Microprocessors And Its Applications March06 Nr312001

NR

Code No: NR312001

III B.Tech I Semester Supplementary Examinations, March 2006 MICROPROCESSORS 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. ii. iii. iv.

SID SOD S0 , S1 , INT A 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. ii. iii. iv.

PUSH XLAT LEA 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 and sets the value of a word parameter to the index of the element in the array if a match is found; otherwise, it puts a -1 in the index word parameter. The parameters are to be passed to the procedure via a parameter address table. Give a sequence for calling SEARCH to search ARY of length LEN for variable ‘ID’ and put the index in IDX? [16] 5. (a) Write an instruction sequence that converts 8-digit packed BCD number to its equivalent ASCII coded hex number. (b) Write a program segment that will copy all ASCII characters in string STG that are enclosed by single quotes to the string MESG and store the number of 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 1 of 2

NR

Code No: NR312001 iv. IN AX, DX

[2+2+2+2]

(b) Discuss the sequence of events during a maskable interrupt and the subsequent return? [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 the frequency will be selected from memory location ‘F 0 . (b) For generating a triangular wave with a maximum voltage of +3V and a minimum of −2V. [8+8] 8. (a) A terminal is transmitting asynchronous serial data at 1200 bd. What is the bit time? Assuming 8 data bits, a parity bit and 1 stop bit how long does it take 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 synchronous transmission? (Assume the necessary data) [8+8] ?????

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