What capacitors to use with crystals at 8 and 16MHz?

As the subject lines suggest, what capacitors would you use?

I know that at 16MHz 22pF is recommended but have heard of problems with this in particular with the 1284P.

So is it worth keeping 18pF handy and would that help?

Also what value should be used for 8MHz and a crystal?

I know that at 16MHz 22pF is recommended

Actually, one should match the load caps using manf of crystal detail - spec sheet. Major parts houses will specify the value to save you the annoyance of pulling the PDF (if you can even ring it!)

Ray

ChilliTronix:
As the subject lines suggest, what capacitors would you use?

I know that at 16MHz 22pF is recommended but have heard of problems with this in particular with the 1284P.

So is it worth keeping 18pF handy and would that help?

Also what value should be used for 8MHz and a crystal?

Depends on the crystal datasheet, Ive seen load caps change between 10 and 20 pf.
To avoid this kind of problem I use resonator, +/-0.5% is enough for me.

I use 22pF with all my '1284P designs.
Some crystals seem to work better with the fuses set with
bobuino.bootloader.low_fuses=0xf7 >> Full Swing Crystal Oscillator

instead of
bobuino.bootloader.low_fuses=0xff >> Low Power Crystal Oscillator

Many thanks everyone!