It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of oscillato… ...

The VHDL code provided with this article (“VHDL Code Listing” at www.electronicdesign.com, Drill Deeper 19222) is an example of one way to implement the LED driver in a CPLD.