in detail with an example about the various data types.

4. Describe the different techniques in which how CPU can communicate with IOP.

5. Explain the difference between data processor and IO processor.


1.Explain in detail about the different types of coprocessor configurations

2.. Describe in detail about the Architecture of 8089 I/O Processor.


PART-A(2 Marks)

1. What is the use of 8251 chip?

2. What are the different types of methods used for data transmission?

3. What are the various programmed data transfer methods?

4. What is synchronous data transfer?

5. What is asynchronous data transfer?

6. What are the functional types used in control words of 8251

7. What are the basic modes of operation of 8255?

8. Write the features of mode 0 in 8255?

9. What are the features used mode 1 in 8255?

10. What are the signals used in input control signal & output control signal?

11. What are the features used mode 2 in 8255?

12. What are the different types of write operations used in 8253?

13. What are the modes of operations used in 8253?

14. Give the different types of command words used in 8259a?

15. Give the operating modes of 8259a?

16. Define scan counter?

17. What is the output modes used in 8279?

18. What are the modes used in keyboard modes?

19. What are the modes used in display modes?

20. What is the use of modem control unit in 8251?

21. Give the register organization of 8257?

22. What is the function of DMA address register?

23. What is the use of terminal count register?

24. What is the function of mode set register in 8257?

25. Distinguish between the memories mapped I/O peripheral I/O?

26. List the operation modes of 8255

27. What is a control word?

28. What is the purpose of control word written to control register in 8255?

29. What is the size of ports in 8255?

30. What is interfacing?

31. What is memory mapping?

32. What is I/O mapping?

33. What is an USART?

34. What is the use of 8251 chip?

35. The 8279 is a programmable                  interface.

36. List the major co mponents of the keyboard/Display interface

37. What is Key bouncing?

38. Define HRQ?

39. What is the use of stepper motor?

40. What is TXD?

41. What is RXD?

42. Draw the status word format for 8254.

43. What is meant by key bouncing?

44. Write the function of crossbar switch?

PART-B(8 Marks)

1. Discuss how memory chips and I/O devices are interfaced to a microprocessor.

2. Draw a timing diagram to interface a 4K  ROM and  a 2K RAM  consecutively with microprocessor 8085, starting with ROM interfacing at address 0000 H. Explain.

3. What are Hardware and Software Interrrupts?What is ISS?

4. Draw a diagram to interface a 6K ROM and a 2K RAM consecutively with microprocessor

8085, starting with ROM interfacing at address 8000 H.

5. Expailn how to use an RST instruction to implement a software breakpoint..

6. Interface a 10 or 12-bit D/A converter with an 8-bit microprocessor.

7. Design a circuit to interface an 8-bit D/A conveter with an 8-bit microprocessor and verify the analog output for a digital signal.

8. 16. .Explain the function of Handshake signals.What is the difference between setting the

8155 I/O ports in ALT 1 and ALT 3.

9. Design a five-minute clock(timer using the 8254 and the interrupt technique. Display minutes and seconds.

10. Explain how the 8237 DMA controller transfers 64K bytes of data per channel with eight address lines.

11. Specify handshaking signals and their functions if port A of 8255 is set-up as input port in mode 1.

12 .explain mode 0 and mode 1 of 8253.

13. Explain terms synchronous,baud rate,parity,half and full duplex transmission.

14. Explain how data bits are transmitted in the asynchronous format,and calculate the the delay required between two successive bits for a given baud.

15. Write a short note on the following:

a) machine cycle

b) instruction cycle c) execute cycle

d) Vectored interrupt

16.  Interface  a  8K  RAM  consecutively  with  microprocessor  8085,  starting  with  ROM

interfacing at address 8000 H.

17. Define Addresing modes,Data formats with examples.

18 . Explain . the process of the Direct Memory Acess(DMA) and the functions of various elements of the 8237.

19. Expain the procedure of interfacing the temperature monitoring system with 8085.


 1.With a neat block diagram, explain in detail  the internal architecture of 8255 and its registers

2.Explain  the  block  diagram  and  the  functions  of  each  block  of  the  8251  USART (Programmable Communication Interface).

3.Explain an interrupt process and the difference between a maskable and non-maskable interrupt by using examples.

4. Explain the block diagram of the 8279 Keyboard/Display interface and its operations.


PART-A(2 Marks)

1. What is mean by microcontroller?

2. Explain DJNZ instructions of intel 8051 microcontroller?

3. State the function of RS1 and RS0 bits in the flag register of intel 8051 microcontroller?

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

5. Give the alternate functions for the port pins of port3?

6. Specify the single instruction, which clears the most significant bit of B

7. Explain the function of the pins PSEN and EA of 8051

8. Explain the 16-bit registers DPTR and SP of 8051

9. Name the special functions registers available in 8051.

10. Explain the register IE format of 8051

11. Compare Microprocessor and Microcontroller

12. Name the five interrupt sources of 8051?

13. List the features of 8051 microcontroller.

14. Name any four additional hardware features available in microcontrollers when compared to microprocessors.

15. List out the Hardware Resources available in 8051.

16. When 8051 is reset, all interrupts are disabled. How to enable these interrupts?

17. What is nested interrupts?

18. How will you double the baud rate in 8051?

19. Explain software and hardware methods to start and stop timers in 8051.

20. Give steps to program 8051 for serial data transfer.

21. Write short notes on interrupt priority.

22. Write the vector address and priority sequence of 8051 interrupts

23. Write a delay routine for 1 millisecond using timer 0 of 8051 for 12 MHz crystal frequency.

PART-B(8 Marks)

1 Discuss the peripheral interface of 8051

2. Explain the interrupt structure of 8051 microcontroller

3. Explain how interrupts are prioritized.

4.What is the difference between the Microprocessorsand Microcontrollers?

5.Explain the I/O port structure of 8051.

6. Explain the different serial communication modes in 8051.

7. Explain the memory structure of 8051.


1.Describe the architecture of 8051 with neat diagram.

2.States various modes available for timer in 8051.