EC-501 Microprocessor & its Application - Dec 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 salient features of advanced microprocessors. Compare RISC and CISC processors.
   How to answer

   • Define advanced microprocessors and list salient features like 32/64-bit, pipelining, cache, MMU
   • Explain superscalar, RISC/CISC hybrid, power management
   • Compare RISC vs CISC on instruction set, addressing, cycles, hardware, examples
   • Conclude with applications
2. 7 Marks
   bDescribe minimum mode and maximum mode operation of 8086 with timing diagrams.
   How to answer

   • Define MN/MX pin and minimum vs maximum mode configuration
   • Explain minimum mode control signals and single-processor operation
   • Explain maximum mode with 8288 bus controller for multiprocessor
   • Draw read/write timing diagrams for both modes
3. 7 Marks
   aExplain the instruction set of 8086 microprocessor with suitable examples.
   How to answer

   • Classify 8086 instruction set into data transfer, arithmetic, logical, string, control transfer, processor control
   • Give syntax and function of each group
   • Provide suitable examples e.g. MOV, ADD, AND, JMP, LOOP
   • Summarize flags affected
4. 7 Marks
   bExplain various addressing modes of 8086 microprocessor. Write an 8086 assembly language program to add an array of 10 numbers.
   How to answer

   • Define addressing mode and list 8086 modes: implied, immediate, register, direct, register indirect, indexed, etc.
   • Give example instruction for each mode with effective address calculation
   • Write ALP using loop to add 10 numbers in array with initialization and pointer update
   • Mention result storage and carry handling
5. 7 Marks
   aExplain the architecture and operation of 8255 Programmable Peripheral Interface.
   How to answer

   • Draw block diagram of 8255 with Port A, B, C, control logic and data bus buffer
   • Explain control word and Mode 0, Mode 1, Mode 2 operation
   • Explain BSR mode for bit set/reset
   • Give interfacing example with 8086
6. 7 Marks
   bExplain ADC and DAC interfacing with microprocessor.
   How to answer

   • Define ADC and DAC function in microprocessor system
   • Explain ADC interfacing via 8255/status with timing and example ADC0808/0809
   • Explain DAC interfacing with DAC0808 and output amplifier
   • Compare interfacing steps and control signals
7. 7 Marks
   aExplain the architecture and working of 8253/8254 Programmable Interval Timer. A 8254 timer is operated with a clock frequency of 2 MHz. Calculate the output frequency for a count of 10,000.
   How to answer

   • Describe 8253/8254 block diagram with 3 counters, control word register
   • Explain 6 operating modes of timer
   • State formula $f_{out} = f_{clk} / N$
   • Calculate $2\,MHz/10000 = 200\,Hz$
8. 7 Marks
   bExplain the need of interrupt system in microprocessor based systems.
   How to answer

   • Define interrupt and polling vs interrupt-driven I/O
   • Explain need for fast response, multitasking, real-time handling
   • Classify hardware/software, maskable/non-maskable, vectored interrupts
   • Give 8086 interrupt example
9. 7 Marks
   aExplain I/O ports, interrupts and addressing modes of 8051 microcontroller.
   How to answer

   • Describe 8051 four I/O ports P0-P3 structure and alternate functions
   • List 5 interrupts with vector addresses and priority/IE, IP registers
   • Explain 8051 addressing modes with examples
   • Summarize register banks and SFR addressing
10. 7 Marks
    bExplain embedded systems and role of microcontrollers in embedded systems. Write a program for 8051 to generate a square wave using Timer-0.
    How to answer

    • Define embedded system characteristics and examples
    • Explain role of microcontroller as CPU+memory+I/O on chip
    • Describe Timer-0 mode programming for delay/square wave
    • Write 8051 ALP toggling port pin with Timer-0 delay loop
11. 7 Marks
    aDifferentiate between microprocessor and microcontroller in details.
    How to answer

    • Define microprocessor vs microcontroller architecture
    • Compare on memory, I/O, instruction set, power, cost in table
    • Give examples 8086 vs 8051/PIC
    • State selection criteria for applications
12. 7 Marks
    bExplain the concept of pipelining in microprocessors.
    How to answer

    • Define pipelining and stages fetch-decode-execute
    • Explain 8086 BIU/EU overlap as 2-stage pipeline example
    • Discuss speedup, throughput, hazards
    • Give modern pipeline extensions
13. 7 Marks
    aAn 8086 operates at 5 MHz clock. Calculate the time taken to execute an instruction requiring 4 T-states.
    How to answer

    • State T-state period $T = 1/f_{clk}$
    • Calculate $T = 1/5\,MHz = 0.2\,\mu s$
    • Multiply by 4 T-states: $0.8\,\mu s$
    • Interpret as instruction execution time
14. 7 Marks
    bExplain USART and serial data communication. Explain interfacing of keyboard and LED display with 8086 microprocessor.
    How to answer

    • Define USART 8251 and synchronous vs asynchronous serial communication
    • Explain baud rate, framing, parity, 8251 block and control words
    • Explain keyboard interfacing via 8279 and scanning
    • Explain LED display interfacing with 8086 multiplexing
15. 7 Marks
    aExplain applications of microprocessors and microcontrollers in real-time systems.
    How to answer

    • Define real-time system and constraints
    • List microprocessor/microcontroller applications: automotive, medical, industrial control, IoT
    • Give examples with justification
    • Summarize advantages
16. 7 Marks
    bExplain memory interfacing with 8086 microprocessor using suitable diagram.
    How to answer

    • Explain 8086 memory segmentation and even/odd banks with BHE, A0
    • Describe address decoding using 74LS138 with example
    • Draw interfacing diagram for RAM/ROM with 8086
    • Explain read/write bus cycles