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MICROPROCESSORS AND INTERFACING

UNIT 1

1. (a) Draw the architectural diagram of 8085 and explain the function of each block in detail ?

    (b) Discuss about Multiplexing in 8086 micro processor?

2. (a)With a neat architectural diagram explain the functioning of an 8086 Micro processor?

    (b) Compare the flag resisters of 8086 & 8085?

3. (a) Explain the functioning of following resisters of 8086 Microprocessor

               i. Segment resisters  ii. Pointer resisters      iii. Index resisters

    (b) Discuss briefly about pre-fetch queue in 8086?

4. The register contents of 8086 is given below.

     CS=5000H, DS=8000H, SS=9000H, ES=7000H, SI=1000H, DI=2000H, BP=0008H,

     SP=0002H, AX=0000H, BX=5200H, CX=8000H, DX=2800H

     Calculate the effective address and physical address of the following instructions.

            (a) MOV AX, [BP+BX-24D]             (b) ADD AX, ES:[SI]

            (c) PUSH CX                                      (d) SUB AX, [DI]

            (e) MOVSB                                        (f) CMP AX, [DI]

            (g) ADD DX, [DI+8D]                      (h) MUL AX, [SI+2D]

5.Explain briefly about Addressing  modes of 8086 with Examples?

UNIT 2

1. Discuss the following instructions

i. ADC                        ii. AAS            iii. IMUL         iv. CBW

2. Explain the following Instructions.

            i. MOV                        ii. POP             iii. XCHG       iv. SAHF

3. Design  an ASM program for  reversal of  the string “microprocessor”?

4. Design  an ASM program to convert the given BCD data 47h into its equivalent ASCII format?

5. Design an ASM program to perform addition between 334455h and 445566h?

UNIT 3

1. (a) With a neat pin diagram explain the minimum mode operation of 8086?

    (b) With a neat timing diagram explain how a READ operation is performed by 8086 in minimum mode?

2. With a neat block diagram, explain the working of 8257 DMA controller  ?

3. Draw the functional pin diagram of 8086 and explain the functions of different pins?

4. Interface two 4k*8 EPROMs and two 4k*8 RAM chips with 8086 microprocessor. Select suitable maps?

5. (a) With a neat pin diagram explain the maximum mode operation of 8086?

    (b) With a neat timing diagram explain how a WRITE operation is performed by 8086 in maximum mode?

UNIT 4

1. Write the necessary instruction sequence to initialize 8255 with address 0C00H to 0C03H  for the following combinations.

(a) Port A as input port in mode 1 and port B as input port in mode 1

(b) Port A in mode 2 as output port and port B as input port in mode 0

(c) Port A in mode 0, port c upper half as input ports and port B as input port in mode 1

(d) Port A as output port in mode 1 with active interrupt, port B as input port in mode 0 and port C lower half as output port in mode 0

2. (a) Explain the following pins of 8255.

            i. A0 and A1               ii. WR             iii. RESET                   iv. PC0-PC7

    (b) Explain the use of handshaking signals used in 8255

3. Explain why 8255 ports are divided into two groups? Discuss how these groups are controlled in   different modes of operation? Explain different control signals and their associated pins for bi-directional I/O mode of operation?

4. Explain about the internal architecture of 8255?

5. Interface an 8255 with 8086 to work as an I/O port. Initialize port A as output port, port B as input port and port C as output port. Port A address should be 0740H.Write a program to sense switch positions SW0 –SW7 connected at port B. The sensed pattern is to be displayed in port A, to which 8 LEDs are connected, which the port C lower displays number of on switches out of the total eight switches

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