VTU Electronics and Communication Engineering (Semester 4)
Microcontroller for Embedded Systems
December 2013
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1 (a) Define microcontroller. Differentiate between microprocessor and microcontroller.
5 M
1 (b) With the neat diagram. Explain the 8051 architecture.
10 M
1 (c) Briefly explain the dual functions of port-3 pins of 8051.
5 M

2 (a) What is addressing mode? Put the number OFALL in register R1, R4 and R5, in four different addressing modes.
6 M
2 (b) Explain the following in brief.
i) The pin that connects external memory
ii) The port that has open-drain output
iii) The register that sequence the program execution
iv) PSW
8 M
2 (c) Show the stack contents, sp contents and contents of any register affected after each step of the following sequence of operation:
MOV SP, #70H
MOV R5, #30H
MOV A, #44H
Add A, R5
6 M

3 (a) Explain the different types of conditional and unconditional jump instruction of 8051. Specify the different ranges associated with jump instructions.
8 M
3 (b) Find the address of first two internal RAM locations between 20H and 40H. Which contains consecutive numbers. If so set the carry flag to one, else clear the carry flag.
6 M
3 (c) Write an 8051 assembly time delay subroutine to generate a time delay of 100 μsec when called. Assume crystal frequency as 12 MHz. Show delay calculations. DO not use timers.
6 M

4 (a) Give bit size and data range details for the widely used seven 'C' data types of 8051.
4 M
4 (b) Write an 8051 ALP to convert packed BCD number 48 to ASCII and display the result on port-2 and port-3.
6 M
4 (c) Write an ALP 8051 program to find the check sum byte of data stream 30H, 4AH, 65H and 10H. Convert the binary values of checksum into decimal and display the value of the BCD digits on ports P0, P1 and P2.
10 M

5 (a) With regard to timer of 8051:
i) Explain briefly the difference between the timer and counter operation,
ii) Indicate how to start/stop the timer if GATE control is also used.
iii) Explain mode-2 operation.
6 M
5 (b) Write an ALP to generate a square wave continuously of 2kHz with a duty cycle of 66%.
6 M
5 (c) A switch is connected to the pin P1.2. Write a 'C' program to monitor the switch and create the following frequencies on pin P1.7:
i) When SW=0; 500Hz
ii) When SW=1; 750Hz
Use timer 0, mode 1 for both of them.
8 M

6 (a) What is serial communication? How serial communication is carried out with RS232 in 8051?
6 M
6 (b) Explain the bit pattern of SCON register.
6 M
6 (c) Write:
i) ALP to transfer serially letter 'A' continuously.
ii) C program to receive bytes of data and put them in P1. Use 9600 baud rate, 8-bits and one stop bit, for both transmission and reception. Use timer 1, mode-2.
8 M

7 (a) Explain briefly the MSP430 RISC CPU architecture.
10 M
7 (b) Give details of register of MSP430.
10 M

Write short notes on:
8 (a) RTC
5 M
8 (b) DMA
5 M
8 (c) DAS
5 M
8 (d) RF Interfaces.
5 M

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