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 : std_logic_vector(31 downto 0) := X"01F78A40"
   9 );
  10
  11 port (
  12         clk_i : in std_logic;
  13         nrst_i : in std_logic;
  14         led2_o : out std_logic;
  15         led3_o : out std_logic;
  16         led4_o : out std_logic;
  17         led5_o : out std_logic
  18 );
  19
  20 end heartbeat;
  21
  22 architecture rtl of heartbeat is
  23 begin
  24
  25 process(clk_i, nrst_i)
  26 variable counter : std_logic_vector(31 downto 0);
  27 variable state : std_logic := '0';
  28 begin
  29
  30 if (clk_i'event AND clk_i = '1') then
  31         if nrst_i = '0' then
  32                 counter := (others => '0');
  33         else
  34                 led5_o <= state;
  35                 led2_o <= state;
  36                 led4_o <= not state;
  37                 led3_o <= not state;
  38                 counter := counter + 1;
  39                 if counter = divider then
  40                         state := not state;
  41                         counter := (others => '0');
  42                 end if;
  43         end if;
  44 end if;
  45 end process;
  46 end architecture;