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OMAP3530: Tolerance (ppm) of CLK input to McBSP

O.H
Genius 5505 points
Part Number: OMAP3530
Other Parts Discussed in Thread: TMDSLCDK138, PCM3008,

Hi experts,

Q:Is there any problem if we connect an oscillator (Square) of ±30ppm at 4.096MHz to McBSP_CLKS?

There is no provision in the datasheet regarding the tolerance (ppm) of CLK input to McBSP. I tried to refer to TMDSLCDK138, but the frequency of "CB3LV-3I-24M5760" for audio is different. We would appreciate it if you could give me an answer, even from a general point of view.

Best regards,
O.H

  • +1
    TI__Guru 71600 points

    I don't think i see a problem with that,, but it is not really a widely used clock for McBSP.  Why can't you use the internal clock to drive the McBSP module?

    Regards,

    James

  • 0 in reply to JJD
    Genius 5505 points

    Hello James,

    Thanks for the reply.

    JJD said:
    I don't think i see a problem with that,, but it is not really a widely used clock for McBSP.  Why can't you use the internal clock to drive the McBSP module?

    This time my client is using OMAP3530 connected to PCM3008. (fs=4.096MHz, Sampling frequency = 8kHz). Since it is a TDM (or PCM) that is being used, the clock application is only to determine the data bits. They are changing the components because the oscillator they originally used is no longer available. We are aware that PPM-class deviation is not necessary, but we were gathering information because we are using a ±30ppm oscillator.

    I would need to confirm with the customer why they are not using an internal clock, but if the accuracy of the crystal input to the OMAP3530 is better, should I use an internal clock?

    Am I correct in my understanding that when using the internal clock, 8 kHz can be achieved by dividing 96M_FCLK by CLKGDV and FPER?

    Best regards,
    O.H

  • +1 in reply to O.H
    TI__Guru 71600 points

    Yes, i would think you could use a divided down version of the 96MHz clock.  They may have used an external clock because of better accuracy.

    Regards,

    James

  • 0 in reply to JJD
    Genius 5505 points

    Hello James,

    Thank you for your support. I understood.

    Best regards,
    O.H