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📄 vhdl—lcd.txt

📁 基于FPGA的lcd的驱动程序
💻 TXT
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;



entity lcd is
    Port ( clk : in std_logic;				 
           reset : in std_logic;
           lcd_rs : out std_logic;
           lcd_rw : out std_logic;
		   lcd_e  : buffer std_logic;
		   data : out std_logic_vector(7 downto 0)
		 --  stateout: out std_logic_vector(10 downto 0);
		 );
end lcd;


architecture Behavioral of lcd is

constant IDLE :         std_logic_vector(10 downto 0) :="00000000000";
constant CLEAR :        std_logic_vector(10 downto 0) :="00000000001";
constant RETURNCURSOR : std_logic_vector(10 downto 0) :="00000000010" ;
constant SETMODE      : std_logic_vector(10 downto 0) :="00000000100";
constant SWITCHMODE   : std_logic_vector(10 downto 0) :="00000001000";
constant SHIFT        : std_logic_vector(10 downto 0) :="00000010000";
constant SETFUNCTION  : std_logic_vector(10 downto 0) :="00000100000";
constant SETCGRAM     : std_logic_vector(10 downto 0) :="00001000000";
constant SETDDRAM     : std_logic_vector(10 downto 0) :="00010000000";
constant READFLAG     : std_logic_vector(10 downto 0) :="00100000000";
constant WRITERAM     : std_logic_vector(10 downto 0) :="01000000000";
constant READRAM      : std_logic_vector(10 downto 0) :="10000000000";




constant cur_inc      : std_logic :='1';
constant cur_dec      : std_logic :='0';
constant cur_shift    : std_logic :='1';
constant cur_noshift  : std_logic :='0';
constant open_display : std_logic :='1';
constant open_cur     : std_logic :='0';
constant blank_cur    : std_logic :='0';
constant shift_display : std_logic :='1';
constant shift_cur    : std_logic :='0';
constant right_shift  : std_logic :='1';
constant left_shift   : std_logic :='0';
constant datawidth8   : std_logic :='1';
constant datawidth4   : std_logic :='0';
constant twoline      : std_logic :='1';
constant oneline      : std_logic :='0';
constant font5x10     : std_logic :='1';
constant font5x7      : std_logic :='0';

signal state : std_logic_vector(10 downto 0);
signal counter : integer range 0 to 127;
signal div_counter : integer range 0 to 15;
signal flag        : std_logic;
constant DIVSS : integer :=15;

signal char_addr : std_logic_vector(5 downto 0);
signal data_in   : std_logic_vector(7 downto 0);
component char_ram
          port( address : in std_logic_vector(5 downto 0) ;
	             data    : out std_logic_vector(7 downto 0)
		         );
end component;


signal clk_int: std_logic;

signal clkcnt: std_logic_vector(20 downto 0);
constant divcnt: std_logic_vector(20 downto 0):="010001001110001000000";--"100001111010001000111";--"100001001110001000000";16'b1001_1100_0100_0000
signal clkdiv: std_logic;
signal tc_clkcnt: std_logic;
begin

process(clk,reset)
begin
  if(reset='0')then
  clkcnt<="000000000000000000000";
  elsif(clk'event and clk='1')then
     if(clkcnt=divcnt)then
     clkcnt<="000000000000000000000";
     else
     clkcnt<=clkcnt+1;
     end if;
  end if;
end process;
tc_clkcnt<='1' when clkcnt=divcnt else
           '0';

process(tc_clkcnt,reset)
begin
   if(reset='0')then
   clkdiv<='0';
   elsif(tc_clkcnt'event and tc_clkcnt='1')then
   clkdiv<=not clkdiv;
   end if;
end process;






process(clkdiv,reset)
begin
  if(reset='0')then
    clk_int<='0';
  elsif(clkdiv'event and clkdiv='1')then
    clk_int<= not clk_int;
  end if;
end process;

process(clkdiv,reset)
begin
   if(reset='0')then
     lcd_e<='0';
   elsif(clkdiv'event and clkdiv='0')then
     lcd_e<= not lcd_e;
   end if;
end process;

aa:char_ram
   port map( address=>char_addr,data=>data_in);

