music_player.vhd

用vhdl实现的电子琴中的音乐播放模块

--Music Player
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity Music_Player is
	port(clk_2MHz : in std_logic;
		scale : in integer range 0 to 21;	--a rest and musical scale from low 1 to high 7
		tune : out std_logic);				--output the tune of the music
end Music_Player;

architecture rtl of Music_Player is
signal count : integer range 0 to 3822 :=0;
signal flag,feq: std_logic;

begin
	process(clk_2MHz,scale)
	begin
		if clk_2MHz'event and clk_2MHz='1' then
			if scale=0 then flag<='0';				--rest
			else
				count<=count+1;
				if scale=1 then						--low 1
					if count<3822 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=2 then					--low 2
					if count<3405 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=3 then					--low 3
					if count<3034 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=4 then					--low 4
					if count<2863 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=5 then					--low 5
					if count<2551 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=6 then					--low 6
					if count<2273 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=7 then					--low 7
					if count<2025 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=8 then					--middle 1
					if count<1911 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=9 then					--middle 2
					if count<1703 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=10 then					--middle 3
					if count<1517 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=11 then					--middle 4
					if count<1432 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=12 then					--middle 5
					if count<1276 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=13 then					--middle 6
					if count<1136 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=14 then					--middle 7
					if count<1012 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=15 then					--high 1
					if count<956 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=16 then					--high 2
					if count<851 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=17 then					--high 3
					if count<758 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=18 then					--high 4
					if count<716 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=19 then					--high 5
					if count<638 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				elsif scale=20 then					--high 6
					if count<568 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				else								--high 7
					if count<506 then flag<='0';
					else flag<='1'; count<=0;
					end if;
				end if;
			end if;
		end if;
	end process;
	
	process(flag)
	begin
		if flag'event and flag='1' then
			feq<=not feq;				--freqency of the audio
		end if;
		tune<=feq;
	end process;
end rtl;