count05.vhd

来自「该程序是用一片HDPLD和若干外围电路实现的十字路口交通控制器,其中包含顶层图形」· VHDL 代码 · 共 29 行

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

ENTITY count05 IS
	PORT(
		clk:IN STD_LOGIC;
		enable:IN STD_LOGIC;
		c:OUT STD_LOGIC);
END count05;
ARCHITECTURE arc_count05 OF count05 IS
BEGIN
	PROCESS(clk)
		VARIABLE cnt:INTEGER RANGE 5 DOWNTO 0;
	BEGIN
		IF (clk 'EVENT AND clk = '1') THEN
			IF enable = '1' AND cnt < 5 THEN
				cnt := cnt + 1;
			ELSE
				cnt := 0;
			END IF;
		END IF;
		IF cnt = 5 THEN
			C <= '1';
		ELSE
			C <= '0';
		END IF;
	END PROCESS;
END arc_count05;