BHARATHIDASAN ENGINEERING COLLEGE III Year / V Semester / EEE MICROPROCESSORS AND MICROCONTROLLERS (R-2013) FREQUENTLY ASKED QUESTIONS IN UNIVERSITY EXAMINATION PART A UNIT 1-8085 PROCESSOR 1. Draw the schematic of latching low-order address bus in 8085 Microprocessor. 2. If the stack segment register contains 3000h and stack pointer register contains 8434h, what is the physical address of the top of the stack in 8086 microprocessor? 3. What is TRAP interrupt and it significance? 4. Define the function of parity flag and zero flag in 8085. 5. List the control and status signals of 8085 microprocessor and mention its need. 6. Write the functional aspects of Execution unit in an 8086 architecture. 7. What is the function of Program Counter in 8085 microprocessor? 8. How many address and data lines are used in 8086 microprocessor? 9. What are the various flags in 8085? 10. What is ALE? NOV/Dec 2013 11. To obtain a 320 ns clock, what should be the input clock frequency? What is the frequency of clock signal at CLK OUT? 12. What is meant by level-triggered interrupt? Which of the interrupts in 8085 are level triggered? 13. What is the use of Stack pointer? 14. Mention the use of ALE. (May / June2015) 15. What is meant by Level triggered interrupt? Which are the interrupts in 8085 level triggered? 16. To obtain a 320ns clock what should be the input clock frequency? What is the frequency of clock signal at CLK OUT? May/June 2014 17. What is TRAP interrupt and its significance? May/June 2012 18. Define the function of parity flag and zero flag in 8085? May/June 2012 19. What is the function of program counter in 8085? April /May 2013
20. Write down the control and status signals of 8085. Nov/Dec 2012 21. Specify the size of data, address, memory word and memory capacity of 8085 microprocessor. 22. Draw the schematic of latching low order address bus in 8085 microprocessor. 23. What are the flags used in 8085? NOV/Dec 2013 24. Specify the function of Address bus and the direction of the information flow on the address bus? Nov./Dec 2012 (R 2004) 25.To obtain a 320 ns clock, what should be the input clock frequency? (May / June 2014) 26. What is the frequency of clock signal at CLK OUT? How are instruments classified? (May / June 2014) 27. What if the function of ALE IN 8085 microprocessor? (May / June2015) 28. What is the maximum number of bytes of memory addressable by 8086 microprocessor. (May / June2015) 29. Why data bus is bi directional? (A/M -17) 30. How many machine cycles does 8085 have, mention them?(a/m -17) PART B 1. (i) Explain in detail the 8085 interrupt structure. (8) (A/M -17) (ii) Draw the timing diagram for IN and OUT instruction of 8085 and explain. (8) 2. (i) Draw the internal block diagram of 8086 and explain the bus interface unit and execution unit. (8) (ii) How address decoding is done in memory Interface. (8) 3. (i) Explain with a neat block diagram the architecture of 8085 microprocessor. (12) (A/M -17) (ii) Draw the pin diagram of 8085 microprocessor. (4) 4. (i) Describe the different types of interrupts used in 8085 microprocessor. (8) (ii) Draw the timing diagram of Opcode fetch machine cycle and I/O Read cycle. (8) 5. (i) Draw the pin diagram of 8085 Microprocessor and list the classification of signals.(8) (ii) Draw the timing diagram for OP-code fetch Machine Cycle and Memory Read Machine Cycle. (8)
6. (i) Write an 8085 assembly language program by assuming that Microprocessor is completing an RST 7.5 interrupt request; Check to see if RST 6.5 is pending. If it is pending, enable RST 6.5 without affecting any other interrupts. Otherwise return to the main program. (ii) Draw the decode logic for LED output port in an I/O interface. (8) 7. (a) (i) Explain with a neat block diagram the architecture of 8086 microprocessor. (16) 8 (i) Compare the features of 8085 and 8086 microprocessors (6) (ii) Describe the interrupt structure of 8086 microprocessors. (10) 9. Draw and explain the architecture of 8085. (16) 10. Explain the interrupt structure of 8085 microprocessor. (16) 11. Explain how pipelined architecture is implemented in 8086. 12. Draw the signal configuration of 8085 and explain the purpose of each signal. 13. Explain with a neat block diagram, the architecture of 8085 microprocessor. (16) 14. (i)explain the interrupt structure of 8085 microprocessor. (8) (ii) Draw the timing diagram of Opcode Fetch machine cycle. (8) 15. Describe the registers of 8085. (16) (A/M -17) 16. What is meant by memory interfacing? Explain with an example. (16)(A/M -17) 17. Explain how pipelined architecture is implemented in 8086. (MAY/JUN 14) 18. Draw the signal configuration of 8085 and explain the purpose of each signals. (MAY/JUN 14)
