vlsi lab programs
DESCRIPTION
labTRANSCRIPT
EX.NO:1(a) Design and Simulation of Half Adder using VHDL
AIM: To design and verify the Half Adder using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
THEORY:
Let's start by adding two binary bits. Since each bit has only two possible values, 0 or 1, there are only four possible combinations of inputs. These four possibilities, and the resulting sums, are:
0 + 0 = 0
0 + 1 = 1
1 + 0 = 1
1 + 1 = 10
That fourth line indicates that we have to account for two output bits when we add two input bits: the sum and a possible carry. Let's set this up as a truth table with two inputsVHDL CODING:
library ieee;use ieee.std_logic_1164.all;entity halfadder isport (a,b:in bit;
sum,carry: out bit);end halfadder;
architecture arch_halfadder of halfadder is begin sum<= a xor b; carry<= a and b;
end arch_halfadder;
080290044 & VLSI Lab 1
PROCEDURE1. Open new file in VHDL source editor 2. Type the VHDL coding for Half Adder in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values.
RESULT: Thus the Half adder is designed and verified using VHDL.
EX.NO:1(b) Design and Simulation of Full Adder using VHDL
AIM: To design and verify the Full Adder using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
THEORY:
To construct a full adder circuit, we'll need three inputs and two outputs. Since we'll have both an input carry and an output carry, we'll designate them as CIN and COUT. At the same time, we'll use S to designate the final Sum output. The resulting truth table is shown to the right.
VHDL CODING:library ieee;use ieee.std_logic_1164.all;entity fulladder isport (x, y, Cin: in bit; Cout,S :out bit);end fulladder;
architecture arch_fulladder of fulladder is begin
080290044 & VLSI Lab 2
S<= (x xor y) xor Cin; Cout<= (x and y) or (y and Cin) or (Cin and x);end arch_fulladder;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for Full Adder in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the Full adder is designed and verified using VHDL.
EX.NO:2(a) Design and Simulation of 4:2 Encoder using VHDL
AIM: To design and verify the 4:2 Encoder using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
Theory: The encoder is a combinational circuit that performs the reverse operation of the decoder. The encoder has a maximum of 2n inputs and n outputs. An encoder performs the opposite function of a decoder. An encoder takes a input on one of its 2n input lines and converts it to a coded output with n lines.
VHDL CODING:library ieee;use ieee.std_logic_1164.all;entity encoder isport (a,b,c,d:in bit;
y:out bit_vector(1 downto 0));end encoder;
080290044 & VLSI Lab 3
architecture arch_encoder of encoder isbeginprocess (a,b,c,d)begin
if (a='1')then y<="00"; elsif (b='1')then y<="01"; elsif (c='1')then y<="10"; elsif (d='1')then y<="11"; end if;
end process;end arch_encoder;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for 4:2 Encoder in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the 4:2 Encoder is designed and verified using VHDL.
EX.NO:2(b) Design and Simulation of 2:4 Decoder using VHDL
AIM: To design and verify the 2:4 Decoder using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
080290044 & VLSI Lab 4
Theory:The basic function of a decoder is to detect the presence of a particular combination of bits at the inputs and indicate the presence of that particular set of bits by outputting a specified output level. Typically a decoder with n input lines requires 2n output lines to decode every possible combination of bits. BCD to decimal conversion, looked at in part3 of this lab, is accomplished using a decoder which has 4 input lines and 10 output lines (the 10 output lines correspond to the decimal numbers 0-9). This device is used to convert between binary numbers and decimal numbers
VHDL CODING:library ieee;use ieee.std_logic_1164.all;entity decoder isport (a,b:in bit;
y:out bit_vector(3 downto 0));end decoder;
architecture arch_decoder of decoder is begin process (a,b)
begin if (a='0' and b='0' )then y<="0001"; elsif (a='0' and b='1' )then y<="0010"; elsif (a='1' and b='0' )then y<="0100"; elsif (a='1' and b='1' )then y<="1000"; end if; end process;
end arch_decoder;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for 2:4 Decoders in the new file.
080290044 & VLSI Lab 5
3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the 2:4 Decoder is designed and verified using VHDL.
