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TAS5780M: How to initialize the IC using a .cfg file

Part Number: TAS5780M
Other Parts Discussed in Thread: , TAS5825M, TAS5754M

I am trying to use PurePath Console 3 to create a .cfg file that I can use to initialize the TAS5780M amplifier on our product.  I started with the TAS5780MEVM.  I can initialize the EVM using PPC3 (with the Audio Processing block), and the amplifier IC outputs are switching as expected.  If I write out a .cfg file of that configuration using the End System Integration block, power cycle the EVM, and then reload the saved .cfg file using the Direct I2C block, all the writes happen but the amplifier IC outputs are not switching.  It seems like there is something missing in the .cfg file.

Is there something else I have to do after loading the .cfg file to get the amplifier to start?

Thank you!

-Dan

  • Hi Daniel

        The dump file from PPC3 should work well and you needn't do anything. Do you still use EVM to do all the tests? Use the I2C block write .cfg to the EVM? If so, you can read the register 0x76 to check if the device stays in PLAY mode. Also 0x23 to see if any error happens.

  • Hi, Shadow He.

    Thanks for your suggestion.  We'll take a look at those registers.

    I discovered loading the .cfg file into a power-cycled EVM didn't work because the other parts on the EVM (DRX, USB interface) hadn't been initialized, and I think they are supplying the clocks.  So that's explainable.

    But we still can't get the part to start on our PCB.  It's odd, because we have used other similar TI amplifiers (TAS5754M, TAS5825M) like this and had no problems at all.  In fact, the TAS5780M is virtually identical to the TAS5754M hardware-wise, except for one pin (/RESET).  We are going to hotwire the EVM main board into our PCB's I2C bus and see if we can initialize using the EVM instead of our own firmware.

    -Dan

  • Hello Daniel,

    We recommend waiting 100 ms to 240 ms for the DVDD power supplies to stabilize before starting I2C communication and providing stable I2S clocks before enabling the device outputs.

    Are you able to readback registers using your firmware? Can you confirm it's writing correctly?

    best regards,

    Luis

  • Hi, Luis.

    We currently assert /RESET, start the I2S clocks, wait 5 seconds for power supplies to stabilize and caps to charge, deassert /RESET, and then wait another 10 msec before starting to write the I2C registers.  So I think we should be OK there.

    We are going to hotwire the EVM into our PCB and see if that tells us anything.  Right now, we don't have a way to display any I2C read results, and that will be the easiest way to see what's going on.

    I'll post again when we have more information.

    Thank you!

    -Dan

  • Hello Daniel,

    Look forward to hear about your results from the test

    best regards,

    Luis

  • We eventually discovered that running the PLL from BCLK does not work in TDM256 mode.  Once we switched to using MCLK instead, the amplifier started switching.