library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_arith.all;
use IEEE.std_logic_unsigned.all;

entity controllore is
	port ( 
		CLK 		: in std_logic;
		RESET 		: in std_logic;
		GIRO_DX 	: in std_logic;
		GIRO_SX 	: in std_logic;
		STOP_IN 	: in unsigned(3 downto 0);
		SOGLIA_PROG : in std_logic;
		ABS_ON 		: out std_logic;
		SOGLIA 		: out unsigned(3 downto 0);
		FRENO_DX 	: out unsigned(3 downto 0);
		FRENO_SX 	: out unsigned(3 downto 0));
end controllore;

architecture ESAME of controllore is

type stato is (normal_mode_state,enabled_mode_state, active_mode_state);
signal cs,ns : stato;

signal soglia_int 									: unsigned(3 downto 0);
signal current_count_50ms, next_count_50ms 			: unsigned(5 downto 0);
signal current_count_100ms_sx, next_count_100ms_sx 	: unsigned(6 downto 0);
signal current_count_100ms_dx, next_count_100ms_dx 	: unsigned(6 downto 0);
signal active_abs,enable_abs,disable_abs,ms50, 
		current_mux, next_mux, abs_active, 
		abs_active_clk,abs_active_clk2,update_soglia: std_logic;
signal current_soglia, next_soglia, next_soglia_int : unsigned(3 downto 0);

begin

--contatore per 0.1 s
process(clk)
begin
	if clk'event and clk='1' then
		if reset = '1' or giro_sx = '1' or active_abs = '1' then
			current_count_100ms_sx <= conv_unsigned(0, 7);
		else
			current_count_100ms_sx <= next_count_100ms_sx;
		end if;
	end if;
end process;
next_count_100ms_sx <= current_count_100ms_sx + conv_unsigned (1,7);

--contatore per 0.1 s
process(clk)
begin
	if clk'event and clk='1' then
		if reset = '1' or giro_dx = '1' or active_abs = '1' then
			current_count_100ms_dx <= conv_unsigned(0, 7);
		else
			current_count_100ms_dx <= next_count_100ms_dx;
		end if;
	end if;
end process;
next_count_100ms_dx <= current_count_100ms_dx + conv_unsigned (1,7);

--attivazione abs
active_abs <= '1' when ((current_count_100ms_sx = conv_unsigned(10,7)) or (current_count_100ms_dx = conv_unsigned(10,7))) else
			  '0';

--definizione della soglia
soglia_int <= conv_unsigned(10,4) when soglia_prog = '0' else
			  current_soglia;

-- comparatore di soglia
enable_abs <= 	'1' when (STOP_IN >= soglia_int) else
				'0';
-- comparatore di soglia 
disable_abs <=  '1' when (STOP_IN <= conv_unsigned(1,4)) else
				'0';

-- contatore per 50 ms
process(clk)
begin
	if clk'event and clk='1' then
		if reset = '1' or ms50='1' then
			current_count_50ms <= conv_unsigned(0, 6);
		else
			current_count_50ms	 <= next_count_50ms;
		end if;
	end if;
end process;

next_count_50ms <= 	current_count_50ms + conv_unsigned (1,6);
ms50 			<= 	'1' when current_count_50ms = conv_unsigned (2,6) else
					'0';

--clk_divider
process(clk,reset,ms50)
begin
	if reset = '1' then
		current_mux <= '0';
	else
		if clk'event and clk='1' then
			if ms50 = '1' then
				current_mux	 <= next_mux;
			end if;
		end if;
	end if;
end process;

next_mux <= not current_mux;

--output mux
process(STOP_IN,abs_active,current_mux)
begin
	if(abs_active = '1') then 
		if current_mux = '1' then
			FRENO_DX <= STOP_IN;
			FRENO_SX <= STOP_IN;
		else
			FRENO_DX <= (others=>'0');
			FRENO_SX <= (others=>'0');
		end if;
	else
		FRENO_DX <= STOP_IN;
		FRENO_SX <= STOP_IN;
	end if;
end process;

-- macchina a stati
process(clk,reset)
begin
	if reset = '1' then
		cs <= normal_mode_state;
	else
		if clk'event and clk='1' then
			cs <= ns;
		end if;
	end if;
end process;

process(cs,enable_abs, active_abs, disable_abs)
begin

abs_active <= '0';

case cs is 
	when normal_mode_state =>
		abs_active <= '0';
		if(enable_abs = '1') then
			ns <= enabled_mode_state;
		else
			ns <= cs;
		end if;
		
	when enabled_mode_state =>
		abs_active <= '0';
		if (enable_abs = '0') then
			ns <= normal_mode_state;
		elsif (active_abs = '1') then
			ns <= active_mode_state;
		else
			ns <= cs;
		end if;
		
	when active_mode_state =>
		abs_active <= '1';
		if (disable_abs = '1') then
			ns <= normal_mode_state;
		else
			ns <= cs;
		end if;
		
	when others =>
		ns <= normal_mode_state;
		
end case;

end process;

abs_on <= abs_active;
SOGLIA <= soglia_int;

--seconda parte
--coppia di registri per campionare il fronte di salita di abs_active
process(clk,reset)
begin
	if reset = '1' then
		abs_active_clk <= '0';
	else
		if clk'event and clk='1' then
			abs_active_clk <= abs_active;
		end if;
	end if;
end process;

process(clk,reset)
begin
	if reset = '1' then
		abs_active_clk2 <= '0';
	else
		if clk'event and clk='1' then
			abs_active_clk2 <= abs_active_clk;
		end if;
	end if;
end process;

update_soglia <= '1' when abs_active_clk2 = '0' and abs_active_clk = '1' else
				 '0';

process(clk,reset,abs_active)
begin
	if reset = '1' then
		current_soglia<= conv_unsigned(0,4);
	else
		if clk'event and clk='1' then
			if update_soglia = '1' then
				current_soglia	 <= next_soglia;
			end if;
		end if;
	end if;
end process;

next_soglia_int <= (current_soglia + stop_in);
next_soglia <= "0"&next_soglia_int(2 downto 0);

end esame;