-------------------------------------------- test wy渨ietlacza graficznego LCD
--
-- Program rysuje na wy渨ietlaczu graficznym G121600N000 (Seiko) regularny
-- wz髍 szachownicy.
------------------------------------------------------------------------------
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;

entity LCDgraph is
port (
         clk:     in  std_logic;                                     --  clock
          E_LCD:   out std_logic;                               --  LCD Enable
          DI_LCD:  out std_logic;                         --  Data/Instruction
          CS1_LCD: out std_logic;                            --  Chip Select 1
          CS2_LCD: out std_logic;                            --  Chip Select 2
         RST_LCD: out std_logic ;                                --  LCD Reset
         D_LCD:   out std_logic_vector(7 downto 0)  --  licznik
     );
end LCDgraph ;

architecture LCD_architecture of LCDgraph  is  -------------------------------

type state_type is (s0,s1,s2,s3);
attribute enum_encoding: string;
attribute enum_encoding of state_type: type is "00 01 10 11";
signal cs: state_type :=s0;
signal ns: state_type;
signal cnt:  std_logic_vector(9 downto 0) := (others =>'0');

begin

u1: process(clk)                    -- proces zmiany stan體 w maszynie stan體
    begin
     if(clk'event and clk='1') then
           cs <= ns;
           cnt <= cnt+1;                  -- licznik zliczaj筩y zbocza zegara
      end if;
    end process;

u2: process(cs)                                  -- realizacja maszyny stan體
    begin
     case cs is
      when s0=>
            ns<=s1;
            RST_LCD <= '0';                             -- reset wy渨ietlacza
      when s1=>
         ns<=s2;
            RST_LCD <= '1';
            DI_LCD  <= '0';
            D_LCD   <= x"3f";                   -- LCD on (w徹cz wy渨ietlacz)
      when s2=>
            ns<=s3;
            RST_LCD <= '1';
            DI_LCD  <= '1';
            if cnt(3) = '1'then 
                D_LCD <=  x"0f";           -- wz髍 kratki co 8-bit體 licznika
             else     
                D_LCD <=  x"f0";  
             end if;
       when s3=>   
            ns<=s2;
            RST_LCD <= '1';
            DI_LCD  <= '0';
            D_LCD<=  "10111" & cnt(9 downto 7); -- zmiana wiersza co 64 stany 
       when others =>
         ns<=s0;
         RST_LCD <= '1';
            DI_LCD <= '0';
            D_LCD<=  x"00";
       end case;
    end process;

   E_LCD   <=  clk;
   CS1_LCD <= '0';
   CS2_LCD <= '0';

end LCD_architecture ;