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SRC4190 Converting from 48kHz(BCK=32fs) to 48kHz(BCK=64fs)

Sadanori Kato
Guru 36490 points
Other Parts Discussed in Thread: SRC4190

Hi,

Could you please give us your advice whether SRC4190 can convert on the following condition?
The output data of SDOUT is invalid although the converting from 48kHz@fs(BCK 32fs) to 48kHz@fs(BCK 64fs) is correct.

Input Condition(Input to Output Sampling Rate = 1:1):
RCKI = 256fs
BCK = 32fs
LRCK = 48kHz
SDI = 24bit I2S

Output Condition:
BCK = 64fs
LRCK = 48kHz
SDOUT = 24bit I2S

Mode Condition:
Mode2 = 0
Mode1 = 1
Mode0 = 1
* Output Port is Master mode with RCKI = 256fs

Input Data Format:
IFMT2 = 0
IFMT1 = 0
IFMT0 = 1

Best Regards,
Kato

  • 0
    TI__Expert 4525 points

    Hello expert,

    Can someone help Kato-san for the SRC4190 question at your erliest?

    Customer is making multipule push to us to provide any comments since they are stuck on system evaluation as they can not work it correctly.

    Thank you and best regads,

    Daisuke KAWASAKI

  • 0
    TI__Guru 57800 points

    Hello Kato-San,

    The Mode Condition and Input data format settings looks correct. I suppose that the output port data format is selected to work in I2S mode with a word length of 24 bits (OFMT1=0, OFMT0=1 and OWL1=0, OWL2=0). Could you please confirm this?

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36490 points

    Hi Diego-san,

    Thank you for your response.
    I will look into the customer settings and get back to you since I do not have the SRC419x evm and can not verify it.

    Best Regards,
    Kato

  • 0 in reply to Sadanori Kato
    Guru 36490 points

    Hi Diego-san,

    I confirmed the customer settings for the pins as below.
    Could please give me your advice about the reason that SRC4190 does not work normally?

    ＜Serial Port Mode＞
    Mode2 = 0
    Mode1 = 1
    Mode0 = 1

    ＜Input Data Format＞
    IFMT2 = 0
    IFMT1 = 0
    IFMT0 = 1

    ＜Output Port Data Format＞
    OFMT1 = 0
    OFMT0 = 1
    OWL1  = 0
    OWL0  = 0

    ＜Bypass Mode＞
    BYPAS = 0

    ＜Low Group Delay Control＞
    LGRP = 0

    ＜Soft Mute Function＞
    MUTE = RDY
    * MUTE is connected to RDY.

    ＜TDM Mode＞
    TDMI = 0

    ＜Reset Mode＞
    RESET = 1

    ＜ARSC Ready Status＞
    RDY = MUTE

    Best Regards,
    Kato

  • 0 in reply to Sadanori Kato
    Guru 36490 points

    Hi Diego-san,

    Do you have any updates on this question?
    Your quick response would be greatly appreciated.

    Best Regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Guru 57800 points

    Hi Kato-San,

    Sorry for the late response, The device pin configuration is correct for the desired conversion.

    Could you please specify what is the problem at the output?, If the device is presenting no output, perhaps the issue is related to the initialization. The device does not have an integrated power-on reset, so a reset sequence after power up is required in order to initialize the device.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36490 points

    Hi Diego-san,

    Thank you for your response.
    The phenomenon which occurred on the customer test board is something that although BCK is converted 32fs to 64fs, the invalid data is output to SDOUT.
    I will confirm whether he initialize SRC4190 by using RST pin after the power-up and get back to you.
    Are there any other causes?

    Best Regards,
    Kato

  • 0 in reply to Sadanori Kato
    Guru 36490 points

    Hi Diego-san,

    The output data from SDOUT is correct if input BCK is 64fs, however the output data from SDOUT is not correct if input BCK is 32fs.
    The sampling rate is 48kHz.
    Could you please give me your advice whether this behavior is correct as the specification of SRC4190?

    Best Regards,
    Kato

  • 0 in reply to Sadanori Kato
    Guru 36490 points

    Hi Diego-san,

    Could you please confirm whether it is possible to convert 48kHz@fs to 48kHz@fs with 32fs@input BCK as the specification?
    Your quick response would be greatly appreciated.

    Best Regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Guru 57800 points

    Hello Kato-San,

    Sorry for the delay. BCK is 32fs, it means that each channel will have 16 BCK pulses, it goes against our specification of having a minimum of one BCK clock cycle per data bit (24). 

    When BCK is 64fs, each channel will have 32 BCK pulses, meeting the specification.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36490 points

    Hi Diego-san,

    Thank you for your great support.
    I understood that the word length limit of the input audio format is 16bit if BCK is 32fs.

    Best Regards,
    Kato

  • 0 in reply to Diego Melendez
    Prodigy 160 points
    Hello Diego,
    I stumbled on this after having the same problem and just posted on e2e.ti.com/.../541941

    My issue here is that the data sheet does NOT specify that BCKI must be 64Fs. Page 16 states "The
    audio data word length may be up to 24 bits for I2S..." suggesting that less than 24 bits is supported in I2S.
    Furthermore, in the same paragraph, it states "In slave mode, BCKI is configured as an input pin, and may
    operate at rates from 32fS to 128fS, with a minimum of one clock cycle per data bit."
    I am doing precisely that in inputting 32Fs (16 bits) at 44.1KHz which is one BCKI cycle per data bit but the SRC only outputs silence with dithering on the LSBs of the serial output. If I increase to 64 Fs or 24 bit input I2S, the SRC operates as expected.
    Can you clarify if the SRC supports 32Fs on the input (16 bit I2S) or is the data sheet incorrect or could I have missed something?
    Thanks
    Killian