leddongtai.vhd

CPLD控制交通灯程序

LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE ieee.std_logic_unsigned.all;
ENTITY leddongtai IS
	PORT
	(
		clock :IN STD_LOGIC;		--clock is 1KHZ
		flash : IN STD_LOGIC;
		ewh,ewl,snh,snl : IN STD_LOGIC_VECTOR(6 DOWNTO 0);
		leddisp : OUT STD_LOGIC_VECTOR(6 DOWNTO 0);
		sel : OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
		dp : OUT STD_LOGIC
	);
END leddongtai;

ARCHITECTURE one OF leddongtai IS
SIGNAL count : INTEGER RANGE 0 TO 4;
BEGIN
	PROCESS (clock)
	BEGIN
		IF rising_edge(clock) THEN
			IF flash = '1' THEN
				count <= 4;
			ELSE
				IF count <3 THEN
					count <= count+1;
				ELSE
					count <= 0;
				END IF;
			END IF;
			CASE count IS
				WHEN 0 => leddisp <= ewl; sel <= "1110";
				WHEN 1 => leddisp <= ewh; sel <= "1101";
				WHEN 2 => leddisp <= snl; sel <= "1011";
				WHEN 3 => leddisp <= snh; sel <= "0111";
				WHEN OTHERS => leddisp <= "1111111"; sel <= "1111";
			END CASE;
		END IF;
	END PROCESS;
	dp <= '1';
END one;