lcd_driver.vhd

this is a LCD Driver VHDL code

library IEEE; 
use IEEE.STD_LOGIC_1164.ALL; 
use IEEE.STD_LOGIC_ARITH.ALL; 
use IEEE.STD_LOGIC_UNSIGNED.ALL; 

entity LCD_Driver is 

port( 
		clock		 			: 	IN 		std_logic; 
		RS 					: 	OUT 		std_logic;
		RW 					: 	OUT 		std_logic;
		EN 					:	OUT 		std_logic;
		Exceed_Speed		:	in			std_logic;
		New_Data				:	in			std_logic;
		Write_complete		:	OUT		std_logic;
		
		Speed_digit1		:	IN			std_logic_vector(7 downto 0);
		Speed_digit2		:	IN			std_logic_vector(7 downto 0);
		Speed_digit3		:	IN			std_logic_vector(7 downto 0);
			
		Range_digit1		:	IN			std_logic_vector(7 downto 0);
		Range_digit2		:	IN			std_logic_vector(7 downto 0);
		Range_digit3		:	IN			std_logic_vector(7 downto 0);
		
		DATA 					:	OUT 		std_logic_vector(3 downto 0)
    ); 

end LCD_Driver; 
	
architecture Behavioral of LCD_Driver is 

		signal substate,counter,Cursor: integer:=0; 
		signal state: integer:=0; 
		signal nhdata_Int			:std_logic_vector(3 downto 0)		:="0000" ;
		signal nldata_Int			:std_logic_vector(3 downto 0)		:="0000" ;
		signal Write_TO_LCD		:std_logic								:='0';	
		signal LCD_Init_done		:std_logic								:='0';	
		signal instruct_to_lcd	:std_logic								:='0';	
		signal New_Data_Previous:std_logic								:='0';	
		signal Clear_LCD			:std_logic								:='0';	

begin 

process(Clock) 
begin 


if(rising_edge(Clock)) then 
      counter<=counter+1; 
      --WAIT FOR 750000 counter ---<POWER ON>--<Wait at least 15ms>
      if(state=0 and counter=750000) then 
            state<=1; 
            counter<=0; 
      --WRITE DATA=0X3 FOR INIATION 
      elsif(state=1) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0000"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="0011"; 
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=2; 
                counter<=0; 
         end if; 
      --WAIT FOR 2050000 counter --<Wait at least 4.1ms>
      elsif(state=2 and counter=205000) then 
            state<=3; 
            counter<=0; 
      --WRITE DATA=0X3 FOR INIATION 
      elsif(state=3) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0000"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="0011"; 
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=4; 
                counter<=0; 
         end if; 
      --WAIT 5000 counter --<Wait at least 100us>
      elsif(state=4 and counter=5000) then 
            state<=5; 
            counter<=0; 
      --WRITE 0X3 FOR INITIATION 
      elsif(state=5) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0000"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="0011"; 
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=6; 
                counter<=0; 
         end if; 
     --WAIT FOR 2050000 counter --<Wait at least 4.1ms>
      elsif(state=6 and counter=205000) then --2050000
            state<=7; 
            counter<=0; 
      --WRITE DATA=0X2 FOR INITIATION       
      elsif(state=7) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0000"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="0010"; 
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=8; 
                counter<=0; 
         end if; 
      --WAIT 2000 counter <Wait 40us>
      elsif(state=8 and counter=2000) then 
            state<=9; 
            counter<=0; 
      --WRITE FUNCTION SET SD_F = 0X28 ;Function Set Command
      elsif(state=9) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0010"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="1000"; --for 5x8 dot matrix--1/16 duty cycle -- 2 `lines'
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=10; --10
                counter<=0; 
         end if; 
      --WAIT 2000 counter <Wait 40us>-- this must go to state 17
      elsif(state=10 and counter=2000) then 
            state<=11; 
            counter<=0; 
      --WRITE ENTRY SET DATA = 0X06 
      elsif(state=11) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0000"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="0110"; --;;Inc cursor to the right when writing  ; and don?t shift screen
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=12; 
                counter<=0; 
         end if; 
      --WAIT 2000 counter 
      elsif(state=12 and counter=2000) then 
            state<=13; 
            counter<=0; 
      --WRITE DISPLAY ON /OFF SD_F=0X0C 
      elsif(state=13) then 
         if(substate=0 and counter=0) then 
                RS<='0'; 
                RW<='0'; 
                DATA<="0000"; 
                counter<=0; 
                substate<=1; 
         elsif(substate=1 and counter=2) then 
                EN<='1'; 
                counter<=0; 
                substate<=2; 
         elsif(substate=2 and counter=12) then 
                EN<='0'; 
                substate<=3; 
                counter<=0; 
         elsif(substate=3 and counter=48) then 
                DATA<="1100"; ---care in this case Display on, Cursor off, Blink off
                counter<=0; 
                substate<=4; 
         elsif(substate=4 and counter=2) then 
                EN<='1';    
                counter<=0; 
                substate<=5; 
         elsif(substate=5 and counter=12) then 
                EN<='0'; 
                substate<=0; 
                state<=14; 
                counter<=0; 
         end if; 
      --WAIT 2000 counter 
      elsif(state=14 and counter=2000) then 
            LCD_Init_done<='1';