how to use SignalTap to slow the clock of DE2

thank you so much for the reply, what you suggest me to do, is to use a counter on 50Mhz to generate ON/OFF switch, my question is, as i wrote my VHDL codes and i alreday downloaded it in the DE2 Board and it works fine with using one push botton as clock, i could use external clock, but how to implement the counter circuit, would it be in the same VHDL program , or it could be different circuit ,,