library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

use work.common_pkg.all;
use work.core_pkg.all;


use work.mem_pkg.all;
use work.extension_pkg.all;
use work.extension_lcd_pkg_8.all;

architecture behav of extension_lcd_8 is

constant CLK_Divide : integer := 16;

signal w1_st_co, w1_st_co_nxt, w2_im_val, w2_im_val_nxt : gp_register_t;
signal w3_im_notused, w3_im_notused_nxt, w4_im_notused, w4_im_notused_nxt : gp_register_t;

signal lcd_count, lcd_count_nxt : integer := 0;
signal lcd_st, lcd_st_nxt : std_logic_vector(1 downto 0);
signal lcd_preStart, lcd_preStart_nxt, lcd_mStart, lcd_mStart_nxt, lcd_done, lcd_done_nxt : std_logic;
signal lcd_en_int, lcd_en_nxt, lcd_start, lcd_start_nxt : std_logic;


signal lcd_rom_addr, lcd_rom_addr_nxt : std_logic_vector(2 downto 0);
signal lcd_rom_data : std_logic_vector(11 downto 0); -- eigentlich 8 downto 0, aber vhdl < 2008 kann 
--keine laenge von bits bei hex angeben und binaer suckt

type LCD_SETUP_STATE_TYPE is (SEND_DATA, WAIT_DONE, DO_WAIT, FETCH_NEW);
signal lcd_set_st, lcd_set_st_nxt : LCD_SETUP_STATE_TYPE;
signal lcd_set_delay, lcd_set_delay_nxt : std_logic_vector(17 downto 0);

begin


LCD_ON <= '1';
LCD_BLON <= '1';
LCD_RW <= '0';

LCD_EN <= lcd_en_int;

LCD_DATA <= lcd_rom_data(7 downto 0);
LCD_RS <= lcd_rom_data(8);

syn : process (clk, reset)
begin
   if (reset = RESET_VALUE) then
		w1_st_co <= (others => '0');
		w2_im_val <= (others => '0');
		w3_im_notused <= (others => '0');
		w4_im_notused <= (others => '0');
		
		--lcd ctrl
		lcd_en_int <= '0';
		lcd_st <= "00";
		lcd_done <= '0';
		lcd_preStart <= '0';
		lcd_start <= '0';
		lcd_mStart <= '0';
		lcd_count <= 0;
		
		--lcd_setup
		lcd_rom_addr <= (others => '0');
		lcd_set_st <= SEND_DATA;
		lcd_set_delay <= (others => '0');
		
	elsif rising_edge(clk) then
		w1_st_co <= w1_st_co_nxt;
		w2_im_val <= w2_im_val_nxt;
		w3_im_notused <= w3_im_notused_nxt;
		w4_im_notused <= w4_im_notused_nxt;
		
		--lcd ctrl
		lcd_en_int <= lcd_en_nxt;
		lcd_st <= lcd_st_nxt;
		lcd_done <= lcd_done_nxt;
		lcd_preStart <= lcd_preStart_nxt;
		lcd_start <= lcd_start_nxt;
		lcd_mStart <= lcd_mStart_nxt;
		lcd_count <= lcd_count_nxt;

		--lcd setup
		lcd_rom_addr <= lcd_rom_addr_nxt;
		lcd_set_st <= lcd_set_st_nxt;
		lcd_set_delay <= lcd_set_delay_nxt;
		
	
   end if;
end process syn;

-------------------------- LESEN UND SCHREIBEN ANFANG ------------------------------------------------------------

gwriten : process (ext_reg, w1_st_co, w2_im_val, w3_im_notused, w4_im_notused)
variable tmp_data : gp_register_t;
begin
	w1_st_co_nxt <= w1_st_co;
	w2_im_val_nxt <= w2_im_val;
	w3_im_notused_nxt <= w3_im_notused;
	w4_im_notused_nxt <= w4_im_notused;

	-- timer logic
	if (w1_st_co(0) = '1') then -- timer enabled?
		w2_im_val_nxt <= std_logic_vector(IEEE.numeric_std.unsigned(w2_im_val) + 1);
		-- n00b overflow (logic elements sparen...)
		if(w2_im_val(31) = '1') then 
			w1_st_co_nxt(16) <= '1';
		end if;
	end if;

	if ext_reg.sel = '1' and ext_reg.wr_en = '1' then
		tmp_data := (others =>'0');			
		for i in 0 to 3 loop
			if ext_reg.byte_en(i) = '1' then
				tmp_data(((i+1)*byte_t'length-1) downto i*byte_t'length) := ext_reg.data(((i+1)*byte_t'length-1) downto i*byte_t'length);
			end if;
		end loop;

		case ext_reg.addr(1 downto 0) is
		when "00" => -- status/config
			w1_st_co_nxt <= tmp_data;
		when "01" => -- timer value
			w2_im_val_nxt <= tmp_data;
		when "10" => null;
		when "11" => null;
		when others => null;
		end case;
	end if;
end process gwriten;

gread : process (clk, ext_reg, w1_st_co, w2_im_val, w3_im_notused, w4_im_notused)
variable tmp_data : gp_register_t;
begin
	tmp_data := (others => '0');
	if ext_reg.sel = '1' and ext_reg.wr_en = '0' then
		case ext_reg.addr(1 downto 0) is
		when "00" => put_word_be(tmp_data, w1_st_co, ext_reg.byte_en);
		when "01" => put_word_be(tmp_data, w2_im_val, ext_reg.byte_en);
		when "10" => put_word_be(tmp_data, w3_im_notused, ext_reg.byte_en);
		when "11" => put_word_be(tmp_data, w4_im_notused, ext_reg.byte_en);
		when others => null;
		end case;
	end if;
	data_out <= tmp_data;
end process gread;



