cnt10.vhd

来自「Alera 的8051 IP core的示例文件5个」· VHDL 代码 · 共 27 行

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY CNT10 IS
    PORT (CLK  :IN   STD_LOGIC ;             
                        
COUT : OUT STD_LOGIC  );           
END CNT10;
ARCHITECTURE behav OF CNT10 IS
BEGIN
   PROCESS(CLK)
     VARIABLE  CQI : STD_LOGIC_VECTOR(19 DOWNTO 0); 
   BEGIN
              
       IF CLK'EVENT AND CLK='1' THEN     
    if  cqi<750000
        then  CQI:=CQI+1   ;   
       ELSE    CQI := (OTHERS =>'0');              
        END IF;  
      END IF;   
       IF CQI =750000 THEN COUT <= '1';             
         ELSE    COUT <= '0';
       END IF;
        
   END PROCESS;
END behav;