----------------------------------------------------------------------------------
-- Engineer:         Pasquale Boemio
--
-- Create Date:    17:48:53 01/03/2012
-- Module Name:    SevenSegmentDisplay - Behavioral
-- Project Name:     ALUProject
-- Target Devices: xc3s1200e-4fg320
-- Description:      Modulo utilizzato per rappresentare un numero sul display
--                   (viene effettuata anche la conversione bin to hex)
--
-- Revision 0.01 - File Created
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

-----------------------------------------------
-- Vista esterna del blocco SevenSegmentDisplay
-----------------------------------------------
entity SevenSegmentDisplay is
    Port ( cifre : in  STD_LOGIC_VECTOR (7 downto 0);
           clock : in  STD_LOGIC;
              complement : in STD_LOGIC;
           anodi : inout  STD_LOGIC_VECTOR (3 downto 0) := "1110";
           sevenSegments : out  STD_LOGIC_VECTOR (6 downto 0));
end SevenSegmentDisplay;
-----------------------------------------------

architecture Behavioral of SevenSegmentDisplay is

----------------------------------------
-- Definizione di un blocco ClockSpeeder
----------------------------------------
component clockGenerator
    Port ( slowerClock : in STD_LOGIC;
             fasterClock : out STD_LOGIC);
end component clockGenerator;
for innerClockGenerator : clockGenerator use entity ClockSpeeder(Behavioral);
----------------------------------------

---------------------------------------------
-- Definizione di un segnale di clock interno
---------------------------------------------
signal innerClock : STD_LOGIC;
---------------------------------------------

-----------------------------------------
-- Definizione delle codifiche dei numeri
-----------------------------------------
constant zero : STD_LOGIC_VECTOR(6 downto 0) := "1000000";
constant uno : STD_LOGIC_VECTOR(6 downto 0) := "1111001";
constant due : STD_LOGIC_VECTOR(6 downto 0) := "0100100";
constant tre : STD_LOGIC_VECTOR(6 downto 0) := "0110000";
constant quattro : STD_LOGIC_VECTOR(6 downto 0) := "0011001";
constant cinque : STD_LOGIC_VECTOR(6 downto 0) := "0010010";
constant sei : STD_LOGIC_VECTOR(6 downto 0) := "0000010";
constant sette : STD_LOGIC_VECTOR(6 downto 0) := "1111000";
constant otto : STD_LOGIC_VECTOR(6 downto 0) := "0000000";
constant nove : STD_LOGIC_VECTOR(6 downto 0) := "0010000";
constant a : STD_LOGIC_VECTOR(6 downto 0) := "0001000";
constant b : STD_LOGIC_VECTOR(6 downto 0) := "0000011";
constant c : STD_LOGIC_VECTOR(6 downto 0) := "1000110";
constant d : STD_LOGIC_VECTOR(6 downto 0) := "0100001";
constant e : STD_LOGIC_VECTOR(6 downto 0) := "0000110";
constant f : STD_LOGIC_VECTOR(6 downto 0) := "0001110";
constant minSimbol : STD_LOGIC_VECTOR(6 downto 0) := "0111111";


signal firstHex : STD_LOGIC_VECTOR(6 downto 0) := zero;
signal secondHex : STD_LOGIC_VECTOR(6 downto 0) := zero;
signal sign : STD_LOGIC_VECTOR(6 downto 0) := "1111111";
-----------------------------------------

-------------------------------------------------------------------
-- Segnali utilizzati per suddividere il numero nelle due cifre hex
-------------------------------------------------------------------
signal lessSignificative : STD_LOGIC_VECTOR(3 downto 0);
signal moreSignificative : STD_LOGIC_VECTOR(3 downto 0);
-------------------------------------------------------------------

begin

innerClockGenerator : clockGenerator port map(clock, innerClock); -- Cablaggio del generatore di clock

