Question about implementing external 24Mhz Clock Oscillator into an RT1051

[cstiegman123]

I have a customer asking a question about implementing external 24Mhz Clock Oscillator into an RT1051.  They plan to clock the RT1051 by dividing an existing external 48Mhz oscillator down to 24Mhz and using the external clock oscillator input functionality of the RT1051.   

The RT105x data sheet (Section 3.1, Table 3) which discusses how to connect an external input clock oscillator.   However, we need some clarification on how exactly this should be implemented.  

• Should they drive the 24Mhz external oscillator into XTALO (clock out) as this section says, instead of XTALI?  
• And, where should XTALI be terminated to through the 18pF cap referenced?

Thank you!

[kerryzhou]

Hi @cstiegman123 ,

    Thank you for your interest in the NXP MIMXRT product, I would like to provide service for you.

    Answer your questions:

1. Should they drive the 24Mhz external oscillator into XTALO (clock out) as this section says, instead of XTALI?  

=>Answer:

Please check the information from the RM below:

You can choose one of three configurations. You also can choose way 2, this is also the very normally used way.

2. And, where should XTALI be terminated to through the 18pF cap referenced?

=>Answer:  I think, you can choose way 2, then you don't need to add the capacitor, just leave XTALO externally floating.

Wish it helps you!

Best Regards,

Kerry