例 1 、三进程方式描述状态机
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LIBRARY IEEE;
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USE IEEE.STD_LOGIC_1164.ALL;
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ENTITY tra# c1 IS
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PORT(clk,tg,ty : IN STD_LOGIC;
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lights : OUT STD_LOGIC_VECTOR(5
DOWNTO 0));
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END tra# c1;
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ARCHITECTURE a OF tra# c1 IS
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TYPE STATE_TYPE IS
(green_red,yellow_red,red_green,red_yellow);
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SIGNAL present_state,next_state:
STATE_TYPE;
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BEGIN
定义状态类型
定义状态信号
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