----------------------------------------------------------
-- keyDecode
-- Author   : Gautam Karnik
-- Date     : March 30, 2001
-- Filename : keyDecode.vhd
-- Architecture : Behavioral
-- Description  : This entity is the decodes the row that
--                has been pressed based on the input
--                lines from the keypad when the input
--                lines have been driven low.
----------------------------------------------------------

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all; 
use ieee.std_logic_unsigned.all; 
library work;
use work.CDMA_pkg.all;

entity keyDecode is
     	generic ( datawidth : positive := 4 );
      	port ( resetn  : in std_logic;
			   clock   : in std_logic;
			   clear   : in std_logic;
			   rowIn   : in std_logic_vector  ( datawidth-1 downto 0 );
			   sense   : in std_logic;
		 	   rowOut  : out std_logic_vector ( datawidth-1 downto 0 )
     	     );
end entity keyDecode;


architecture behavioral of keyDecode is 

begin

decode : process (clock, resetn ) is
	begin
   		wait until rising_edge ( clock );
   		if (resetn = '0') then
	  		rowOut <= (others => '1'); -- active low
   		else
	 		if sense = '0' then
				rowOut <= rowIn;
			elsif clear = '1' then
				rowOut <= (others => '1');
		 	end if;
   		end if;
	end process decode;

end behavioral;