tone_rom.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

--tone_rom
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity tone_rom_CtoG is
port (index: in std_logic_vector(3 downto 0);
       code: out std_logic_vector(3 downto 0);
       high: out std_logic_vector(3 downto 0);
       tone: out std_logic_vector(10 downto 0));
end;

architecture one of tone_rom_CtoG is
signal index1:integer range 0 to 15;
signal tone1: integer range 0 to 16#7ff#;
signal code1: integer range 0 to 15;
begin 
   index1<=conv_integer(index);
   tone<=conv_std_logic_vector(tone1,11);
   code<=conv_std_logic_vector(code1,4);
  search:process(index)
  begin 
    case index1 is
      when 0=>tone1<=2047;  code1<=0; high<="0000"; 
      when 1=>tone1<=773;   code1<=1; high<="0000";  
      when 2=>tone1<=912;   code1<=2; high<="0000"; 
      when 3=>tone1<=1036;  code1<=3; high<="0000";  
      when 4=>tone1<=1092;  code1<=4; high<="0000"; 
      when 5=>tone1<=1197;  code1<=5; high<="0000";  
      when 6=>tone1<=1290;  code1<=6; high<="0000"; 
      when 7=>tone1<=1372;  code1<=7; high<="0000";  
      when 8=>tone1<=1372;  code1<=1; high<="0001"; 
      when 9=>tone1<=1410;  code1<=2; high<="0001";  
      when 10=>tone1<=1480; code1<=3; high<="0001"; 
      when 11=>tone1<=1542; code1<=4; high<="0001";  
      when 12=>tone1<=1570; code1<=5; high<="0001"; 
      when 13=>tone1<=1622; code1<=6; high<="0001";  
      when 14=>tone1<=1669; code1<=7; high<="0001"; 
      when 15=>tone1<=1710; code1<=1; high<="0010";  
      when others => null;
   end case;
  end process;
end one;