library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
  
entity RAM9X8_Peripheral is	
	generic(
		PER_BASE_ADDRESS : integer := 40;
		
		DATA_BUS_WIDTH : integer := 8;
		ADDRESS_BUS_WIDTH : integer := 9
	);
	
	port(
		clk : in std_logic;
		
		data : inout std_logic_vector(DATA_BUS_WIDTH - 1 downto 0);
		address : in std_logic_vector(ADDRESS_BUS_WIDTH - 1 downto 0);
		we : in std_logic;
		oe : in std_logic;
		ce : in std_logic;	
	
		asyncline : out std_logic := '1';
      divclk : out std_logic := '1';
      error : in std_logic;
		init : in std_logic
	); 
end entity;

architecture behavorial of RAM9X8_Peripheral is

signal PER_ACTIVE_DEVICE_LOWER : integer := PER_BASE_ADDRESS;
signal PER_ACTIVE_DEVICE_UPPER : integer := PER_BASE_ADDRESS + 1;
signal PER_REZERVED_1_LOWER : integer := PER_BASE_ADDRESS + 2;
signal PER_REZERVED_1_UPPER : integer := PER_BASE_ADDRESS + 3;
signal PER_REZERVED_2_LOWER : integer := PER_BASE_ADDRESS + 4;
signal PER_REZERVED_2_UPPER : integer := PER_BASE_ADDRESS + 5;

signal activeDeviceBuf : std_logic_vector(15 downto 0) := (others => '0');
signal rezerved1Buf : std_logic_vector(15 downto 0) := (others => '0');
signal rezerved2Buf : std_logic_vector(15 downto 0) := (others => '0');

signal divClkBuf : std_logic := '0';
signal divClkBufPWM : std_logic := '0';

signal addrBuf : std_logic_vector(3 downto 0) := (others => '0');

signal LedState : std_logic_vector(1 downto 0) := (others => '0');

type   BusSt is (Waiting, A3, A2, A1, A0, Dt, Finish);  
signal BusState  : BusSt := Waiting;

signal countBuf : std_logic_vector(3 downto 0) := (others => '0');
signal countBufPWM : std_logic_vector(3 downto 0) := (others => '0');

begin	

	process (we, oe, ce)
		variable addr : integer range 0 to 2**ADDRESS_BUS_WIDTH - 1 := 0;
	begin
		if (ce = '0') then  -- Если микросхема выбрана
			addr := conv_integer(address);
			if (addr = PER_ACTIVE_DEVICE_UPPER or addr = PER_ACTIVE_DEVICE_LOWER 
				or addr = PER_REZERVED_1_UPPER or addr = PER_REZERVED_1_LOWER
				or addr = PER_REZERVED_2_UPPER or addr = PER_REZERVED_2_LOWER) then
				if (oe = '0' and we = '1') then  -- Если сигнал чтения активен, а записи нет	
					case addr is
						when PER_ACTIVE_DEVICE_UPPER =>
							data <= activeDeviceBuf(15 downto 8);
						when PER_ACTIVE_DEVICE_LOWER =>
							data <= activeDeviceBuf(7 downto 0);
						when PER_REZERVED_1_UPPER =>
							data <= rezerved1Buf(15 downto 8);
						when PER_REZERVED_1_LOWER =>
							data <= rezerved1Buf(7 downto 0);
						when PER_REZERVED_2_UPPER =>
							data <= rezerved2Buf(15 downto 8);
						when PER_REZERVED_2_LOWER =>
							data <= rezerved2Buf(7 downto 0);	
						when others => 
							data <= (others => 'Z');  -- Запретить запись на шину
					end case;				
				elsif (oe = '1' and we = '0') then  -- Если сигнал записи активен, а чтения нет
					case addr is
						when PER_ACTIVE_DEVICE_UPPER =>
							activeDeviceBuf(15 downto 8) <= data;
						when PER_ACTIVE_DEVICE_LOWER =>
							activeDeviceBuf(7 downto 0) <= data;
						when PER_REZERVED_1_UPPER =>
							rezerved1Buf(15 downto 8) <= data;
						when PER_REZERVED_1_LOWER =>
							rezerved1Buf(7 downto 0) <= data;
						when PER_REZERVED_2_UPPER =>
							rezerved2Buf(15 downto 8) <= data;
						when PER_REZERVED_2_LOWER =>
							rezerved2Buf(7 downto 0) <= data;	
						when others =>
							data <= (others => 'Z');  -- Запретить запись на шину
					end case;
				else
					data <= (others => 'Z');  -- Запретить запись на шину
				end if;
			else 
				data <= (others => 'Z');  -- Запретить запись на шину
			end if;	
		else
			data <= (others => 'Z');  -- Запретить запись на шину
		end if;
	end process;
	
