Library ieee;
use ieee.std_logic_1164.all;
PORT (Right,Left,Hazard : IN STD_LOGIC;
Clk, Reset : IN STD_LOGIC;
LA,LB,LC : OUT STD_LOGIC;
RA,RB,RC : OUT STD_LOGIC);
END Vehicle_Tail_Lights_control;
ARCHITECTURE state_machine OF Vehicle_Tail_Lights_control IS
TYPE state_type IS (Idle,L1,L2,L3,R1,R2,R3,LR3);
attribute ENUM_ENCODING: STRING;
attribute ENUM_ENCODING of state_type: type is
"000 001 011 010 101 111 110 100";
SIGNAL current_state, next_state : state_type;
BEGIN
PROCESS(Clk,Reset,next_state)
BEGIN
if (Reset='0') then
current_state<= Idle;
elsif (Clk'event AND Clk='1') then
current_state <= next_state;
end if;
END PROCESS;
PROCESS(current_state,Right,Left,Hazard)
BEGIN
CASE current_state IS
WHEN idle =>
Lc<='0';Lb<='0';La<='0';Ra<='0';Rb<='0';Rc<='0';
IF ( (Hazard='1') OR ((Left='1') AND (Right='1')))
THEN next_state <= LR3;
ELSIF ( (Hazard='0') AND (Left='0') AND (Right='1'))
THEN next_state <= R1;
ELSIF ((Hazard='0') AND (Left='1') AND (Right='0'))
THEN next_state <= L1;
ELSE
next_state <= Idle;
END IF;
WHEN L1 =>
Lc<='0';Lb<='0';La<='1';Ra<='0';Rb<='0';Rc<='0';
IF (Hazard = '1') THEN next_state <= LR3;
ELSE next_state <= L2;
END IF;
WHEN L2 =>
Lc<='0';Lb<='1';La<='1';Ra<='0';Rb<='0';Rc<='0';
IF (Hazard = '1') THEN next_state <= LR3;
ELSE next_state <= L3;
END IF;
WHEN L3 =>
Lc<='1';Lb<='1';La<='1';Ra<='0';Rb<='0';Rc<='0';
next_state <= Idle;
WHEN R1 =>
Lc<='0';Lb<='0';La<='0';Ra<='1';Rb<='0';Rc<='0';
IF (Hazard = '1') THEN next_state <= LR3;
ELSE next_state <= R2;
END IF;
WHEN R2 =>
Lc<='0';Lb<='0';La<='0';Ra<='1';Rb<='1';Rc<='0';
IF (Hazard = '1') THEN next_state <= LR3;
ELSE next_state <= R3;
END IF;
WHEN R3 =>
Lc<='0';Lb<='0';La<='0';Ra<='1';Rb<='1';Rc<='1';
next_state <= Idle;
WHEN LR3 =>
Lc<='1';Lb<='1';La<='1';Ra<='1';Rb<='1';Rc<='1';
next_state <= idle;
END CASE;
END PROCESS;
END state_machine;
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