topic Re: K60 EXTAL0 EXTAL1 operation question in Kinetis Microcontrollers

K60 EXTAL0 EXTAL1 operation question

pk2 — Tue, 23 Jul 2013 23:20:48 GMT

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.

Re: K60 EXTAL0 EXTAL1 operation question

Hui_Ma — Wed, 24 Jul 2013 01:59:29 GMT

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.

Re: K60 EXTAL0 EXTAL1 operation question

Monica — Tue, 30 Jul 2013 17:37:37 GMT

Hello pk2,

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

Best,

Monica.

Re: K60 EXTAL0 EXTAL1 operation question

pk2 — Thu, 08 Aug 2013 00:11:01 GMT

Thank you for the useful information Monica.