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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use ieee.std_logic_unsigned.all;

entity pwm is

port (
 RESET : in STD_LOGIC;
 CLK : in STD_LOGIC;
 DATA_OUT :in STD_LOGIC_VECTOR (7 downto 0);
 ADRES : in STD_LOGIC_VECTOR (1 downto 0);
 NR_W :in STD_LOGIC;

 PWM_OUT : out STD_LOGIC;
 DATA_IN : out STD_LOGIC_VECTOR (7 downto 0)
);
end pwm;

architecture Behavioral of pwm is
SIGNAL WYPELNIENIE : STD_LOGIC_VECTOR (7 downto 0) := "00000000";
SIGNAL OKRES : STD_LOGIC_VECTOR (7 downto 0) := "00000000" ;
SIGNAL START : STD_LOGIC := '0' ;
SIGNAL LICZNIK : STD_LOGIC_VECTOR (7 downto 0) := "00000000";
SIGNAL BUFOR : STD_LOGIC_VECTOR (7 downto 0) := "00000000";
begin

KONFIGURATOR : PROCESS (CLK, RESET)
begin
	if(RESET = '0') then
		WYPELNIENIE <= (others => '0');
		OKRES <= (others => '0');
		LICZNIK <= (others => '0');
		BUFOR <= (others => '0');

	elsif (CLK'EVENT AND CLK = '1') then
		if ( NR_W = '1') then
			case ADRES is
               when "00" => OKRES <= DATA_OUT;
               when "01" => WYPELNIENIE <= DATA_OUT;
               when "10" => START <= DATA_OUT(0);
               when others => BUFOR <= "00000000";
			end case;

		elsif (NR_W = '0') then
			case ADRES is
               when "00" => BUFOR <= OKRES;
               when "01" => BUFOR <= WYPELNIENIE;
               when "10" => BUFOR <= "0000000" & START;
               when others => BUFOR <= "00000000";
			end case;
		end if;
end if;
end process KONFIGURATOR;


ZLICZNIK : PROCESS (CLK, RESET, START)
begin
	if(RESET = '0') then
		LICZNIK <= (others => '0');

	elsif (CLK'event and CLK = '1') then
		if (START = '0') then
			LICZNIK <= (others => '0');
		elsif ( START = '1') then
			if ( LICZNIK >= OKRES - 1) then
				LICZNIK <= LICZNIK + "00000001" ;
			elsif( LICZNIK > OKRES ) then
				LICZNIK <= (others => '0');
					end if;
			end if;
	end if;
end process ZLICZNIK;

KOMPARATOR : PROCESS (CLK, RESET, LICZNIK)
begin
	if ( START = '1') then
		if (CLK'event and CLK = '1') then
			if ( LICZNIK <= OKRES) then
					 PWM_OUT <= '1';
			elsif ( LICZNIK > OKRES) then
					 PWM_OUT <= '0';
			end if;
		end if;
	end if;
end process KOMPARATOR;

end Behavioral;