COLLEGE OF ENGINEERING AND TECHNOLOGY (LICET)
Loyola College Campus, Nungambakkam , Chennai – 34
Branch: CSE / IT Date: 28.04.2014
Semester: II Time: 8.00 – 11.00 am (3 Hrs)
MODEL EXAMINATION
DIGITAL PRINCIPLES AND SYSTEM DESIGN (CS6201)
Part-A (Answer all the questions) (10x2=20)
1. Differentiate prime and essential implicant.
2. Determine the decimal value of the fractional number 0.1011
3. What is combinational circuit?
4. Draw the full adder circuit as a collection of two half adder.
5. What is meant by Race around condition?
6. What is module-N counter?
7. Draw a circuit that has no static hazards and implement the Boolean function
F (A, B, C, D) = ∑ (0, 2,6, 7, 8, 10, 12).
8. What is meant by Edge Triggered Flip Flop?
9. Differentiate PROM, PLA and PAL.
10. Program the PROM using 1:2 decoders for the value 1011.
PART B – (5 x 16 = 80 marks)
11.a.(i) Reduce the following function using k-map technique
F(A,B,C,D)= M(0,3,4,7,8,10,12,14)+d(2,6) (8)
(ii) Reduce Using k-MAP Y=A’B+AC’D+A’B’C’D’+C’D’ (8)
(or)
(b).Reduce the expression using Quine McCluskey method.
F(A,B,C,D,E ) = ∑m (0, 2, 4, 5, 6, 7, 8, 10, 14, l7, l8, 21, 29, 31) + d(11, 20, 22). (16)
12.a.(i)Explain the 4-bit ripple carry Parallel adder. (6)
(ii).Explain the excess 3 to BCD Code Converter. (10)
(or)
b.(i).Design and implement 4-bit priority encoder. (8)
(ii).Implement the Boolean function using two 4:1 MUX.
F(A,B,C,D)=A’BD’+ACD+B’CD+A’C’D (8)
13.(a) Design the following non binary sequence counters as specified in each case. Treat the unused states as don’t care conditions. Analyze the final circuit to ensure that it is self-correcting. If your design produces a non-self-correcting counter, modify the circuit to make it correcting.
(i) Design a counter with the following repeated binary sequence: 0, 1, 2, 3, 4, 5, 6. Use JK
flip-flops. (8)
(ii) Design a counter with the following repeated binary sequence: 0, 1, 2, 4, 6. Use D flip-
flops. (8)
(or)
(b) (i) Design the MOD-11 synchronous counter using T-flip flop. (16)
14.(a)(i)What is theobjective of state assignment in asynchronous circuit? Explain race-
free state assignment with an example. (8)
(ii)Discuss about static, dynamic and essential hazards in asynchronous sequential
circuits. (8)
(or)
(b).Design a asynchronous sequential circuit with inputs X1 and X2 and one output Z. Initially
and at any time if both inputs are 0,output is equal to 0.When X1 or X2 becomes 1, Z
becomes 1.When second input also becomes 1,Z=0;The output stays at 0 until circuit goes
back to initial state.
15.(a)(i) Implement the following Boolean functions using PLA with 3 inputs ,4 product terms and
2 outputs. F1=∑m(3,5,6,7) and F2=∑m(1,2,3,4) (10)
(ii)Implement the following Boolean function usins 8 x 2 PROM
F1=∑m(3,5,6,7) and F2=∑m(1,2,3,4). (6)
(or)
(b) (i) Explain the architecture of Xilinx XC4000. (8)
(ii)What is programmable array? How it differs from PROM? (8)