Multiplexer is a digital switch.It allows digital information from several sources to be rooted on to a single output line.The basic multiplexer has several data input lines and a single output line.The selection of a particular input line is controlled by a set of selection lines.Normally there are 2^N input lines and N selection lines whose bit combinations determine which input is selected.Therefore multiplexer is many into one and it provides the digital equivalent of an analog selector switch.
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity Mux8_1 is
port ( SEL: in STD_LOGIC_VECTOR(2 downto 0);
A,B,C,D,E,F,G,H :in STD_LOGIC;
MUX_OUT: out STD_LOGIC );
end Mux8_1;
architecture BEHAVIORAL of Mux8_1 is
begin
process (SEL,A,B,C,D,E,F,G,H)
begin
case SEL is
when "000" => MUX_OUT <= A;
when "001" => MUX_OUT <= B;
when "010" => MUX_OUT <= C;
when "011" => MUX_OUT <= D;
when "100" => MUX_OUT <= E;
when "101" => MUX_OUT <= F;
when "110" => MUX_OUT <= G;
when "111" => MUX_OUT <= H;
when others => null;
end case;
end process;
end BEHAVIORAL;
