cnt10b.vhd

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LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY CNT10B IS
	PORT(LD,CLK,RST,EN:IN STD_LOGIC;
		Q:IN STD_LOGIC_VECTOR(3 DOWNTO 0);
		CQ:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
		COUT:OUT STD_LOGIC );
END CNT10B;

ARCHITECTURE BEHAV OF CNT10B IS
BEGIN
 PROCESS(CLK,RST,EN)
  VARIABLE CQI:STD_LOGIC_VECTOR(3 DOWNTO 0);
 BEGIN
 	IF RST='1' THEN CQI:=(OTHERS=>'0');
 	 ELSIF CLK'EVENT AND CLK='1' THEN
 	  IF LD='1' THEN CQI:=Q;
 	  ELSIF EN='1' THEN
 	   IF CQI<9 THEN  CQI:=CQI+1 ;
 	    	  COUT<='0';
 	   ELSE   CQI:=(OTHERS=>'0') ;
 	          COUT<='1';
 	   END IF;
 	  END IF;
 	 END IF;
 	CQ<=CQI ;
 	END PROCESS ;
 END BEHAV;