lcd1602.vhd

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY LCD1602 IS
    PORT (
        CLK : IN std_logic; --clock
        Reset : IN std_logic;
        LCD_RS : OUT std_logic; --LCD Reset
        LCD_RW : OUT std_logic; --LCD Read / Write
        LCD_EN : OUT std_logic; --LCD Enable

        LCD_Data : OUT std_logic_vector(7 DOWNTO 0)); --8-bit LCD data
END LCD1602;
ARCHITECTURE Behavioral OF LCD1602 IS
    TYPE state IS (set_dlnf, set_cursor, set_dcb, set_cgram, write_cgram, set_ddram, write_LCD_Data);
    SIGNAL Current_State : state;
    TYPE ram1 IS ARRAY(0 TO 30) OF std_logic_vector(7 DOWNTO 0);
    TYPE ram2 IS ARRAY(0 TO 30) OF std_logic_vector(7 DOWNTO 0);
    TYPE ram3 IS ARRAY(0 TO 30) OF std_logic_vector(7 DOWNTO 0);
	 --Wazzup my boi? Let's partay !!!
    CONSTANT cgram1 : ram1 := (x"6a",x"62",x"6f",x"72",x"7a",x"61",x"2e",x"63",x"6f",x"6d",x"20",x"20",x"20",x"20",x"20",x"20",x"4c",x"43",x"44",x"31",x"36",x"30",x"32",x"20",x"64",x"65",x"6d",x"6f",x"20",x"20",x"20");
    --jborza.com      LCD1602 demo   
    CONSTANT cgram3 : ram3 := (x"4c",x"43",x"44",x"31",x"36",x"30",x"32",x"20",x"64",x"65",x"6d",x"6f",x"20",x"20",x"68",x"74",x"74",x"70",x"3a",x"2f",x"2f",x"6a",x"62",x"6f",x"72",x"7a",x"61",x"2e",x"63",x"6f",x"6d");
    --Hello World Hello World Hello
    CONSTANT cgram2 : ram2 := (x"48",x"65",x"6c",x"6c",x"6f",x"20",x"57",x"6f",x"72",x"6c",x"64",x"20",x"48",x"65",x"6c",x"6c",x"6f",x"20",x"57",x"6f",x"72",x"6c",x"64",x"20",x"48",x"65",x"6c",x"6c",x"6f",x"20",x"57");
    
    SIGNAL CLK1 : std_logic;
    SIGNAL Clk_Out : std_logic;
    SIGNAL LCD_Clk : std_logic;
    SIGNAL m : std_logic_vector(1 DOWNTO 0);
BEGIN
    LCD_EN <= Clk_Out;
    LCD_RW <= '0';
    PROCESS (CLK)
        VARIABLE n1 : INTEGER RANGE 0 TO 19999;
    BEGIN
        IF rising_edge(CLK) THEN
            IF n1 < 19999 THEN
                n1 := n1 + 1;
            ELSE
                n1 := 0;
                Clk_Out <= NOT Clk_Out;
            END IF;
        END IF;
    END PROCESS;
    LCD_Clk <= Clk_Out;
    PROCESS (Clk_Out)
        VARIABLE n2 : INTEGER RANGE 0 TO 499;
    BEGIN
        IF rising_edge(Clk_Out) THEN
            IF n2 < 499 THEN
                n2 := n2 + 1;
            ELSE
                n2 := 0;
                Clk1 <= NOT Clk1;
            END IF;
        END IF;
    END PROCESS;
    PROCESS (Clk1)
        VARIABLE n3 : INTEGER RANGE 0 TO 14;
    BEGIN
        IF rising_edge(Clk1) THEN
            n3 := n3 + 1;
            IF n3 <= 4 THEN
                m <= "00";
            ELSIF n3 <= 9 AND n3 > 4 THEN
                m <= "01";
            ELSE
                m <= "10";
            END IF;
        END IF;
    END PROCESS;
    PROCESS (LCD_Clk, Reset, Current_State)
        VARIABLE cnt1 : std_logic_vector(4 DOWNTO 0);
    BEGIN
        IF Reset = '0'THEN
            Current_State <= set_dlnf;
            cnt1 := "11110";
            LCD_RS <= '0';
        ELSIF rising_edge(LCD_Clk) THEN
            Current_State <= Current_State;
            LCD_RS <= '0';
            CASE Current_State IS
                WHEN set_dlnf =>
                    cnt1 := "00000";
                    LCD_Data <= "00000001"; --  /*ÇĺłýĎÔĘž*/ 
                    Current_State <= set_cursor;
                WHEN set_cursor =>
                    LCD_Data <= "00111000"; --/*ÉčÖĂ8Îť¸ńĘ˝,2ĐĐ,5*7*/  
                    Current_State <= set_dcb;
                WHEN set_dcb =>
                    LCD_Data <= "00001100"; --/*ŐűĚĺĎÔĘž,šŘšâąę,˛ťÉÁ˸*/  
                    Current_State <= set_cgram;
                WHEN set_cgram =>
                    LCD_Data <= "00000110";
                    Current_State <= write_cgram;
                WHEN write_cgram =>
                    LCD_RS <= '1';
                    IF m = "00" THEN
                        LCD_Data <= cgram1(conv_integer(cnt1));
                    ELSIF m = "01"THEN
                        LCD_Data <= cgram2(conv_integer(cnt1));
                    ELSE
                        LCD_Data <= cgram3(conv_integer(cnt1));
                    END IF;
                    Current_State <= set_ddram;
                WHEN set_ddram =>
                    IF cnt1 < "11110" THEN
                        cnt1 := cnt1 + 1;
                    ELSE
                        cnt1 := "00000";
                    END IF;
                    IF cnt1 <= "01111" THEN
                        LCD_Data <= "10000000" + cnt1;--80H 
                    ELSE
                        LCD_Data <= "11000000" + cnt1 - "10000";--80H 
                    END IF;
                    Current_State <= write_LCD_Data;
                WHEN write_LCD_Data =>
                    LCD_Data <= "00000000";
                    Current_State <= set_cursor;
                WHEN OTHERS => NULL;
            END CASE;
        END IF;
    END PROCESS;
END Behavioral;