tonetaba.vhd

基于ALTERA CYCLONE 系列的音乐播放示例实验教程.

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
ENTITY ToneTaba IS
    PORT ( Index :  IN INTEGER RANGE 0 TO 31 ;
           CODE  : OUT INTEGER RANGE 0 TO 15 ;
           HIGH  : OUT STD_LOGIC; 
           Tone  : OUT INTEGER RANGE 0 TO 16#7FF#  );
END;
ARCHITECTURE one OF ToneTaba IS
BEGIN
    Search : PROCESS(Index)
    BEGIN
        CASE Index IS              -- 译码电路，查表方式，控制音调的预
            WHEN 0  => Tone <= 2047; CODE <= 0; HIGH <= '0';  

            WHEN 1  => Tone <= 773;  CODE <= 1; HIGH <= '0';  
            WHEN 2  => Tone <= 912;  CODE <= 2; HIGH <= '0';
            WHEN 3  => Tone <= 1036; CODE <= 3; HIGH <= '0';  
            WHEN 4  => Tone <= 1116; CODE <= 4; HIGH <= '0'; 
            WHEN 5  => Tone <= 1197; CODE <= 5; HIGH <= '0';  
            WHEN 6  => Tone <= 1290; CODE <= 6; HIGH <= '0';  
            WHEN 7  => Tone <= 1372; CODE <= 7; HIGH <= '0'; 
 
            WHEN 8  => Tone <= 1410; CODE <= 1; HIGH <= '1';  
            WHEN 9  => Tone <= 1480; CODE <= 2; HIGH <= '1';  
            WHEN 10 => Tone <= 1542; CODE <= 3; HIGH <= '1';  
            WHEN 11 => Tone <= 1600; CODE <= 4; HIGH <= '1';  
            WHEN 12 => Tone <= 1622; CODE <= 5; HIGH <= '1';  
            WHEN 13 => Tone <= 1668; CODE <= 6; HIGH <= '1';  
            WHEN 14 => Tone <= 1690; CODE <= 7; HIGH <= '1';  

            WHEN 15 => Tone <= 1730;  CODE <= 1; HIGH <= '1'; 
            WHEN 16 => Tone <= 1750;  CODE <= 2; HIGH <= '1'; 
            WHEN 17 => Tone <= 1770;  CODE <= 3; HIGH <= '1'; 
            WHEN 18 => Tone <= 1790;  CODE <= 4; HIGH <= '1';  
            WHEN 19 => Tone <= 1815;  CODE <= 5; HIGH <= '1';  
            WHEN 20 => Tone <= 1830;  CODE <= 6; HIGH <= '1';  
            WHEN 21 => Tone <= 1930;  CODE <= 7; HIGH <= '1';  
  
            WHEN 22 => Tone <= 100;  CODE <= 1; HIGH <= '1';  
            WHEN 23 => Tone <= 200;  CODE <= 2; HIGH <= '1'; 
            WHEN 24 => Tone <= 300;  CODE <= 3; HIGH <= '1'; 
            WHEN 25 => Tone <= 400;  CODE <= 4; HIGH <= '1';  
            WHEN 26 => Tone <= 500;  CODE <= 5; HIGH <= '1';  
            WHEN 27 => Tone <= 600;  CODE <= 6; HIGH <= '1';  
            WHEN 28 => Tone <= 700;  CODE <= 7; HIGH <= '1';  
            WHEN OTHERS => NULL;
        END CASE;
    END PROCESS;
END;