EX.NO:3(a) Design and Simulation of 8:1 Multiplexer using VHDL
AIM: To design and verify the 8:1 Multiplexer using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
THEORY:A multiplexer or MUX is a device that allows digital information from
several different sources on different input lines to be routed onto a single line. A basic MUX has several input lines, several data select lines or control signals and one output signal. The input that gets selected to pass to the output is determined by the control signals.
VHDL CODING:library ieee;use ieee.std_logic_1164.all;use ieee.std_logic_unsigned.all;entity mux8to1 isport(y:out std_logic;
s:in std_logic_vector(2 downto 0); i:in std_logic_vector(0 to 7));
end mux8to1;architecture arch_mux8to1 of mux8to1 isbeginprocess(s,i)begincase s is
080290044 & VLSI Lab 6
when "000" => y <=i(0);when "001" => y <=i(1);when "010" => y <=i(2);when "011" => y <=i(3);when "100" => y <=i(4);when "101" => y <=i(5);when "110" => y <=i(6);when "111" => y <=i(7);when others =>null;end case;end process;end arch_mux8to1;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for 8:1 Multiplexer in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:
Thus the 8:1 Multiplexer is designed and verified using VHDL.
EX.NO:3(b) Design and Simulation of 1:8 Demultiplexer using VHDL
AIM: To design and verify the 1:8 Demultiplexer using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
080290044 & VLSI Lab 7
THEORY:A demultiplexer is the opposite of a multiplexer. In electronic devices, demultiplexer is a logical circuit which takes a single input and sends out this input to one of several outputs available. During this process the output that has been selected is assigned the value 1, while the other outputs are assigned the value 0. The definition is slightly different when we are talking about demultiplexers in the context of networking. In the networking context, a demultiplexer is a device that receives multiple signals that have been transmitted on one line and then decodes these single line signals into separate multiple signals. A demultiplexer is usually always used in tandem with a multiplexer. Demultiplexers can be analog demultiplexers or digital demultiplexers. Digital demultiplexers generally function as decoders.
VHDL CODING:library ieee;use ieee.std_logic_1164.all;use ieee.std_logic_unsigned.all;entity demux1to8 isport(y:out std_logic_vector(0 to 7);
s:in std_logic_vector(2 downto 0); i:in std_logic);
end demux1to8;architecture arch_demux1to8 of demux1to8 isbeginprocess(s,i)begincase s iswhen "000" => y(0)<=i;when "001" => y(1)<=i;when "010" => y(2)<=i;when "011" => y(3)<=i;when "100" => y(4)<=i;when "101" => y(5)<=i;when "110" => y(6)<=i;when "111" => y(7)<=i;
080290044 & VLSI Lab 8
when others =>null;end case;end process;end arch_demux1to8;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for 1:8 Demultiplexers in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:
Thus the 1:8 Demultiplixer is designed and verified using VHDL.
EX.NO:4 Design and Simulation of 4x4 Multiplier using VHDL
AIM: To design and verify the 4X4 Array Multiplier using VHDL.
TOOLS REQUIRED:1.Computer with ModelSim Software
THEORYThe simple serial by parallel booth multiplier is particularly well suited
for bit serial processors implemented in FPGAs without carry chains because all of its routing is to nearest neighbors with the exception of the input. The serial input must be sign extended to a length equal to the sum of the lengths of the serial input and parallel input to avoid overflow, which means this multiplier takes more clocks to complete than the scaling accumulator version.
