LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
ENTITY ToneTaba IS
PORT ( Index : IN STD_LOGIC_VECTOR (3 DOWNTO 0) ;
CODE : OUT STD_LOGIC_VECTOR (3 DOWNTO 0) ;
HIGH : OUT STD_LOGIC;
Tone : OUT STD_LOGIC_VECTOR (10 DOWNTO 0) );
END;
ARCHITECTURE one OF ToneTaba IS
BEGIN
Search : PROCESS(Index)
BEGIN
CASE Index IS -- 譯碼電路，查表方式，控制音調的預置數
WHEN "0000" => Tone<="11111111111" ; CODE<="0000"; HIGH <='0';-- 2047
WHEN "0001" => Tone<="01100000101" ; CODE<="0001"; HIGH <='0';-- 773;
WHEN "0010" => Tone<="01110010000" ; CODE<="0010"; HIGH <='0';-- 912;
WHEN "0011" => Tone<="10000001100" ; CODE<="0011"; HIGH <='0';--1036;
WHEN "0101" => Tone<="10010101101" ; CODE<="0101"; HIGH <='0';--1197;
WHEN "0110" => Tone<="10100001010" ; CODE<="0110"; HIGH <='0';--1290;
WHEN "0111" => Tone<="10101011100" ; CODE<="0111"; HIGH <='0';--1372;
WHEN "1000" => Tone<="10110000010" ; CODE<="0001"; HIGH <='1';--1410;
WHEN "1001" => Tone<="10111001000" ; CODE<="0010"; HIGH <='1';--1480;
WHEN "1010" => Tone<="11000000110" ; CODE<="0011"; HIGH <='1';--1542;
WHEN "1100" => Tone<="11001010110" ; CODE<="0101"; HIGH <='1';--1622;
WHEN "1101" => Tone<="11010000100" ; CODE<="0110"; HIGH <='1';--1668;
WHEN "1111" => Tone<="11011000000" ; CODE<="0001"; HIGH <='1';--1728;
WHEN OTHERS => NULL;
END CASE;
END PROCESS;
END;