cnt5.vhd

来自「这是本人在Max plus2环境下用VHDL语言编的交通灯控制程序。做EDA课程」· VHDL 代码 · 共 34 行

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY CNT5 IS
 PORT(CLK,EN5M,EN5B: IN STD_LOGIC;
      DOUT5:OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END ENTITY CNT5;
ARCHITECTURE  one OF CNT5 IS
  SIGNAL CNT3B:STD_LOGIC_VECTOR(2 DOWNTO 0);
 BEGIN 
PROCESS(CLK,EN5M,EN5B) IS
BEGIN 
IF(CLK'EVENT AND CLK='1') THEN
 IF EN5M='1' OR EN5B='1' THEN
CNT3B<=CNT3B+1;
ELSE
CNT3B<=CNT3B-CNT3B-1;
END IF;
END IF;
END PROCESS;
PROCESS (CNT3B)IS
 BEGIN 
  CASE CNT3B IS
WHEN "000" =>DOUT5<="00000101";
WHEN "001" =>DOUT5<="00000100";
WHEN "010" =>DOUT5<="00000011";
WHEN "011" =>DOUT5<="00000010";
WHEN "100" =>DOUT5<="00000001";
WHEN OTHERS=> DOUT5<="00000000";
END CASE;
END PROCESS;
END ARCHITECTURE one;