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12 MHz or 72 MHz


#1

Excuse me if this information is somewhere I couldn’t find.

I noticed FEZ Domino has a 12 MHz crystal.

Does that mean the Domino is going at 1/6th of the 72 MHz processor speed it is capable of?


#2

No, Domino runs at 72 MHz. The crystal is used to keep track of time by providing a very precise frequency.


#3

As a general piece of info…processors NEVER use high frequency crystals like 72Mhz. Instead, they use lower clock frequency crystals, like 12Mhz, and then they multiply it internally, by 6 for example to get the final clock in which the processor internally use.

12 x 6 = 72 :wink:


#4

I was aware of clock multipliers and I tried in vain to find it documented.

I even looked on the forum to see if anyone else stepped up to ask the stupid question.

So I did. :wink:

Thanks for the confirmation.


#5

No question is stupid :wink: I think no one asked the question because the clock frequency is transparent to your application. This is what is nice about NETMF, you do not have to worry about anything!


#6

Hey, pursuant to this; Do you all think Fez can be overclocked! What if i swapped out the crystal for something higher?


#7

It draws more current , getting warmer and if the freqency is too high it’s like a normal processor.
It burns away :smiley:

For what do you want to overclock?

If you need more power then you can use ChipworkX B)


#8

Why over clock? You maybe able to go to 100 Mhz but with losing reliability is getting 50% more processing worth it? Maybe for fun but you should never use it at a higher frequency


#9

Wow 50% reliability at 100mhz. Ah well just a thought.