LIBRARY IEEE;
USE IEEE.std_logic_1164.ALL;

ENTITY LCD IS
PORT 	( 	clock_400hz_en		: IN 	STD_ULOGIC;	--400Hz Taktsignal
			reset	        : IN 	STD_ULOGIC;	--Reset-Signal
			data_input	: IN 	STD_ULOGIC_VECTOR (13 DOWNTO 0); --Token-Signal des Decoders / Morse
			data_keyboard	: IN	STD_ULOGIC_VECTOR (7 DOWNTO 0);	 --Keyboard-Daten nach Betätigung einer Taste
			data_cntr	: OUT 	STD_ULOGIC_VECTOR (3 DOWNTO 0);	--Steuersignale des LCD, wie z.B. LCD_EN, LCD_RW etc.
			data_out	: OUT	STD_ULOGIC_VECTOR (7 DOWNTO 0);	--Datensignale für das LCD (sowohl druckbare-, als auch Steuerzeichen)
			enable_char	: IN 	STD_ULOGIC;	--Pausen-Signal der Morse-Entity zur Überprüfung ob ein Token-Signal "fertig" ist
			enable		: IN	STD_ULOGIC;	--Switch Signal zum Umschalten zwischen dem Decoder und Encoder
			done_pressing	: IN	STD_ULOGIC	--gibt an ob die Tastaturtaste losgelassen wurde und die Datenübertragung beendet wurde
	);
END LCD;



ARCHITECTURE structure of LCD IS


SIGNAL 		LCD_ON, LCD_EN, LCD_RS, LCD_RW: STD_ULOGIC;		--Stuersignale für das LCD
SIGNAL 		LCD_DATA		      : STD_ULOGIC_VECTOR (7 DOWNTO 0); 	--Datensignal für das LCD

SIGNAL 		sig_old	: STD_ULOGIC;
SIGNAL 		sig_rise: STD_ULOGIC;

SIGNAL 		sig_old2:  STD_ULOGIC;
SIGNAL 		sig_rise2: STD_ULOGIC;
SIGNAL		sig_fall2: STD_ULOGIC;

SIGNAL 		sig_old3:  STD_ULOGIC;
SIGNAL 		sig_rise3: STD_ULOGIC;

BEGIN

		
	--------------------------------------------------------------
	--Ansteuerung des LCD mit Initialisierung und Zeichenausgabe--
	--------------------------------------------------------------
	LCD_Initialising:	PROCESS (clock_400hz_en, reset, data_input, enable_char, enable, data_keyboard, done_pressing)
		
		VARIABLE ini		: NATURAL RANGE 0 TO 9 	:= 0;
		VARIABLE next_command	: NATURAL RANGE 0 TO 9 	:= 0;
		VARIABLE char_cnt	: NATURAL RANGE 0 TO 34 := 0;
		
		BEGIN
		
				--LCD neu initialisieren
				IF reset = '0' THEN
				
					LCD_ON <= '1'; --LCD_ON
					LCD_EN <= '1'; --LCD_EN
					LCD_RW <= '0'; --LCD_RW
					LCD_RS <= '0'; --LCD_RS
					LCD_DATA <= x"38"; --x"38" = Display OFF, 2-lines of Display in use ( = reset)
					ini := 0;
					next_command := 0;
					char_cnt := 0;
				
				ELSIF Clock_400hz_en'EVENT AND Clock_400hz_en = '1' THEN
					
					CASE ini IS
					
					--LCD Initialisierung
						WHEN 0 =>
							
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"38"; --x"38" = Display OFF, 2-lines of Display in use
								next_command := next_command+1;
								ini := 8;
								
						WHEN 1 =>
						
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"38"; --x"38" = Display OFF, 2-lines of Display in use
								next_command := next_command+1;
								ini := 8;
								
						WHEN 2 =>
						
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"38"; --x"38" = Display OFF, 2-line mode
								next_command := next_command+1;
								ini := 8;
								