VHDL CODING:
080290044 & VLSI Lab 9
// 4X4 Array Multiplierlibrary ieee;use ieee.std_logic_1164.all;
entity a1 isport(a,b:in std_logic;c:out std_logic);end a1;architecture a of a1 isbeginc <= a and b;end a;
library ieee;use ieee.std_logic_1164.all;entity fa isport(a,b,c:in std_logic;s,ca:out std_logic);end fa;architecture fa1 of fa isbeginca <= (a and b) or ( b and c) or ( a and c);s <= a xor b xor c;end fa1;
library ieee;use ieee.std_logic_1164.all;entity mul isport(a,b:in std_logic_vector(3 downto 0);
p:out std_logic_vector(7 downto 0));end mul;
architecture multiplier of mul iscomponent a1 port(a,b:in std_logic;c:out std_logic);end component;component fa port(a,b,c:in std_logic;s,ca:out std_logic);
080290044 & VLSI Lab 10
end component;signal c :std_logic_vector(15 downto 0);signal s:std_logic_vector(15 downto 0);signal q :std_logic_vector(15 downto 0);signal z : std_logic := '0';begina0: a1 port map(a(0),b(0),p(0));a2: a1 port map(a(1),b(0),c(1));a3: a1 port map(a(2),b(0),c(2));a4: a1 port map(a(3),b(0),c(3));a5: a1 port map(a(0),b(1),c(4));a6: a1 port map(a(1),b(1),c(5));a7: a1 port map(a(2),b(1),c(6));a8: a1 port map(a(3),b(1),c(7));a9: a1 port map(a(0),b(2),c(8));a10: a1 port map(a(1),b(2),c(9));a11: a1 port map(a(2),b(2),c(10));a12: a1 port map(a(3),b(2),c(11));a13: a1 port map(a(0),b(3),c(12));a14: a1 port map(a(1),b(3),c(13));a15: a1 port map(a(2),b(3),c(14));a16: a1 port map(a(3),b(3),c(15));f0:fa port map(c(1),c(4),z,p(1),q(0));f1:fa port map(q(0),c(2),c(5),s(1),q(1));f2:fa port map(q(1),c(3),c(6),s(2),q(2));f3:fa port map(q(2),z,c(7),s(3),q(3));f4:fa port map(s(1),z,c(8),p(2),q(4));f5:fa port map(q(4),s(2),c(9),s(4),q(5));f6:fa port map(q(5),s(3),c(10),s(5),q(6));f7:fa port map(q(6),q(3),c(11),s(6),q(7));f8:fa port map(s(4),z,c(12),p(3),q(8));f9:fa port map(q(8),s(5),c(13),p(4),q(9));f10:fa port map(q(9),s(6),c(14),p(5),q(10));f11:fa port map(q(10),q(7),c(15),p(6),p(7));end multiplier;
PROCEDURE
080290044 & VLSI Lab 11
1. Open new file in VHDL source editor 2. Type the VHDL coding for multiplier in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the 4X4 Array Multiplier Half adder is designed and verified
using VHDL.
EX.NO:5(a) Design and Simulation of JK Flip Flop using VHDL
AIM: To design and verify the JK Flipflop using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
THEORY:
The JK flip-flop behaves just like the RS flip-flop. The Q and Q' outputs will only change state on the falling edge of the CLK signal, and the J and K inputs will control the future output state pretty much as before. However, there are some important differences.
If both the J and K inputs are held at logic 1 and the CLK signal continues to change, the Q and Q' outputs will simply change state with each falling edge of the CLK signal. (The master latch circuit will change state with each rising edge of CLK.) We can use this characteristic to advantage in a number of ways. A flip-flop built specifically to operate this way is typically designated as a T (for Toggle) flip-flop. The lone T input is in fact the CLK input for other types of flip-flops.
VHDL CODING:
080290044 & VLSI Lab 12
// JK Flipfloplibrary ieee;use ieee.std_logic_1164.all;entity jkff isport (j,k,clk:in std_logic;
q,qb:inout std_logic);end jkff;architecture arch_jkff of jkff isbeginprocess (j,k,clk)beginif (rising_edge(clk))then
if (j='0' and k='0')then q<=q; qb<=qb; elsif (j='0' and k='1')then q<=’0’;qb<=’1’; elsif (j='1' and k='0')then q<=’1’; qb<=’0’; elsif (k='1' and k='1')then q<= not q; qb<= not qb; end if;
end if;end process;end arch_jkff;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for JK Flip Flop in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the JK flip-flop is designed and verified using VHDL.
080290044 & VLSI Lab 13
EX.NO:5(b) Design and Simulation of D Flip Flop using VHDL
AIM: To design and verify the D Flipflop using VHDL.
TOOLS REQUIRED:1.Computer with ModelSim Software
THEORY:
The edge-triggered D flip-flop is easily derived from its RS counterpart. The only requirement is to replace the R input with an inverted version of the S input, which thereby becomes D. This is only needed in the master latch section; the slave remains unchanged.
