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Cyclone V internal oscillator specification

SZack
Partner
267 Views

What is the frequency specification for the internal oscillator?  In the handbook and Quartus itself it says you can choose a 12.5, 25, 50 or 100 MHz internal oscillator but in the datasheet it only shows a 12.5 MHz setting.  Is the datasheet wrong?

 

This is what the datasheet says:

SZack_0-1625859472445.jpeg

 

In the Cyclone V Handbook on page 7-18 it says:

If you use the internal oscillator, you can choose a 12.5, 25, 50, or 100 MHz clock under the Device and Pin Options dialog box, in the Configuration page of the Intel Quartus Prime software.

And in Quartus (I looked in 18.1) it gives the same four options described in the Handbook.

Steve

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3 Replies
Ash_R_Intel
Employee
238 Views

Hi,

There is no specification mentioning the internal oscillator frequency. However, based on internal team discussions, I came to know that this oscillator is meant for configuration and initialization only. It is not recommended for user design.


Regards.


SZack
Partner
231 Views

Hi Ash_R,

Actually I specifically mention where in the documentation it specifies the different frequencies that are allowed.  I'm not asking for how accurate the clock is or how much jitter it has.  And I realize it is only meant for configuration only.   What I was pointing out was that the datasheet only mentions a 12.5 MHz option whereas the Handbook and Quartus provide four different frequency options.

Ash_R_Intel
Employee
57 Views

The table that you shared is only for initialization. The options available for DCLK are same as Quartus:

DCLK Frequency Specification in the AS Configuration Scheme (intel.com)


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