• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 1 answer
  • Subscribers 28 subscribers
  • Views 727 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TAS2557: Question of TAS2557 SDOUT Waveforms

Wayne Chen (Audio AE)
Genius 15950 points
Part Number: TAS2557
Other Parts Discussed in Thread: TAS2770

Hi Sirs,

Would you please assist us to review if the TAS2557's SDOUT for echo reference goes to zero gradually with 16 bits ASI a normal behavior? Should we program the TAS2557's ASI to 32 bits all the way to avoid this problem?

1.   TAS2557 ASI Word Length = 16, BCLK = 512kHz, LRCK=8kHz

SDOUT floating - TAS2770 SDOUT goes to zero gradually



SDOUT connected to SOC's SDIN. TAS2770 SDOUT goes to zero gradually



2.   TAS2557 ASI Word Length = 32, SDOUT floating. BCLK = 2.822MHz, LRCK=441.kHz, TAS2770 SDOUT goes to zero sharply




SDOUT connected to SOC's SDIN. TAS2770 SDOUT, TAS2770 SDOUT goes to zero sharply



Thank you and Best regards,

Wayne Chen
03/05/2019

  • 0
    TI__Guru** 104005 points
    Hi Wayne,

    Do you know the value of B00_P00_R01? Bit 0 of this register configures the DOUT to Hi-Z when there is no valid data transmitted.
    You could try to set this bit to 1 (enable Hi-Z) and also enable buskeeper on B00_P01_R05 Bit 7.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Genius 15950 points

    Thank you Ivan. 

    Customer's lTAS2557 loos like  B00_P00_R01/ B00_P01_R05 are zeros. Can the problem be fixed by writing B00_P01_R05 = 0x80? 


    sh-3.2# cat /sys/kernel/debug/regmap/registers
    00: 00
    01: 00
    02: 00
    03: a0
    04: 00
    05: 00

    Thank you and Best regards,

    Wayne Chen
    03/05/2019

  • 0 in reply to Wayne Chen (Audio AE)
    TI__Guru** 104005 points
    Hi Wayne,

    Yes, I think this should be fixed by writing:
    B00_P00_R01 = 0x01
    B00_P01_R05 = 0x80

    This will enable tri-state for DOUT and also bus keeper.

    Best regards,
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Guru** 104005 points
    Hi Wayne,

    Were you able to test this on customer setup? Is this working fine now?

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Genius 15950 points

    Hi Ivan,

    Thanks for your concern. Customer is trying to update I2C registers through Linux driver. We will get you back customer's test result shortly.

    Thank you and Best regards,

    Wayne Chen
    03/14/2019   

  • 0 in reply to Wayne Chen (Audio AE)
    TI__Guru** 104005 points
    Hi Wayne,

    Do you have additional information on this? If you consider this could take some time we could close this thread and start another one if customer is still having issues.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Genius 15950 points

    Hi Ivan,

    Sorry foe delay. Customer found that the SDOUT waveform problem could be solved by setting the TAS2557 to 32 bit I2S format.
    Customer thinks this is a workaround but not root cause, hence we need to keep following this issue.

    Thank you and Best regards,

    Wayne Chen
    03/25/2019