EX-602 Microprocessor and Microcontroller - Jun 2025 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aExplain the internal architecture of 8086 microprocessor. Discuss the roles of EU and BIU in instruction execution.
   How to answer

   • Block diagram of 8086 showing BIU and EU partitions
   • BIU components: segment registers, IP, queue, bus control
   • EU components: ALU, flags, general registers, control
   • Pipelining / queue working and roles in fetch vs execute
2. 7 Marks
   bDescribe the memory segmentation in 8086. If memory locations DS:1200H = 45H and DS:1201H = 5AH, what will be the value at memory location DS:1202H after execution of following code? MOV AX, 2000H MOV DS, AX MOV AL, [1200H] MOV BL, [1201H] ADD AL, BL MOV [1202H], AL
   How to answer

   • Segment registers, offset and physical address formula: Physical = Segment*10H + Offset
   • 1 MB memory division into segments, overlap
   • Execute MOV/ADD sequence step by step
   • 45H + 5AH = 9FH stored at DS:1202H
3. 7 Marks
   aDerive and explain the timing diagram for memory read and write operations in 8086.
   How to answer

   • Minimum mode read/write bus cycles and T-states T1-T4
   • ALE, M/IO, RD, WR, DT/R, DEN signal sequence
   • Address-data multiplexing on AD0-AD15
   • Differences between memory read vs memory write timing
4. 7 Marks
   bGiven the following control word is written to 8255: 10011000B, answer:

   1. i)What is the mode of Port A?
   2. ii)Is Port B input or output?
   3. iii)What is the configuration of Port C?
   How to answer

   • Decode D7=1: I/O mode, D6-D5 for Port A mode
   • Decode D2-D0 for Port B and Port C directions
   • 10011000B => Port A Mode 0 output, Port B input etc.
   • Answer i) ii) iii) explicitly
5. 7 Marks
   aExplain the working of DMA controller 8257 with block diagram. How are priority and control signals managed?
   How to answer

   • Functional block diagram of 8257: channels, priority, control logic
   • Master, slave, DMA request/acknowledge, HRQ/HLDA sequence
   • Priority resolution: fixed vs rotating
   • Control signals: MEMR, MEMW, IOR, IOW, AEN, ADSTB
6. 7 Marks
   bDifferentiate between Memory-mapped I/O and Isolated I/O techniques. Highlight advantages and disadvantages.
   How to answer

   • Definition of memory-mapped vs isolated I/O addressing
   • Control signals and address space usage
   • Advantages: instructions, hardware, speed
   • Disadvantages: memory space, decoding complexity
7. 7 Marks
   aExplain the interrupt structure of 8051. How is priority handled when multiple interrupts occur simultaneously?
   How to answer

   • 8051 interrupt sources: IE, IP registers, vector addresses
   • Enable and priority structure, polling sequence
   • Simultaneous interrupts: high priority and natural order
   • Interrupt servicing and RETI operation
8. 7 Marks
   bExplain the addressing modes of 8051 with examples. Why is direct addressing preferred in many cases?
   How to answer

   • Immediate, register, direct, indirect, indexed addressing
   • One example instruction for each mode
   • Direct addressing: on-chip RAM access, shorter opcode
   • Speed and code size benefits
9. 7 Marks
   aWhat is the function of accumulator in microcontroller? For the following assembly code of 8051 microcontroller given below, what will be the final content of Accumulator A? MOV A, #0F0H ANL A, #0AAH ORL A, #55H CPL A
   How to answer

   • Role of accumulator A in ALU operations and data transfer
   • Stepwise ANL, ORL, CPL on 0F0H
   • Intermediate values: 0A0H -> BFH -> 40H
   • Final content of A = 40H
10. 7 Marks
    bExplain how ADC can be interfaced with 8051.
    How to answer

    • ADC 0808/0809 signals: SOC, EOC, OE, clock
    • Port connections and control via 8051 pins
    • Algorithm: start conversion, wait for EOC, read data
    • Timing and interfacing diagram
11. 7 Marks
    aExplain the various serial communication modes of 8051. Compare mode 1 and mode 3 in terms of control and applications.
    How to answer

    • Modes 0-3: shift register, 8-bit UART, 9-bit UART
    • SCON, baud rate, multiprocessor communication
    • Mode 1 vs Mode 3: data bits, stop bit, parity/9th bit
    • Applications of each mode
12. 7 Marks
    bExplain the design of an 8051-based thyristor firing circuit. How can timing be controlled accurately?
    How to answer

    • Zero-cross detection and opto-isolation
    • 8051 timer to generate firing angle delay
    • Trigger pulse amplification to thyristor gate
    • Accurate timing via timer interrupts
13. 7 Marks
    aDraw the functional block diagram of 8096 and explain each block in detail. How is it superior to 8051?
    How to answer

    • 8096 blocks: CPU, PTS, timers, HSI/HSO, ADC, serial, I/O
    • Function of each block in brief
    • 16-bit architecture, higher speed and peripherals
    • Comparison points superior to 8051
14. 7 Marks
    bExplain the addressing modes of 8096 with suitable code examples.
    How to answer

    • 8096 addressing types: immediate, direct, indirect, indexed
    • Code example for each mode
    • Use of register file and stack pointer
    • Long vs short indexed modes
15. 14 Marks
    Write short notes on (any two)

    1. a)Role and function of control and status registers in 8096
    2. b)16-bit PIC and 32-bit DSPIC microcontrollers
    3. c)Stack structure of 8086
    4. d)8254 Programmable Interval Timer
    How to answer

    • Select any two topics for detailed notes
    • Definition, diagram/registers and working
    • Key features and applications
    • Comparison or significance where applicable