FREQUENTLY ASKED QUESTIONS (FAQ) PART A UNIT II 1. Why do we need look-up table?(n/d-14) 2. How are the 8085 instructions classified according to the functional categories?(a/m-17) (N/D 11) 3. What are the types of addressing mode in 8085 microprocessor? 4. What is the use of branching instructions? Give example. 5. What is Indexing? 6. What is the different control machine control instruction used in 8085 microprocessor? 7. What is the function of stack? 8. What are the different addressing modes of 8085? 9. What are the instructions associated with a subroutine? 10. Mention the similarity and difference between compare and subtract instructions. 11. State the purpose and importance of NOP instruction. 12. How is time Delay generated using subroutines? 13. Explain the functioning of CMP instruction 14. What is a stack in an 8085 microcomputer system? 15. What is the different control machine control instructions used in 8085 microprocessor? 16. What is the function of stack? M/J 2013 17. Mention the similarity and difference between compare and Subtract instructions (M/J 2014) 18. State the purpose and importance of NOP instruction. M/J 2014 19. What are the types of addressing modes of 8085.M/J2012, N/D 2013? 20. What is the use of branching instructions? Give examples. M/J2012 21. State the function of given 8085 instruction: JP, JPE, JPO, JNZ. (A/M 11) 22. How is PUSH B instruction executed? Find the status after the execution (A/M 11) 23. Why do we need look up table? (N/D 11) 24. What is the function of rotate instruction?(may/jun 2015) 25. What is a stack in an 8085 microcomputer system? N/D 2012
PART B 1. (i) Write a program to count from 0 to 9 with one second delay between each count. At the count of 9, the counter should reset itself to 0 and repeat the sequence continuously. Assume the clock frequency is 1 MHz. (8) (ii) Write a program with a flowchart to multiply two 8-bit numbers.(8) 2. (i) Compare the similarities and differences of CALL and RET instructions with PUSH and POP instructions. (8) (ii) Sixteen bytes are stored in memory locations at XX50h to XX5Fh.Transfer the entire block of data to new memory locations starting at XX70h. (8) Program: 3. (i) Describe the addressing modes of 8085 microprocessor with suitable instructions.(8)(a/m-17) (ii) Describe with a suitable example the operation of stack. (8) 4. (i) Describe with suitable example the data transfer, loading and storing instruction. (ii) Write an assembly language program for arranging an array of 8 bit unsigned number in ascending order.(8) 5. (i) What are the different addressing modes in 8085 Microprocessor? Explain it with an Example. (8) (ii) Write an 8085 assembly language program to multiple two 8-bit numbers. (8) 6 (i) Describe with suitable examples the data transfer instructions in 8085 microprocessor. (8) 7. (ii) Write an 8085 assembly language program to sort numbers in ascending orders (8) (i) Describe the categories of instructions used for data manipulations in 8085 microprocessor. (8) (ii) Describe with a suitable 8085 assembly language program the use of subroutine instructions. (8) 8. Discuss in detail about the 8085 instruction set, explaining about the various types of operations. 9.(i) Give two examples for data transfer instructions, arithmetic instructions, logic instructions and branch instructions. (8) (ii) Six bytes of data are stored in memory locations starting at XX50 h. Add all the data bytes. Use register B to save any carries generated while adding data bytes. Display the entire sum 10. Write an assembly language program with its output to add two 16 bit number using 8085.
