speakera.vhd

音乐

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity speakera is
  port(clk:in std_logic;
       tone:in std_logic_vector(10 downto 0);
       spks:out std_logic);
end;

architecture one of speakera is
  signal preclk,fullspks:std_logic;
begin
 divideclk:process(clk)
  variable count4:std_logic_vector(3 downto 0);
  begin
    preclk<='0';
    if count4>11 then preclk<='1';count4:="0000";
    elsif clk'event and clk='1' then count4:=count4+1;
    end if;
  end process;

 genspks:process(preclk,tone)
   variable count11:std_logic_vector(10 downto 0);
 begin 
   if preclk'event and preclk='1' then
    if count11=16#7FF# then count11:=tone; fullspks<='1';
    else count11:=count11+1;fullspks<='0';
    end if;
   end if;
 end process;

delayspks:process(fullspks)
 variable count2:std_logic;
  begin
   if fullspks'event and fullspks='1' then count2:=NOT count2;
      if count2='1' then spks<='1';
      else spks<='0';
      end if;
   end if;
end process; 
end;