						WHEN 3 =>
						
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"38"; --x"38" = Display OFF, 2-lines of Display in use (4-mal zum initialisieren!)
								next_command := next_command+1;
								ini := 8;
								
						WHEN 4 =>
						
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"08"; --x"08" = Display OFF, Cursor OFF, Blinking Cursor Position OFF (0F = Display
                                                                                   --ON and Cursor ON, Blinking cursor position ON)
								next_command := next_command+1;
								ini := 8;
								
						WHEN 5 =>
						
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"01"; --x"01" = Clear Display
								next_command := next_command+1;
								ini := 8;
								
						WHEN 6 =>
						
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"0C"; --x"0C" = Display ON (0E = Display ON, Cursor ON and Blinking cursor OFF)
								next_command := next_command+1;
								ini := 8;
								
						WHEN 7 =>
					
								LCD_ON <= '1';
								LCD_EN <= '1';
								LCD_RW <= '0';
								LCD_RS <= '0';
								LCD_DATA <= x"06"; --x"06" = Auto increment address and move cursor to the right
								next_command := 9;
								ini := 8;
								-- Initialisierung ist ab hier abgeschlossen!!!
								

								
						WHEN 8 =>
								
								--Dieser Zyklus dient dazu das Enable-Signal in LCD_EN auch auf '0' zu setzen.
								--Ansonsten können die Daten nicht an den Bildschirm übertragen werden!!!
								LCD_ON <= '1';
								LCD_EN <= '0';
								ini := next_command;			
						
						WHEN 9 =>
										
									IF char_cnt = 16 THEN
										LCD_RS <= '0';
										LCD_EN <= '1';
										LCD_RW <= '0';
										LCD_ON <= '1';
										
										LCD_DATA <= x"C0"; --Setze Cursor an den Anfang der zweiten Zeile des Displays
										char_cnt := char_cnt + 1;
										ini := 8;
									
									ELSIF char_cnt = 34 THEN
									
										LCD_ON <= '1';
										LCD_EN <= '1';
										LCD_RW <= '0';
										LCD_RS <= '0';
										
										LCD_DATA <= x"01"; --x"01" = clear Display
										char_cnt := 0;
										ini := 8;
										
										
									ELSE
						
				
								  -- defaults
								 sig_rise 	<= '0';	--setzt das Signal "sig_rise" standardmäßig auf ein LOW, da das 
                                                                                        --enable_char-Signal NICHT immer eine steigende Flanke hat
								 sig_rise2 	<= '0';
								 sig_rise3	<= '0';
								 sig_fall2	<= '0';
								 
								 -- shift value in
								 sig_old 	<= enable_char;	--als altes Signal wird "sig_old" das aktuelle 
                                                                                                --standard_char-Signal zugewiesen
								 sig_old2 	<= enable;
								 sig_old3	<= done_pressing;
								 
								 -- do some real action
								 IF sig_old = '0' AND enable_char = '1' AND enable = '0' THEN		
--es wird geprüft ob sich das alte Signal zum neuen Signal unterscheidet. Ist dies der Fall, gab es eine positive Flanke, da die Zuweisung erst im NÄCHSTEN 
--Taktzyklus erfolgt, prüft man somit IMMER die vorherige Zuweisung!!! 
--(Quelle: https://www.uni-ulm.de/fileadmin/website_uni_ulm/iui.inst.050/vorlesungen/sose09/lrob/Crashkurs_VHDL.pdf  Kap. 4.2.3)
									sig_rise <= '1';
								 END IF;					 
								 
								 
								 
								IF sig_old2 = '0' AND enable = '1' THEN
									sig_rise2 <= '1';
								ELSIF sig_old2 = '1' AND enable = '0' THEN
									sig_fall2 <= '1';
								END IF;
				
				
				
