Kinetis MicrocontrollersのトピックSetting Core clock frequency of MK02FN128VFM10 = 100 MHz

Setting Core clock frequency of MK02FN128VFM10 = 100 MHz

shrutikharwandi — Fri, 26 Aug 2016 05:00:59 GMT

Hello,

I'm using Kinetis Design Studio 3.0.0 for the controller MK02FN128VFM10 with 8 MHz external crystal. I want to set core clock of this controller to its maximum value, i.e. 100 MHz.

Right now, MCG_C4[DMX32] = 1 and MCG_C4[DRST_DRS] = 11 (High Range). In this case, default value 80 MHz as core clock frequency is being set. How to set it for 100 MHz?

Please help.

Want to get the solution to this as soon as possible.

Thanks!

Re: Setting Core clock frequency of MK02FN128VFM10 = 100 MHz

kerryzhou — Fri, 26 Aug 2016 07:34:04 GMT

Hi Shruti,

8Mhz external crystal can't get 100Mhz core clock.

If you want to get 100Mhz core clock, please choose 10Mhz external crystal.

Let me tell you why 8Mhz crystal can't get 100Mhz core clock.

If you want to get 100Mhz, from reference manual:

You can get that the input frequency should be 39.0625Khz.

If you use the 8Mhz external crystal choose FEE mode, you will find the you need FRDIV = 8000/39.0625=204.5.

Did the FRDIV have 204.5 data? No, please see this picture:

But if you choose 10Mhz external crystal, you can get FRDIV= 10000/39.0625=256, from the above picture, you can find FRDIV=0b011 meet the demand.

Actually, from the KDS PE configuration, you also can get that:

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Jingjing

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Re: Setting Core clock frequency of MK02FN128VFM10 = 100 MHz

shrutikharwandi — Mon, 29 Aug 2016 06:07:22 GMT

Thanks a lot!

Though in the current scenario I cannot use 10 MHz external crystal, this information was extremely helpful :smileyhappy: