EC-501 Microprocessor and its Applications - Nov 2023 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
   aWhat are the advantages of memory segmentation? Explain with example, how physical address is formed in 8086?
   How to answer

   • Define memory segmentation in 8086 - 1MB divided into 64KB segments
   • List advantages - memory management, modularity, multitasking, larger addressing with 16-bit registers
   • Physical address formula: Physical = Segment*10H + Offset
   • Worked example with segment and offset values
2. 7 Marks
   bDraw the timing diagram for the execution of the following instructions: LXI H, 5000H; MVI A, FFH.
   How to answer

   • Recall 8085 timing - opcode fetch, memory read machine cycles
   • Show LXI H,5000H - 3 opcode fetch + memory reads, 10 T-states
   • Show MVI A,FFH - opcode fetch + memory read, 7 T-states
   • Draw CLK, ALE, IO/M, RD, WR, AD0-AD7, A8-A15 waveforms
3. 7 Marks
   aWhy is the 8086 memory organized in to two banks of even and odd address? Explain.
   How to answer

   • Need for 16-bit access with 8-bit banks using BHE and A0/BLE
   • Even bank D0-D7 and odd bank D8-D15 organization
   • Byte vs word access on even/odd addresses
   • Role of BHE and A0 signals table
4. 7 Marks
   bWhat are the addressing modes available in 8086? Explain any two with example. Show the content of the PSW register after the execution of the following instructions: MOV A, 9CH; ADD A, 64H.
   How to answer

   • List 8086 addressing modes - immediate, register, direct, indirect, indexed etc.
   • Explain any two with 8086 examples
   • Compute 9CH + 64H = 00H with carry and auxiliary carry
   • Show PSW flags: CF=1, ZF=1, SF=0, PF=1, AF=1, OF=0
5. 14 Marks
   Write a program in 8086 assembly language for ten data bytes are stored at memory location 01BC:2842 onwards, find the frequency (number of occurrence) of data BC in this array. Store the result at memory location 01CD:2842.
   How to answer

   • Initialize DS, SI=2842H, CX=10, count=0
   • Loop: compare array byte with BCH, increment count if equal
   • Point to next byte and use LOOP/JNZ
   • Store count at 01CD:2842
6. 7 Marks
   aHow to generate square wave using programmable parallel interface chip in BSR mode? Explain.
   How to answer

   • Recall 8255 PPI control word and BSR mode format
   • BSR word to set/reset PC bit for square wave toggling
   • Software delay loop between SET and RESET
   • Circuit connection of output pin
7. 7 Marks
   bHow will you interface DAC chip to 8086 microprocessor and explain how it will read converted data?
   How to answer

   • Select DAC chip e.g. DAC0808 and 8086 interfacing via 8255 or latch
   • Address decoding and I/O mapped connection diagram
   • Write data to DAC port to generate analog output
   • Explain conversion and output voltage reading
8. 7 Marks
   aExplain the mode-1 operation of programmable parallel interface chip when its port is working as a output port.
   How to answer

   • Recall 8255 modes and Mode-1 strobed I/O concept
   • Control word and handshake signals OBF, ACK, INTR for output
   • Timing sequence for output transfer
   • Example initialization
9. 7 Marks
   bExplain the functional block diagram of programmable timer chip.
   How to answer

   • Identify chip e.g. 8253/8254 programmable interval timer blocks
   • Describe data bus buffer, control logic, counters
   • Explain control word and counting modes briefly
   • Sketch functional block diagram
10. 14 Marks
    If an 8051 microcontroller has on-chip and off-chip ROM, how are they accessed? Which pins/signals are used in accessing external program memory? Write the names of special function registers used in 8051 serial communication. Discuss the function of each in brief.
    How to answer

    • EA pin selection of on-chip vs external ROM and memory map
    • Pins for external program memory: ALE, PSEN, EA, P0, P2
    • Multiplexed address/data fetch sequence
    • SFRs SCON, SBUF, PCON, IE/IP functions for serial
11. 7 Marks
    aWith functional block diagram, explain the operation and programming of 8253 in details.
    How to answer

    • Sketch 8253 functional block diagram - 3 counters, control logic
    • Explain control word format and initialization steps
    • Describe operating modes 0-5 with waveforms
    • Give programming example
12. 7 Marks
    bWhat do you mean by addressing modes? Explain addressing modes available in 8051 microcontroller.
    How to answer

    • Define addressing mode concept
    • List 8051 modes - direct, indirect, register, immediate, indexed etc.
    • Give one example instruction for each mode
    • Explain effective address calculation
13. 14 Marks
    Write short notes on any two of the following:

    1. a)Salient features of Pentium processor
    2. b)USART
    3. c)8257 DMA controller
    4. d)Interrupts
    How to answer

    • Select any two topics from four options
    • Give definition, features/diagram and applications for each
    • Include key registers/pins/modes where relevant
    • Conclude with uses in microprocessor systems