Simple X-tal question

Nick Mueller

Hi!

Sorry if that sounds dumb. I simply don't understand the data-sheet.

My question is: Can I use a 20MHz x-tal?
Or more general: What's the frequency-range of x-tals that work on the propeller?

Of course, the maximum PLL factor will be 4 with the 20MHz x-tal.


Thanks,
Nick

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LoopyByteloose

I think NO.
You can use 8Mhz, maybe 10Mhz at tops.

As I recall, the PLL is always 16X and then divided down.

So 20Mhz would overclock at 320Mhz!

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Kaio

Nick,

you can use a crystal up to 80MHz, but then you can not use the PLL. If you want to use the PLL then you must use a crystal in the range of 4 - 8MHz. Please refer also the Propeller manual at page 29 to set the right configuration depending from your crystal frequence your are using.

Nick Mueller

Thanks Kaio!

Now I understand the data sheet.

The question arose, not because I can't invest in an 5MHz crystal, but to reduce inventory with a bag of 20MHz x-tals sitting around for an other project.

Thanks,
Nick

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Never use force, just go for a bigger hammer!

The DIY Digital-Readout for mills, lathes etc.:
YADRO