• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 2 answers
  • Subscribers 52 subscribers
  • Views 2325 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

CC2564: PCM/I2S interface

Kevin Lam61
Prodigy 240 points
Part Number: CC2564
Other Parts Discussed in Thread: PCM5100

Hi,

Some questions about the PCM/I2S interface of CC2564

1) Is there any specification of CC2564 mentioned the tolerance of PCM/I2C interface for the input sampling frequency?

2) If there is a tolerance, what CC2564 can do if the input sampling frequency is out of the tolerance? Can it be converted to 44.1kHz / 48kHz automatically?

3) If the input sampling frequency is  96kHz (DVD-Audio) or 2.8MHz (SACD), could CC2564 convert to 48KHz? If not, would you please advise what can we do for such high sampling frequency.

Thanks and best regards,

Kevin

  • 0
    TI__Mastermind 29301 points

    Kevin,

    Kevin Lam61 said:
    1) Is there any specification of CC2564 mentioned the tolerance of PCM/I2C interface for the input sampling frequency?

    Yes, please refer to the Section 5.7.3.2. PCM under the Timing and Switching Characteristics section of the device datasheet.

    www.ti.com/.../cc2564.pdf

    Kevin Lam61 said:
    2) If there is a tolerance, what CC2564 can do if the input sampling frequency is out of the tolerance? Can it be converted to 44.1kHz / 48kHz automatically?

    No the AUD_FSYNC has to be within the spec defined in the device datasheet for each of the PCM Master or PCM Slave roles.

    Kevin Lam61 said:
    3) If the input sampling frequency is  96kHz (DVD-Audio) or 2.8MHz (SACD), could CC2564 convert to 48KHz? If not, would you please advise what can we do for such high sampling frequency.

    The PCM interface of the CC256x may be used for either the assisted A2DP (16/32/44.1/48 kHz according to the profile spec) or the HFP (8 or 16kHz depending on NBS or WBS). So what use-case will you use this 96kHz or 2.8MHz sampled audio in? To answer your question, the CC256x will not do any sample rate conversion, but such high sample rate are not needed for any Bluetooth profile in the first place.

    Best regards,

    Vihang

  • 0 in reply to Vihang Parmar
    Prodigy 240 points

    Thanks for the valuable answers Vihang.

    The use-case for 96kHz audio in is for supporting HD audio format, could you please advise if any TI bluetooth SoC that can support 96kHz audio in?

  • 0 in reply to Kevin Lam61
    Prodigy 240 points

    Hi Vihang,

    Two more questions:

    1) In the below Architecture captured in datasheet, the bit rate for audio codec is 16bits, but the Data format (6.4.3.3) described in Digital Codec Interface(6.4.3) that should be up to 24bits, would you please confirm what is the max bit rate can be supported?

    2) According to Section 5.7.3.2. PCM under the Timing and Switching Characteristics section of the device datasheet, we can see the timing requirement for the waveform in PCM Master and PCM Slave, but seems doesn't mention the tolerance (%) about the signal. Let say if in PCM slave mode, audio signal is 16bits/48kHz, then the AUD_CLK should be a 1.572864MHz signal. Assuming the tolerance +/-10%, the signal will be discarded when the frequency is under 1.415578MHz or above 1.73015MHz, so would you please advise the PCM tolerance of CC2564?

    Thanks and best regards,

    Kevin

  • 0 in reply to Kevin Lam61
    Intellectual 330 points

    Regarding tolerance on a digital audio signal.   The tolerance is +- 0 percent.  They must be driven from the same clock otherwise there will be missing or extra samples with pops and clicks.    If clocks are not identical the most common method to resolve is an asynchronous sample rate converter(ASRC).  This is true of all digital I2S/PCM audio interfaces.   

  • 0 in reply to Dave Jordahl
    Prodigy 240 points

    Hi Dave,

    I appreciate for your support.

    Understood that the clock signal must be identical. How about the tolerance of sampling frequency? I am reading this thread and noticed that the sampling frequencies of PCM5100 DAC can support +/-4% tolerance, is it the same in CC2564?

    Thanks and best regards,

    Kevin

  • 0 in reply to Kevin Lam61
    Intellectual 330 points
    Hi Kevin,
    I have interpreted this spec. to be set by the Bluetooth spec. which if I remember correctly is +- 30ppm. This is very tight and matches the carrier spec. for Bluetooth. I would guess the CC2564 probably doesn't need to spec the tolerance because of the Bluetooth requirement .