QUESTION BANK - V SEMESTER ECE
EC2304 – MICROPROCESSORS AND MICROCONTROLLERS
UNIT I
Part A
1. When the 8086 processor is in minimum mode and maximum mode (April 2011)
2. Define segment override prefix (April 2011)
3. What are Tristate devices (Nov 2010)
4. Mention the advantages of using direct memory access (Nov 2010)
5. List out the number of memory cycles and T states taken by the instruction STA
4500H (Nov 2009)
6. What is the function of XRA A instruction? (Nov 2009)
7. State the use of RESET IN and RESET OUT pins of 8085 processor. (Nov 2009)
8. Define a register array? (June 2009)
9. What is buffer? (June 2009)
10. List out the function of Accumulator. (Nov 2008)
11. What do you mean by Non Maskable Interrupt? (Nov 2008)
12. State the number of machine cycles and T-states requires to complete the
execution of the 8085 instruction MOV M,A. (Nov 2008)
13. Let PC= 8500H and SP = E000H when a current instruction is being executed by
8085. What will be new value of these registers, when a device interrupts the
processor on RST 5.5? (Nov 2008)
14. What is the function of HOLD and HLDA? (May 2008)
15. Let the accumulator content is 9A H and CY= 1. What will be content of CY after
RRC being executed? (May 2008)
9. What information is conveyed when Qs1 Qs0 bits are 01? (May 2008)
10. What is the addressing mode of the following instructions? (May 2008)
JMP [3001H]
MOV AX,55H [BX] [SI]
11. List the different flags affected by the arithmetic and logic operations. (Nov 2007)
12. Draw the contents of the stack and the registers after a PUSH instruction.
(Nov2007)
13. Write about multiplexing of 8085 address bus. (Nov 2007)
14. What are the various registers available in 8085? (Nov 2007)
15. How address and data lines are demultiplexed in 8085? (May 2007)
16. What is the function performed by SIM instruction in 8085? (May 2007)
17. Name the various Flag bits available in an 8085 microprocessor. (Nov 2006, ‘09)
18. Give the significance of SIM and RIM instruction available in 8085. (Nov 2006)
19. Define STACK. (Nov 2006)
20. Write description of XCHG (May 2006)
21. What is the maximum capacity of memory that can be identified with 8085?
(May 2006)
22. What is the difference between RAR and RAL instructions in 8085? (Nov 2005)
Part B
1. Explain the Architecture of 8086 in Detail (May 2011)
2. Write Briefly about Direct memory Access (May 2011)
3. Explain the External memory addressing in 8086 (May 2011)
4. Discuss the Interrupt types of 8086 micro processor (May 2011)
5. Explain Implied Addressing mode and relative addressing mode in detail (Nov
2010)
6. Explain the 8086 interrupt types in detail (Nov2010)
7. What are the peripheral I/O instructions write its syntax and explain the same with
the timing diagram (Nov 2010)
8. Explain 8085 microprocessor with functional block diagram. (June 9,Nov’09,10)
9. Write an assembly language program to subtract two 8 bit numbers using 8085.
(Nov 2009)
10. Explain any FOUR two byte instructions used in 8085 processor. (8) (Nov’09)
11. Explain programming techniques of 8085 (June 2009)
12. (i).Write a program to convert Binary number to BCD number and explain.
(ii).Draw the block diagram of 8085 microprocessor and explain. (Nov 2008)
13. (i).Write BCD and Binary code Conversion Program and explain.
