www.pudn.com > ep1c6_12_1_2_moto.rar > DEC2.VHD

LIBRARY IEEE ; 
 USE IEEE.STD_LOGIC_1164.ALL ; 
  ENTITY Dec2 IS 
    PORT ( CLK : IN STD_LOGIC; 
           A  : IN  STD_LOGIC_VECTOR(1 DOWNTO 0) ; 
           D  : OUT STD_LOGIC_VECTOR(3 DOWNTO 0)  ) ; 
 END ; 
 ARCHITECTURE one OF Dec2 IS 
 SIGNAL CQ : STD_LOGIC_VECTOR(1 DOWNTO 0); 
 BEGIN 
   PROCESS( CQ ) 
    BEGIN 
        CASE  CQ  IS 
          WHEN "00" =>  D <= "1001" ;  
          WHEN "01" =>  D <= "1100" ;  
          WHEN "10" =>  D <= "0110" ;  
          WHEN "11" =>  D <= "0011" ;  
          WHEN OTHERS =>  NULL ; 
        END CASE ; 
    END PROCESS ; 
 PROCESS(CLK) 
    BEGIN 
       IF CLK'EVENT AND CLK = '1' THEN CQ <= A; END IF; 
    END PROCESS; 
END ;