control.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;
use ieee.std_logic_unsigned.all;


entity control is 
  port( START :in std_logic;
        WAIT_T: in std_logic;
        READY: in std_logic;
        TEST: in std_logic;
		FIRE: in std_logic;
        SETUP: in std_logic;
        CLK: in std_logic;
        SLB,SLT :out std_logic);
end entity;

architecture control_behave of control is

 type state_type is(QA,QB,QC,QD,QE,QF,QG);
 SIGNAL present_state,next_state:state_type;

begin
 nextstate_logic:
   process(present_state)
     begin
     if(START='1')then
       case present_state is
           when QA=> 
                SLB<='0';SLT<='0';
                if(WAIT_T='0')then
                    next_state<=QA;
                else
                    next_state<=QB;
             	end if; 
           when QB=>
                SLB<='0';SLT<='0';
                if(READY='0')then
                    next_state<=QB;
                else
                    next_state<=QC;
       			end if; 
           when QC=> 
				SLB<='0';SLT<='0';
                if(TEST='0')then
					next_state<=QE;                    
                elsif(TEST='1')then			
					next_state<=QD; 		             
                else
                    next_state<=QC;
             end if;
           when QD=> 
                SLB<='0';SLT<='0'; 
                if(READY='1')then
                    next_state<=QC;
                elsif(FIRE='1')then
                    next_state<=QG;                
                else
					next_state<=QD; 
                end if;
           when QE=> 
                SLB<='0';SLT<='0';
                if(READY='1')then
                    next_state<=QC;
                elsif(FIRE='1')then
                    next_state<=QF;
				else
                    next_state<=QE;
                end if;
           when QF=>  
                SLB<='1';SLT<='0'; 
                if(SETUP='0')then
                    next_state<=QF;
				else
                    next_state<=QB;
                end if;
		   when QG=> 
                SLB<='0';SLT<='1'; 
                if(WAIT_T='0')then
                    next_state<=QG;
				else
                    next_state<=QA;
                end if;
        end case;
     else
        next_state<=QA;
     end if;
     end process;
      
   state_register:
     process(CLK)
     begin
         if(CLK'event and CLK='1')then
              present_state<=next_state;
         end if;
     end process;

end control_behave;