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TAS5716 input & output mixers

Nicholas D'Amato
Prodigy 100 points
Other Parts Discussed in Thread: TAS5716, TAS5706, TAS5706A

I have some questions regarding the additional input mixers and output mixers diagrammed on page 6 of the TAS5716 datasheet:   

Input mixers: V1 IM1 0x096, V1 IMDML0x0A9, V2 IM2 0x099, V2 IMDMR 0x0AA
Output mixers: V1 OM1 0x51[0], V1 OM3 0x52[1], V2 OM2 0x52[0], V2 OM4 0x52[1], V2 OM6 0x52[2]

My understanding is that these mixers give the TAS5716 a bit more flexibility when it comes to routing & mixing signals in the DSP (compared to the TAS5706).  But the documentation regarding these mixers is not very clear.  

  • Where are the input mixers 'located' in the signal chain?  Before the 0x21 input mux? After the mux?  Or does the input mixer replace the mux?  
  • Where are the output mixers 'located' relative to the 0x20 output mux?
  • Can the output mixers be used and with the amplifier in two channel BTL mode?
Using the TAS5716 GDE, I don't see any settings or diagram blocks for these mixers.  I see the input and output multiplexers, but not mixers.  How can I access and/or adjust these mixers using the GDE software?  Specifically, I’m looking for a way to mix the BassBoost signal (channel 6) back into channels 1 & 2.  

Note:  I am using the GDE software without the TAS5716 EVM right now.   The EVM should arrive next week. 

Thanks in advance.
-Nick D.
  • 0
    TI__Guru**** 189399 points

    Hey, Nick D.

    I've asked one of my guys to work on this with you next week.

    Did you look at our newer parts? TAS5716 is a little long in the tooth for new designs, but you probably need 192 kHz operation or something the newer parts don't support, right?

    -d2

  • 0 in reply to Don Dapkus
    Prodigy 100 points

    Hi Don,

    Looking forward to hearing from your guy.  I was told someone from the TI audio team (class-D focus) would be in Boston area this week.  So I've got a meeting set up for Wednesday.

    There are several features in the TAS5716 that I need and not found in the newer parts:  both headphone and subwoofer outputs, feedback output stage, bass enhancement, and the additional input/output mixers.  Your comment about the age of the TAS5716 concerns me, though.  Is this part possibly going NRND anytime soon?  

    I just received the EVMs this morning (still need the mother board).  I noticed they were populated with the TAS5716A.  Is this a newer version of the TAS5716?  If so, what changed?

     

    Thanks,

    Nick D.

  • 0 in reply to Nicholas D'Amato
    TI__Guru**** 189399 points

    Nick,

    You didn't get the MC57xx-PSIA boards? Argh! Sorry about that. I've asked Ravinder to ship those to you.

    The A version has some bug fixes over the non-A version. We actually aren't shipping the non-A version any longer.

    -d2

  • 0
    TI__Mastermind 21385 points

    Hello Nick,

    The input and output mux are on either end of the signal chain. The input mux before the input mixers and the output mux after the output mixers. I am still looking into your queries about the two channel BTL and using the software to mix the BassBoost back into channels 1 & 2.

     

    -Mike

  • 0 in reply to Michael Gambrill
    TI__Mastermind 21385 points

    Nick,

    While I am looking for information specific to the TAS5716 BTL, take a look at this post about the TAS5706A BTL.

    http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/p/87432/302180.aspx#302180

     

  • 0 in reply to Michael Gambrill
    Prodigy 100 points

    Hi Mike,

    Thanks for the link, but I'm not sure that it applies to my situation.  It seems that setup would send Left and Right information to the headphones, but only the Left information would go to the OUTA/B BTL output.  It's mono, but not mixed mono.