One essential point about the D flip-flop is that when the clock input falls to logic 0 and the outputs can change state, the Q output always takes on the state of the D input at the moment of the clock edge. This was not true of the RS and JK flip-flops. The RS master section would repeatedly change states to match the input signals while the clock line is logic 1, and the Q output would reflect whichever input most recently received an active signal. The JK master section would receive and hold an input to tell it to change state, and never change that state until the next cycle of the clock. This behavior is not possible with a D flip-flop
VHDL CODING:// D Flipfloplibrary ieee;use ieee.std_logic_1164.all;entity dff isport (d,clk:in std_logic;
q:out std_logic);end dff;architecture arch_dff of dff isbeginprocess (d,clk) begin
080290044 & VLSI Lab 14
if(rising_edge(clk) )then q<=d;
end if; end process;end arch_dff;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for D Flip Flop in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the D flip-flop is designed and verified using VHDL.
EX.NO:6(a) Design and Simulation of 4 bit UP Counter using VHDL
AIM: To design and verify the Up counter using VHDL.
TOOLS REQUIRED:1.Computer with ModelSim Software
THEORY:The result is a four-bit synchronous "up" counter. Each of the higher-
order flip-flops are made ready to toggle (both J and K inputs "high") if the Q outputs of all previous flip-flops are "high." Otherwise, the J and K inputs for that flip-flop will both be "low," placing it into the "latch" mode where it will maintain its present output state at the next clock pulse.
Since the first (LSB) flip-flop needs to toggle at every clock pulse, its J and K inputs are connected to Vcc or Vdd, where they will be "high" all the time. The next flip-flop need only "recognize" that the first flip-flop's Q output is high to be made ready to toggle, so no AND gate is needed.
080290044 & VLSI Lab 15
However, the remaining flip-flops should be made ready to toggle only when all lower-order output bits are "high," thus the need for AND gates.
VHDL CODING:// up Counterslibrary ieee;use ieee.std_logic_1164.all;use ieee.std_logic_signed.all;entity counter is port(clk, rst : in std_logic; Q : out std_logic_vector(3 downto 0));end counter;architecture archi of counter is signal tmp: std_logic_vector(3 downto 0); begin
process (clk, rst) begin if (rst='1') then tmp <= "0000"; elsif (clk'event and clk='1') then tmp <= tmp + 1; end if;
end process; Q <= tmp;end archi;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for Up Counter in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the 4 bit up counter is designed and verified using VHDL.
080290044 & VLSI Lab 16
EX.NO:6(b) Design and Simulation of 4 bit DOWN Counter using VHDLAIM: To design and verify the Down counter using VHDL.
TOOLS REQUIRED:1.Computer with ModelSim Software
THEORY:To make a synchronous "down" counter, we need to build the circuit to recognize the appropriate bit patterns predicting each toggle state while counting down. Not surprisingly, when we examine the four-bit binary count sequence, we see that all preceding bits are "low" prior to a toggle (following the sequence from bottom to top.
VHDL CODING:// Down Counterslibrary ieee;use ieee.std_logic_1164.all;use ieee.std_logic_signed.all;entity counter is port(clk, rst : in std_logic;
Q : out std_logic_vector(3 downto 0));end counter;architecture archi of counter is signal tmp: std_logic_vector(3 downto 0); begin process (clk, rst) begin
if (rst='1') then tmp <= "0000"; elsif (clk'event and clk='1') then tmp <= tmp - 1; end if;
end process; Q <= tmp;end archi;
080290044 & VLSI Lab 17
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for Down Counter in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the 4 bit down counter is designed and verified using VHDL.
EX.NO:7(a) Design and Simulation of SISO Shift Register using VHDL
AIM: To design and verify the Serial in Serial out Shift Registers using VHDL.
TOOLS REQUIRED:
1. Computer with ModelSim Software
THEORY:
Serial-in, serial-out shift registers delay data by one clock time for each stage. They will store a bit of data for each register. A serial-in, serial-out shift register may be one to 64 bits in length, longer if registers or packages are cascaded. Below is a single stage shift register receiving data which is not synchronized to the register clock. The "data in" at the D pin of the type D FF (Flip-Flop) does not change levels when the clock changes for low to high. We may want to synchronize the data to a system wide clock in a circuit board to improve the reliability of a digital logic circuit.
