git.zerfleddert.de Git - raggedstone/blob - heartbeat/source/heartbeat.vhd

   1 library ieee;
   2
   3 use ieee.std_logic_1164.all;
   4 use ieee.std_logic_unsigned.all;
   5
   6 entity heartbeat is
   7 generic (
   8         divider : integer := 33000000
   9 );
  10
  11 port (
  12         clk_i : in std_logic;
  13         nrst_i : in std_logic;
  14         led_o : out std_logic
  15 );
  16
  17 end heartbeat;
  18
  19 architecture rtl of heartbeat is
  20 begin
  21
  22 process(clk_i, nrst_i)
  23 variable counter : std_logic_vector(31 downto 0);
  24 variable state : std_logic := '0';
  25 begin
  26
  27 if (clk_i'event AND clk_i = '1') then
  28         if nrst_i = '0' then
  29                 counter := (others => '0');
  30         else
  31                 led_o <= state;
  32                 counter := counter + 1;
  33                 if counter = divider then
  34                         state := not state;
  35                 end if;
  36         end if;
  37 end if;
  38 end process;
  39 end architecture;