K60 EXTAL0 EXTAL1 operation question

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K60 EXTAL0 EXTAL1 operation question

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pk2
Contributor III

I am using a MK60FN1M0VLQ12 in a project and using the RMII Ethernet interface.  This interface requires a RMII_REFCLK from the PHY which connects to the EXTAL0 pin of the K60.  I am planning on running the K60 with this clock.  I also generate a RESET signal to the PHY using a GPIO pin. 

However, when the PHY is reset, the REFCLK pin of the PHY is tri-stated which will kill the clock to the K60.

The MK60FN1M0VLQ12 has a second external oscillator pin, EXTAL1 which I would like to use to run the K60 using a clock that is always present.  How do I power up the K60 and configure it to use the clock on EXTAL1?  I understand there are some restrictions when using EXTAL1.

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3 Replies

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Monica
Senior Contributor III

Hello pk2,

was that information helpful? Don't forget to keep us posted :smileywink:

Best,

Monica.

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pk2
Contributor III

Thank you for the useful information Monica.

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Hui_Ma
NXP TechSupport
NXP TechSupport

Hi,

You can refer TWR-K60F120M board design, which is usin external 50MHz clock connect with K60 EXTAL0 pin. The 50MHz external clock also could get from tower system(50MHz clock source from TWR-SER board). You also need to check your chip mask set, which is second line print info at the chip surface.
There exists errata info 3898 (e3898: MCG: Setting the MCG_C6[PLLS] bit will enable both OSC0 and OSC1.) for both mask set: 1N96B and 3N96B. More detailed info, please check below link:

http://cache.freescale.com/files/microcontrollers/doc/errata/KINETIS_1N96B.pdf

http://cache.freescale.com/files/microcontrollers/doc/errata/KINETIS_3N96B.pdf

Wish it helps.