11. (i) Describe the interrupt structure of 8085 microprocessor. Compare the same with 8086 microprocessor. (ii)write an 8085 Assembly Language Program to generate a Z delay of 1ms. Show the calculations. 12.Write a program to calculate and store in the results as mentioned. Five memory locations 2401H, 2402H, 2403H, 2404H and 2405H have called Xl, X2, X3, X4 and X5. (2405H) = X1 + X2 + X3 + X4 (2403H) = X5 X3 X2 X1 13. (i) Explain the addressing modes of 8085 microprocessor with example for each.(8) (ii) Write a 8085 assembly language program to divide a 8-bit number by another 8-bit number and store the remainder and quotient in memory locations 4252 and 4253 14. Write an 8085 assembly language program to solve the following equation :Z = 2X + Y where X and Y are stored in memory locations 4200 and 4201 respectively. The value of Y should be stored in 4202 (Lower Byte) and 4203 (Higherbyte). (16) 15.(i) Describe the categories of instructions used for data manipulation in 8085 microprocessor? (ii) Describe with suitable 8085 ALP the use of subroutine instruction?(10) (MAY/JUN 13) (A/M -17)
FREQUENTLY ASKED QUESTIONS(FAQ) PART A UNIT III 1. List the on-chip peripherals of 8051 microcontroller. 2. What are the addressing modes of 8051 microcontroller? 3. What are the main features of 8051 microcontroller? 4. Draw the flowchart for programming of serial port of 8051. 5. Write an 8051 assembly language program to clear the accumulator and add 3 to the accumulator to times. 6. What does the mnemonics LCALL and ACALL stand for? 7. What are the addressing modes of 8051 Microcontroller? (MAY/JUN 2012)(A/M -17) 8. What are the addressing modes of 8051 Microcontroller? (MAY/JUN 2012)(A/M -17) 9. What is meant by level-triggered interrupt? Which of the interrupts in 8085 are level triggered? (MAY/JUN 2014) 10. What is the function of rotate instruction?(may/jun 2015) 11. What is the function of B registers in 8051 Microcontroller? 12. What is instruction pipelining? 13. What is the purpose of overflow flag in 8051 Microcontroller? 14. Mention the purpose of PSEN and EA in 8051 microcontroller. 15.List the interrupt sources in 8051 microcontroller. 16. List the interrupts of 8051 microcontroller. 17. Write the function of TMOD Register in 8051 microcontroller. 18. List any four special function registers. (A/M -17) 19. What is indexing? ( NOV/DEC 12) 20.Mention the similarity and difference between compare and subtract instructions. (MAY/JUN 2014) PART-B 1. (i) Explain the program memory and data memory structure of 8051 microcontroller. (ii) Draw the pin diagram of 8051 microcontroller and explain its port structure. (8) 2 (i) Draw the TMOD register format and explain the different operating modes of timer in 8051 microcontroller. (8) (ii) Explain how serial communication is performed in 8051 microcontroller. (8) 3. Explain with a neat block diagram the architecture of 8051 microcontroller. (16)
4. (i) Explain the different operating modes of timer in 8051 Microcontroller. (8) (ii) Explain program memory interfacing in 8051 microcontroller. (8) 5. (i) Draw the data memory structure of 8051 Microcontroller and Explain. (8) (ii) Write an 8051 assembly language program to copy the value 55H into the RAM memory locations 40H to 45H using register indirect addressing with a loop. (8) 6. (i) Assuming the clock Pulse are fed into PinT1. Write a Program for Counter 1 in Mode 2 to count the Pulses and display the state of the TL1 Count on P2. (8) (ii) Explain the interrupt structure of 8051 Microcontroller. (8) 7. Explain with a neat block diagram the architecture of 8051 microcontroller. (16) 8. (i) Explain the different addressing modes of 8051 Microcontroller. (8) (ii) Explain the vectored interrupts in 8051 microcontroller. (8) 9. Discuss about the timers in 8051 with suitable examples. (16) 10. Discuss the addressing modes microcontroller of 8051 with suitable examples. (16) 11. Explain the port operation in 8051 microcontroller. 12. Explain the different modes with which the timer/counter in 8051 microcontroller can be programmed. 13. Explain the Timers of 8051 microcontroller with appropriate diagrams. (16) 14. Explain the I/O ports and their functions of 8051 microcontroller. (16) 15.Explain Timer modes of 8051 micro controller. (A/M -17) 16.. Explain the architecture of 8051 micro controller with a block diagram. (A/M -17)
