Reply To: The Well synchronized asynchronous FIFO buffer – Slaved I2S reclocker

Posted byThe Well Audio

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04/10/2022 at 12:13 #1819
The Well Audio
Participant

    Ivan Said

    And the second question.

    Seems like on your FIFO (TWSAFB-LT) there is no external xtal (clock) selection pin like it is realized on your separate TWTMC-STS-FSDO-S board. Is this means that I am forced to use another (separate) xtals/clocks for the I2S source as your FIFO is waiting for already formed I2S for proper clock freq recognition?

    Some explanation of my existing working scheme. In my existing DAC I do use your DRIXO clocks for generating/creating of the I2S from the very beginning. It works this way:

    BeagleBone Black (LAN-I2S endpoint, botic driver) sends the signal of 0 (44k) or 1 (48k) from the dedicated GPIO pins in accordance with the playing sampling rate (through my board with the isolator chip) to J7 header of your TWTMC-STS-FSDO-S. Your TWTMC-STS-FSDO-S switches between two clocks (45/49MHz) and sends the needed masterclock (through my board over the isolator chip) back to BBB. BBB creates the I2S from the incoming (correctly chosed) DRIXO masterclock and sends it to FIFO (and then to DAC).

    What is my point? I do not like situation when the initial I2S is formed from the other xtals/clocks that are worse than your DRIXO clocks. Will be sad to lost a possibility of a single clocking scheme for the whole chain from I2S initiation till the DAC tacting itself.

    My questions are relates to the upcoming order and I just want to be ready for your stuff will come some months later. Andrea what can you suggest in conjuction with the above described?

    Thank you!
    Ivan.

     

    The FIFO Lite detects the I2S sample rate family and automatically selects the proper clock.

    If you want to drive the source with the same master clock of the FIFO you can simply get the MCK output from one of the u.fl connectors labelled MCK (J12 or J21).
    It comes from the external oscillators (DRIXO in your case), it’s already converted to square wave and it’s already selected by the I2S input sample rate family.

    • This reply was modified 1 year, 9 months ago by Moderator.