--27MHZ分频成1hz:LIBRARYIEEE;USEIEEE.STD_LOGIC_1164.ALL;USEIEEE.STD_LOGIC_UNSIGNED.ALL;ENTITYFENPINISPORT(CLK_IN:INSTD_LOGIC;CLK_OUT:OUTSTD_LOGIC);ENDENTITYFENPIN;ARCHITECTUREBEHAVEOFFENPINISCONSTANTBB:INTEGER:=12;-----------------SIGNALCNTTEMP:STD_LOGIC:='0';BEGINPROCESS(CLK_IN)ISVARIAB