VHDL CODING:// Serial In Serial Out
library ieee; use ieee.std_logic_1164.all;
080290044 & VLSI Lab 18
use ieee.std_logic_unsigned.all; entity siso is port(di,clk,rst:in std_logic; dout:out std_logic); end siso;architecture arch_siso of siso is signal s:std_logic_vector(0 to 6);beginprocess(di,clk,rst)begin if(rst='1')then dout<='0'; elsif(clk'event and clk='1')then s(0)<=di; s(1)<=s(0); s(2)<=s(1); s(3)<=s(2); s(4)<=s(3); s(5)<=s(4); s(6)<=s(5); dout<=s(6); end if; end process; end arch_siso;
PROCEDURE1. Open new file in VHDL source editor 2. Type the VHDL coding for Serial In Serial Out shift Register in the
new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus Serial in Serial out Shift Registers is designed and verified using VHDL.
080290044 & VLSI Lab 19
EX.NO:7(b) Design and Simulation of SIPO Shift Register using VHDL
AIM: To design and verify the Serial In Parallel Out Shift Register using VHDL.
TOOLS REQUIRED:
1. Computer with ModelSim Software
THEORY:A serial-in/parallel-out shift register is similar to the serial-in/ serial-out
shift register in that it shifts data into internal storage elements and shifts data out at the serial-out, data-out, pin.
It is different in that it makes all the internal stages available as outputs. Therefore, a serial-in/parallel-out shift register converts data from serial format to parallel format. If four data bits are shifted in by four clock pulses via a single wire at data-in, below, the data becomes available simultaneously on the four Outputs QA to QD after the fourth clock pulse.
VHDL CODING:library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_unsigned.all; entity sipo_new is port(di,clk,rst:in std_logic; dout:out std_logic_vector(0 to 7)); end sipo_new;
architecture arch_sipo of sipo_new is signal s:std_logic_vector(0 to 7);beginprocess(di,clk,rst)begin if(rst='1')then dout<="00000000";
080290044 & VLSI Lab 20
elsif(clk'event and clk='1')then s(0)<=di; s(1)<=s(0); s(2)<=s(1); s(3)<=s(2); s(4)<=s(3); s(5)<=s(4); s(6)<=s(5); s(7)<=s(6); dout(0)<=s(0); dout(1)<=s(1); dout(2)<=s(2); dout(3)<=s(3); dout(4)<=s(4); dout(5)<=s(5); dout(6)<=s(6); dout(7)<=s(7); end if; end process; end arch_sipo; PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for Serial In Parallel Out Shift Register in the
new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:
Thus Serial in Parallel out Shift Register is designed and verified using VHDL.
EX.NO:8 Design and Simulation of Frequency Divider using VHDL
080290044 & VLSI Lab 21
AIM: To design and verify the Frequency Divider using VHDL.
TOOLS REQUIRED:1. Computer with ModelSim Software
THEORY:
A frequency divider is an electronic circuit that takes an input signal with a frequency, fin, and generates an output signal with a frequency:
where n is an integer. Phase-locked loop frequency synthesizers make use of frequency dividers to generate a frequency that is a multiple of a reference frequency. Frequency dividers can be implemented for both analog and digital applications.
VHDL CODING:library ieee;use ieee.std_logic_1164.all;use ieee.std_logic_signed.all;entity freqdiv is port(clk, rst : in std_logic;
clkby2,clkby4,clkby8,clkby16:out std_logic); end freqdiv;architecture archi of freqdiv is signal Q: std_logic_vector(3 downto 0); begin process (clk, rst) begin if (rst='1') then
Q <= "0000"; elsif (clk'event and clk='1') then Q <= Q + 1; end if;
end process; clkby2<=Q(0);
080290044 & VLSI Lab 22
clkby4<=Q(1);clkby8<=Q(2);clkby16<=Q(3);end archi;
PROCEDURE
1. Open new file in VHDL source editor 2. Type the VHDL coding for Frequency Divider in the new file.3. Save the file with the extension of .vhd4. Compile and Simulate the Program.5. Add the selected signal to the wave form window.6. Force the input signals values and verify the output signal values
RESULT:Thus the Frequency Divider is designed and verified using VHDL.
