library IEEE;			   ----利用DP-FPGA與精電蓬遠液晶MDLS16265B測試	
use IEEE.STD_LOGIC_1164.ALL;	   --顯示magic!
use IEEE.STD_LOGIC_ARITH.ALL;      --與上面程序功能相同，但顯示速度很快，基本看不清光標的閃爍移位
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity lcd_display is
    generic(N:integer:=25000;
            delay:integer:=1);     --改了此延時，造成該情況發生！

Port ( clk : in std_logic;     
       reset:in std_logic;      --定義一個拔盤
       lcdda : out std_logic;	  
       lcdrw : out std_logic;	  
       lcden : out std_logic;	  
       test :  out  std_logic_vector(7 downto 0)  
	  );    
end lcd_display;
architecture Behavioral of lcd_display is 
type state is (set_dlnf,clear_lcd,set_cursor,set_dcb,set_location,write_data);
signal current_state:state;
type rom is array(0 to 5) of std_logic_vector(7 downto 0);
constant datarom:rom:=(("01001101"),("01000001"),("01000111"),("01001001"),("01000011"),("00100001"));
signal clkk:std_logic;
signal data : std_logic_vector(7 downto 0);

begin
divider:process(clk,reset) 		 	--分頻為1000HZ為1ms
variable cnt:integer range 0 to 100000;
  begin
    if reset='1'then cnt:=0;clkk<='0';
    elsif rising_edge(clk) then
	    cnt:=cnt+1;
	 if cnt=N then clkk<='1';		 --N=25000
	 elsif cnt=2*N then cnt:=0;clkk<='0';
	 end if;
    end if;
 end process divider;

control:process(clkk,reset,current_state)
	variable cntt,cnt2:integer;
	begin
	if reset='1'then		--復位信號初始化
 	   current_state<=set_dlnf;
	            cntt:=0;
	            cnt2:=0;
	elsif rising_edge(clkk)then
	            test<=data;	--顯示
       case current_state is
	    when set_dlnf=>	    --功能設置
	         lcden<='0';
	         lcdda<='0';
	         lcdrw<='0';
	         data<="00111100";	         
	      if cntt=delay and cntt<delay*2 then   --delay=100 延時100ms
		    lcden<='1';cntt:=cntt+1;	                
		 else 
		    lcden<='0';cntt:=cntt+1;   
	      end if;
	      if cntt=delay*2 then
	         current_state<=clear_lcd;
	         cntt:=0;
	      end if;
         when clear_lcd=>  --清屏幕
	         lcden<='0';       
		    lcdda<='0';
		    lcdrw<='0';
		    data<="00000011";		    
            if cntt=delay and cntt<delay*2 then   --delay=100 延時100ms
		    lcden<='1';cntt:=cntt+1;	                
		 else 
		    lcden<='0';cntt:=cntt+1;   
	      end if;
	      if cntt=delay*2 then
	         current_state<=set_cursor;
	         cntt:=0;
	      end if;
         when set_cursor=>   --顯示開關設置
	         lcden<='0';	
		    lcdda<='0';
		    lcdrw<='0';
		    data<="00000010";		    
           if cntt=delay and cntt<delay*2 then   --delay=100 延時100ms
		    lcden<='1';cntt:=cntt+1;	                
		 else 
		    lcden<='0';cntt:=cntt+1;   
	      end if;
	      if cntt=delay*2 then
	         current_state<=set_dcb;
	         cntt:=0;
	      end if;
         when set_dcb=>	   --輸入方式設置
              lcden<='0';
		    lcdda<='0';
		    lcdrw<='0';
		    data<="00001101";		    
            if cntt=delay and cntt<delay*2 then   --delay=100 延時100ms
		    lcden<='1';cntt:=cntt+1;	                
		 else 
		    lcden<='0';cntt:=cntt+1;   
	      end if;
	      if cntt=delay*2 then
	         current_state<=set_location;
	         cntt:=0;
	      end if;
	    when set_location=>	 --ddram設置
	         lcden<='0';
              lcdda<='0';
		    lcdrw<='0';
              data<="10000000";	         
	      if cntt=delay and cntt<delay*2 then   --delay=100 延時100ms
		    lcden<='1';cntt:=cntt+1;	                
		 else 
		    lcden<='0';cntt:=cntt+1;   
	      end if;
	      if cntt=delay*2 then
	         current_state<=write_data;
	         cntt:=0;
	      end if;
         when write_data=>   --寫數據
	         lcden<='0';
		    lcdda<='1';
		    lcdrw<='0';
		 if cnt2<=5 then
		    data<=datarom(cnt2);
		 if cntt=delay and cntt<delay*2 then   --delay=100 延時100ms
		    lcden<='1';cntt:=cntt+1;	                
		 else 
		    lcden<='0';cntt:=cntt+1;   
	         end if;
	         if cntt=delay*2 then
		       current_state<=write_data;
                 cntt:=0;
		       cnt2:=cnt2+1;
		    end if;
		  else
		    cnt2:=0;
		    current_state<=set_dlnf;
		  end if;
     end case;
 end if;
end process;
end Behavioral;