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AIC3263App2x1x PPS framework is broken.

Tomasz Motylewski
Prodigy 170 points


Hallo,

In additioon to the problem from   to which I have received no answer I have noticed addition problem, this time with DAC.

Here is what I see on HPR output when I feed 1 kHz, 0.8 amplitude, 44100 sample rate stereo signal from Audacity:

ZOOM:

The frequency of superimposed variable amplitude interference is equal to the sampling rate 44100 Hz.

The PPS project is attached, I have not modified any settings:

EvalBoard3.zip

Could someone from TI have a look and fix that?

Would using a framework from similar codec help?

And why don't you just open the miniDSP instruction specs and assembler source code so I could fix that bugs myself?

  • 0
    TI__Guru 57800 points

    Hi, Tomasz,

    We will test this and try to find a solution, however, the engineer in charge of these devices is out of the office so he will be able to get back to you until next week.

    Our apologies in advance for any inconvenience. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Prodigy 170 points

    Hi Diego,

    I am attaching my full design, so in case you start looking into it you may make sure all elements are working. In this design the problem is reproducable.

    AllFilters1.zip

    My last very simple example EvalBoard3.zip I have posted last week somehow works today without any changes - I do see sinus 1 kHz about 1200 mVpp on HPR. Could it be that working with other designs on the same eval board put it in some undefined state, and power off/on fixed it?

    Generally, I have observed unstable behaviour of miniDSP on my own hardware as well.

    Best regards,

  • 0 in reply to Tomasz Motylewski
    TI__Guru* 84915 points

    Hi, Tomasz,

    This should be related with the framework and interpolator filter that you are using in PurePath Studio. You may see in the attached documents the help windows of the interpolator and frameworks blocks:

    AIC3263_Frameworks.pdf

    Interpolator.pdf

    In your example, you're using 44100Hz as sample rate. So, for these cases, you should select a different framework (AIC3263 8x4x) and interpolator (Int8xOut). This will ensure that your application would work. Could you try with these blocks, please?

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 170 points

    Hi Louis,


    We had been trying AIC3263App8x4x framework with Dec4xIn and Int8xOut since some time. It is the only one which does not have the "input overload" problem . But still the other bug (unstability when switching ADC and DAC ON/OFF) is there :

    In addition we have noticed that what we thought is a good workaround B100_P0_R50 bit4 "auto clear of the read and write pointer of the CIC FIFO at the start of the frame" has a side effect that the input antialiasing filter does not work at all ! The frequencies much above 22 kHz are aliased into the 0-22 kHz band.