Filename: generics_1.vhd
-- VHDL generic parameters example
--
-- generics_1.vhd
--
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
entity addern is
generic(
width : integer := 8
);
port(
A, B : in std_logic_vector(width - 1 downto 0);
Y : out std_logic_vector(width - 1 downto 0)
);
end addern;
architecture bhv of addern is
begin
Y <= A + B;
end bhv;
Library IEEE;
use IEEE.std_logic_1164.all;
entity generics_1 is
port(
X, Y, Z : in std_logic_vector(12 downto 0);
A, B : in std_logic_vector(4 downto 0);
S : out std_logic_vector(17 downto 0));
end generics_1;
architecture bhv of generics_1 is
component addern
generic(width : integer := 8);
port(
A, B : in std_logic_vector(width - 1 downto 0);
Y : out std_logic_vector(width - 1 downto 0));
end component;
for all : addern use entity work.addern(bhv);
signal C1 : std_logic_vector(12 downto 0);
signal C2, C3 : std_logic_vector(17 downto 0);
begin
U1 : addern generic map(width => 13) port map(X, Y, C1);
C2 <= C1 & A;
C3 <= Z & B;
U2 : addern generic map(width => 18) port map(C2, C3, S);
end bhv;
Note: When overriding generic values during instantiation, splitting up different array elements is not supported.
For example, if there is a generic my_gen defined as an array, as follows, it will not work:
my_gen(1) => x,
my_gen(0) => y
Instead, it should be set as follows:
my_gen => (x,y)