VHDL code for Even Parity Generator

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_ep is
port(x,y,z:in std_logic;
p:out std_logic);
end bejoy_ep;

architecture a of bejoy_ep is
begin
p<=((x xor y) xnor z);
end a;

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VHDL code for Half Subtractor

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_hs is
port (x,y,en : in bit ;
d,b : out bit; y1: inout bit);
end bejoy_hs;

architecture arc of bejoy_hs is
begin
process (en,y1)
begin
if en='1' then
d<= x xor y;
y1<= not (y);
b <= x and y1;
end if;
end process;
end arc;

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VHDL code for 4x1 Multiplexer using structural style

library IEEE;
use IEEE.std_logic_1164.all;

entity bejoy_4x1 is
port(s1,s2,d00,d01,d10,d11 : in std_logic;
z_out : out std_logic);
end bejoy_4x1;

architecture arc of bejoy_4x1 is

component mux
port(sx1,sx2,d0,d1 : in std_logic;
z : out std_logic);
end component;

component or_2
port(a,b : in std_logic;
c : out std_logic);
end component;

signal intr1, intr2, intr3, intr4 : std_logic;
begin
mux1 : mux port map(s1,s2,d00,d01,intr1);
mux2 : mux port map(not s1,s2, d10,d11,intr2);
o1 : or_2 port map(intr1, intr2, z_out);
end arc;

library ieee;
use ieee.std_logic_1164.all;

entity mux is
port(sx1,sx2,d0,d1 :in std_logic;
z1,z2: inout std_logic;
z: out std_logic);
end mux;

architecture arc of mux is
begin
z1 <= d0 and (not sx1) and (not sx2);
z2 <= (d1 and (not sx1) and sx2);
z<= z1 or z2;
end arc;

entity or_2 is
port(a,b : in bit;
c : out bit);
end or_2;
architecture arc of or_2 is
begin
c<=a or b;
end arc;

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VHDL code for Basic Gates

AND Gate

library ieee;

use ieee.std_logic_1164.all;

entity and_gate is

port (a,b : in std_logic ;

c : out std_logic);

end and_gate;

architecture arc of and_gate is

begin

c <= a and b; end arc;


OR Gate

library ieee;

use ieee.std_logic_1164.all;

entity or_gate is

port (a,b : in std_logic ;

c : out std_logic);

end or_gate;

architecture arc of or_gate is

begin

c <= a or b; end arc;



NOT Gate

library ieee;

use ieee.std_logic_1164.all;

entity not_gate is

port (a: in std_logic ;

b : out std_logic);

end not_gate;

architecture arc of not_gate is

begin

b <= not a; end arc;


NAND Gate

library ieee;

use ieee.std_logic_1164.all;

entity nand_gate is

port (a,b : in std_logic ;

c : out std_logic);

end nand_gate;

architecture arc of nand_gate is

begin

c <= a or b; end arc;


NOR Gate

library ieee;

use ieee.std_logic_1164.all;

entity nor_gate is

port (a,b : in std_logic ;

c : out std_logic);

end nor_gate;

architecture arc of nor_gate is

begin

c <= a nor b; end arc;


XOR Gate

library ieee;

use ieee.std_logic_1164.all;

entity xor_gate is

port (a,b : in std_logic ;

c : out std_logic);

end xor_gate;

architecture arc of xor_gate is

begin

c <= a xor b;

end arc;

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Master Slave JK Flip Flop

library ieee;
use ieee.std_logic_1164.all;

entity master_slave_jk is
port(j,k,clk:in std_logic;q1,q1x,z1x:inout std_logic;
q2,q2x,z2x: inout std_logic);
end master_slave_jk;

architecture arc of master_slave_jk is
begin
process(clk)
begin

if clk='1' then

z1x<=(j and (not q2)) or ((not k)and q2);
q1<=z1x after 5 ns;
q1x<=not z1x after 5ns;

else

z2x<=(q1 and (not q2)) or ((not q1x)and q2);
q2<=z2x after 5 ns;
q2x<=not z2x after 5ns;

end if;
end process;
end arc;

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VHDL code for T Flip Flop

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_tff is
port(t,clk:in std_logic;q,q1,z:inout std_logic);
end bejoy_tff;

architecture arc of bejoy_tff is
begin
process(clk)
begin

if clk='1' then
z<=((t and (not q)) or ((not t) and q));
q<=z after 5ns;
q1<=not z after 5ns;

end if;
end process;
end arc;

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VHDL code for Odd Parity Generator

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_op is
port(x,y,z:in std_logic;
p:out std_logic);
end bejoy_op;

architecture a of bejoy_op is
begin
p<=((x xor y) xor z);
end a;

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VHDL code for 3x8 Decoder

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_3x8 is
port(a,b,c:in std_logic;
d0,d1,d2,d3,d4,d5,d6,d7:out std_logic);
end bejoy_3x8;

architecture arc of bejoy_3x8 is
begin
d0<= (not a) and (not b) and (not c);
d1<= (not a) and (not b) and c;
d2<= (not a) and b and (not c);
d3<= (not a) and b and c;
d4<= a and (not b) and (not c);
d5<= a and (not b) and c;
d6<= a and b and (not c);
d7<= a and b and c;
end arc;

