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PCM1861: TDM mode

Mochi
Genius 3915 points
Part Number: PCM1861
Other Parts Discussed in Thread: PCM1791A, , PCM1863

Hello,

Our customer is considering to employ PCM186x and PCM179xA at TDM mode.

When look at PCM1791A datasheet, TDMCA mode is supported.
In this case 2-BCK width LRCK is required.

pcm1791a TDM.pdf


The PCM1861 datasheet required 1-BCK width LRCK is required.
If those cases just triggered rising edge of LRCK, then width is not matter.
We can connect both devices on same LRCK.
Is it possible solution?

pcm1861 TDM.pdf

Regards,

Mochizuki

  • 0
    TI__Mastermind 23050 points

    Hi Mochizuki-san,

    The two-channel hardware controlled devices in the PCM186x family do not support TDM output, only left-justified and I2S. Since the default for these is 50% duty cycle on LRCK, a 2-BCK wide LRCK would not work for these devices. However, I believe this would work with one of the software controlled variants like PCM1863, which allows you to configure the output for TDM with a 1/256fs LRCK. I believe in this case the rising edge and a 1/256fs period are all that is needed. 

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Genius 3915 points

    Hi Zak,

    Thank you for your prompt reply.

     

    I got your suggestion, PCM1683 can be used on same TDM bus with PCM1791A if DSP can provide special TDMCA LRCK pattern.

    We will verify the function to proceed this project.

     

    Regards,

    Mochizuki