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Forced to Run Core Clock at Half Speed

Question asked by Derek Schumacher on Nov 5, 2015
Latest reply on Nov 5, 2015 by Mark Butcher

Using processor expert, I am trying to set up the microcontroller to run off of an external clock source. I think we have the processor expert settings mostly figured out, but for reasons that are unclear to me, we can't run the core clock at the MCG output frequency.

 

We are using the MK22F256VLL12. Here is the working configuration (note core clock speed of 56 MHz):
Capture.PNG

 

And here is the non-working configuration (note core clock speed of 112 MHz):
Capture2.PNG

 

According to this image from the manual, it really seems like we should be able to run the core clock at the MCGOUTCLK frequency.

Capture.PNG

 

Is this an error in processor expert? Or have I neglected to do something important with the configuration? Or am I  just misunderstanding how the MCG works?

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