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K64 input clocks

Question asked by roymessinger on Dec 21, 2016
Latest reply on Dec 21, 2016 by roymessinger

I'm designing a board according to the FRDM-K64F eval board. I saw 2 external clocks are used in the design (32.768kHz and 50MHz). The 50MHz is passed from the PHY (which should receive a 25MHz) and the 32kHz is passed from external oscillator.

If I'm not using the Ethernet communcation, do I still need to supply 50MHz clock?

A friend of mine also designed such board. He did not used the 32kHz input (left it open) but rather supplied a 50MHz to EXTAL0 (pin 50) input - in the eval design it is passed from the PHY - even though he's not using Ethernet.

All is working well, which kinda left me confused... Any highlights on this matter?

Thanks.

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