								IF sig_old3 = '0' AND done_pressing = '1' AND enable = '1' THEN
									sig_rise3 <= '1';
								END IF;
				
				
								----------------------------------------
								--Ansteuerung des LCD im Decoder-Modus--
								----------------------------------------
								If sig_rise = '1' THEN						
									LCD_ON <= '1';
									LCD_EN <= '1';
									LCD_RW <= '0';
									LCD_RS <= '1';
									
									
									
										CASE data_input IS
											
											 --Buchstaben
											 WHEN "00000000000111" => LCD_DATA <=x"41"; -- A
											 WHEN "00000011010101" => LCD_DATA <=x"42"; -- B
											 WHEN "00000011011101" => LCD_DATA <=x"43"; -- C
											 WHEN "00000000110101" => LCD_DATA <=x"44"; -- D
											 WHEN "00000000000001" => LCD_DATA <=x"45"; -- E
											 WHEN "00000001011101" => LCD_DATA <=x"46"; -- F
											 WHEN "00000000111101" => LCD_DATA <=x"47"; -- G
											 WHEN "00000001010101" => LCD_DATA <=x"48"; -- H
											 WHEN "00000000000101" => LCD_DATA <=x"49"; -- I
											 WHEN "00000001111111" => LCD_DATA <=x"4A"; -- J
											 WHEN "00000000110111" => LCD_DATA <=x"4B"; -- K
											 WHEN "00000001110101" => LCD_DATA <=x"4C"; -- L
											 WHEN "00000000001111" => LCD_DATA <=x"4D"; -- M
											 WHEN "00000000001101" => LCD_DATA <=x"4E"; -- N
											 WHEN "00000000111111" => LCD_DATA <=x"4F"; -- O
											 WHEN "00000001111101" => LCD_DATA <=x"50"; -- P
											 WHEN "00000011110111" => LCD_DATA <=x"51"; -- Q
											 WHEN "00000000011101" => LCD_DATA <=x"52"; -- R
											 WHEN "00000000010101" => LCD_DATA <=x"53"; -- S
											 WHEN "00000000000011" => LCD_DATA <=x"54"; -- T
											 WHEN "00000000010111" => LCD_DATA <=x"55"; -- U
											 WHEN "00000001010111" => LCD_DATA <=x"56"; -- V
											 WHEN "00000000011111" => LCD_DATA <=x"57"; -- W
											 WHEN "00000011010111" => LCD_DATA <=x"58"; -- X
											 WHEN "00000011011111" => LCD_DATA <=x"59"; -- Y
											 WHEN "00000011110101" => LCD_DATA <=x"5A"; -- Z
											 
											 --Zahlen
											 WHEN "00001111111111" => LCD_DATA <=x"30"; -- 0
											 WHEN "00000111111111" => LCD_DATA <=x"31"; -- 1
											 WHEN "00000101111111" => LCD_DATA <=x"32"; -- 2
											 WHEN "00000101011111" => LCD_DATA <=x"33"; -- 3
											 WHEN "00000101010111" => LCD_DATA <=x"34"; -- 4
											 WHEN "00000101010101" => LCD_DATA <=x"35"; -- 5
											 WHEN "00001101010101" => LCD_DATA <=x"36"; -- 6
											 WHEN "00001111010101" => LCD_DATA <=x"37"; -- 7
											 WHEN "00001111110101" => LCD_DATA <=x"38"; -- 8
											 WHEN "00001111111101" => LCD_DATA <=x"39"; -- 9
											 
