music_freq.vhd

利用VHDL编写的电子琴发生器

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY  MUSIC_FREQ IS
    PORT ( Index :  IN STD_LOGIC_VECTOR(6 DOWNTO 0);
           HOLD_SW  :  IN STD_LOGIC; 
           MUSIC_CODE  : OUT INTEGER RANGE 0 TO 15;
           SW_DISP  : OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
           TONE_HL  : OUT STD_LOGIC; 
           MUSIC_FREQ_OUT  : OUT INTEGER RANGE 0 TO 16#7FF#  );
END;
ARCHITECTURE a OF MUSIC_FREQ IS
   SIGNAL HOLD_SW_TEMP :  STD_LOGIC_VECTOR(1 DOWNTO 0);
BEGIN
   first: PROCESS(HOLD_SW)
     BEGIN
        IF HOLD_SW'EVENT AND HOLD_SW = '1' THEN      HOLD_SW_TEMP <= HOLD_SW_TEMP + 1;   
                  END IF;
          SW_DISP <= '0'&'0'& HOLD_SW_TEMP; 
   END PROCESS first;     
    second : PROCESS(Index)
    BEGIN
        IF HOLD_SW_TEMP = "00" THEN
        CASE Index IS       -- 译码电路，查表方式，控制音调的预置数
            WHEN "0000001"  => MUSIC_FREQ_OUT <= 773;  MUSIC_CODE <= 1; TONE_HL <= '0';  
            WHEN "0000010"  => MUSIC_FREQ_OUT <= 912;  MUSIC_CODE <= 2; TONE_HL <= '0';  
            WHEN "0000100"  => MUSIC_FREQ_OUT <= 1036; MUSIC_CODE <= 3; TONE_HL <= '0'; 
            WHEN "0001000"  => MUSIC_FREQ_OUT <= 1116; MUSIC_CODE <= 4; TONE_HL <= '0'; 
            WHEN "0010000"  => MUSIC_FREQ_OUT <= 1197; MUSIC_CODE <= 5; TONE_HL <= '0';  
            WHEN "0100000"  => MUSIC_FREQ_OUT <= 1290; MUSIC_CODE <= 6; TONE_HL <= '0';  
            WHEN "1000000"  => MUSIC_FREQ_OUT <= 1372; MUSIC_CODE <= 7; TONE_HL <= '0';  
            WHEN   OTHERS   => MUSIC_FREQ_OUT <= 2047; MUSIC_CODE <= 0; TONE_HL <= '0';  
        END CASE;
        ELSIF HOLD_SW_TEMP = "01" THEN
        CASE Index IS       -- 译码电路，查表方式，控制音调的预置数
            WHEN "0000001"  => MUSIC_FREQ_OUT <= 1410;  MUSIC_CODE <= 1; TONE_HL <= '1';  
            WHEN "0000010"  => MUSIC_FREQ_OUT <= 1490;  MUSIC_CODE <= 2; TONE_HL <= '1'; 
            WHEN "0000100"  => MUSIC_FREQ_OUT <= 1560;  MUSIC_CODE <= 3; TONE_HL <= '1'; 
            WHEN "0001000"  => MUSIC_FREQ_OUT <= 1600;  MUSIC_CODE <= 4; TONE_HL <= '1';  
            WHEN "0010000"  => MUSIC_FREQ_OUT <= 1622;  MUSIC_CODE <= 5; TONE_HL <= '1';  
            WHEN "0100000"  => MUSIC_FREQ_OUT <= 1650;  MUSIC_CODE <= 6; TONE_HL <= '1';  
            WHEN "1000000"  => MUSIC_FREQ_OUT <= 1690;  MUSIC_CODE <= 7; TONE_HL <= '1';  
            WHEN   OTHERS   => MUSIC_FREQ_OUT <= 2047;  MUSIC_CODE <= 0; TONE_HL <= '1'; 
        END CASE;
       ELSIF HOLD_SW_TEMP = "10" THEN
        CASE Index IS       -- 译码电路，查表方式，控制音调的预置数
            WHEN "0000001"  => MUSIC_FREQ_OUT <= 1730;  MUSIC_CODE <= 1; TONE_HL <= '1'; 
            WHEN "0000010"  => MUSIC_FREQ_OUT <= 1750;  MUSIC_CODE <= 2; TONE_HL <= '1'; 
            WHEN "0000100"  => MUSIC_FREQ_OUT <= 1770;  MUSIC_CODE <= 3; TONE_HL <= '1'; 
            WHEN "0001000"  => MUSIC_FREQ_OUT <= 1790;  MUSIC_CODE <= 4; TONE_HL <= '1';  
            WHEN "0010000"  => MUSIC_FREQ_OUT <= 1815;  MUSIC_CODE <= 5; TONE_HL <= '1';  
            WHEN "0100000"  => MUSIC_FREQ_OUT <= 1830;  MUSIC_CODE <= 6; TONE_HL <= '1';  
            WHEN "1000000"  => MUSIC_FREQ_OUT <= 1930;  MUSIC_CODE <= 7; TONE_HL <= '1';  
            WHEN   OTHERS   => MUSIC_FREQ_OUT <= 2047;  MUSIC_CODE <= 0; TONE_HL <= '1'; 
        END CASE;

        ELSE
            CASE Index IS       -- 译码电路，查表方式，控制音调的预置数
            WHEN "0000001"  => MUSIC_FREQ_OUT <= 100;  MUSIC_CODE <= 1; TONE_HL <= '1';  
            WHEN "0000010"  => MUSIC_FREQ_OUT <= 200;  MUSIC_CODE <= 2; TONE_HL <= '1'; 
            WHEN "0000100"  => MUSIC_FREQ_OUT <= 300;  MUSIC_CODE <= 3; TONE_HL <= '1'; 
            WHEN "0001000"  => MUSIC_FREQ_OUT <= 400;  MUSIC_CODE <= 4; TONE_HL <= '1';  
            WHEN "0010000"  => MUSIC_FREQ_OUT <= 500;  MUSIC_CODE <= 5; TONE_HL <= '1';  
            WHEN "0100000"  => MUSIC_FREQ_OUT <= 600;  MUSIC_CODE <= 6; TONE_HL <= '1';  
            WHEN "1000000"  => MUSIC_FREQ_OUT <= 700;  MUSIC_CODE <= 7; TONE_HL <= '1';  
            WHEN   OTHERS   => MUSIC_FREQ_OUT <= 2047; MUSIC_CODE <= 0; TONE_HL <= '1'; 
        END CASE;
      END IF;
    END PROCESS second;
END a;