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Setting up clock rate for I2S with SGTL5000

Question asked by Tak Ming Marco Pang on May 14, 2018
Latest reply on May 15, 2018 by xiangjun.rong

G'day!
I've been reading up on how to use the I2S module in my K70 elevator tower with the SGTL as the TWR-AUDIO extension.
I am a little confused as to what the right question to as is..

 

So I have the system oscillator set at 50Mhz as default and have noticed the I2S module is derived from the (Core/System clock)*((I2SFrac+1/I2SDiv+1)). For example, If I wanted 48 Khz as my sampling rate, I would multiply by 256 to get 12.288 Mhz for the I2S clock.

 

P.3 from AN4520 - I2S

 

And further more, on the next page,
    P.4 from AN4520 - I2S

 

I could not find the I2Sx_PCCR register in the K70 Sub-Family Reference Manual, so I don't know what PM stands for.

 

My question is "should I be changing the K70 OSC0 to 12.288Mhz or 4Mhz"?
Which I think would be a bad idea due to other clocks prescalar on it...

Another idea I had was that I just keep it at 50Mhz and derive the 12.288Mhz on the Bus Clock but the closest I can get it is 12.5 Mhz which is not good enough.

 

- Component Inspector KDS

Thank you for your time!

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