JNTU B.Tech II Semester Examinations, MICROPROCESSORS AND MICRO CONTROLLERS, Apr/May 2008

JNTU B.Tech II Semester Examinations, MICROPROCESSORS AND MICRO CONTROLLERS, Apr/May 2008

(Electrical & Electronic Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

SET-II

1. (a) Discuss about the interface signals of the 8086 processor in maximum mode

(b) Discuss SBB, AAD, TEST, SCAS instructions of 8086. [8+8]

 

2. (a) Explain the following Assembler Directives

i. EXTRN

ii. GROUP

iii. PUBLIC

iv. DW

v. GLOBAL

(b) Write an ALP to Subtract two 16-bit numbers. [10+6]

 

3. Interface a 4 x 4 key board with 8086 using 8255 and write an ALP for detecting

the key closure and return the key code in AL. The debouncing period for a key is

10 ms.Use software key debouncing technique. DEBOUNCE is an available 1 ms

delay routine. [16]

 

4. (a) Explain the priorities of DMA requests

(b) Explain the interfacing if 8257 with 8086. [6+10]

 

5. (a) List and briefly describe the function of the three signal groups of the GPIB.

(b) Draw the data transfer and handshake waveforms. [10+6]

 

6. (a) Discuss in detail about 8051 instruction set.

(b) Give the comments for the following instructions.

i. MOV @RP , #n

ii. MOV A, 80h

iii. MOV 0A8h, 77h

iv. MOV A, add

v. MOV add, @RP

vi. MOV A, @R0 [10+6]

 

7. (a) Write 8051 program as an example of interrupt call to a routine, timer 0 is

used in mode 0 to overflow and set the timer 0 interrupt flag. When the

interrupt is generated, the program vectors to the interrupt routine, resets the

timer 0 interrupt flag, stops the timer, and returns.

1 of 2

(b) Discuss the bit format of IP register of 8051? [8+8]

 

8. (a) Draw the circuit diagram to interface the DAC to the microcontroller and

explain.

(b) Give the differences between microprocessors and microcontrollers? [8+8]

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