--------------------------------------------------
-- Processo che mostra le cifre su ciascun display
--------------------------------------------------
display_process : process(innerClock) begin
    if innerClock'event and innerClock = '1' then
        case anodi is
            when "1110" => sevenSegments <= firstHex; --firstHex;
                                anodi <= "1101";
            when "1101" => sevenSegments <= secondHex;
                                anodi <= "1011";
            when "1011" => sevenSegments <= "0001001";
                                anodi <="0111";
            when "0111" => sevenSegments <= sign;
                                anodi <= "1110";
            when others => null;
        end case;
    end if;
end process display_process;
--------------------------------------------------

---------------------------------------------------------
-- Processo che codifica le cifre per essere visualizzate
---------------------------------------------------------
numberDecoder_process: process(cifre)
begin
    lessSignificative <= cifre(3 downto 0);
    moreSignificative <= cifre(7 downto 4);

    if complement = '0' then
        case lessSignificative is
            when "0000" => firstHex <= zero;
            when "0001" => firstHex <= uno;
            when "0010" => firstHex <= due;
            when "0011" => firstHex <= tre;
            when "0100" => firstHex <= quattro;
            when "0101" => firstHex <= cinque;
            when "0110" => firstHex <= sei;
            when "0111" => firstHex <= sette;
            when "1000" => firstHex <= otto;
            when "1001" => firstHex <= nove;
            when "1010" => firstHex <= a;
            when "1011" => firstHex <= b;
            when "1100" => firstHex <= c;
            when "1101" => firstHex <= d;
            when "1110" => firstHex <= e;
            when "1111" => firstHex <= f;
            when others => null;
        end case;

        case moreSignificative is
            when "0000" => secondHex <= zero;
            when "0001" => secondHex <= uno;
            when "0010" => secondHex <= due;
            when "0011" => secondHex <= tre;
            when "0100" => secondHex <= quattro;
            when "0101" => secondHex <= cinque;
            when "0110" => secondHex <= sei;
            when "0111" => secondHex <= sette;
            when "1000" => secondHex <= otto;
            when "1001" => secondHex <= nove;
            when "1010" => secondHex <= a;
            when "1011" => secondHex <= b;
            when "1100" => secondHex <= c;
            when "1101" => secondHex <= d;
            when "1110" => secondHex <= e;
            when "1111" => secondHex <= f;
            when others => null;
        end case;

        sign <= "1111111";
    else
        case lessSignificative is
            when "0000" => firstHex <= zero;
            when "0001" => firstHex <= f;
            when "0010" => firstHex <= e;
            when "0011" => firstHex <= d;
            when "0100" => firstHex <= c;
            when "0101" => firstHex <= b;
            when "0110" => firstHex <= a;
            when "0111" => firstHex <= nove;
            when "1000" => firstHex <= otto;
            when "1001" => firstHex <= sette;
            when "1010" => firstHex <= sei;
            when "1011" => firstHex <= cinque;
            when "1100" => firstHex <= quattro;
            when "1101" => firstHex <= tre;
            when "1110" => firstHex <= due;
            when "1111" => firstHex <= uno;
            when others => null;
        end case;

        case moreSignificative is
            when "0000" => secondHex <= zero;
            when "0001" => secondHex <= uno;
            when "0010" => secondHex <= due;
            when "0011" => secondHex <= tre;
            when "0100" => secondHex <= quattro;
            when "0101" => secondHex <= cinque;
            when "0110" => secondHex <= sei;
            when "0111" => secondHex <= sette;
            when "1000" => secondHex <= sette;
            when "1001" => secondHex <= sei;
            when "1010" => secondHex <= cinque;
            when "1011" => secondHex <= quattro;
            when "1100" => secondHex <= tre;
            when "1101" => secondHex <= due;
            when "1110" => secondHex <= uno;
            when "1111" => secondHex <= zero;
            when others => null;
        end case;

        if moreSignificative(3)='1' then
            sign <= minSimbol;
        else
            sign <= "0000000";
        end if;

    end if;

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

end Behavioral;