FREQUENTLY ASKED QUESTIONS (FAQ) PART A UNIT IV 1. Draw the Mode Word format of 8251 USART. 2. State the use of ISR and PR registers in 8259 PIC. 3. What are the applications of D/A converter interfacing with 8255? 4. What is keyboard interfacing? 5. Draw the 3-bit Digital to Analog Converter block and plot its analogue output. 6. Draw the mode word format of 8251 USART. 7. What are the different Peripheral Interfacing used with the 8085 Microprocessor? 8. What are the output terminals in USART 8251? 9. What is the need for 8259 PIC? 10. What are the basic modes of operation of 8255? 11. What are the salient features of INTEL 8259 programmable interrupt controller? 12. How data is transmitted in asynchronous serial communication? 13. Write the control word value for 8255 PPI when PORT A and PORT B are inputs in simple input output mode. 14. What are the working modes of 8254 Timer? 15. What are the different ways to end the interrupt execution in 8259 PIC? (A/M 11) 16. What is the function of Scan section in 8279 programmable keyboard/display controller? (A/M 11) 17. State the use of ISR and PR registers in 8259 PIC. (N/D 11) 18. What are the salient features of INTEL 8259 Programmable interrupt controller? M/J 14 19. How data is transmitted in asynchronous serial communication? M/J 14 20. What are the applications of D/A converter interfacing with 8255? M/J 12 21. What is keyboard interfacing? M/J 12 22. What are the different peripheral interfacing used with 8085 processor? M/J 13 23. What is the need for 8259 PIC? 24. What are the basic modes of 8255? N/D 2013
PART-B 1. (i) Explain the operating modes of 8255 programmable peripheral interface. (A/M -17) (MAY/JUN 15) (ii) Draw the logical block diagram of 8279 keyboard display controller and explain. (NOV/DEC 14) 2.(i) Draw the control word of 8253 timer/counter and explain the operating modes of 8253 timer/counter. (8) (ii) Why do we need A/D converter and D/A converter? Draw the block diagram to interface 8085 microprocessor with A/D convertor. (8) 3.(i) Describe the comparison of 1/O mapped and memory mapped 1/O interfacing. (6) (ii) Explain with a neat diagram the interfacing of 8251 to 8085 microprocessor. a(10) 4.(î) Draw and explain the functional block diagram of 8259 programmable interrupt controller. (MAY/JUN 15) (ii) Draw and describe the interfacing of AID and D/A converter interfacing to 8085 Micro processor. (8) 5. (i) List the major components of the 8079 keyboard/display interface and explain their functions in detail. (8) (ii) Explain in detail, the operating modes of 8255 PPI with control registers. (8) 6. (i) List of the major components of 8259 A Interrupt Controller and explain their functions. (8) (ii) Explain the different operating modes of 8253 timer. (8) 7.(i) Draw and explain the functional block diagram of 8255 PPI. (8) (ii) Draw and Explain the functional block diagram of 8251 USART. (8) 8. (î) Draw and explain the functional block diagram of 8279 keyboard display controller. (8) ( (ii) Draw and explain the functional block diagram of 8253 timer. (8) 9. Explain the 8255 PPI architecture with different modes by neat sketch (16) 10. With neat diagram, explain the architecture and feature of 8279 keyboard/ display controller. (16) 11. Draw the block diagram of 8255A programmable peripheral interface and explain each block. 12. Discuss the internal architecture of 8253 programmable interval timer. 13. Explain the block diagram, architecture and registers of the 8279 keyboard/display controller. (16) 14. (i) Explain the block diagram and modes of the 8254 timer. (8) (ii) Explain the architecture, functions and registers of the 8255 PPI. (8) (8)
