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TAC5212EVM-K: QuickStart Help?

Brian Neltner
Prodigy 20 points

Part Number: TAC5212EVM-K

I recently received one of your evaluation boards and am finding the documentation a bit hard to follow. I was wondering if you might be able to suggest an initial set of configurations that I can use to do a basic loopback test.

I installed your software to let it activate the hardware, and am able to use it as an audio device (microphone) to record audio. So far it is just noise, but the jumpers tentatively seem okay in the default positions. I need to look closer, but if you have suggestions for getting a specific coaxial port (top or bottom, they aren't labeled super clearly to me) wired up to be either AC or DC coupled to an ADC I can test it with a signal generator properly. I'm just not sure why I see no sign of life while the device is active (I did power up the ADC).

I installed Audacity to let me generate tones and record audio while playing them. I connected OUT1 (P?) to IN1 (P?) and tried to play 440Hz while recording and that just showed the same noise. I connected OUT1 up to an oscilloscope in single-ended stereo mode and it seems like a clipped waveform with a heavy discontinuity which doesn't change as volume shifts. I thought I had the jumpers okay, but it's definitely a little tricky.

Right now, honestly all I want to do is a loopback test and then to be able to measure the harmonic distortion accurately on my precision instruments to validate the performance. Is there a simple set of jumper configurations that would let me just output stereo audio and make one of these coaxial ports the left channel? I can switch to differential output to get a more fair distortion measurement once I get it to work at all...

Thanks! I'm very excited about the performance this will have and am looking forward to characterizing it.

  • 0
    TI__Mastermind 29775 points

    Hi,

    The default jumper configurations on the EVM are ac-coupled differential analog output and analog input.

    If you are using the AC-MB (the host controller comes with the EVM) for the audio interface, then you can directly load the preset configuration for either playback or record.

    User guide section 3.4 has more details on configuration examples.

    For record, you can provide analog input from the RCA J2 or J3 connector and for playback you can take the analog output on J38 or J39.

    Again, these are differential output, for single ended jumper J6, J7, J36 and J37 will need to be installed accordingly.

    You can refer to Table 2-1 in the user guide for the jumper setting for different configurations.

    Here is a script to have differential analog in analog out, this is analog bypass path; INx to OUTx path.

    Analog Loopback Diff ac-coupled to LINEOUT setting.cfg

    Regards.

  • 0 in reply to pdjuandi
    Prodigy 20 points

    Thank you so much for the reply, this helped a lot with getting the loopback wiring and jumpers.

    Initially there were some issues, but it seems like it eventually works a bit, but it's extremely unstable (software) for me.

    I loaded the "Playback Lineout OUT1-OUT2 Differential" preset with the OUT1 P/M going to my oscilloscope channels where I could make them pseudodifferential. This didn't work well before, but now it seems to be okay.

    And then turning back on the ADC input and connecting the coaxial cables now gives a loopback test that looks like this, far better.

    The software there is Audacity, a standard sound editing and recording program. I generated that top signal (440Hz) and recorded the bottom channel simultaneously from the ADC input. Looks pretty good, though I didn't analyze the distortion yet.

    I am finding that periodically the audio interface seems to fail. I will record something like the above loopback, leave the coaxial cables connected, and then find that the ADC is seeing no signal (no change in configuration). Then I connect the OUT1 signal to my scope and there's no signal there either, so it seems to be shutting down the audio output without me asking.

    Is there anything on the chip that would shut down the output? I am not finding an obvious set of steps to reproduce it, I'm afraid, but if there's a log file I can make sure to check it out when it happens again.

  • 0 in reply to Brian Neltner
    TI__Mastermind 29775 points

    The script above is purely analog in and analog out, it's direct path without any AD or DA conversion.

    How do you record with the above script?

  • 0 in reply to pdjuandi
    Prodigy 20 points

    Sorry, I changed it to DAC Input for the USB Audio and forgot to mention it.

    I route from the USB Audio Output via coaxial cable differentially to the IN1 pair and record while playing via the USB Audio interface.

  • +1 in reply to Brian Neltner
    TI__Mastermind 29775 points

    I recorded the loopback configuration by sending digital data from USB AC-MB -> DUT OUTx and physically connect the analog output OUT1 (J49) and OUT2 (J50) back to the analog input IN1 and IN2 header J47 and J48 and not seeing any issue after 15 minutes and it's still running.

    The script is just straight forward as shown below.

    ##### Playback and Record AC-Couple Differential OUTx to INx path ######
    # Target Mode, TDM, 32-bit
    # Primary ASI only, multiple of 48KHz Sampling
    #
    w a0 00 00 # Set page 0
    w a0 01 01 # Software Reset
    w a0 02 09 # Wake up with AVDD > 2v and all VDDIO level
    w a0 26 01 # Offset 1BCLK for AC-MB host; this is only needed if using the AC-MB host.
    w a0 76 cc # Enable Input Ch1 and Ch2, enable output channels
    w a0 78 c0 # Power up ADC and DAC

    Regards.

  • 0 in reply to pdjuandi
    Prodigy 20 points

    Thanks, it seems better now. I think the driver was becoming unstable from trying to change the sample rate between 44.1kHz and 48kHz.

    I am able to get it to work long enough to measure the THD, at least in that mode, using Audacity in "overdub" mode where it plays and records simultaneously, so this works for me!