											 --Sonderzeichen
--											 WHEN "00000111110111" => LCD_DATA <=x"8F"; -- Å
											 WHEN "00000001110111" => LCD_DATA <=x"E1"; -- Ä
--											 WHEN "00000111010111" => LCD_DATA <=x"8A"; -- È
--											 WHEN "00000101110101" => LCD_DATA <=x"90"; -- É
											 WHEN "00000011111101" => LCD_DATA <=x"EF"; -- Ö
											 WHEN "00000001011111" => LCD_DATA <=x"F5"; -- Ü
											 WHEN "01010111110101" => LCD_DATA <=x"E2"; -- ß
											 WHEN "00110111011101" => LCD_DATA <=x"3B"; -- ;
											 WHEN "00010111110101" => LCD_DATA <=x"3F"; -- ?
											 WHEN "00110101010111" => LCD_DATA <=x"2D"; -- -
											 WHEN "00010111110111" => LCD_DATA <=x"5F"; -- _
--											 WHEN "00001111011111" => LCD_DATA <=x"A5"; -- Ñ
											 WHEN "00011101110111" => LCD_DATA <=x"2E"; -- .
											 WHEN "00111101011111" => LCD_DATA <=x"2C"; -- ,
											 WHEN "00111111010101" => LCD_DATA <=x"3A"; -- :
											 WHEN "00001101111101" => LCD_DATA <=x"28"; -- (
											 WHEN "00110111110111" => LCD_DATA <=x"29"; -- )
											 WHEN "00011111111101" => LCD_DATA <=x"27"; -- '
											 WHEN "00001101010111" => LCD_DATA <=x"3D"; -- =
											 WHEN "00000111011101" => LCD_DATA <=x"2B"; -- +
											 WHEN "00001101011101" => LCD_DATA <=x"2F"; -- /
											 WHEN "00011111011101" => LCD_DATA <=x"40"; -- @
											 
											 WHEN OTHERS => LCD_DATA <= x"00";  
												
										END CASE;
										char_cnt := char_cnt + 1;
										ini := 8;
										
										-------------------------------------------
										--Umschalten zwischen Decoder und Encoder--
										-------------------------------------------
										
										--Prüfen ob gerade erst zwischen Encoder und Decoder umgestellt wurde
										ELSIF sig_rise2 = '1' OR sig_fall2 = '1' THEN	
											LCD_ON <= '1';
											LCD_EN <= '1';
											LCD_RW <= '0';
											LCD_RS <= '0';
										
											LCD_DATA <= x"01"; --x"01" = clear Display
											ini := 8;

											char_cnt := 0;
									
										----------------------------------------
										--Ansteuerung des LCD im Encoder-Modus--
										----------------------------------------
										
										--Prüfen ob eine Tastureingabe gerade beendet wurde
										ELSIF sig_rise3 = '1' THEN
										
											LCD_ON <= '1';
											LCD_EN <= '1';
											LCD_RW <= '0';
											LCD_RS <= '1';
										
											CASE data_keyboard IS
												
												--Buchstaben
												 WHEN x"1C" => LCD_DATA <=x"41"; -- A
												 WHEN x"32" => LCD_DATA <=x"42"; -- B
												 WHEN x"21" => LCD_DATA <=x"43"; -- C
												 WHEN x"23" => LCD_DATA <=x"44"; -- D
												 WHEN x"24" => LCD_DATA <=x"45"; -- E
												 WHEN x"2B" => LCD_DATA <=x"46"; -- F
												 WHEN x"34" => LCD_DATA <=x"47"; -- G
												 WHEN x"33" => LCD_DATA <=x"48"; -- H
												 WHEN x"43" => LCD_DATA <=x"49"; -- I
												 WHEN x"3B" => LCD_DATA <=x"4A"; -- J
												 WHEN x"42" => LCD_DATA <=x"4B"; -- K
												 WHEN x"4B" => LCD_DATA <=x"4C"; -- L
												 WHEN x"3A" => LCD_DATA <=x"4D"; -- M
												 WHEN x"31" => LCD_DATA <=x"4E"; -- N
												 WHEN x"44" => LCD_DATA <=x"4F"; -- O
												 WHEN x"4D" => LCD_DATA <=x"50"; -- P
												 WHEN x"15" => LCD_DATA <=x"51"; -- Q
												 WHEN x"2D" => LCD_DATA <=x"52"; -- R
												 WHEN x"1B" => LCD_DATA <=x"53"; -- S
												 WHEN x"2C" => LCD_DATA <=x"54"; -- T
												 WHEN x"3C" => LCD_DATA <=x"55"; -- U
												 WHEN x"2A" => LCD_DATA <=x"56"; -- V
												 WHEN x"1D" => LCD_DATA <=x"57"; -- W
												 WHEN x"22" => LCD_DATA <=x"58"; -- X
												 WHEN x"1A" => LCD_DATA <=x"59"; -- Y
												 WHEN x"35" => LCD_DATA <=x"5A"; -- Z
												 