FREQUENTLY ASKED QUESTIONS (FAQ) PART A UNIT V 1. Why do we need opto-isolator circuit between microcontroller and the Stepper motor? 2. Mention the I/O instructions of 8051 microcontroller. 3. What is program status word of 8051? 4. What are the applications of 8051 microcontroller? 5. Give an example for DA instruction of 8051 Microcontroller. 6. How many ports are bit-addressable in an 8051 Microcontroller? 7. Write an ALP to receive input from port 1.5 and if it is high then an output 35H is sent to Port Port 0. What are I/O instructions in 8051 Microcontroller? 8. How is pulse generated from Microcontroller for Stepper Motor Control? 9. Mention the interrupts of 8051 microcontroller. 10.State the functions performed by JBC and CJNE instructions in 8051 microcontroller. 11.What is Program Status Word? 12.What is meant by PSW? 13. List out the difference between MOV and the MOV X instructions 14. List the different types of 8051 instructions. (April/may -2010, Nov/Dec-2011) 15.What are the various operations performed by Boolean variable instructions of 8051?( April/may -2010, April/may -2011) 16. What is the operation of the given 8051 microcontroller instructions: XRL A, direct? 17. What are the applications of 8051 microcontroller? (May/June -2012) 18. How is the pulse generated from microcontroller for stepper motor control (May/June 2013) 19. Why do we need opto-isolator circuit between microcontroller and the stepper motor? (Nov/Dec-2011) 20. Why interfacing is needed for I/0 devices? (Nov-2009] 21. What is meant by cascading in 8259? (A/M -17) 22. Give the operation modes of 8259A? (A/M -17)
PART B 1. (i) Explain with a program to rotate the stepper motor in both clockwise and anticlockwise direction using 8051 microcontroller. (8) (ii) How to interface a 7 segment display using 8051 microcontroller. (8) 2. (i) How 8051 is used in washing machine control? (8) (ii) How do you interface a 4 4 matrix keyboard using 8051 microcontroller? (8) 3. (i) Explain the Stepper Motor Control using 8051. (ii) Write a program to generate pulses to drive and for Continuous operation of a stepper motor. 4. Explain with a neat diagram the application of 8051 microcontroller in Washing Machine control. 5. (i) Draw the circuit diagram to interface an LCD display with 8051 Microcontroller and explain how to display a character using LCD display. (ii) Explain how to control the Servomotor using 8051 Micro controller and this any four applications of Servomotor. 6. (i) How to interface a 4 4 matrix keyboard using 8051 Microcontroller and Explain how to identify the key press. (ii) Explain how to control the speed of the stepper motor using 8051 microcontroller with algorithmic steps. 7. Describe with a neat diagram the stepper motor control using microcontroller. 8. Explain with a neat diagram the closed loop control of servo motor using microcontroller. (16) (MAY/JUN 13) (A/M-17) 9. Write an 8051 C program that continuously gets a single bit of date from P1.7 and sends it to P1.0, while simultaneously creating a square wave of 200 us period on pin P2.5. Use timer 0 to create the square wave. Assume that XTAL=11.0592 MHz 10. A Switch is connected to pin P2.7. Write an ALP to mention the status of SW and perform the following i) If SW=0 The stepper motor moves clockwise. ii) If SW=1 The stepper motor moves counter clockwise. (NOV/DEC 13) 11. Explain the different operand addressing modes in 8051 microcontroller with examples. 12. Describe the control system design of washing machine. 13. Explain the working of a washing machine and how it is controlled by the 8051 Microcontroller. (MAY/JUN 15) 14.Explain how to control a stepper motor using 8051 microcontroller with a neat interfacing diagram and assembly program. (16) NOV/DEC 12) (A/M -17)