decoder_8b.vhd

-- Implementacao de um decoder de 8 bits.
-- Para cada valor possivel na sequencia
-- de 3 bits, e mapeado um vetor de 8 bits
-- cujo valor e 1 em uma posicao e 0 nas demais.
--
-- Recebe um vetor de 3 bits.
-- Retorna um vetor de 8 bits unico.
library ieee;
use ieee.std_logic_1164.all;

entity decoder_8b is
  port (
    input : in std_logic_vector(0 to 2);
    output : out std_logic_vector(0 to 7)
  ) ;
end decoder_8b ;

architecture bhv of decoder_8b is
begin
    with input select
        output <= "00000001" when "000",
                 "00000010" when "001",
                 "00000100" when "010",
                 "00001000" when "011",
                 "00010000" when "100",
                 "00100000" when "101",
                 "01000000" when "110",
                 "10000000" when "111",
                 "00000000" when others;
end architecture ; -- bhv