     

    I need something entirely different.  I have a stereo pair of speakers, a subwoofer output, and a stereo headphone output.  So ultimately, I'm trying to do something like the following:

    SDIN1L --> ch1

    SDIN1R --> ch2

    (SDIN1L + SDIN1R) / 2 --> ch6 (mixed mono signal to be processed for bass boost)

     

    OUTA & OUTB (in BTL mode):  ch1 + ch6 (Left channel with bass boost mixed back in)

    OUTC & OUTD (in BTL mode): ch2 + ch6 (Right channel with bass boost mixed back in)

    HPL: ch1 or ch1 + ch6 (Left channel with or without bass boost mixed back in)

    HPR: ch2 or ch2 + ch6 (Right channel with or without bass boost mixed back in)

    SUB +/-: ch6 (Bass boost signal or some other mixed-mono signal)

     

    In other words, I need stereo information plus the mixed-mono bass boost signal going to my speaker outputs (in BTL configuration).   I need the bass boost signal or a low-passed mono signal going to my Subwoofer output.  And I need stereo information (with or without the bass boost) going to my headphone output.

    Is this do-able?

     

    FYI, I just got the MC57xxPSIA board today, and I have the Eval up and running.  I'll play around with it and see what I can make it do.

     

    Thanks,

    Nick

  • 0 in reply to Nicholas D'Amato
    TI__Mastermind 22965 points

    Hi Nick,

    All the scenario's you listed in the previous post are do-able. I have described these below.

    1.) SDIN1L to Ch1 is the default settings (Input Multiplex register defined by register 0x20)

    2.) SDIN1R to Ch2 is the default settings (Input Multiplexer register defined by register 0x20)

    3.) (SDIN1L + SDIN1R) / 2 toCh6 is also the default setting (Input Multiplxer register-2, defined by register 0x21) **
    **     Down-mix settings are assumed to be at default 

    4.) OUTA & OUTB (in BTL mode) =  ch1 + ch6  - This can be set by by the output mixer, defined by register 0x51 (8-bytes). Default is 00-80-00-00 00-00-00-00

    For example, to mix 50%Ch1 & 50% Ch6, 0x51 should be updated to 00-40-00-00 00-40-00-00

    5.) OUTC & OUTD (in BTL mode) =  ch1 + ch6  - This can be set by the output mixer, defined by register 0x52 (12-bytes) (Default is 00-80-00-00 00-00-00-00 00-00-00-00)

    For example, to mix 50%Ch2 & 50% Ch6, 0x52  should be updated to 00-40-00-00 00-00-00-00 00-40-00-00

    6.) HPL: ch1 or ch1 + ch6 (Left channel with or without bass boost mixed back in)

    When HP is enabled, speaker signals go low. The channels routed to the HP (& speaker) are defined by output multiplexer register (0x25). As in bullet#4, the input mixer can be used to accomplish the mix with Ch6. Additionally, the output multiplexer register (register 0x25) would need to be set appropriatley.

     

    7.) HPR: ch2 or ch2 + ch6 (Right channel with or without bass boost mixed back in)

    Same as above.

     

    8.) SUB +/-: ch6 (Bass boost signal or some other mixed-mono signal)

    Ch6 setting is defined by Input Multiplex register 0x21. One of three options can be selected for Ch6 (as indicated in the block-diagram):

    1.) Bass-Management processed signal to Ch-6
    2.) Ch-6 raw data to Ch-6
    3.) Down-mix data to Ch-6 (Note: This option is similar to bullet #3 above)

    Please let me know if this helps answer your question or if you need any additoinal information.

     Best Regards,

    Ravinder

  • 0 in reply to Ravi Singh
    Prodigy 100 points

    Hi Raviner,

    Thank you very much!   I figured out some of this while playing with the EVM, but your thorough explanation filled in some gaps for me.  Now I am confident I have it configured as you described, and it seems to be working properly.  

    However. there is one issue.  I can only get this configuration by using a combination of the GDE and the I2C tool.  Shouldn't this be possible using only the dedicated GDE TAS5716 workflow using the 'BassBoost' functionality?  It appears the associated 'BassMixer' setting is designed to adjust the output mixer (% of ch6 mixed into ch1 & ch2), but I can't get it to work.  

