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-- This a demo to test the led_counter --
-- 2009.10.13 written by kr --
LIBRARY IEEE;
USE IEEE.std_logic_1164.ALL;
ENTITY led_counter IS
PORT(
i:IN std_logic;
a:OUT std_logic;
b:OUT std_logic);
-- c:OUT std_logic;
-- e:OUT std_logic;
-- f:OUT std_logic;
-- g:OUT std_logic;
-- h:OUT std_logic);
END led_counter;
ARCHITECTURE behave_arc OF led_counter IS
Shared VARIABLE count : integer RANGE 0 TO 255 :=0;
BEGIN
PROCESS(i)
BEGIN
IF(i = '1') THEN count := count+1;
END IF;
IF(count>=1)THEN a<='1';
END IF;
IF(count>=2)THEN a<='1'; b<='1';
END IF;
END PROCESS;
END behave_arc;
我的想法是,先弄简单点,按一下,a灯亮,再按一次,a,b灯亮,现在问题是不按键,a,b灯都亮。不知为何,仿真也一样。
小弟初学,问题比较幼稚,谢谢大家了。 |
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