scan_2.vhd

数字密码引爆器的输入描述：1、 在开始输入密码以前的等待状态

library ieee;
use ieee.std_logic_1164.all;

entity SCAN_2 is
	PORT(
 			SCAN_CLK:IN STD_LOGIC;
            S,G:IN STD_LOGIC_VECTOR(3 DOWNTO 0);
            SW,GW:OUT STD_LOGIC;
			OUTPUT:OUT STD_LOGIC_vector(3 downto 0));
END SCAN_2 ;

architecture behave of SCAN_2 is
 signal TOUT:std_logic;
begin 
 process(SCAN_CLK)  
   begin	
  IF(SCAN_CLK'EVENT AND SCAN_CLK='1')THEN
	IF(TOUT='0')THEN
		sw <= '1';
		gw <= '0';
        TOUT<='1';
		outPUT<= s;
	ELSIF(TOUT='1')THEN
		sw <= '0';
		gw <= '1';
        TOUT<='0';
		outPUT <= g;
    ELSE
		sw <= '1';
		gw <= '0';
        TOUT<='1';
		outPUT<= s;
    END IF;
  END IF;
  end process;
end behave;