Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 30 subscribers
  • Views 907 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.

SRC4190 sample rate range

Steven Weng1
Expert 2200 points
Other Parts Discussed in Thread: SRC4190

Hi,

I am searching a SRC to convert I2S audio sample rate in our design.

SRC4190 seems meet our requirement:

There is a HDMI Rx in our board and it capture HDMI audio as I2S signal(sample rate range: 32KHz ~ 192KHz). The I2S audio need to be converted to 48KHz or 44.1KHz before enter to our audio codec(for mixing multi analog and digital audio signal). Block diagram as below:

HDMI Rx -> SRC->Audio codec

audio input : I2S sample rate from 32KHz to 196KHz

audo output:  44.1KHz/48KHz

Please help me check:

(1) SRC is set both input and output  slave mode, so the BCKI and LRCKI is provided from HDMI Rx and BCKO and LRCKO is from audio codec. RCKI is must for SRC4190 as reference clock(from Crystal Oscillator), is it right?

(2) Auto resample is done when input/output clock is actived? There is no additional configuration for resampling?

(3) The sample rate range of HDMI audio source is 32KHz~196KHz. So all sample rate in the range could be resample to 44.1KHz or 48KHz?

(such as 32KHz->44.1KHz, 48KHz->44.1KHz, 96KHz->44.1KHz etc...I know that max sample rate range is 4KHz~212KHz in SRC4190 and ratio is 1:16)

(4) The sample rate ratio 1:16 means when input sample rate is 4KHz, it could be resample to maxmium 4x16=64KHz,  so 4~64KHz output sample rate is available?

Thanks!

BR,

Steven

  • 0
    TI__Mastermind 27900 points
    Hi Steven,

    1. Yes an RCKI is required to run the part, but there is no crystal oscillator in the SRC4190, you must provide a CMOS clock for the RCKI pin.

    2. There is a bypass pin, which will send the input directly to the output, make sure this pin is set correctly (low to use ASRC).

    3. Yes all sampling rates from 32 kHz to 192 kHz will be able to be re-sampled to 44.1 kHz or 48 kHz.

    4. Correct, the max ratio from input sampling rate to output sampling rate is 16:1 or 1:16.

    Justin
  • 0 in reply to Justin Bohr
    Expert 2200 points
    Hi Justin,

    Thanks for your reply.

    Another question about input/output port mode of SRC4190. Please help me check.

    (1) There are two modes about both input/output is slave mode: MODE0/MODE1/MODE2: 0/0/0 or 0/0/1, it's different?

    (2) In slave mode, the sample rate is the same as LRCLK? How about RCKI? How could I decide RCKI frequency?

    In master mode, the sample rate is derived from RCKI. If our target is output I2S sample with 44.1KHz or 48KHz sample rate. I need two different RCKI frequency from crystal oscillator?

    Thanks
  • 0 in reply to Steven Weng1
    TI__Mastermind 27900 points
    Hi Steven,

    1. The different mode selections are explained on page 16 in Table 1 of the data sheet.

    2. Yes, in slave mode, the sample rate of the port is determined by the LRCK input to that port. If a port is in master mode, then it will be a divided down clock sourced from RCKI, and that divisor is decided by the MODE pins.

    Yes, if you want to be able to output at 48 kHz multiples and 44.1 kHz multiples you will need two different clock sources for RCKI.

    Justin
  • 0 in reply to Justin Bohr
    Expert 2200 points
    Hi Justin,
    Thanks for reply.
    If I want to be able to output at 48 kHz and 44.1 kHz and the SRC is set as slave mode. The RCKI is dont care and all I have to do is provide two different LRCK input(48kHz and 44.1kHz). it's right?
    Thank you very much
  • 0 in reply to Steven Weng1
    TI__Mastermind 27900 points
    Hi Steven,

    Correct, if the output port is in slave mode, the audio data will follow the LRCK that is given to the output port, whether that be 48 kHz or 44.1 kHz.

    Justin