LIBRARY IEEE;                                            -- 8進制計數(shù)器
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY CNT8 IS
    PORT ( CLK : IN STD_LOGIC;
             CQ : OUT STD_LOGIC_VECTOR(3 DOWNTO 0));
END CNT8;
ARCHITECTURE behav OF CNT8 IS
    SIGNAL CQI : STD_LOGIC_VECTOR(4 DOWNTO 0);
BEGIN
    PROCESS(CLK)
    BEGIN
       IF CLK'EVENT AND CLK = '1' THEN  CQI <= CQI + 1;  END IF;
    END PROCESS;
  CQ <= CQI(4 DOWNTO 1);
END behav;