lcd_setup : process(clk, lcd_set_st, lcd_start, lcd_set_delay, lcd_rom_addr, lcd_done)
begin
	lcd_set_st_nxt <= lcd_set_st;
	lcd_start_nxt <= lcd_start;
	lcd_set_delay_nxt <= lcd_set_delay;
	lcd_rom_addr_nxt <= lcd_rom_addr;
	
	if lcd_rom_addr < "101000" then
		case lcd_set_st is
			when SEND_DATA =>
				lcd_start_nxt <= '1';
				lcd_set_st_nxt <= WAIT_DONE;

			when WAIT_DONE =>
				if lcd_done = '1' then
					lcd_set_st_nxt <= DO_WAIT;
					lcd_start_nxt <= '0';
				end if;

			when DO_WAIT =>
				if lcd_set_delay < x"3fffe" then
					lcd_set_delay_nxt <= lcd_set_delay + 1;
				else
					lcd_set_delay_nxt <= (others => '0');
					lcd_set_st_nxt <= FETCH_NEW;
				end if;

			when FETCH_NEW =>
				lcd_rom_addr_nxt <= lcd_rom_addr + 1;
				lcd_set_st_nxt <= SEND_DATA;
		end case;
	end if;
		
end process lcd_setup;

lcd_ctrl : process(clk, lcd_en_int, lcd_count, lcd_mStart, lcd_start, lcd_done, lcd_preStart, lcd_st)
begin
	lcd_en_nxt <= lcd_en_int;
	lcd_count_nxt <= lcd_count;
	lcd_mStart_nxt <= lcd_mStart;
	
	lcd_preStart_nxt <= lcd_start;
	lcd_done_nxt <= lcd_done;
	
	--start detection
	if lcd_preStart = '0' and lcd_start = '1' then
		lcd_mStart_nxt <= '1';
		lcd_done_nxt <= '0';
	end if;
	lcd_st_nxt <= lcd_st;
	case lcd_st is
		when "00" =>
			if  lcd_mStart = '1' then
				lcd_st_nxt <= "01"; -- wait setup
			else
				lcd_st_nxt <= "00";
			end if;
		when "01" =>
			lcd_en_nxt <= '1';
			lcd_st_nxt <= "10";
		when "10" =>
			if(lcd_count < CLK_Divide) then
				lcd_count_nxt <= lcd_count+1;
			else
				lcd_st_nxt <= "11";
			end if;
		when "11" =>
			lcd_en_nxt <= '0';
			lcd_mStart_nxt <= '0';
			lcd_done_nxt  <= '1';
			lcd_count_nxt <= 0;
			lcd_st_nxt <= "00";
	end case;


end process lcd_ctrl;

lcd_data_rom : process(lcd_rom_addr)
begin
	case lcd_rom_addr is
		--init of display
		when "000" => lcd_rom_data <= x"038";
		when "001" => lcd_rom_data <= x"00c";
		when "010" => lcd_rom_data <= x"038";
		when "011" => lcd_rom_data <= x"00c";
		when "100" => lcd_rom_data <= x"001";
		when "101" => lcd_rom_data <= x"006";
		when "110" => lcd_rom_data <= x"080";
		when others => lcd_rom_data <= x"0b0"; --goto 0,0
		--	Line 1
		--when "000111" => lcd_rom_data <= x"120";	--	Welcome to the
		--when "001000" => lcd_rom_data <= x"13C";
		--when "001001" => lcd_rom_data <= x"133";
		
		--when "010110" => lcd_rom_data <= x"120";
		--	Change Line
		--when "010111" => lcd_rom_data <= x"0c0";
		--	Line 2
		--when "011000" => lcd_rom_data <= x"120";	--	Altera DE2-70
		--when "011001" => lcd_rom_data <= x"141";	
		--when "011010" => lcd_rom_data <= x"085"; --back to upper line + forward
		--when "011011" => lcd_rom_data <= x"174";
--		when "011100" => lcd_rom_data <= x"165";
--		when "011101" => lcd_rom_data <= x"172";
--		when "011110" => lcd_rom_data <= x"161";
--		when "011111" => lcd_rom_data <= x"120";
--		when "100000" => lcd_rom_data <= x"144";
--		when "100010" => lcd_rom_data <= x"145";
--		when "100011" => lcd_rom_data <= x"132";
--		when "100100" => lcd_rom_data <= x"1b0";
--		when "100101" => lcd_rom_data <= x"131";
--		when "100110" => lcd_rom_data <= x"131";
--		when "100111" => lcd_rom_data <= x"135";
--		when "101000" => lcd_rom_data <= x"120";
--		when others => lcd_rom_data <= x"120";
	end case;
end process lcd_data_rom;


-------------------------- LESEN UND SCHREIBEN ENDE ---------------------------------------------------------------
-------------------------- INTERNE VERARBEITUNG ANFANG ------------------------------------------------------------
-------------------------- INTERNE VERARBEITUNG ENDE --------------------------------------------------------------
end behav;