-----------------------------------------------------------------
-- ascii_to_vector.vhd
-- Christopher Kowalski
-- 
-- ASCII converter from a recieved ASCII value to an encoded bit
-- Vector
--
-- Following the code is a table containing the ASCII conversion.
--

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity ascii_to_vector is
	port(ascii : in std_logic_vector(6 downto 0);
		reset,
		clock,
		transfer : in std_logic;
		done : out std_logic;
		vector : out std_logic_vector(4 downto 0));
end ascii_to_vector;

architecture behavioural of ascii_to_vector is

	-- declare internal signals
		
begin

		
	convert : process (clock) is

	-- process variable
	variable count:natural range 0 to 2;
	
	begin
		if rising_edge(clock) then
		if reset = '1' then
			vector <= (others => '0');
			count := 0;
			done <= '0';
		elsif transfer = '1' then  -- a load signal
			if count = 2 then 	-- this gives the circuit time to have the
				done <= '1';	-- correct value at it's output

			else
			case ascii is
				
			when "0000000" =>
				vector <= "00000";

			when "0100000" =>
				vector <= "00001";

			when "0101110" =>
				vector <= "00010";

			when "0110000" =>
				vector <= "00011";

			when "0110001" =>
				vector <= "00100";

			when "0110010" =>
				vector <= "00101";

			when "0110011" =>
				vector <= "00110";

			when "0110100" =>
				vector <= "00111";

			when "0110101" =>
				vector <= "01000";

			when "0110110" =>
				vector <= "01001";

			when "0110111" =>
				vector <= "01010";

			when "0111000" =>
				vector <= "01011";

			when "0111001" =>
				vector <= "01100";

			when "0111010" =>
				vector <= "01101";

			when "1000001" =>
				vector <= "01110";

			when "1000010" =>
				vector <= "01111";

			when "1000011" =>
				vector <= "10000";

			when "1000100" =>
				vector <= "10001";

			when "1000101" =>
				vector <= "10010";

			when "1000110" =>
				vector <= "10011";

			when "1101101" =>
				vector <= "10100";

			when "1001110" =>
				vector <= "10101";

			when "1001111" =>
				vector <= "10110";

			when "1010010" =>
				vector <= "10111";

			when "1010011" =>
				vector <= "11000";

			when "1010100" =>
				vector <= "11001";

			when "1010101" =>
				vector <= "11010";

			when "1010110" =>
				vector <= "11011";

			when "1010111" =>
				vector <= "11100";

			when "1011010" =>
				vector <= "11101";

			when "0001101" =>
				vector <= "11110";

			when "1111111" =>
				vector <= "11111";

			when others =>
				vector <= "11111";

			end case;
			count:= (count +1);
			end if;

		elsif transfer = '0' then
			done <= '0';
			count := 0;

		end if;		
		end if;

	end process convert;
end behavioural;


--------------------------------------------------------------------------
-- |ASCII	|	ASCII in HEX	|	Binary Value	|	Encoded Vector	|
-- |--------|-------------------|-------------------|-------------------|
-- | Null	|	00				|	000 0000		|	00000			|
-- | Space	|	20				|	010 0000		|	00001			|
-- | Period	|	2E				|	010 1110		|	00010			|
-- | 0		|	30				|	011 0000		|	00011			|
-- | 1		|	31				|	011 0001		|	00100			|
-- | 2		|	32				|	011 0010		|	00101			|
-- | 3		|	33				|	011 0011		|	00110			|
-- | 4		|	34				|	011 0100		|	00111			|
-- | 5		|	35				|	011 0101		|	01000			|
-- | 6		|	36				|	011 0110		|	01001			|
-- | 7		|	37				|	011 0111		|	01010			|
-- | 8		|	38				|	011 1000		|	01011			|
-- | 9		|	39				|	011 1001		|	01100			|
-- | :		|	3A				|	011 1010		|	01101			|
-- | A		|	41				|	100 0001		|	01110			|
-- | B		|	42				|	100	0010		|	01111			|
-- | C		|	43				|	100	0011		|	10000			|
-- | D		|	44				|	100 0100		|	10001			|
-- | E		|	45				|	100 0101		|	10010			|
-- | F		|	46				|	100	0110		|	10011			|
-- | m		|	6D				|	110	1101		|	10100			|
-- | N		|	4E				|	100	1110		|	10101			|
-- | O		|	4F				|	100 1111		|	10110			|
-- | R		|	52				|	101	0010		|	10111			|
-- | S		|	53				|	101	0011		|	11000			|
-- | T		|	54				|	101 0100		|	11001			|
-- | U		|	55				|	101 0101		|	11010			|
-- | V		|	56				|	101 0110		|	11011			|
-- | W		|	57				|	101 0111		|	11100			|
-- | Z		|	5A				|	101	1010		|	11101			|
-- | <CR>	|	0D				|	000	1101		|	11110			|
-- | ERROR  |	--				|	--- ----		|	11111			|
--------------------------------------------------------------------------