Microprocessors & Interfacing

1. a) With a neat diagram explain the structure of a microcomputer
b) Explain with an example, the sequence of operations performed when
an instruction is being executed by the microprocessor.
c) Briefly discuss the evolution of microprocessors.
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2. a) Write and Explain the template for MOV instruction. Find the machine code for
the following instruction: MOV CS:[BX], AL
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b) Find and explain the errors, if there are any, in the following instructions:
i) MOV BH, AX
ii) IN AL, 280H
iii) DIV AL, BL
iv) PUSH CL
v) ROR AL, 4
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3. a) How are the flags of 8086 categorized? Explain each of the flag bits.
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b) Write code segments to do the following:
i) Average of 4 bytes stored in an array
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ii) Convert packed BCD byte to two ASCII Characters, each representing a
digit in the packed BCD.
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4. a) What are the sequence of operations that take place when a procedure is called
and when the control is returned from the procedure back to calling program?
b) Write a procedure to check whether the password entered is correct or not.
(Assume a simple password of 6-10 characters length).
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PART B
5. a) How do you take care of labels in a MACRO? Give an example. Write a macro to convert
the given 2 digit BCD number to corresponding binary.
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b) Write a delay loop to produce a delay of approximately 10 milliseconds in a
microprocessor working with 10 MHz frequency.
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6. a) Explain the minimum mode configuration of 8086 with a neat diagram 10
b) Describe memory-mapped I/O and direct I/O. Give the main advantages
and disadvantages of each.
7. a) Briefly explain the structure of Interrupt Vector Table with a neat diagram. 08
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b) Describe the sequence of actions that an 8259A and an 8086 will take when
8259A receives an interrupt signal on its IR2 input. Assume only IR2 is
unmasked in the 8259A and that 8086 INTR input has been enabled with a
STI instruction.
8 a) Explain the different methods of parallel data transfer.
b) Explain the control word register of 8255A in detail