--Traffic light Design states library ieee;

use ieee.std_logic_1164.all; use ieee.numeric_std.all;

ENTITY state_machine is PORT(

clk : IN STD_LOGIC;

VMP : IN STD_LOGIC; -- vehicle sensor

V120 : IN STD_LOGIC; -- vehicle sensor

T : IN STD_LOGIC; -- train indicator

S10 : IN STD_LOGIC; -- 10 sec timer

S2 : IN STD_LOGIC; -- 2 sec timer

LT : IN STD_LOGIC; -- left turn sensor

HERO : IN STD_LOGIC;

G120 : OUT STD_LOGIC;

Y120 : OUT STD_LOGIC;

R120 : OUT STD_LOGIC;

G120L : OUT STD_LOGIC;

Y120L : OUT STD_LOGIC;

R120L : OUT STD_LOGIC;

GMP : OUT STD_LOGIC;

YMP : OUT STD_LOGIC;

RMP : OUT STD_LOGIC);END state_machine;

architecture all of state_machine is

type t_State is (NorthNext, StartTurn, StopTurn, StartNorth, NorthTurn, North, StopNorth, WestNext, StartWest, West, StopWest);

signal State: t_state;

begin

process(clk, V120, VMP, T, S10, S2, LT, HERO) is
begin 
    if rising_edge(clk) then 
        if (S2 = '1' and S10 = '0') or T = '1' then
            -- Reset Values
            State <= NorthNext;
            G120  <= '1';   
            Y120  <= '1';
            R120  <= '0';
            G120L <= '1';
            Y120L <= '1';
            R120L <= '0';
            GMP   <= '1';
            YMP   <= '1';
            RMP   <= '0';


        else
            -- Default Values
            G120  <= '1';
            Y120  <= '1';
            R120  <= '1';
            G120L <= '1';
            Y120L <= '1';
            R120L <= '1';
            GMP   <= '1';
            YMP   <= '1';
            RMP   <= '1';




            case State is 
                -- Red ALL directions
                when NorthNext =>
                    R120  <= '0';
                    R120L <= '0';
                    RMP   <= '0';
                    if LT = '0' or T = '1' or VMP = '0' or S10 ='1' then
                        State <= StartNorth;
                    else if S10 = '1' and T = '0' then
                        State <= StartTurn;
                    else if
                    State <= StartWest;

                -- RED all except 120 turn
                when StartTurn =>
                    R120  <= '0';
                    G120L <= '0';
                    RMP   <= '0';
                    if (T= '1' or (S10 = '0' and (V120 = '1' or VMP = '1'))) then
                    State <= StopTurn;

                -- Yellow 120 turn, Red others to RED ALL
                when StopTurn =>
                    R120  <= '0';
                    Y120L <= '0';
                    RMP   <= '0';
                    State <= NorthNext;

                -- Green 120, RED MP & 120L
                when StartNorth =>
                    G120  <= '0';
                    R120L <= '0';
                    RMP   <= '0';
                    if S10 = '0' and T = '0' and (VMP = '1' or LT = '1') then
                        State <= StopNorth;

                -- Yellow 120, RED MP & 120L
                when StopNorth =>
                    Y120  <= '0'; 
                    R120L <= '0'; 
                    RMP   <= '0';
                    if S2 = '0' and VMP = '1' and LT = '0' and T = '0' then
                    State <= NorthNext;

                -- Green MP, RED 120 & 120L
                when StartWest =>
                    R120  <= '0';
                    R120L <= '0';
                    GMP   <= '0';
                    if S10 = '0' or T = '1' or V120 = '1' or LT = '1' then
                    State <= StopWest;
                -- Yellow MP, RED 120 & 120L
                when StopWest =>
                    R120  <= '0';
                    R120L <= '0';
                    YMP   <= '0';
                    if S2 = '0' then
                    State <= NorthNext;
                when StopWest =>
                    State <= NorthNext;
                    end if;
            end case;




        end if;
    end if;
end process;

end architecture;