-------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
entity command_mapper is
Port (
	rst:		in std_logic;					-- reset
	busy:	in std_logic;					-- sincronizacao
	scan_code:in std_logic_vector(7 downto 0);	-- keyboard scan code 

	ascii	:	out std_logic_vector(7 downto 0);
	cursor_pos:	out std_logic_vector(10 downto 0)	-- posicao do cursor
	);
end command_mapper;
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
architecture Behavioral of command_mapper is

	signal posx: natural range 4 to 35 := 4;	-- coluna
	signal posy: natural range 4 to 25 := 4;	-- linha


begin

-------------------------------------------------------------------------------
process(scan_code, busy)
begin
	
	if busy /= '1' then				
	case scan_code is
					
	--Digitos
		when x"45" =>	ascii <= x"30";
		when x"16" =>	ascii <= x"31";
		when x"1E" =>	ascii <= x"32";
		when x"26" =>	ascii <= x"33";
		when x"25" =>	ascii <= x"34";
		when x"2E" =>	ascii <= x"35";
		when x"36" =>	ascii <= x"36";
		when x"3D" =>	ascii <= x"37";
		when x"3E" =>	ascii <= x"38";
		when x"46" =>	ascii <= x"39";
	
	--Caracteres
		when x"1C" =>	ascii <=x"41"; --A
		when x"32" =>	ascii <=x"42"; --B
		when x"21" =>	ascii <=x"43"; --C
		when x"23" =>	ascii <=x"44"; --D
		when x"24" =>	ascii <=x"45"; --E
		when x"2B" =>	ascii <=x"46"; --F
		when x"34" =>	ascii <=x"47"; --G
		when x"33" =>	ascii <=x"48"; --H
		when x"43" =>	ascii <=x"49"; --I
		when x"3B" =>	ascii <=x"4A"; --J
		when x"42" =>	ascii <=x"4B"; --K
		when x"4B" =>	ascii <=x"4C"; --L
		when x"3A" =>	ascii <=x"4D"; --M
		when x"31" =>	ascii <=x"4E"; --N
		when x"44" =>	ascii <=x"4F"; --O
		when x"4D" =>	ascii <=x"50"; --P
		when x"15" =>	ascii <=x"51"; --Q
		when x"2D" =>	ascii <=x"52"; --R
		when x"1B" =>	ascii <=x"53"; --S
		when x"2C" =>	ascii <=x"54"; --T
		when x"3C" =>	ascii <=x"55"; --U
		when x"2A" =>	ascii <=x"56"; --V
		when x"1D" =>	ascii <=x"57"; --W
		when x"22" =>	ascii <=x"58"; --X
		when x"35" =>	ascii <=x"59"; --Y
		when x"1A" =>	ascii <=x"5A"; --Z

	--Movimentacao
	-- escreve um espaço no ecra e muda a posicao do cursor,
	-- conforme space ou backspace
		when x"66" 	=>	ascii <= x"20";	-- BACKSPACE
		
		when x"29"	=>	ascii <= x"20";	-- SPACE
		
		when others	=>	null;

	end case;
	end if;
			
end process;
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
cursor_pos <= conv_std_logic_vector(posx+posy*39,11);
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
process(busy, scan_code, rst)
begin
	
	if rst='0' then
		posx <= 4; posy <= 4;
	
	elsif falling_edge(busy) then
		
		case scan_code is

		when x"16" => posx <= posx+1;	-- Digitos
		when x"1E" => posx <= posx+1;
		when x"26" => posx <= posx+1;
		when x"25" => posx <= posx+1;
		when x"2E" => posx <= posx+1;
		when x"36" => posx <= posx+1;
		when x"3D" => posx <= posx+1;
		when x"3E" => posx <= posx+1;
		when x"46" => posx <= posx+1;
		when x"45" => posx <= posx+1;

		when x"29" => posx <= posx+1;	-- SPACE
		when x"66" => posx <= posx-1;	-- BACKSPACE

		when x"1C" =>	posx <= posx+1; --A
		when x"32" =>	posx <= posx+1; --B
		when x"21" =>	posx <= posx+1; --C
		when x"23" =>	posx <= posx+1; --D
		when x"24" =>	posx <= posx+1; --E
		when x"2B" =>	posx <= posx+1; --F
		when x"34" =>	posx <= posx+1; --G
		when x"33" =>	posx <= posx+1; --H
		when x"43" =>	posx <= posx+1; --I
		when x"3B" =>	posx <= posx+1; --J
		when x"42" =>	posx <= posx+1; --K
		when x"4B" =>	posx <= posx+1; --L
		when x"3A" =>	posx <= posx+1; --M
		when x"31" =>	posx <= posx+1; --N
		when x"44" =>	posx <= posx+1; --O
		when x"4D" =>	posx <= posx+1; --P
		when x"15" =>	posx <= posx+1; --Q
		when x"2D" =>	posx <= posx+1; --R
		when x"1B" =>	posx <= posx+1; --S
		when x"2C" =>	posx <= posx+1; --T
		when x"3C" =>	posx <= posx+1; --U
		when x"2A" =>	posx <= posx+1; --V
		when x"1D" =>	posx <= posx+1; --W
		when x"22" =>	posx <= posx+1; --X
		when x"35" =>	posx <= posx+1; --Y
		when x"1A" =>	posx <= posx+1; --Z

		when others => null;
		end case;

		if posx=35 then
			posx <= 4; posy <= posy+1;
		elsif posy=25 then
			posy <= 25;
		-- se esta a apagar e esta no inicio de uma linha:
		elsif (posx=4 and scan_code=x"66" and posy>4) then
			posy <= posy-1; posx <= 35;
		-- dar a volta se chegar ao fim da janela:
		elsif (posx=35 and posy=25) then
			posx <= 4; posy <= 4;
		end if;
			
	end if;		

end process;
-------------------------------------------------------------------------------

end Behavioral;