CristalCaveGem » LustreC » Lustrec-Tests

library IEEE;

use IEEE.std_logic_1164.all;

entity user_handler is

   port

   (

      i_clock:             in std_logic;  -- System's clock.

      i_reset:             in std_logic;  -- System reset.

      i_synced_start_btn:  in std_logic;  -- User input. Synchronized.

      i_synced_raz_btn:    in std_logic;  -- User input. Synchronized.

      i_limit_reached:     in std_logic;  -- Time Wizard has reached limit.

      o_enable:            out std_logic; -- Enable time passing.

      o_raz:               out std_logic  -- Reset system.

   );

end user_handler;

architecture Behavioral of user_handler is

   -- Previous value of BP_START_STOP (Lustre inspired).

   signal synced_start_btn_r1: std_logic;

   -- Remember if we are currently counting time or not.

   signal time_is_passing: std_logic;

begin

   P_ENABLE_TIME: process (i_clock, i_reset)

   begin

      if (i_reset = '1')

      then

         time_is_passing <= '0';

      else

         if (rising_edge(i_clock))

         then

            if ((synced_start_btn_r1 = '0') and (i_synced_start_btn = '1'))

            then

               time_is_passing <= (not time_is_passing);

            end if;

         end if;

      end if;

   end process;

   P_PRE_SYNCED_START_BTN: process (i_clock, i_reset)

   begin

      if (i_reset = '1')

      then

         synced_start_btn_r1 <= '0';

      else

         if (rising_edge(i_clock))

         then

            synced_start_btn_r1 <= i_synced_start_btn;

         end if;

      end if;

   end process;

   o_raz <= (i_synced_raz_btn and time_is_passing);

   o_enable <= time_is_passing;

end;