Synergy Oscillator

Hi All

 just finished my first board with the synergy S7 micro and can not get the xtal oscillator to work.

I am using a 12MHz crystal with 18pF capacitors.

Can some one please assist with some advice on how to get the oscillator to work.

When selecting the subclock or the internal oscillator it works great.

I also could not find any information in the user manual.

Thanks for any assistance.

Regards

Brian