GTU previous year question papers
GUJARAT TECHNOLOGICAL UNIVERSITY
B. E. Sem. – V – Examination – June- 2011
Subject code: 151001
Subject Name: Microcontroller & Interfacing
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) What are the interrupts available in the 8051 microcontroller?
Explain interrupt enable (IE) SFR and Interrupt priority (IP) SFR.
(b) Explain operation of timer in mode 1. Discuss programming steps to
generate time delay using mode 1. Write program to generate delay
of 0.1 second using timer 0 in mode 1.
Q.2 (a) Explain basic architecture of 8051 microcontroller. Discuss RAM structure.
(b) Explain pin configuration with circuit diagram for port 0 and port 1
(b) Draw and explain RESET and clock circuit of 8051 microcontroller.
What is the purpose of capacitor in RESET circuit?
Q.3 (a) Answer the following questions
 What is the purpose of EA pin in 8051 microcontroller?
 What is the purpose of EA bit in IE SFR?
 What is the function of ALE signal?
 Why pull-up resistors are necessary with port P0 in
 What is the function of SMOD bit in TCON SFR?
 What is the function of GATE bit in TMOD SFR?
 Write instruction to select register bank 2.
(b) Explain following instructions
 SWAP A  ADD A,B  DIV AB  MUL AB
 RL A  XCHD A,R0  MOV A,@R0
Q.3 (a) Write program to generate square wave on port pin P2.0 with
frequency of 10 KHz and duty cycle 50%. Use timer interrupt. Use
timer 0 in mode 2. Assume crystal frequency 12 MHz.
(b) Draw interfacing diagram to interface push-button switch at port pin
P3.3 and relay with transistor circuit at port pin P2.0. Write program
such that when push-button key is pressed, relay should become
ON. When push-button key is pressed again relay should become
OFF (i.e. toggling of relay by push-button switch).
Q.4 (a) Explain interfacing of analog to digital converter (ADC) with
microcontroller. Write program to read analog value from ADC on
port P1 and display digital values on LEDs connected at port P0
(b) Draw and explain interfacing of 4×4 matrix keyboard with 8051
microcontroller. Write program to read switch.
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