-- The Electronic Gardener
--
-- BCD to ASCII decoder
--
-- Mark Kudryk, Kim Ellis
-- 
-- module: bcd_ascii.vhd
-- author: Mark Kudryk
-- date: 
-- status: 
--
-- delay: 39.8 ns
-- gates: 50

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

entity bcd_ascii is
	port (bcd: in std_logic_vector (7 downto 0);
		  reset: in std_logic;
		  ascii_0, ascii_1: out std_logic_vector (7 downto 0));
end entity bcd_ascii;

architecture behaviour of bcd_ascii is

constant ascii_mask: std_logic_vector (7 downto 0) := "00110000";
signal ones: std_logic_vector(7 downto 0);

begin

	conversion: process(bcd, reset)

	begin
		
		if reset = '1' then
			ascii_0 <= "00000000";
			ascii_1 <= "00000000";
			ones <= "00000000";

		elsif bcd >= 50 then
			ascii_1 <= "00110101";
			ones <= bcd - 50;
			ascii_0 <= ones or ascii_mask;
		elsif bcd >= 40 then
			ascii_1 <= "00110100";
			ones <= bcd - 40;
			ascii_0 <= ones or ascii_mask;
		elsif bcd >= 30 then
			ascii_1 <= "00110011";
			ones <= bcd - 30;
			ascii_0 <= ones or ascii_mask;
		elsif bcd >= 20 then
			ascii_1 <= "00110010";
			ones <= bcd - 20;
			ascii_0 <= ones or ascii_mask;
		elsif bcd >= 10 then
			ascii_1 <= "00110001";
			ones <= bcd - 10;
			ascii_0 <= ones or ascii_mask;
		else
			ascii_1 <= "00100000";
			ascii_0 <= bcd or ascii_mask;
		end if;
		
	end process conversion;

end architecture behaviour;