Visvesvaraya Technological University (VTU) 2008-4th Sem B.E Electrical and Electronics Engineering Microcontrollers-ester , e/y 08 - Question Paper

Microcontrollers

Time:3 hrs Maximum marks:100

Note: ans any 5 ques. choosing at lowest 2 from every part

Part A

1 a. discuss the differences ranging from the subsequent.[Marks 8]
i) Risc and Cisc processors ii) Harvard and Von-Neumann architectures.

b. With the help of timing diagram, discuss how to interface 8K EPROM and 4K RAM to 8051 microcontroller.[Marks 7]

c. discuss TCON and TMOD registers of 8051, with the help of timer/counter control logic.[Marks 5]

2. a. Write a progaram to put the number 34h in registers R4, R5, R6 and R7 using various addressing modes.[Marks 6]

b. discuss the operation performed by the subsequent instructions:[Marks 6]
i) SWAP A ii)MOV c, b iii)DA A iv)SUBB A, Sr

c. Write a C program to swap the contents of registers R7 and R6 in register block 0, in 4 various ways.[Marks 8]

3. a. discuss various ranges for jump instruction available in 8051 microcontroller.[Marks 8]

b. discuss with a neat diagram, the significance of stack memory, whenever a CALL instruction is executed by the 8051 microcontroller.[Marks 5]

c. write a program to obtain the address of the 1st 2 internal RAM locations betweeen 20h to 60h, which contains consecutive numbers. If so, set the carry flag to one else clear the flag, using a subroutine.[Marks 7]

4. a. Write an 8051 C program to toggle all the bits fo P1, P2 and P0 continously with a 250 ms delay. Use sfr keyword to declare the port addresses.[Marks 6]

b. discuss with an example, bit-wise logic operators for 8051 C.[Marks 6]

c. A switch(SW) is connected to P2.0 port pin, Write a C program to send out the value 44h seially 1 bit at a time via P1.0, depending upon the switch condition: When SW=0; LSB should go out first, When SW=1; MSB should go out first.[Marks 8]

Part B

5. a. discuss the steps to program timers in model and write an 8051 program to generate a square wave of 50% duty cycle on the pin P1.5.[Marks 6]

b. presume that a one Hz frequency pulse is connected to input pin P3.4. Write an 8051 program to display counter one on an LCD. Set the initial value to get 1 minute delay.[Marks 6]

c. A switch is connected to the pin P1.2. Write an 8051 C program to monitor the switch and create the subsequent frequencies on pin P1.7.[Marks 8]
i) When SW=0; 500Hz ii) When SW=1; 750 Hz
Use timer 0. mode one for both of them.

6. a. List the advantages of serial communication over parallel communication.[Marka 8]

b. Write an 8051 program to send the message "the Earth is beautiful", to the serial port continuously. presume XTAL=11.0592 MHz, 9600 baud rate, 8-bit data and 1 stop bit.[marks 8]

c. Write an 8051 program to send the text string "Good Luck" to serial #1 of the DS 89C4XO. Set the band rate at 9600, eight bit data and one stop bit.[Marks 6]

7. a. elaborate the edge triggered interrupts? How to set INT0 as level triggered interrupt and INT1 as edge triggered interrupt, discuss with the help of SFR related to it.[Marks 8]

b. Write an 8051 C program using interrupts to do the following:[Marks 12]
i) Receive the data seriallly and send it to P0
ii) learn port P1 transmit data serially and provide a copy to P2
iii) Make to generate a square wave of 5kHz frequency on P0.1. presume that XTAL=11.0592 MHz, set
the baud rate at 4800.

8. a. Draw the block schematic of DAC 0808 interfaced to 8051 at port P1 and write an 8051 program to generate sine wave.[Marks 10]

b. How to interface DC motor to 8051 microcontroller using opto isolator? Write a C program to move DC motor with 25% duty cycle pulse.[Marks 10]

Earning:   Approval pending.