Using GCLK by a Quartz Crystal

[Altera_Forum]

Hi all, 

 Can I use a quartz crystal to drive the GCLK pin of FPGAs? I mean just like the microcontroller XTAL pin which needs a quartz crystal with 2 capacitors?   Thanks in advance.

[Altera_Forum]

No, you need a crystal oscillator or an unbuffered CMOS inverter to build an oscillator.

[Altera_Forum]

thnx man for ur fast answer ;)

[Altera_Forum]

That's an interesting question, though! Has anybody here ever tried to use the FPGA itself to build a crystal oscillator? It's quite easy to have a simple inverter from on pin to another. So after configuration, the FPGA should oscillate with the crystal. Any experience with that?

[Altera_Forum]

There have been some discussions of this on the comp.arch.fpga newsgroup. It isn't at all reliable. 

 Leon