												 --Zahlen
												 WHEN x"45" => LCD_DATA <=x"30"; -- 0
												 WHEN x"16" => LCD_DATA <=x"31"; -- 1
												 WHEN x"1E" => LCD_DATA <=x"32"; -- 2
												 WHEN x"26" => LCD_DATA <=x"33"; -- 3
												 WHEN x"25" => LCD_DATA <=x"34"; -- 4
												 WHEN x"2E" => LCD_DATA <=x"35"; -- 5
												 WHEN x"36" => LCD_DATA <=x"36"; -- 6
												 WHEN x"3D" => LCD_DATA <=x"37"; -- 7
												 WHEN x"3E" => LCD_DATA <=x"38"; -- 8
												 WHEN x"46" => LCD_DATA <=x"39"; -- 9
												 
												 --Sonderzeichen
--												 WHEN x"" => LCD_DATA <=x"8F"; -- Å
												 WHEN x"52" => LCD_DATA <=x"E1"; -- Ä
--												 WHEN x"" => LCD_DATA <=x"8A"; -- È
--												 WHEN x"" => LCD_DATA <=x"90"; -- É
												 WHEN x"4C" => LCD_DATA <=x"EF"; -- Ö
												 WHEN x"54" => LCD_DATA <=x"F5"; -- Ü
												 WHEN x"4E" => LCD_DATA <=x"E2"; -- ß
--												 WHEN x"" => LCD_DATA <=x"3B"; -- ;
--												 WHEN x"" => LCD_DATA <=x"3F"; -- ?
												 WHEN x"4A" => LCD_DATA <=x"2D"; -- -
--												 WHEN x"" => LCD_DATA <=x"5F"; -- _
--												 WHEN x"" => LCD_DATA <=x"A5"; -- Ñ
												 WHEN x"49" => LCD_DATA <=x"2E"; -- .
												 WHEN x"41" => LCD_DATA <=x"2C"; -- ,
--												 WHEN x"" => LCD_DATA <=x"3A"; -- :
--												 WHEN x"" => LCD_DATA <=x"28"; -- (
--												 WHEN x"" => LCD_DATA <=x"29"; -- )
--												 WHEN x"" => LCD_DATA <=x"27"; -- '
--												 WHEN x"" => LCD_DATA <=x"3D"; -- =
												 WHEN x"5B" => LCD_DATA <=x"2B"; -- +
--												 WHEN x"" => LCD_DATA <=x"2F"; -- /
--												 WHEN x"" => LCD_DATA <=x"40"; -- @
												 WHEN x"29"	=>	LCD_DATA	<=x"20"; -- " "
												 												 
												 
												 WHEN OTHERS => LCD_DATA <= x"00";  
												 
											END CASE;
												 
											char_cnt := char_cnt + 1;
											ini := 8;
															
										END IF;
										
									END IF;	
																		
						END CASE;
						
						--Übertragung der Steuersignale und Datenbits an das LCD
						data_cntr(3) <= LCD_ON;
						data_cntr(0) <= LCD_EN;
						data_cntr(1) <= LCD_RW;
						data_cntr(2) <= LCD_RS;
						data_out <= LCD_DATA;											
						
					END IF;

				END PROCESS;
		
END structure;