    lcd_rs <= '1' when state =WRITERAM or state = READRAM else '0';
	lcd_rw <= '0' when state =CLEAR or state = RETURNCURSOR or state=SETMODE or state=SWITCHMODE or state=SHIFT or state= SETFUNCTION or state=SETCGRAM or state =SETDDRAM or state =WRITERAM else
	          '1';
     data <= "00000001" when state =CLEAR else
	         "00000010" when state =RETURNCURSOR else
			 "000001"& cur_inc & cur_noshift  when state = SETMODE else
			 "00001" & open_display &open_cur & blank_cur when state =SWITCHMODE else
			 "0001" & shift_display &left_shift &"00" when state = SHIFT else
			 "001" & datawidth8 & twoline &font5x10 & "00" when state=SETFUNCTION else
			 "01000000" when state =SETCGRAM else
			 "10000000" when state =SETDDRAM and counter =0 else
			 "11000000" when state =SETDDRAM and counter /=0 else
			  data_in when state = WRITERAM else
			 "ZZZZZZZZ";

   char_addr  <=conv_std_logic_vector( counter,6) when state =WRITERAM and counter<40 else
	            conv_std_logic_vector( counter-41+8,6) when state= WRITERAM and counter>40 and counter<81-8 else
			    conv_std_logic_vector( counter-81+8,6) when state= WRITERAM and counter>81-8 and counter<81 else
				"000000";
						
						
  
  process(clk_int,Reset)
  begin
      if(Reset='0')then 
		   state<=IDLE;
		   counter<=0;
		   flag<='0';
           div_counter<=0;
      elsif(clk_int'event and clk_int='1')then 
		   case state is
			when IDLE =>
			        if(flag='0')then 
						     state<=SETFUNCTION;
							 flag<='1';
							 counter<=0;
							 div_counter<=0;
                    else
						 if(div_counter<DIVSS )then
							 div_counter<=div_counter +1;
                             state<=IDLE;
                         else
							 div_counter<=0;
							 state <=SHIFT;
                         end if;
                    end if;
         when CLEAR    =>
			           state<=SETMODE;
         when SETMODE  =>
			           state<=WRITERAM;
         when RETURNCURSOR =>
			           state<=WRITERAM;
         when SWITCHMODE =>
			           state<=CLEAR;
         when SHIFT      =>
			           state<=IDLE;
         when SETFUNCTION =>
			           state<=SWITCHMODE;
         when SETCGRAM   =>
			           state<=IDLE;
         when SETDDRAM   =>
			           state<=WRITERAM;
         when READFLAG   =>
			           state<=IDLE;
         when WRITERAM   =>
			           if(counter =40)then 
						     state<=SETDDRAM;
							 counter<=counter+1;
                        elsif(counter/=40 and counter<81)then
						     state<=WRITERAM;
							 counter<=counter+1;
                        else
						    state<=SHIFT;
                    end if;
         when READRAM =>
			           state<=IDLE;
         when others  =>
			           state<=IDLE;
         end case;
    end if;
  end process;

  
end Behavioral;




































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

entity char_ram is
port( address : in std_logic_vector(5 downto 0) ;
		data    : out std_logic_vector(7 downto 0)
		);
end char_ram;

