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-- Company: 
-- Engineer: 
-- 
-- Create Date: 09.07.2021 09:54:12
-- Design Name: 
-- Module Name: ScreenDriver - Behavioral
-- Project Name: 
-- Target Devices: 
-- Tool Versions: 
-- Description: 
-- 
-- Dependencies: 
-- 
-- Revision:
-- Revision 0.01 - File Created
-- Additional Comments:
-- 
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
--use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating
-- any Xilinx leaf cells in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity ScreenDriver is
    Generic ( Nb_bits : Natural
            );
    Port ( CLK : in STD_LOGIC;
           Value : in STD_LOGIC_VECTOR (Nb_Bits - 1 downto 0);
           ValueAv : in STD_LOGIC;
           IsInt : in STD_LOGIC;
           OutData : out STD_LOGIC_VECTOR (0 to 6);
           OutDataAv : out STD_LOGIC);
end ScreenDriver;

architecture Behavioral of ScreenDriver is

    signal intern_value : STD_LOGIC_VECTOR (Nb_Bits - 1 downto 0) := (others => '0');
    signal current_hexa : STD_LOGIC_VECTOR (3 downto 0) := (others => '0');
    subtype compteur_T is Integer range -2 to Nb_bits/4 - 1;
    signal compteur : compteur_T := -2;
    signal first_detected : BOOLEAN := false;
     
    
    constant Code_ASCII_Zero : STD_LOGIC_VECTOR (0 to 6) := "0110000";
    

begin

    current_hexa <= intern_value(Nb_Bits - 1 - compteur * 4 downto Nb_Bits - compteur * 4 - 4) when compteur >= 0 and compteur < Nb_Bits else "0000";

    process
    begin
        wait until CLK'event and CLK = '1';
        if ValueAv = '1' then  
            if IsInt = '0' then
                OutData <= Value (6 downto 0);
            else 
                intern_value <= Value;
                OutData <= Code_ASCII_Zero;
                compteur <= compteur + 1;
            end if;
            OutDataAv <= '1';
        elsif compteur = -1 then
            OutData <= "1111000";
            compteur <= compteur + 1;
        elsif compteur >= 0 then
            if (current_hexa >= "0000" and current_hexa <= "1001") then
                if (not(current_hexa = "0000") or first_detected or compteur = Nb_bits/4 - 1 ) then
                    OutData <= "011" & current_hexa;
                    OutDataAv <= '1';
                    first_detected <= true;
                else
                    OutDataAv <= '0';
                end if;
            else 
                OutData <= ("000" & current_hexa) + "0110111";
                OutDataAv <= '1';
                first_detected <= true;
            end if;
        
            if (compteur = Nb_bits/4 - 1) then
                compteur <= -2;   
                first_detected  <= false;
            else 
                compteur <= compteur + 1;
            end if;
        else 
            OutDataAv <= '0';
        end if;
    end process;

end Behavioral;