(ii).Explain the instruction set of 8085. (Nov 2008)
14. (i)Explain the function of the following signals of 8085: RST 7.5, TRAP, HOLD
and INTA. (8)
(ii)Draw and explain the use of bits in PSW in8085. What are the flags affected by
the MVI M,00 AND XRA A instructions? (8) (Nov 2008)
15. (i)Enumerate the addressing modes of 8085 instruction set with suitable examples
for each. (8)
(ii)Write an assembly language program using 8085 instruction mnemonics that
converts a given 2 digit BCD into its equivalent hexadecimal value. Make the
program self explanatory with appropriate comments. (8) (Nov 2008)
16. (i)Describe the signals present in 8085
(ii)Write a program to convert 8 bit binary number to BCD. (May 2008)
17. (i)Write a program for block transfer of data types
(ii)Write a program to add a series of 10 numbers stored from location 3000H
onwards. (May 2008)
18. (i)Explain the various logical and arithmetic instructions available in 8085
microprocessor. (10)
(ii) Explain the function of various flags of 8085 microprocessor (6) (May 2007)
19. Write an 8085 assembly language program to convert 8 bit binary to
ASCII code. (May 2007)
20. (i)With a neat block diagram explain the architecture of an 8085
Microprocessor? (12)
(ii) List out the Mask able and Non – Mask able interrupts available in an
8085 processor. (4) (Nov 2006)
21. (i) How do the instructions of 8085 is classified based on their functions
and word length? Give an example. (10)
(ii) Write an ALP to add two 8 bit numbers. (Nov 2006)
UNIT II
Part A
1. What are the 8086 instruction used for BCD Arithmetic (May 11)
2. List any four program control instructions available in 8086 (May 11)
3. What is the purpose of following commands in 8086 (Nov 2010)
AAD,RCL
4. Write an assembly language program to multiply two sixteen bit numbers. Assume
the two numbers are in CX and DX (Nov 2010)
5. Give the significance of Interrupt flag in 8086 processor. (Nov 2009)
6. What is indexed addressing? Give an example. (Nov 2009)
7. State the use of READY signal in 8086 processor. (Nov 2009)
8. What is the need of a flag register in 8086? (June 2009)
9. What is an interrupt service routine? (June 2009)
10. What do you mean by Assembler? (Nov 2008)
11. How do you pass parameters to Macros? (Nov 2008)
12. What is the function of Bus Interface Unit? (Nov 2008)
13. List out the Segment Registers of 8086 (Nov 2008)
14. What is storage space required to store the interrupt vectors of 8086 ? (May 2008)
15. What is pipelined architecture? (May 2007)
16. What do you mean by pipelining in an 8086 processor? (Nov 2006)
17. How the 20-bit effective, address is calculated in an 8086 processor? (Nov 2006)
18. What are the maximum address space and data bus width of 8086 processor?
19. Mention the addressing modes of the following 8086 instructions:
MOV AL, disp[BX]; MOV AH, disp[BX] [SI] (Nov 2008)
20. The CS contains A820, while the IP contains CE24. What is the resulting physical
address? (Nov 2008)
21. What do these instructions do? : STD, IRET. (Nov 2007)
22. What is Macro? (Nov 2007)
23. How does 8086 generate physical address? (Nov 2007)
24. List the interrupts present in 8086 with interrupt vector table. (Nov 2007)
25. What are the flags in 8086? (May 2007)
26. What are the various interrupts in 8086? (May 2007)
27. What is the Physical address corresponding to DS: 103FH if DS=94D0H?
28. What are the advantages of using memory segmentation in 8086? (Nov 2006)
29. What is Macro and when it is used? (Nov 2006)
30. What is a segment override prefix? Give an example (Nov 2006)
31. Give some examples of Assembler Directives. (May 2006)
32. Can the 8086 processor operate on more than one instruction at a time? If so explain
how it is done? (Nov 2005)
33. What does REP prefix accomplish and what type of instruction is it used with?
34. Give the function of the following signals of 8086: READY, TEST (Nov 2005)
Part B
1. Explain thje assembler Directives ASSUME,EQU,DW and EVEN with suitable
Examples (May 2011)
2. Write an 8086 ALP to sort the array of elements in ascending order (May 2011)
3. Write an ALP to find the largest element in an array element (May 11)
4. Explain the data Transfer group and logical group of 8086 instructions (May 11)
5. Explain the 8086 bit manipulation instruction with an example of each (Nov 10)
6. Write an 8086 program to convert BCD to Binary (Nov 10)
7. Explain the relative addressing mode and Implied addressing mode with its
syntax (Nov 10)
8. Explain any EIGHT addressing modes used in 8086 processor with an example.
(Nov 2009)
9. Write an assembly language program to find the largest number in an array.
(Nov 2009)
10. Explain the role of the following.
(1) Address Conversion Mechanism (2) Instruction Queue (Nov2009)
11. Explain the significance of the following signals :
(1) HOLD (2) IO/M (3) LOCK (Nov2009)
12. Explain how the memory unit is addressed by 8086 with a neat diagram.
(Nov 2009)
13. Write about Instruction set of 8086 (June 2009)
14. Describe the addressing mode of 8086. (June 2009)
15. (i).Draw and explain the flag register of 8086 in brief.