	process(clk) is
		variable count50000 : integer range 0 to 50000 := 0;
		variable count50 : integer range 0 to 50 := 0;
	begin
		if rising_edge(clk) then
			if count50000 < 50000 then	
				count50000 := count50000 + 1;
			else
				divClkBufPWM <= not divClkBufPWM;
				count50000 := 0;
				if count50 < 50 then
					count50 := count50 + 1;
				else
					count50 := 0;
					divClkBuf <= not divClkBuf;
				end if;	
			end if;	
		end if;	
	end process;
	
	process(divClkBufPWM) is
	begin
		if conv_integer(countBufPWM) < 15 then
			countBufPWM <= conv_std_logic_vector(conv_integer(countBufPWM) + 1, 4);
		else
			countBufPWM <= (others => '0');
		end if;	
	end process;

	process(divClkBuf) is
		variable direction : integer range 0 to 1 := 0;
	begin
		if direction = 0 then
			if conv_integer(countBuf) < 15 then
				countBuf <= conv_std_logic_vector(conv_integer(countBuf) + 1, 4);
			else
				direction := 1;
			end if;
		else	
			if conv_integer(countBuf) > 0 then
				countBuf <= conv_std_logic_vector(conv_integer(countBuf) - 1, 4);
			else
				direction := 0;
			end if;
		end if;	
	end process;
	
	process(divClkBuf) is
		variable count15 : integer range 0 to 15 := 0;
	begin
		case LedState is
			when b"00" =>
				if count15 < 15 then
					count15 := count15 + 1;
				else
					count15 := 0;
					LedState <= b"01";
				end if;
				divclk <= '0';
			when b"01" =>
				if count15 < 7 then
					count15 := count15 + 1;
				else
					count15 := 0;
					LedState <= b"10";
				end if;
				divclk <= '1';
			when b"10" =>
				if count15 < 15 then
					count15 := count15 + 1;
				else
					count15 := 0;
					LedState <= b"11";
				end if;
				divclk <= '0';
			when b"11" =>
				if count15 < 4 then
					count15 := count15 + 1;
				else
					count15 := 0;
					LedState <= b"00";
				end if;
				divclk <= '1';
			when others =>	
				LedState <= b"00";
		end case;	
	end process;
	
	process(clk) is
		variable count50 : integer range 0 to 50 := 0;
		variable count15 : integer range 0 to 15 := 15;
	begin
		if rising_edge(clk) then
			if init = '0' then
				case BusState is
					when Waiting =>
						if count50 < 38 then	
							count50 := count50 + 1;
						else							
							if count15 < 15 then
								count15 := count15 + 1;
							else 
								count15 := 0;								
							end if;
							if activeDeviceBuf(count15) = '1' then
								addrBuf <= conv_std_logic_vector(count15, 4);
								asyncline <= '0';
								count50 := 0;
								BusState <= A3;
							end if;	
						end if;
					when A3 =>
						if count50 < 18 then
							count50 := count50 + 1;
						else
							count50 := 0;
							asyncline <= addrBuf(3);
							BusState <= A2;
						end if;
					when A2 =>
						if count50 < 38 then
							count50 := count50 + 1;
						else
							count50 := 0;
							asyncline <= addrBuf(2);
							BusState <= A1;
						end if;
					when A1 =>
						if count50 < 38 then
							count50 := count50 + 1;
						else
							count50 := 0;
							asyncline <= addrBuf(1);
							BusState <= A0;
						end if;
					when A0 =>
						if count50 < 38 then
							count50 := count50 + 1;
						else
							count50 := 0;
							asyncline <= addrBuf(0);
							BusState <= Dt;
						end if;
					when Dt =>
						if count50 < 38 then
							count50 := count50 + 1;
						else
							count50 := 0;
							asyncline <= divClkBuf;
							BusState <= Finish;
						end if;	
					when Finish =>
						if count50 < 38 then
							count50 := count50 + 1;
						else
							count50 := 0;
							asyncline <= '1';
							BusState <= Finish;
						end if;
					when others =>
						BusState <= Waiting;
						count50 := 0;
						count15 :=15;
				end case;
			else	
				BusState <= Waiting;
				count50 := 0;
				count15 := 15;
				if error = '0' then
					if countBuf < countBufPWM then
						asyncline <= '1';
					else
						asyncline <= '0';
					end if;	
				else
					asyncline <= '1';
				end if;	
			end if;	
		end if;	
	end process;
	
end behavorial;