car.vhd

汽车转向灯控制电路,采用循环点亮三个指示灯指出汽车的转弯方向。

LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE ieee.std_logic_arith.all;
USE ieee.std_logic_signed.all;
USE ieee.std_logic_unsigned.all;
ENTITY car IS
	PORT(
		CLK			: IN	STD_LOGIC;
		left,right	: IN	STD_LOGIC;
		lamp_left	: OUT 	STD_LOGIC_VECTOR(2 DOWNTO 0);
		lamp_right	: OUT 	STD_LOGIC_VECTOR(2 DOWNTO 0));
END car;
ARCHITECTURE car_body OF car IS
	SIGNAL ltmp : STD_LOGIC_VECTOR(2 DOWNTO 0);
	SIGNAL rtmp : STD_LOGIC_VECTOR(2 DOWNTO 0);
BEGIN
COUNT:
PROCESS(CLK)
	--VARIABLE __variable_name : STD_LOGIC;
BEGIN 
	IF CLK'EVENT AND CLK='1' THEN
		IF left='1' THEN
			IF ltmp="000" THEN 
				ltmp(0)<='1';
			ELSE ltmp(1)<=ltmp(0);ltmp(2)<=ltmp(1);ltmp(0)<=ltmp(2);
			END IF;
		ELSE ltmp<="000";
		END IF;
		IF right='1' THEN
			IF rtmp="000" THEN 
				rtmp(0)<='1';
			ELSE rtmp(1)<=rtmp(0);rtmp(2)<=rtmp(1);rtmp(0)<=rtmp(2);
			END IF;
		ELSE rtmp<="000";
		END IF;
	END IF;
	lamp_left<=ltmp;
	lamp_right<=rtmp;

END PROCESS COUNT;

END car_body;