(ii).Explain the addressing modes of 8086 with example. (Nov 2008)
16. i).Write a short notes on Interrupts and Interrupt service routines.
ii).Explain the instruction set of 8086. (Nov 2008)
17. Draw the architectural block diagram of 8086. (Nov 2008)
18. (i)List and explain the use of segment registers in 8086.(8)
(ii)Explain how instruction pipeline works in 8086 and mention how it helps in
improving CPU’s performance. (8) (Nov 2008)
19. (i)Explain the physical memory organization in an 8086 system (8)
(ii)Distinguish between the following pairs : NEAR and FAR procedures, macros
and subroutines. (8) (Nov 2008)
20. List and explain the use of index and pointer registers in 8086.(8) (Nov 2008)
21. Explain the internal block diagram of 8086. (Nov 2008)
22. (i)Write a program to find the number of positive numbers and negative numbers
in a given series of signed numbers using 8086.
(ii)Explain the following assembly directives
SHORT, TYPE, FAR PTR (May 2008)
23. (i) Describe the action taken by 8086 when INTR pin is activated. (6)
(ii) Write an assembly language program in 8086 to search the largest data in
an array. (10) (May 2007)
24. (i) Discuss the various addressing modes of 8086 microprocessor. (10)
(ii) Explain the following assembler directives used in 8086
(1) ASSUME
(2) EQU
(3) DW (6) (May 2007)
25. (i)Explain in detail about memory access mechanism in 8086 (8)
(ii) Explain the function of following 8086 signals.
(1) HLDA
(2) RQ/GTO
(3) DEN
(4) ALE. (8) (May 2007)
26. (i)Explain in detail about the various addressing modes used in 8086
processor? Give an example. (12)
(ii) Name the various segment registers and their usage in 8086 processor. (4)
(Nov 2006)
27. (i)With the neat sketch explain the architecture of an 8086 processor.
(ii) Give the significance of O Flag, T Flag and I Flag, D Flag of 8086. (4) (Nov
2006)
UNIT III
Part A
1. List the major functions performed by CRT interface (May 2011)
2. Give the salient features of the 8254 programmable timer (Nov 2010)
3. What is sample and Hold circuit (Nov2010 may 11)
4. Differentiate minimum and maximum mode of 8086. (Nov 2009)
5. What are the advantages of the multiprocessor systems? (May 2009)
6. What is coprocessor? (May 2009)
7. The length of short integer in 8087 NDP is ………. (Nov 2008)
8. Which form of data representation is used by the 8087 for numbers when it
process them internally and how many bits are used for this representation? (Nov
2008)
9. What is the size of internal register stack of 8087 and how they are named? (May
2008)
10. Differentiate closely coupled configuration and loosely coupled configuration
(May 2008)
11. How many different data types are supported by 8087? (Nov 2007)
12. Define closely coupled configuration. (Nov 2007)
13. Define loosely coupled configuration. (May 2007)
14. What are the advantages of loosely coupled configuration? (May 2007)
15. What is Daisy chaining? (May 2007)
16. What is polling? (Nov 2006)
17. Name the three bus allocation schemes used in loosely coupled multiprocessor
system. (Nov 2006)
