-- EE552 
-- keyASCII.vhd
-- This code converts the scancode from the AT keyboard to ASCII code.

library ieee;
use ieee.std_logic_1164.all;
library work;
use work.key_pack.all;

entity keyASCII is
	generic(datawidth: positive:= 8);
	port(	key_in	:	in std_logic_vector(datawidth-1 downto 0);
			key_ascii:	out std_logic_vector(datawidth-1 downto 0));

end entity keyASCII;

architecture converter of keyASCII is
-- The alphabet - lower case only.
constant a:     std_logic_vector(datawidth-1 downto 0) := "01100001";--Hex: 61
constant b:     std_logic_vector(datawidth-1 downto 0) := "01100010";--Hex: 62
constant c:     std_logic_vector(datawidth-1 downto 0) := "01100011";--Hex: 63
constant d:     std_logic_vector(datawidth-1 downto 0) := "01100100";--Hex: 64
constant e:     std_logic_vector(datawidth-1 downto 0) := "01100101";--Hex: 65
constant f:     std_logic_vector(datawidth-1 downto 0) := "01100110";--Hex: 66
constant g:     std_logic_vector(datawidth-1 downto 0) := "01100111";--Hex: 67
constant h:     std_logic_vector(datawidth-1 downto 0) := "01101000";--Hex: 68
constant i:     std_logic_vector(datawidth-1 downto 0) := "01101001";--Hex: 69
constant j:     std_logic_vector(datawidth-1 downto 0) := "01101010";--Hex: 6A
constant k:     std_logic_vector(datawidth-1 downto 0) := "01101011";--Hex: 6B***
constant l:     std_logic_vector(datawidth-1 downto 0) := "01101100";--Hex: 6C
constant m:     std_logic_vector(datawidth-1 downto 0) := "01101101";--Hex: 6D
constant n:     std_logic_vector(datawidth-1 downto 0) := "01101110";--Hex: 6E
constant o:     std_logic_vector(datawidth-1 downto 0) := "01101111";--Hex: 6F
constant p:     std_logic_vector(datawidth-1 downto 0) := "01110000";--Hex: 70
constant q:     std_logic_vector(datawidth-1 downto 0) := "01110001";--Hex: 71
constant r:     std_logic_vector(datawidth-1 downto 0) := "01110010";--Hex: 72
constant s:     std_logic_vector(datawidth-1 downto 0) := "01110011";--Hex: 73
constant t:     std_logic_vector(datawidth-1 downto 0) := "01110100";--Hex: 74
constant u:     std_logic_vector(datawidth-1 downto 0) := "01110101";--Hex: 75
constant v:     std_logic_vector(datawidth-1 downto 0) := "01110110";--Hex: 76
constant w:     std_logic_vector(datawidth-1 downto 0) := "01110111";--Hex: 77***
constant x:     std_logic_vector(datawidth-1 downto 0) := "01111000";--Hex: 78 
constant y:     std_logic_vector(datawidth-1 downto 0) := "01111001";--Hex: 79****
constant z:     std_logic_vector(datawidth-1 downto 0) := "01111010";--Hex: 7A
-- The number and symbols
constant zero:	std_logic_vector(datawidth-1 downto 0) := "00110000";--Hex: 30
constant one:	std_logic_vector(datawidth-1 downto 0) := "00110001";--Hex: 31
constant two:	std_logic_vector(datawidth-1 downto 0) := "00110010";--Hex: 32
constant three:	std_logic_vector(datawidth-1 downto 0) := "00110011";--Hex: 33 *****
constant four:	std_logic_vector(datawidth-1 downto 0) := "00110100";--Hex: 34
constant five:	std_logic_vector(datawidth-1 downto 0) := "00110101";--Hex: 35**
constant six:	std_logic_vector(datawidth-1 downto 0) := "00110110";--Hex: 36
constant seven:	std_logic_vector(datawidth-1 downto 0) := "00110111";--Hex: 37*-*-*
constant eight:	std_logic_vector(datawidth-1 downto 0) := "00111000";--Hex: 38
constant nine:	std_logic_vector(datawidth-1 downto 0) := "00111001";--Hex: 39****
constant SP:	std_logic_vector(datawidth-1 downto 0) := "00100000";--Hex: 20
constant coma:	std_logic_vector(datawidth-1 downto 0) := "00101100";--Hex: 2C
constant period:std_logic_vector(datawidth-1 downto 0) := "00100111";--Hex: 27


-- Special Function: SHIFT:Read, ESC:Delete, ENTER:End of paragraph
constant ESC:   std_logic_vector(datawidth-1 downto 0) := "00010000";--Hex: 10
constant SHIFT: std_logic_vector(datawidth-1 downto 0) := "00010001";--Hex: 11
constant ENTER: std_logic_vector(datawidth-1 downto 0) := "00010010";--Hex: 12

begin

	key_ascii<= ENTER when key_in = x"5A" else
				ESC   when key_in = x"76" else
				SHIFT when key_in = x"12" else
				a when key_in = x"1c" else
				b when key_in = x"32" else
				c when key_in = x"21" else
				d when key_in = x"23" else
				e when key_in = x"24" else
				f when key_in = x"2b" else
				g when key_in = x"34" else
				h when key_in = x"33" else
				i when key_in = x"43" else
				j when key_in = x"3b" else
				k when key_in = x"42" else
				l when key_in = x"4b" else
				m when key_in = x"3a" else
				n when key_in = x"31" else
				o when key_in = x"44" else
				p when key_in = x"4d" else
				q when key_in = x"15" else
				r when key_in = x"2d" else
				s when key_in = x"1b" else
				t when key_in = x"2c" else
				u when key_in = x"3c" else
				v when key_in = x"2a" else
				w when key_in = x"1d" else
				x when key_in = x"22" else
				y when key_in = x"35" else
				z when key_in = x"1a" else
				zero   when key_in = x"45" else
				one    when key_in = x"16" else
				two    when key_in = x"1e" else
				three  when key_in = x"26" else
				four   when key_in = x"25" else
				five   when key_in = x"2e" else
				six    when key_in = x"36" else
				seven  when key_in = x"3d" else
				eight  when key_in = x"3e" else
				nine   when key_in = x"46" else
				SP     when key_in = x"29" else
				coma   when key_in = x"41" else
				period when key_in = x"49" ;

end architecture;