music_rom_stop.vhd

这是一个在Quartus II软件中编写的vhdl程序。程序下载后可用蜂鸣器播放音乐

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity music_rom_stop is
port(clk:in std_logic;
  index:out std_logic_vector(3 downto 0));
end entity;

architecture bhv of music_rom_stop is
component data_rom 
  port( address		: IN STD_LOGIC_VECTOR (8 DOWNTO 0);
		clock		: IN STD_LOGIC ;
		q		    : OUT STD_LOGIC_VECTOR (3 DOWNTO 0)	);
end component;
--subtype word is integer range 0 to 15;
--type memory is array(0 to 523)of word;
--signal rom: memory;
signal clk_cnt: integer range 0 to 333;
signal clk_4hz:std_logic;
signal adr:integer range 0 to 270;
signal adr1:std_logic_vector(8 downto 0);
begin

divide:process(clk)
begin
 if(clk'event and clk='1')then
  if clk_cnt=333 then clk_cnt<=0;clk_4hz<='1';
  else clk_cnt<=clk_cnt+1;clk_4hz<='0';
  end if;
 end if;
end process;

cnt:process(clk_4hz)
begin
  if adr=270 then adr<=0;
  else 
     if(clk_4hz'event and clk_4hz='1')then 
       adr<=adr+1;
     end if;  
  end if;
end process;
adr1<=conv_std_logic_vector(adr,9);  
               
u1:data_rom port map (address=>adr1,q=>index,clock=>clk_4hz);

end;