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Code No: NR312001 NR

III B.Tech I Semester Supplementary Examinations, March 2006MICROPROCESSORS AND ITS APPLICATIONS

(Production Engineering)Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

1. (a) Explain various interrupt of 8085 Microprocessor and their priorities.

(b) Explain the

i. SID

ii. SOD

iii. S0, S1,

iv. INTA pins of 8085 Microprocessor [8+8]

2. (a) Explain the flag register of 8086.

(b) Explain the concept of memory segmentation.

(c) Explain, when Queue is failing to speed up the execution. [6+6+4]

3. (a) Explain the following Instructions.

i. PUSH

ii. XLAT

iii. LEA

iv. LAHF

(b) Write a program to check whether the given string is palindrome or not.[8+8]

4. Write a FAR procedure SEARCH that searches a byte array for a given byte andsets the value of a word parameter to the index of the element in the array if a matchis found; otherwise, it puts a -1 in the index word parameter. The parameters areto be passed to the procedure via a parameter address table. Give a sequence forcalling SEARCH to search ARY of length LEN for variable ID and put the indexin IDX? [16]

5. (a) Write an instruction sequence that converts 8-digit packed BCD number toits equivalent ASCII coded hex number.

(b) Write a program segment that will copy all ASCII characters in string STGthat are enclosed by single quotes to the string MESG and store the numberof characters moved in COUNT? [8+8]

6. (a) Give the machine language code for each of the following instructions?

i. IN AL, 52H

ii. OUT 0CH, AL

iii. OUT DX, AX

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Code No: NR312001 NR

iv. IN AX, DX [2+2+2+2]

(b) Discuss the sequence of events during a maskable interrupt and the subsequentreturn? [8]

7. Interface a 12-bit DAC to 8255 with an address map of 0C00H to 0C03H. The DAC

provides output in the range of +5V to

5V. Write the instruction sequence.

(a) For generating a square wave with a peak to peak voltage of 4V and thefrequency will be selected from memory location F.

(b) For generating a triangular wave with a maximum voltage of +3V and aminimum of2V. [8+8]

8. (a) A terminal is transmitting asynchronous serial data at 1200 bd. What is thebit time? Assuming 8 data bits, a parity bit and 1 stop bit how long does ittake to transmit one character?

(b) Draw necessary circuit to interface 8251 to an 8086 based system with an

address 0C0H. Write the sequence of instructions to initialize 8251 for syn-chronous transmission? (Assume the necessary data) [8+8]

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