EX.NO:9 CMOS INVERTER
AIM: To design and verify the CMOS inverter using SPICE
TOOLS REQUIRED:1. WinSpice3 2. Computer
PROCEDURE:1. Open a notepad file 2. Write a program for CMOS inverter.3. Specify the input and output4. Save the file with the extension of .cir5. Open the Winspice software6. Click the file and open the Program file7. Verify the input and output plots
WINSPICE PROGRAM:M1 3 2 1 1 p L=2u w=3u
080290044 & VLSI Lab 23
M2 3 2 0 0 n L=2u w=3uvdd 1 0 dc 5vvin 2 0 pulse(0 5 0 1n 1n 10n 50n).plot tran v(2).plot tran v(3).tran 1n 100n.model p pmos.model n nmos.end
RESULT:
Thus CMOS Inverter is designed and verified using SPICE
EX.NO:10(A) CMOS NAND GATE
AIM: To design and verify the CMOS NAND gate using SPICE
TOOLS REQUIRED:1.WinSpice3
2.Computer
PROCEDURE:
1. Open a notepad file 2. Write a program for CMOS NAND gate.3. Specify the input and output4. Save the file with the extension of .cir5. Open the Winspice software6. Click the file and open the Program file7. Verify the input and output plots
WINSPICE PROGRAM:
M1 3 2 1 1 p L=2u w=3uM2 3 4 1 1 p L=2u w=3u
080290044 & VLSI Lab 24
M3 3 4 5 0 n L=2u w=3uM4 5 2 0 0 n L=2u w=3uvdd 1 0 dc 5vv1 2 0 pulse(0 5 0 1n 1n 40n 80n)v2 4 0 pulse(0 5 0 1n 1n 40n 80n).plot tran v(2) .plot tran v(4) .plot tran v(3).tran 1n 200n.model n nmos.model p pmos.end
RESULT:Thus CMOS NAND is designed and verified using SPICE
EX.NO:10(B) CMOS NOR GATE
AIM: To design and verify the CMOS NOR gate using SPICE
TOOLS REQUIRED:1.WinSpice3
2.ComputerPROCEDURE:
1. Open a notepad file 2. Write a program for CMOS NOR gate.3. Specify the input and output4. Save the file with the extension of .cir5. Open the Winspice software6. Click the file and open the Program file7. Verify the input and output plots
WINSPICE PROGRAM:M1 5 2 1 1 p L=2u w=3u
080290044 & VLSI Lab 25
M2 5 4 3 1 p L=2u w=3uM3 3 2 0 0 n L=2u w=3uM4 3 4 0 0 n L=2u w=3uvdd 1 0 dc 5vv1 2 0 pulse(0 5 0 1n 1n 40n 80n)v2 4 0 pulse(0 5 0 1n 1n 40n 80n).plot tran v(2) .plot tran v(4) .plot tran v(3).tran 1n 200n.model p pmos.model n nmos.end
RESULT:Thus CMOS NOR is designed and verified using SPICE
EX.NO:11 CMOS D LATCH
AIM: To design and verify the CMOS D Latch using SPICE
TOOLS REQUIRED:1.WinSpice3
2.Computer
PROCEDURE:1. Open a notepad file 2. Write a program for CMOS D Latch.3. Specify the input and output4. Save the file with the extension of .cir5. Open the Winspice software6. Click the file and open the Program file7. Verify the input and output plots
080290044 & VLSI Lab 26
WINSPICE PROGRAM:M1 2 3 1 7 p L=2u w=3uM2 2 4 1 0 n L=2u w=3uM3 2 3 5 0 n L=2u w=3uM4 2 4 5 7 p L=2u w=3uM5 6 2 7 7 p L=2u w=3uM6 6 2 0 0 n L=2u w=3uM7 5 6 7 7 p L=2u w=3uM8 5 6 0 0 n L=2u w=3uM9 3 8 7 7 p L=2u w=3uM10 3 8 0 0 n L=2u w=3uM11 4 3 7 7 p L=2u w=3uM12 4 3 0 0 n L=2u w=3uvdd 7 0 dc 5vv1 1 0 pulse(0 5 0 1n 1n 20n 40n)v2 8 0 pulse(0 5 0 1n 1n 20n 50n).plot tran v(1).plot tran v(8) .plot tran v(2).tran 1n 100n.model p pmos.model n nmos.end
RESULT:Thus CMOS D LATCH is designed and verified using SPICE
EX.NO:12 FPGA Implementation of 4 Bit Adder
AIM: To design and verify the 4-bit Adder using VHDL and Implement in FPGA.TOOLS REQUIRED:
1. ModelSim 5.7g2. XILINX ISE 9.2i3. Spartan IIIE FPGA Kit
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THEORY:
It is possible to create a logical circuit using multiple full adders to add N-bit numbers. Each full adder inputs a Cin, which is the Cout of the previous adder. This kind of adder is a ripple carry adder, since each carry bit "ripples" to the next full adder. Note that the first (and only the first) full adder may be replaced by a half adder.