18. What are the three basic multiprocessor configurations that the 8086 can support?
19. What is independent request? (Nov 2006)
20. State the need of 8087 NDP. (May 2006)
21. What is Bus Arbitration? (May 2006)
22. What does Qs1 Qs0 of 8087 represent? (May 2006)
23. Give the status word format of 8087. (May 2006)
24. State the need of 8089 IOP. (Nov 2005)
25. Give the Tag word format of 8087. (Nov 2005)
Part B
1. Explain the minimum mode of operation of 8086 with a neat sketch. (Nov2009)
2. Explain Multi microprocessor configuration methods? (June 2009)
3. Discuss about the multiprocessor configurations. (Nov 2008)
4. Explain the basic bus access control and arbitration schemes used in
multiprocessor systems. (8) (May 2008)
5. Explain 8089 architecture with a neat diagram. (Nov 2007)
6. Explain 8087 architecture with a neat diagram. (Nov 2007)
7. Name the different data types supported by 8087 and explain (May 2007)
8. Explain closely coupled configuration with necessary diagrams. (May 2007)
9. Explain interconnection of 8089 IOP with 8086. (Nov 2006)
10. Explain with necessary diagrams loosely coupled configuration. (Nov 2006)
11. Explain how Co-processor works and interacts with 8086. (May 2006)
UNIT IV
Part A
1. State the role of In-service register of 8259 interrupt controller. (Nov 2009)
2. How are semiconductor memories classified? (June 2009)
3. What are the operating modes of 8253? (June 2009)
4. What is the use of IRR(Interrupt Request Register)? (Nov 2008)
5. What does it imply if 8259’s ICW1 bit fields LTIM and SNGL bits are set to
zero? (Nov 2008)
6. What is key bouncing? (May 2008)
7. List the uses of USART. (Dec 2007)
8. List the features of 8251. (Apr 2007)
9. What are the different modes of operations of 8259? (Apr 2007)
10. List the functions performed by 8279. (Apr 2007)
11. What is the function of gate signal in 8254 timer? (May 2007)
12. Write the format of ICW1 in 8259. (May 2007)
13. Name the two modes used by the DMA processes to transfer data. (Nov 2006)
14. Name the six modes of operations of an 8253 programmable interval timer. (Nov
2006)
15. Using two 8259-interrupt controllers what is the maximum number of peripherals
that can be provided with interrupt facility. (Apr 2006)
16. Sketch the control word for Programmable timer. (Apr 2006)
17. Write about DMA controller. (Apr 2006)
18. Draw the mode word format of 8251A. (Apr 2006)
19. Write the BSR control word of 8255 to set bit 0 of port C (Nov 2005)
20. Define PPI. (Nov 2005)
21. Draw the data format used while asynchronous serial data transmission/reception
is done using 8251. (Nov 2005)
22. What is the internal operating frequency of the 8279? How can you derive it from
any available clock signal? (Apr 2005)
23. Draw the command word format for8251. (Apr 2005)
24. Specify the bit of a control word for the 8255.Wchich differentiates b/w I/O mode
and BSR mode? (Apr 2005)
25. Specify the two types of serial communication. (May 2005)
Part B
1. Describe the DMA controller 8237 Internal architecture? (June 2009)
2. Explain Mode of Operation and command words of 8279. (June 2009)
3. Draw the block diagram of 8237 and explain the functions of each block. (Nov
2008)
4. Draw the block diagram of 8279 and explain the function of each block. (Nov
2008)
5. Discuss the architecture and working of 8253 timer. (May 2008)
6. Describe the working of 8259 Interrupt controller (May 2008)
7. With a neat block diagram explain PPI. (Nov 2007)
8. (i) With the help of block diagram explain the operation of USART (8251A)
(10)
(ii) Discuss the salient features of 8259 – programmable interrupt controller.
(6) (May 2007)
9. (i) Describe the various modes of operations in 8253 programmable interval
Timer. (8)
(ii) Explain the operation of DMA controller (8237). (May 2007)
10. (i)With a neat sketch and explain the operation of an Interrupt controller(8259)
(14)
(ii) What is the use of CAS0, CAS1 and CAS2 signals? (Nov 2006)
11. Draw the block diagram of a DMA controller (8237) and explain its
operation. (Nov 2006)
