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[/] [lcd1/] [trunk/] [src/] [BACKUP/] [lcd.vhd] - Blame information for rev 6

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1 2 dimo 
library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use IEEE.STD_LOGIC_ARITH.ALL;
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use IEEE.STD_LOGIC_UNSIGNED.ALL;
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entity lcd is
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    Port ( lcd_data   : out std_logic_vector (7 downto 4);
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           clk        : in  std_logic;
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           reset      : in  std_logic;
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           lcd_enable : out STD_LOGIC_VECTOR (1 DOWNTO 0);
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           lcd_rs     : out std_logic;
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           lcd_rw     : out std_logic
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         );
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end lcd ;
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architecture behavioural of lcd is
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    type state_type is (warmup, setfunc, clear1, clear2, setmode1, setmode2, write1, home1, home2);
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    signal state : state_type;
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    attribute syn_state_machine : boolean;
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    attribute syn_state_machine of state : signal is true;
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    signal count    : std_logic_vector(3 downto 0);
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    signal finished : std_logic;         -- set high if done write cycle
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    signal  char_mode : std_logic_vector(1 downto 0);
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    --defining the display
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    constant N: integer :=8;
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    type arr is array (1 to N) of std_logic_vector(7 downto 0);
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    constant display_char1 : arr :=    (x"A0",  --blank
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                                        X"68",  --h
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                                        X"74",  --t
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                                        X"74",  --t
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                                        X"70",  --p
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                                        X"3A",  --:
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                                        X"2F",  --/
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                                        X"2F"); --/
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    constant display_char2 : arr :=    (X"77",  --w
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                                        X"77",  --w
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                                        X"77",  --w
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                                        X"2E",  --.
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                                        X"66",  --f
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                                        X"70",  --p
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                                        X"67",  --g
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                                        X"61"); --a
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    constant display_char3 : arr :=    (X"2E",  --.
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                                        X"62",  --b
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                                        X"65",  --e
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                                        X"88",  --blank
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                                        X"88",  --blank
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                                        X"88",  --blank
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                                        X"88",  --blank
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                                        X"88"); --blank
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    constant display_char4 : arr :=    (X"A0",  --blank
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                                        X"88",  --blank
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                                        X"58",  --X
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                                        X"49",  --I
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                                        X"4F",  --O
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                                        X"53",  --S
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                                        X"88",  --blank
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                                        X"88"); --blank
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    signal display_char : arr;
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begin
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    lcd_rw <= '0';
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    lcd_enable(1) <= clk; --not clk;  -- this is very important! if enable is not pulsed, lcd will not write
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    lcd_enable(0) <= clk;
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    char_mode_process: process (char_mode)
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    begin
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        case char_mode  is
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            when "00" =>
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                display_char <= display_char1;
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            when "01" =>
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                display_char <= display_char2;
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            when "10" =>
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                display_char <= display_char3;
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            when "11" =>
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                display_char <= display_char4;
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            when OTHERS  =>
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                display_char <= display_char1;
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         end case;
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    end process;
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    state_set: process (clk, reset, finished)
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    begin
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      if (reset = '1') then
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         state     <= warmup;   --setfunc;
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         count     <= (others => '0');
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         char_mode <= (others => '0');
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      elsif (clk'event and clk = '1') then
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         case state is
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            when warmup =>
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               lcd_rs <= '0';
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               lcd_data <= "0011"; --"0000";  -- do nothing
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               if count = "0111" then  --0111
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                  count <= (others => '0');
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                  state <= setfunc;
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               else
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                  count <= count + '1';
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                  state <= warmup;
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               end if;
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            when setfunc =>
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               lcd_rs <= '0';
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               lcd_data <= "0010";
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               finished <= '0';
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               if count = "0010" then  --0010
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                  count <= (others => '0');
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                  state <= clear1;
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               else
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                  count <= count + '1';
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                  state <= setfunc;
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               end if;
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            when clear1 =>
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               lcd_rs <= '0';
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               lcd_data <= "0000";
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               state <= clear2;
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            when clear2 =>
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               lcd_rs <= '0';
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               if count = "0111" then
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                    state <= setmode1;
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                    count <= (others => '0');
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                    lcd_data <= "1111";
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               else
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                    count <= count + '1';
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                    lcd_data <= "0001";
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                    state <= clear1;
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               end if;
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            when setmode1 =>
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               lcd_rs   <= '0';
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               lcd_data <= "0000";
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               state    <= setmode2;
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               finished <= '0';
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            when setmode2 =>
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               lcd_rs   <= '0';
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               lcd_data <= "0110";
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               state    <= write1;
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            when write1 =>
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               if finished = '1' then
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                  state <= home1;
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               else
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                  lcd_rs <= '1';
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                  count  <= count  + '1';
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                  state  <= write1;
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                  CASE count IS
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                     WHEN "0000" =>
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                         lcd_data <= display_char(1)(7 downto 4);
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                     WHEN "0001" =>
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                         lcd_data <= display_char(1)(3 downto 0);
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                     WHEN "0010" =>
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                         lcd_data <= display_char(2)(7 downto 4);
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                     WHEN "0011" =>
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                         lcd_data <= display_char(2)(3 downto 0);
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                     WHEN "0100"=>
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                         lcd_data <= display_char(3)(7 downto 4);
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                     WHEN "0101"=>
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                         lcd_data <= display_char(3)(3 downto 0);
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                     WHEN "0110"=>
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                         lcd_data <= display_char(4)(7 downto 4);
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                     WHEN "0111"=>
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                         lcd_data <= display_char(4)(3 downto 0);
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                     WHEN "1000" =>
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                         lcd_data <= display_char(5)(7 downto 4);
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                     WHEN "1001" =>
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                         lcd_data <= display_char(5)(3 downto 0);
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                     WHEN "1010" =>
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                         lcd_data <= display_char(6)(7 downto 4);
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                     WHEN "1011" =>
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                         lcd_data <= display_char(6)(3 downto 0);
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                     WHEN "1100" =>
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                         lcd_data <= display_char(7)(7 downto 4);
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                     WHEN "1101" =>
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                         lcd_data <= display_char(7)(3 downto 0);
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                     WHEN "1110" =>
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                         lcd_data <= display_char(8)(7 downto 4);
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                         --finished <= '1';  -- needed to set done low before valid data is gone
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                         --char_mode  <= char_mode + '1';
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                    WHEN "1111" =>
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                         lcd_data <= display_char(8)(3 downto 0);
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                         finished <= '1';  -- needed to set done low before valid data is gone
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                         char_mode  <= char_mode + '1';
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                     WHEN OTHERS =>
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                         lcd_data <= "0000";  -- ' '
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                  END CASE;
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               end if;
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            when home1 =>
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               lcd_rs <= '0';
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               lcd_data <= "0000";
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               state <= home2;
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               finished <= '0';
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               count <= (others => '0');
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            when home2 =>
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               lcd_rs <= '0';
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               lcd_data <= "0111";
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               state <= write1;
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         end case;
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      end if;
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   end process;
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end behavioural;

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