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.

Can DIR9001 recognize protection when ripping from CD/DVD?

Other Parts Discussed in Thread: DIR9001

Customer product has recording function to USB or to internal memory. 

This feature available for all input including optical input - DIR9001 used.

Customer would like to confirm whether DIR9001 can recognize the protection when inputs from DVD/CD which has protection to prevent copy to other device?

Thanks.

Best regards,

Chin

  • Hi Chin.

    DIR9001 decode channel-status data from S/PDIF signal. It has direct pins for indication of presence of AUDIO and pre-emphasis on EMPH pin. If you want information if decoded signal is copyrighted, that you must read channel-status data on COUT pin and decode them with external logic. There is 192bit long block. First 6 bits are control code and bit 2 is information about copyright.

    best regards, Pavel.

  • Hi Chin,

    Pavel is correct, the information can be encoded in the SPDIF stream by the source device, and the DIR9001 will indicate certain bits on pins but the other information must be read from the COUT pin and then decoded from the 192 bit frame.

    Justin
  • Hi Pavel, Justin,

    Thanks for your informative reply.

    For the decoding of the channel-status data with external logic, could you advise what type of logic circuit? Since customer system has SoC on board, so probably they could use an I/O port to decode the data, am I right?

    Thanks.

    Best regards,

    Chin

  • Hi Chin,

    It would probably require 2 pins at a minimum. One for the data stream and another for the sync signal to signify the start of a frame.

    Justin
  • Dear Justin,

     

    My customer has further question regarding the error detection.

    Currently their design has no connection to micro P (SoC) to detect any error from optical in IC.

    It means SoC doesn't know the error and what kind of error from optical In. 

    Could you advise what kind of error possibility and how to recover.

    Besides connecting Pin 27- ERROR to SoC, how about Pin 9 -CLKST ?

     

    Thanks.

    Best regards,

    Chin

  • Hi Chin,

    The ERROR pin is for PLL errors or parity data errors. The means that the PLL is not able to lock onto the clock from the incoming signal. The parity error means that the data is getting manipulated in transmission, and therefore is incorrect.

    The CLKST pin is to gain further information about whether or not the PLL is locked or not.

    These errors cannot be fixed by the DIR9001, but have pins to signal this so that the output can be muted and the system can have some knowledge as to why.

    Justin
  • Hi Justin,

    Thanks for your further explanation.

    Customer has questions regarding the error message.

    i) If non-compliant signal is input to the IC, error signal (High) will be output, am I right?

    ii) What will happen after compliant signal is input? Example, when non compliant signal input -> Error (High). Customer corrects the input to compliant signal. Can the IC self-recover or need to reset the IC?

    iii) If reset can recover the IC, what is the reset timing requirement? Is it minimum low for 100ns as indicated in datasheet?

    iv) Will the IC output Error high when the IC is malfunction due to other reasons such as external noise applied?In this case, can we reset the IC to recover the IC?

    iv) Customer would like to simulate the error symptom. Could you advise how to simulate PLL error and parity data error?

    Thanks.

    Best regards,

    Chin

  • Hi Chin,

    The part does not need to reset to recover. As soon as the DIR9001 can lock on to a valid SPDIF signal, it will convert the audio. How long it takes to lock will vary.

    If enough noise is present, yes the signal integrity could be bad enough to cause the DIR9001 to loose lock.

    There are tests on the Audio Precision to test these errors. The parity is difficult without a program to create the right data to cause the error, the other error should be caused by unplugging the SPDIF signal.

    Justin
  • Dear Justin,

    I need your advice regarding request from customer:

    Issue  (Problem) : When Player (input to DIR9001) change audio format from “supported audio” format (LPCM) or Freq. sampling  to unsupported ( DD, DTS or higher freq. sampling) there is “jerk” sound happens. This is due to “Audio pin” output from DIR IC has delay  to go “ High” to inform SoC to activate Mute. Therefore even add hardware mute immediately after Audio pin becomes high, jerk sound was still heard as the DSP needs 10ms to be muted. Please refer to the attachment. 

    Jerk Sound when change input to unsupported format.ppt

    Customer request to confirm  : Can Audio pin high at the same time when receive info of change format from input (Player)?

    If DIR9001 can't improve for the jerk noise, could you suggest any recommendation to eliminate the noise?

    Thanks.

    Best regards,

    Chin 

  • Hi Chin,

    I would take a look at table 12 of the DIR9001 data sheet to see what situation the customer is in, in terms of their clock settings. You might be able to tie AUDIO to the CKSEL pin to be able to mute the output of the DIR9001 when AUDIO is high.

    Justin
  • Hi Justin,

    I have checked with customer that they had tried your suggestion before but still can not improve since Audio pin "High" already delay after the jerk sound was heard.

    They need to detect the changes before the Audio pin goes high.

    Is there any detection pin that can notify the changes format of input signal?

    Thanks.

    Best regards,

    Chin 

  • Hi Chin,

    It seems the audio pin goes high in time, just that the coding of the DSP does not let the DSP respond fast enough. You could try tying the audio pin from the DIR9001, which will be the quickest indication if the format is no longer audio, straight to the amplifier mute. This way as soon as the DIR9001 sees that the data is not correct/audio data, it will mute the amplifier before the audio makes it to the speaker.

    Justin
  • Hi Justin,

    Sorry to trouble you again.

    Customer had tried to tie the AUDIO pin to CKSEL, mute pin of DSP & Damp, there has some improvement but still cannot totally eliminate the 'jerk' sound.

    Jerk Sound when change input to unsupported format .ppt

    Refer to the slide page 4, the error pin goes high when change to unsupported format of input. 

    Questions:

    1) The error pin goes high awhile then low again even though the input signal is unsupported format. Is this condition correct?

    2) If you zoom in the waveform, there is a very short period of noise just after error pin goes high -> DIR9001 muted. This should be the delay. So customer would like to utilize the error pin to trigger the muting on DSP in order to eliminate the noise after error pin goes low. 

    I think the noise in front is not possible to be eliminated. For your info, there is small 'tick' sound occurs in previous reference design which using Cirrus Logic IC. So QA not accept for the louder 'jerk' sound.

     3) Any cautious point if customer use error pin to trigger for muting?

    Thanks,

    Best regards,

    Chin

  • Dear Justin,

    Refer to last info that customer would like to use ERROR pin as reference to mute the DSP.

    However, their software member reject this idea as sometimes, the error pin will go high if for example have parity error or unlock. 

    This may cause unwanted muting on the DSP.  So they still want to use Audio pin high to activate mute.

    So they want to check with TI why the Audio pin high is delayed by around 16ms.

    Refer to waveform, Audio pin goes high only after changing to unsupported input data, why not goes high together with ERROR pin?

    What is the specs of audio pin high duration for the following condition :
    1. LPCM to NO data
    2. LPCM to Unsuppoted data.

    Thanks.

    Best regards,

    Chin

  • Hi Chin,

    The reason there is a delay is because this data is the extra data transferred over 192 frames in SPDIF, so the AUDIO pin will update at the start of each 192 frames of SPDIF data. This is explained in section 8.3.8 of the data sheet. You could try reading out the COUT and UOUT data directly from the pins, which might be faster and allow the SOC to mute quicker.

    How often is there a parity error that causes a mute? Is this a common occurrence with the source audio?

    Justin