12. Explain the working of Mode 3 operation of timer with a suitable timing diagram.
(May 2006)
13. Differentiate between Synchronous and Asynchronous modes of serial
communications. Interpret the mode of operation of 8251 if its mode instruction
command word is initialized to FE H. (May 2006)
UNIT V
Part A
1. What happens in power down mode of 8051 micro controller (May 2011)
2. What are the different ways of operand addressing in 8051 (May 2011)
3. what is that register addressing mode in 8051 microcontroller (Nov 2010)
4. Write an assembly language program to monitor PI continuously It should
stop monitoring when PI reaches 63. (Nov 2010)
5. Name the two external interrupt of 8051 microcontroller. (Nov 2009)
6. Specify any two applications of Microcontrollers. (Nov 2009)
7. List the applications of a microcontroller. (June 2009)
8. Define XTAL1 and XTAL2. (June 2009)
9. What do you mean by Indirect Addressing Mode? (Nov 2008)
10. What is the function of DPTR register? (Nov 2008)
11. What is the possible branching range when an AJMP/ACALL of 8051
instruction is executed? (Nov 2008)
12. Name the interrupt sources of 8051 for which the priority levels are highest
and lowest, respectively. (Nov 2008)
13. How does the status of EA pin affect the access to internal and external
program memory? (May 2008)
14. State the difference between RET and RET1 instruction in 8051. (May 2008)
15. List the interrupts of 8051 micro controller. (Nov 2007)
16. What are register banks in 8051 microcontroller? (Nov 2007)
17. Differentiate a microprocessor and a microcontroller. (May 2007)
18. Differentiate RRA and RRCA instruction in 8051 microcontroller.(May 2007)
19. Draw the format of PSW of 8051. (Nov 2006)
20. List the addressing modes supported by 8051. (Nov 2006)
21. What is SFR? (Dec 2006)
22. What are the features of 8051 microcontrollers? (Dec 2006)
23. Which control signals of 8051 are used to access external data memory and
external program memory? (Apr 2006)
24. State any two applications of 8051. (Apr 2006)
25. How does 8051 differentiate between external and internal program memory?
(May 2006)
26. What is the function of GATE bit in the TMOD register of 8051? (May 2006)
27. Explain the function of following pins of 8051 microcontroller
a. PSEN b. EA (Nov 2005)
28. Write the various interrupts supported by 8051 with priority level and vector
address (Nov 2005)
29. How do you calculate baud rate for serial communication for 8051 (Nov 2005)
30. What is the use of DTPR? (May 2005)
31. What are the addressing modes supported by 8051
Which of the following are illegal?
A) ADD R3, #50H B) ADD A, #50H
C) ADD R7, R4H D) ADD A,#255H
E) ADD A ,R5H (May 2005)
26. Draw the interfacing diagram of LCD with 8051 controller. (May 2005)
27. What are the operating modes of serial port of 8051? (May 2005)
Part B
1. Explain the operations of 8051. (June 2009)
2. Describe Interrupts and instruction set of 8051. (June 2009)
3. (i).Write a short notes on interrupt of 8051. (ii).Explain the instruction set of 8051.
(Nov 2008)
4. Explain the architecture of 8051 with its diagram. (Nov 2008)
5. (i)Draw and explain the functions of bits in TMOD and TCON registers of
8051.(10)
(ii) Explain how 8051 distinguishes between internal and external
ROMs.(6) (Nov 2008)
6. (i) Write a brief note on interrupts and their priorities of 8051. Draw the format
and explain the bit functions of interrupt enable register (10)
(ii) List the addressing modes of 8051 and give a specific example for each
of them. (6) (Nov 2008)
7. (i)Explain the architecture of 8051.
(ii) Write a program to find the number of positive and negative numbers
in an array. (May 2008)
8. Explain each PORT circuitry available in 8051. (Nov 2007)
9. Explain serial communication interface available in 8051. (Nov 2007)
10. With a suitable block diagram, explain the architecture of 8051 microcontroller.
(May 2007)
11. Give the PIN details of an 8051 microcontroller and explain. (16) (May 2007)
12. Write short notes on LCD interface. (6) (Nov 2006)
13. Explain different addressing modes used in 8051 microcontroller (Nov 2006)
14. Explain the programming of counter and Timer of 8051 (May 2006)
15. With neat diagram, explain the interfacing of LCD with 8051 and write an ALP
for the same. (May 2006)