This coding example shows the structural description of a half-Adder composed of four nand2 components.
Filename: instantiation_simple.vhd
--
-- A simple component instantiation example
-- Involves a component declaration and the component instantiation itself
--
-- instantiation_simple.vhd
--
entity sub is
generic(
WIDTH : integer := 4
);
port(
A, B : in BIT_VECTOR(WIDTH - 1 downto 0);
O : out BIT_VECTOR(2 * WIDTH - 1 downto 0)
);
end sub;
architecture archi of sub is
begin
O <= A & B;
end ARCHI;
entity instantiation_simple is
generic(
WIDTH : integer := 2);
port(
X, Y : in BIT_VECTOR(WIDTH - 1 downto 0);
Z : out BIT_VECTOR(2 * WIDTH - 1 downto 0));
end instantiation_simple;
architecture ARCHI of instantiation_simple is
component sub -- component declaration
generic(
WIDTH : integer := 2);
port(
A, B : in BIT_VECTOR(WIDTH - 1 downto 0);
O : out BIT_VECTOR(2 * WIDTH - 1 downto 0));
end component;
begin
inst_sub : sub -- component instantiation
generic map(
WIDTH => WIDTH
)
port map(
A => X,
B => Y,
O => Z
);
end ARCHI;