Fundamentals of HDL - Jun 2014

Electronics & Communication (Semester 4)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Mention the types of HDL descriptions. Explain how half adder can be modelled in VHDL and verilog in any one description method.(10 marks) 1 (b) Discuss the shift operators used in VHDL and verilog with example.(4 marks) 1 (c) Write switch level description of an inverter in verilog.(3 marks) 1 (d) A=110, B=111, C=011000, D=111011, evaluate (A and not B) or (C nor 2 and D).(3 marks) 2 (a) Write a data flow description in VHDL for two-bit magnitude comparator. Show simulation waveforms.(8 marks) 2 (b) Write a verilog code to realize D-latch with active high enable in data flow modelling method. Show simulation waveforms.(6 marks) 2 (c) Write HDL code for 2×2 combinational array multiplier (VHDL or verilog).(6 marks) 3 (a) Write a VHDL code to realize JK flip flop with synchronous reset.(4 marks) 3 (b) Write verilog description to realize.
i) 3-bit counter using case statement
ii) 4:1 multiplexer using if statement(6 marks) 3 (c) Explain Booth algorithm with an example and write the flow chart of Booth multiplication algorithm. Write VHDL or verilog code 4×4 bit Booth algorithm.(10 marks) 4 (a) Write the VHDL description of a 2:4 decoder using structural modelling method.(5 marks) 4 (b) Write the excitation table of an SRAM memory cell and write its structural description in VHDL or verilog.(10 marks) 4 (c) Write the structural description of a 4-bit asynchronous down counter using generate statement in verilog.(5 marks) 5 (a) Write a VHDl/verilog code to convert unsigned binary to an integer using procedure/task.(6 marks) 5 (b) Write a VHDL/verilog description to find the floating sum $$ y=\sum^{3}{i=0} (-1)^i (x)^i; 0\ltx\lt1 $$="" using="" function.<="" a="">

</x<1>(6 marks) 5 (c) Write a VHDL code to write integers to a file(8 marks) 6 (a) Discuss about mixed type description and its advantages. Illustrate with an example(6 marks) 6 (b) Write short notes on VHDL package and discuss the syntax of declaration of a package(7 marks) 6 (c) Write the VHDl/verilog description of 16×8 SRAM.(7 marks) 7 (a) Explain how a VHDL entity can be invoked from a verilog module with full adder as an example(10 marks) 7 (b) Write the mixed language description to invoke verilog module of JK flip-flop with clear from VHDL module(10 marks) 8 (a) Discuss mapping of signal assignment statement and level with suitable examples.(5 marks) 8 (b) Explain mapping of if-else statement with a suitable example(5 marks) 8 (c) Show the synthesis information extracted from the listing shown below:
Package codes is
type op is (add, mul, divide, none);
end;
work codes;
entity ALUS2 is
port (a, b; in std_logic_vector (3 downto 0);
c_in: in std_logic;
o_pc: in op;
z: out std_logic_vector (7 downto 0);
c_out: out std_logic;
err: out Boolean);
end ALUS2;(10 marks)