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PCM1772: Pin status before and after internal reset

Kazuki Kuramochi
Genius 11255 points
Part Number: PCM1772


Hello expert,

I have question for PCM1772.

I'd like to know about pin status before and after internal reset.
Would you tell me pin status of following pins?

Port Name Before Reset After Reset
xPD
DATA
BCK
LRCK
SCKI
MS
MC
MD

 My expected answer is as like as "pull down to GND by 47kohm".

I'm looking forward to hearing back from you.


Best regards,
Kazuki Kuramochi

  • 0
    TI__Genius 11255 points

    Hello Expert,

    Is there someone to answer my question?
    Sorry for short notice but would you answer this as soon as possible?


    Best regards,
    Kazuki Kuramochi

  • 0 in reply to Kazuki Kuramochi
    TI__Guru 55473 points

    Hi Kuramochi-san,

    All of these pins are inputs, So it should not really be an issue if they are either high or low.  I recommend the following state both before AND after POR.

    PD and MS pull to VCC with resistor, 10k-100kΩ

    DATA, BCK,LRCK, SCK, MC, MD connected to GND with resistor, 10k-100kΩ.  

    Thanks,

    Paul

  • 0 in reply to Paul_Frost
    TI__Genius 11255 points

    Hi Paul-san,

    Thank you for your reply.

    Sorry for making your confusion.
    However, I don't want to know about termination or handling the pin.
    I want to know about internal pin status I listed up. (For example, xPD is pulled low by 47kohm resister internally but I2S signal's pins are floating or something.)

    Would you tell me it?


    Best regards,
    Kazuki Kuramochi

  • 0 in reply to Kazuki Kuramochi
    TI__Genius 11255 points

    Hi Paul-san,

    Sorry for bothering you but I'd like to know about internal status of listed pin before and after toggling PD.
    Would you provide it as well?


    Best regards,
    Kazuki Kuramochi

  • 0 in reply to Kazuki Kuramochi
    TI__Guru 55473 points

    Hi Kuramochi-san,

    In this case there are no internal pull-ups or pull-downs specified on the pins in the datasheet.  All of the pins would be high-impedance and floating if not externally driven.  I would expect minimal leakage current for all of these pins, so they would not strongly drive against any input voltage.

    If you customer is wondering how to handle this pins before or after the POR event, I think my previous suggestion is valid.

  • 0 in reply to Paul_Frost
    TI__Genius 11255 points

    Hi Paul-san,

    Thank you for you reply.
    I understand, all pins are Hi-z and floating.
    This question is from that customer want to these info for making decision of pin termination.

    I'll recommend your suggested pull-up and down method.

    Best regards,
    Kazuki Kuramochi