architecture fun of char_ram is

function char_to_integer ( indata :character) return integer is
variable result : integer range 0 to 16#7F#;
begin
	case indata is
	when ' ' =>		result := 32;
	when '!' =>		result := 33;
	when '"' =>		result := 34;
	when '#' =>		result := 35;
	when '$' =>		result := 36;
	when '%' =>		result := 37;
	when '&' =>		result := 38;
	when ''' =>		result := 39;
	when '(' =>		result := 40;
	when ')' =>		result := 41;
	when '*' =>		result := 42;
	when '+' =>		result := 43;
	when ',' =>		result := 44;
	when '-' =>		result := 45;
	when '.' =>		result := 46;
	when '/' =>		result := 47;
	when '0' =>		result := 48;
	when '1' =>		result := 49;
	when '2' =>		result := 50;
	when '3' =>		result := 51;
	when '4' =>		result := 52;
	when '5' =>		result := 53;
	when '6' =>		result := 54;
	when '7' =>		result := 55;
	when '8' =>		result := 56;
	when '9' =>		result := 57;
	when ':' =>		result := 58;
	when ';' =>		result := 59;
	when '<' =>		result := 60;
	when '=' =>		result := 61;
	when '>' =>		result := 62;
	when '?' =>		result := 63;
	when '@' =>		result := 64;
	when 'A' =>		result := 65;
	when 'B' =>		result := 66;
	when 'C' =>		result := 67;
	when 'D' =>		result := 68;
	when 'E' =>		result := 69;
	when 'F' =>		result := 70;
	when 'G' =>		result := 71;
	when 'H' =>		result := 72;
	when 'I' =>		result := 73;
	when 'J' =>		result := 74;
	when 'K' =>		result := 75;
	when 'L' =>		result := 76;
	when 'M' =>		result := 77;
	when 'N' =>		result := 78;
	when 'O' =>		result := 79;
	when 'P' =>		result := 80;
	when 'Q' =>		result := 81;
	when 'R' =>		result := 82;
	when 'S' =>		result := 83;
	when 'T' =>		result := 84;
	when 'U' =>		result := 85;
	when 'V' =>		result := 86;
	when 'W' =>		result := 87;
	when 'X' =>		result := 88;
	when 'Y' =>		result := 89;
	when 'Z' =>		result := 90;
	when '[' =>		result := 91;
	when '\' =>		result := 92;
	when ']' =>		result := 93;
	when '^' =>		result := 94;
	when '_' =>		result := 95;
	when '`' =>		result := 96;
	when 'a' =>		result := 97;
	when 'b' =>		result := 98;
	when 'c' =>		result := 99;
	when 'd' =>		result := 100;
	when 'e' =>		result := 101;
	when 'f' =>		result := 102;
	when 'g' =>		result := 103;
	when 'h' =>		result := 104;
	when 'i' =>		result := 105;
	when 'j' =>		result := 106;
	when 'k' =>		result := 107;
	when 'l' =>		result := 108;
	when 'm' =>		result := 109;
	when 'n' =>		result := 110;
	when 'o' =>		result := 111;
	when 'p' =>		result := 112;
	when 'q' =>		result := 113;
	when 'r' =>		result := 114;
	when 's' =>		result := 115;
	when 't' =>		result := 116;
	when 'u' =>		result := 117;
	when 'v' =>		result := 118;
	when 'w' =>		result := 119;
	when 'x' =>		result := 120;
	when 'y' =>		result := 121;
	when 'z' =>		result := 122;
	when '{' =>		result := 123;
	when '|' =>		result := 124;
	when '}' =>		result := 125;
	when '~' =>		result := 126;
	when	others => result :=32;
	end case;
	return result;
end function;

begin 
process (address)
begin
	case address is
	when "000000" =>data<=conv_std_logic_vector(char_to_integer ('W') ,8);
	when "000001" =>data<=conv_std_logic_vector(char_to_integer ('e') ,8);
	when "000010" =>data<=conv_std_logic_vector(char_to_integer ('l') ,8);
	when "000011" =>data<=conv_std_logic_vector(char_to_integer ('e') ,8);
	when "000100" =>data<=conv_std_logic_vector(char_to_integer ('c') ,8);
	when "000101" =>data<=conv_std_logic_vector(char_to_integer ('o') ,8);
	when "000110" =>data<=conv_std_logic_vector(char_to_integer ('m') ,8);
	when "000111" =>data<=conv_std_logic_vector(char_to_integer ('e') ,8);
	when "001000" =>data<=conv_std_logic_vector(char_to_integer (' ') ,8);
	when "001001" =>data<=conv_std_logic_vector(char_to_integer ('t') ,8);
	when "001010" =>data<=conv_std_logic_vector(char_to_integer ('o') ,8);
	when "001011" =>data<=conv_std_logic_vector(char_to_integer (' ') ,8);
	when "001100" =>data<=conv_std_logic_vector(char_to_integer ('2') ,8);
	when "001101" =>data<=conv_std_logic_vector(char_to_integer ('1') ,8);
	when "001110" =>data<=conv_std_logic_vector(char_to_integer ('c') ,8);
	when "001111" =>data<=conv_std_logic_vector(char_to_integer ('o') ,8);
	when "010000" =>data<=conv_std_logic_vector(char_to_integer ('n') ,8);
	when "010001" =>data<=conv_std_logic_vector(char_to_integer ('t') ,8);
	when "010010" =>data<=conv_std_logic_vector(char_to_integer ('r') ,8);
	when "010011" =>data<=conv_std_logic_vector(char_to_integer ('o') ,8);
	when "010100" =>data<=conv_std_logic_vector(char_to_integer ('l') ,8);
	when "010101" =>data<=conv_std_logic_vector(char_to_integer ('.') ,8);
	when "010110" =>data<=conv_std_logic_vector(char_to_integer ('c') ,8);
	when "010111" =>data<=conv_std_logic_vector(char_to_integer ('o') ,8);
	when "011000" =>data<=conv_std_logic_vector(char_to_integer ('m') ,8);
	when others   =>data<=conv_std_logic_vector(char_to_integer (' ') ,8);
	end case;
end process;
end fun;

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