external reference clock cortex M4

[olivier_burelle]

Hello dear experts,

I would like to use several cortex M4 with a 16Mhz  external oscillator instead of a 16Mhz quartz  in our application in order to distribute the same clock to several cortex M4 chips. We really need the same drift and accuracy in our inter chip communication. Is it possible to use a TCXO at 16Mhz with a specialized clock distribution chip. Are the specifications the same concerning the external reference clock  (max 16Mhz) ? What kind of  care has to be taken in the routing and pcb design ?

Thanks in advance for your help.

O

[xiangjun_rong]

Hi, Olivier,

can you tell me the part number you are using? anyway, pls check the data sheet of the Kinetis and know the required clock source frequency for Extal0 pin.

I think it is a good idea to use a 16MHz clock source plus clock distributor, and connect them to different Kinetis clock source input pin, because of frequency consistency, the communication quality will improve for example uart. regarding the caring, the trace on pcb is as short as possible, the 16mHz clcok signal is not very high frequency, you do not need consider the signal integrity.

Hope it can help you

BR

Xiangjun rong

[olivier_burelle]

Hello Xiangjun and thank you for your answer,

I am using the mk20dx256VLH7 Cortex M4 and I agree with you, a good TCXO

16MHZ with low ppm and a clock distribution chip as the LTC 6957-3 should

provide a good solution to my problem inclucing your advices.

BR

Olivier

Le mar. 31 juil. 2018 à 08:36, xiangjun.rong <admin@community.nxp.com> a

écrit :

NXP Community

<https://community.freescale.com/resources/statics/1000/35400-NXP-Community-Email-banner-600x75.jpg>

Re: external reference clock cortex M4

reply from xiangjun.rong

<https://community.nxp.com/people/xiangjun.rong?et=watches.email.thread>

in Kinetis Microcontrollers - View the full discussion

<https://community.nxp.com/message/1040281?commentID=1040281&et=watches.email.thread#comment-1040281>