ledcontrol.vhd

交通灯的硬件描述语言设计

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY ledcontrol IS
	PORT(
		reset,clk,urgen		: IN	STD_LOGIC;
		state				: OUT	STD_LOGIC_VECTOR(1 DOWNTO 0);
		sub,set1,set2		: OUT	STD_LOGIC);
END ledcontrol;
ARCHITECTURE a OF ledcontrol IS
	SIGNAL count : STD_LOGIC_VECTOR(6 DOWNTO 0);
	SIGNAL subtemp: STD_LOGIC;

BEGIN
sub<=subtemp AND (NOT clk) ;
statelabel:
PROCESS (reset,clk)
BEGIN
IF reset='1' THEN
    count<="0000000";
	state<="00";
ELSIF clk'event AND clk='1' THEN
    IF urgen='0' THEN count<=count+1;subtemp<='1';ELSE subtemp<='0';END IF;
	IF count=0 then state<="00";set1<='1';set2<='1'; 
	ELSIF count=40 then state<="01";set1<='1';
	ELSIF count=45 THEN state<="10";set1<='1';set2<='1';
	ELSIF count=85 THEN state<="11";set2<='1';
	ELSIF count=90 THEN count<="0000000"; ELSE set1<='0'; set2<='0';END IF;
END IF;
END PROCESS statelabel;
END a;