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VHDL code for JK Flip Flop

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_jkff is
port(j,k,clk:in std_logic;q,q1,z:inout std_logic);
end bejoy_jkff;

architecture arc of bejoy_jkff is
begin
process(clk)
begin

if clk='1' then
z<=(j and (not q)) or ((not k) and q);
q<=z after 5ns;
q1<=not z after 5ns;

end if;
end process;
end arc;

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VHDL code for Full Adder using structural style

library IEEE;
use IEEE.std_logic_1164.all;

entity bejoy_fa is
port(In1,In2,c_in : in std_logic;
sum, c_out : out std_logic);
end bejoy_fa;

architecture arc of bejoy_fa is

component half_adder
port(a,b : in std_logic;
sum, carry : out std_logic);
end component;

component or_2
port(a,b : in std_logic;
c : out std_logic);
end component;

signal s1, s2, s3 : std_logic;

begin

H1: half_adder port map(a=>In1, b=>In2, sum=>s1, carry=>s3);

H2: half_adder port map(a=>s1, b=>c_in, sum=>sum, carry=>s2);

O1: or_2 port map(a=> s2, b=>s3, c=>c_out);

end arc;

entity half_adder is

port (a,b : in bit ;
sum,carry : out bit);

end half_adder;

architecture arc of half_adder is

begin

sum<= a xor b;
carry <= a and b;

end arc;

entity or_2 is

port (a,b : in bit ;
c : out bit);

end or_2;

architecture arc of or_2 is

begin

c<= a or b;

end arc;

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VHDL code for Half Adder

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_ha is

port (a,b : in bit ;

s,c : out bit);

end bejoy_ha;

architecture arc of bejoy_ha is

begin

s<= a xor b;
c <= a and b;

end arc;

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VHDL code for 1x2 Demultiplexer

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_1x2 is
port(d,s:in std_logic;

z0,z1:out std_logic);
end bejoy_1x2;

architecture arc of bejoy_1x2 is
begin
z0 <= d and (not s);
z1 <= (d and s);
end arc;

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VHDL code for Full Subtractor

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_fs is
port(x,y,bi: in bit; b2,do,bo: out bit; d,b: inout bit);
end bejoy_fs;

architecture arc of bejoy_fs is
begin
d<=x xor y;
b<=x and (not y);
do<=bi xor d;
b2<=bi and (not b);
end arc;

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VHDL code for 4 bit Gray to Binary converter

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_g2b is
port(g:in std_logic_vector(3 downto 0);

b:inout std_logic_vector(3 downto 0));
end bejoy_g2b;


architecture a of bejoy_g2b is
begin

b(3)<=g(3);
b(2)<=b(3) xor g(2);
b(1)<=b(2) xor g(1);
b(0)<=b(1) xor g(0);
end a;

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VHDL code for 4 bit Binary to Gray code converter

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_b2g is
port(b:in std_logic_vector(3 downto 0);

g:out std_logic_vector(3 downto 0));
end bejoy_b2g;

architecture a of bejoy_b2g is
begin

g(3)<=b(3);
g(2)<=b(3) xor b(2);
g(1)<=b(2) xor b(1);
g(0)<=b(1) xor b(0);
end a;

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VHDL code for SR Flip Flop

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_rsff is
port(s,r,clk:in std_logic;q,q1,z:inout std_logic);
end bejoy_rsff;

architecture arc of bejoy_rsff is
begin
process(clk)
begin

if clk='1' then
z<=s or ((not r) and q);
q<=z after 5ns;
q1<=not z after 5ns;

end if;
end process;
end arc;

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VHDL code for 1x4 Demultiplexer using structural style

library IEEE;
use IEEE.std_logic_1164.all;

entity bejoy_1x4 is
port(s1,s2,data_in : in std_logic;
d1,d2,d3,d4 : out std_logic);
end bejoy_1x4;

architecture arc of bejoy_1x4 is

component dmux
port(sx1,sx2,d : in std_logic;
z1,z2 : out std_logic);
end component;

begin
dmux1 : dmux port map(s1,s2,data_in,d1,d2);
dmux2 : dmux port map(not s1,s2,data_in,d3,d4);
end arc;

library ieee;
use ieee.std_logic_1164.all;

entity dmux is
port(sx1,sx2,d :in std_logic;
z1,z2: out std_logic);
end dmux;

architecture arc of dmux is
begin
z1 <= d and (not sx1) and (not sx2);
z2 <= d and (not sx1) and sx2;
end arc;

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VHDL code for D Flip Flop

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_dff is
port(d,clock :in std_logic;
Q:out std_logic);
end bejoy_dff;

architecture arc of bejoy_dff is

begin
process(clock)
begin

if clock'event and clock='1' then
Q<=D;

end if;
end process;
end arc;

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VHDL code for 8x3 Encoder

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_8x3 is
port(d0,d1,d2,d3,d4,d5,d6,d7:in std_logic;

a0,a1,a2:out std_logic);
end bejoy_8x3;

architecture arc of bejoy_8x3 is
begin
a2<= d4 or d5 or d6 or d7;
a1<= d2 or d3 or d6 or d7;
a0<= d1 or d3 or d5 or d7;
end arc;

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VHDL code for 2x1 Multiplexer

library ieee;
use ieee.std_logic_1164.all;

entity bejoy_2x1 is
port(d0,d1,s:in std_logic;

z:out std_logic;
z1,z2: inout std_logic);
end bejoy_2x1;

architecture arc of bejoy_2x1 is
begin
z1 <= d0 and (not s);
z2 <= (d1 and s);
z <= z1 or z2;
end arc;

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