The layout of ripple carry adder is simple, which allows for fast design time; however, the ripple carry adder is relatively slow, since each full adder must wait for the carry bit to be calculated from the previous full adder. The gate delay can easily be calculated by inspection of the full adder circuit. Each full adder requires three levels of logic. In a 32-bit [ripple carry] adder, there 32 full adders,so the critical path (worst case) delay is 32 * 3 = 96 gate delays.
VHDL CODING:library ieee;use ieee.std_logic_1164.all;entity fulladder isport (x,y,Cin:in bit;Cout,S:out bit);end fulladder;architecture arch_fulladder of fulladder isbeginS<= (x xor y) xor Cin;Cout<= (x and y) or (y and Cin) or (Cin and x);end arch_fulladder;entity add4 isport (A,B:in bit_vector (3 downto 0);Cin:in bit;Cout:out bit;S:out bit_vector(3 downto 0));end add4;architecture arch_add4 of add4 iscomponent fulladderport (x,y,Cin:in bit;Cout,S:out bit);end component;signal C:bit_vector (2 downto 0);beginFA0:fulladder port map (A(0),B(0),Cin,C(0),S(0));
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FA1:fulladder port map (A(1),B(1),C(0),C(1),S(1));FA2:fulladder port map (A(2),B(2),C(1),C(2),S(2));FA3:fulladder port map (A(3),B(3),C(2),Cout,S(3));end arch_add4;
PROCEDURE1. Open new VHDL source editor in Xilinx ISE tool2. Type the VHDL coding for 4 bit Adder in the new file.3. Save the file with the extension of .vhd4. Assign the I/O Signal to the FPGA package pins.5. Synthesis the VHDL Code.6. Place and Route the Design by click on Implement Design7. Generate the bit file8. Configure the bit file on Spartan IIIE FPGA and verify the result.
RESULT:Thus the 4-bit Adder is designed and verified using VHDL.
EX.NO:13 FPGA Implementation of Real Time Clock
AIM: To design and verify the Real Time Clock VHDL and Implement in FPGA.TOOLS REQUIRED:
1. ModelSim 5.7g2. XILINX ISE 9.2i3. Spartan III E FPGA kit
VHDL CODING:library IEEE;use IEEE.STD_LOGIC_1164.ALL;use IEEE.STD_LOGIC_ARITH.ALL;use IEEE.STD_LOGIC_UNSIGNED.ALL;entity rtc is
Port (clk : in std_logic;rst : in std_logic;
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sl : out std_logic_vector(5 downto 0);atoh : out std_logic_vector(7 downto 0));
end rtc;architecture Behavioral of rtc is
signal sig2 : std_logic_vector(26 downto 0) := (others => '0');signal sig3 : std_logic_vector(19 downto 0) := (others => '0');
beginprocess(clk, rst)
variable ssdigit1, ssdigit2,ssdigit3, ssdigit4,ssdigit5, ssdigit6 : std_logic_vector(7 downto 0) := (others => '0');variable digit1, digit2,digit3, digit4,digit5, digit6 : integer := 0;
beginif (rst = '0') thendigit1 := 0;
digit2 := 0;digit3 := 0;digit4 := 0;digit5 := 0;
digit6 := 0;sig2 <= (others => '0');sig3 <= (others => '0');
elsif rising_edge(clk) thensig2 <= sig2 + 1;case sig2(24 downto 23) is
when "00" => digit6 := digit6 + 1;
if (digit6 > 9) thendigit6 := 0;digit5 := digit5 + 1;if (digit5 > 5) then
digit5 := 0;digit4 := digit4 + 1;if (digit4 > 9) then
digit4 := 0;
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digit3 := digit3 + 1;if (digit3 > 5) thendigit2 := digit2 + 1;
digit3 := 0;if (digit2 > 9) then
digit1 := digit1 + 1;digit2 := 0;