    I suspect it has something to do with these errors I'm seeing in the output section when I start the GDE tool:  

      Removing obsolete property: BassMixerH from TAS5716EVM
      Removing obsolete property: DirectPathH from TAS5716EVM
      Removing obsolete property: InDirectPathH from TAS5716EVM
      Removing obsolete property: BassBoostH from TAS5716EVM
      Removing obsolete property: SurroundH from TAS5716EVM

    I can enable the 'BassBoost' setting, but if I try to adjust the 'BassMixer' setting, I get a pop-up window saying, "Property value is not valid".  If I click for details, it says "TAS5716EVM: Requested property (BassMixerH) not found".

    Any ideas?

     

    Thanks, 

    Nick D.

  • 0 in reply to Nicholas D'Amato
    TI__Mastermind 22965 points

    Hi Nick,

    The GUI error messages you reported certainly indicate an issue, which is likely causing the Bass-mixer block to not work.

    I just tried installing & running the GUI on a PC  and  this seemed to be okay. No errors were reported, and I was able to make updates to the Bass-Mixer/Bass-Boost blocks in the GUI. (Note: EVM not used, just quick check for GUI functionality).

    I am wondering if an un-install & fresh install might resolve this issue. I have attached a ZIP file containg the install file I used (Ver 2.01, Build11).

     1057.TAS5716_V2.01_Build11_Jan21_2011.zip

    As a side-note, also wanted to point out that some blocks (like MUX etc.) can only be updated with "target disconnected". You proably have figured this out already, but just wanted to include for reference.

    Best Regards,

    Ravinder

  • 0 in reply to Ravi Singh
    Prodigy 100 points

    Thanks Ravinder.  

    That's the same GDE version I had, but I did a clean reinstall anyway.  The fresh install eliminated the error messages.  BassBoost seems to be doing something now, just not exactly what I expected.  I'll have to play around with it some more.

     

    BR,

    Nick D.

     

  • 0 in reply to Nicholas D'Amato
    TI__Guru**** 189399 points

    Hi, Nick,

    Did you get it working to your satisfaction? 

    -d2

  • 0 in reply to Don Dapkus
    Prodigy 100 points

    Hi Don,

    Thanks for the follow-up.  I had to put the board aside for a couple days, but I am anxious to get back to it.  

    Last time it was running, I was having issues with the eval board not getting updated when changes were made in the GDE.  Some changes would update, others would not. These problems were first noticed while I was trying to verify output levels and frequency response using an Audio Precision test system.  Certain GDE changes -especially on the ch6/subwoofer chain- had no effect on the audio.  

    I suspect the problem might be related to the test setup.  Possibly having the eval board and AP test system connected to the same computer is causing ground issues and/or communications errors.  I plan to create a new test setup with better isolation to see if it fixes the problem.  Right now, I just need to clear my plate of other tasks so I can get back to it.

    -Nick D.

  • 0 in reply to Nicholas D'Amato
    Prodigy 100 points

    Hi Don,

    After re-running tests with a different test setup, I was still having issues.  Specifically, the biquad filters would not always update.  And if I tried to update the biquads on-the-fly, other settings often became mis-configured.  

    To get the biquads to update consistently or fix a mis-configuration, I had to shutdown, disconnect the target board, press master reset on the board, reconnect, and re-run the script.  

    Then I had an idea....  

    I disabled coefficient banking and --sure enough-- I can now update biquads on-the-fly.  Maybe I missed this somewhere in documentation?  Maybe it needs to be added?

     

    Anyway, I've got coefficient banking disabled now and I'm making progress.  

     

    -Nick D.

  • 0 in reply to Nicholas D'Amato
    TI__Guru**** 189399 points

    Hey, Nick,

    Actually, it is not safe to update the biquads on the fly on this part. You need to mute the audio first, update the BQs, then unmute.

    -d2