decoder4to2.vhd

红外4PPM解码的源程序

LIBRARY  ieee;
use ieee.std_logic_1164.all;
entity  decoder4to2  is 
port  (x:in  std_logic_vector(3 downto 0);
       y:out std_logic_vector(1 downto 0));
end  decoder4to2 ;
architecture  encoder1 of  decoder4to2 is
 begin
  y<="00"when x="1000" else
     "01"when x="0100" else
     "10"when x="0010" else
     "11"when x="0001" else
     "ZZ";
  end encoder1;