if ((digit1 >= 2) and (digit2 >= 4)) thendigit1 := 0;digit2 := 0;
end if;end if;
end if;end if;
end if;end if;
sig2(24 downto 23) <= "01";when "11" =>
if (sig2(22 downto 19) = "1001") thensig2 <= (others => '0');
end if;when others =>
end case;sig3 <= sig3 + 1;case sig3(17 downto 15) is
when "000" => sl <= "111110";case digit1 is
when 0 => ssdigit1 := "00111111";when 1 => ssdigit1 := "00000110";when 2 => ssdigit1 := "01011011";when others => ssdigit1 := "00000000";
end case;atoh <= ssdigit1;
when "001" => sl <= "111101";case digit2 is
when 0 => ssdigit2 := "00111111";when 1 => ssdigit2 := "00000110";
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when 2 => ssdigit2 := "01011011";when 3 => ssdigit2 := "01001111";when 4 => ssdigit2 := "01100110";when 5 => ssdigit2 := "01101101";when 6 => ssdigit2 := "01111101";when 7 => ssdigit2 := "00000111";when 8 => ssdigit2 := "01111111";when 9 => ssdigit2 := "01101111";when others => ssdigit2 := "00000000";
end case;atoh <= ssdigit2;
when "011" => sl <= "111011"; case digit3 is
when 0 => ssdigit3 := "00111111";when 1 => ssdigit3 := "00000110";when 2 => ssdigit3 := "01011011";when 3 => ssdigit3 := "01001111";when 4 => ssdigit3 := "01100110";when 5 => ssdigit3 := "01101101";when others => ssdigit3 := "00000000";
end case;atoh <= ssdigit3;
when "100" => sl <= "110111";case digit4 is
when 0 => ssdigit4 := "00111111";when 1 => ssdigit4 := "00000110";when 2 => ssdigit4 := "01011011";when 3 => ssdigit4 := "01001111";when 4 => ssdigit4 := "01100110";when 5 => ssdigit4 := "01101101";when 6 => ssdigit4 := "01111101";when 7 => ssdigit4 := "00000111";when 8 => ssdigit4 := "01111111";when 9 => ssdigit4 := "01101111";when others => ssdigit4 := "00000000";
end case;atoh <= ssdigit4;
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when "110" => sl <= "101111"; case digit5 is
when 0 => ssdigit5 := "00111111";when 1 => ssdigit5 := "00000110";when 2 => ssdigit5 := "01011011";when 3 => ssdigit5 := "01001111";when 4 => ssdigit5 := "01100110";when 5 => ssdigit5 := "01101101";when others => ssdigit5 := "00000000";
end case;atoh <= ssdigit5;
when "111" => sl <= "011111";case digit6 is
when 0 => ssdigit6 := "00111111";when 1 => ssdigit6 := "00000110";when 2 => ssdigit6 := "01011011";when 3 => ssdigit6 := "01001111";when 4 => ssdigit6 := "01100110";when 5 => ssdigit6 := "01101101";when 6 => ssdigit6 := "01111101";when 7 => ssdigit6 := "00000111";when 8 => ssdigit6 := "01111111";when 9 => ssdigit6 := "01101111";when others => ssdigit6 := "00000000";
end case;atoh <= ssdigit6;
when others => sl <= "111111";end case;
end if;end process;end Behavioral;PROCEDURE
1. Open new VHDL source editor in Xilinx ISE tool2. Type the VHDL coding for Real Time Clock in the new file.3. Save the file with the extension of .vhd4. Assign the I/O Signal to the FPGA package pins.
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5. Synthesis the VHDL Code.6. Place and Route the Design by click on Implement Design7. Generate the bit file8. Configure the bit file on Spartan IIIE FPGA and verify the result.
RESULT:Thus the real time clock is designed and verified using VHDL.
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