simple blink light for the arty 35 thing

blink.vhdl

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity blinkfrien is
  port (
    i_clock     : in  std_logic;
    o_led       : out std_logic
    );
end blinkfrien;

architecture rtl of blinkfrien is
    constant CLOCK_HZ : integer := 1e8;
    constant TARGET : integer := (CLOCK_HZ / 2)-1; -- twice a second
    signal counter : integer range 0 to TARGET := 0;
    signal blink_status : std_logic := '0';
begin
    process(i_clock) is
    begin
        if rising_edge(i_clock) then
            if counter = TARGET then
                blink_status <= not blink_status;
                counter <= 0;
            else
                counter <= counter+1;
            end if;
        end if;
    end process;
    
    o_led <= blink_status;
end rtl;