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Original question:

PCM1865EVM: configuration

PCM1865EVM: PCM1865evk mode coniguration

Malay Dhrangadhria1
Prodigy 230 points
Part Number: PCM1865EVM
Other Parts Discussed in Thread: PCM1865, PCM9211,

Hello

I need some help regarding different operating modes of PCM1865evk.

There are three operating modes for the codec module. (mode 0, mode 1 , mode 2)

I want to use PCM1865 codec as slave and configure the BCK, LRCK clock (I2S interface) from external iMX8M devlopment board and for that i should operate the module in mode 2.

As per the PCM1865evk guide,

I don't see any configuration difference for Mode 0 and Mode 2 for PCM1865evk. I want to operate PCM1865evk in mode 2 where i can interface codec module with iMX8M development board through I2S protocol and give clock from the iMX8M dev board and get DOUT to the dev board.

I hope i am clarifying my doubts. Let me know you if you don't understand anything specifically.

  • 0
    TI__Mastermind 23050 points

    Hey Malay,

    Unfortunately the PCM1865EVM was not designed to interface with other I2S devices. The EVM modes allow you to select the master, allowing you to choose from the PCM9211, the PCM1865, or the TAS1020b on the I2X board. In order to interface with another board, you will have to modify the EVM. You can do this by removing resistors R3, R20, R21, and R22. Then you can apply your clocks to the test points on the board, or remove them to replace with single pin headers. Just make sure you provide good ground connections for your clock signals! Since you will not be using the crystal you should use the jumper settings for either mode 0 or mode 2.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 230 points

    Hello Zak,

    Thank you very much for your reply,

    So if i am using PCM1865 as a slave,

    I can keep R3 as it is (SCKI resistor) and get clock from internal board (from PCM9211) and other I2S connection from external iMX8 board.

    Will this configuration work as slave mode.?

  • 0 in reply to Malay Dhrangadhria1
    TI__Mastermind 23050 points

    Hi Malay,

    If you are using the PCM1865 as a slave then it is not necessary to provide and SCKI as the device can generate this internally from BCK and LRCK.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 230 points

    Hello Zak,

    So i don't need to connect SCKI pin of PCM1865 to work the codec in slave mode ? So the only connection would require are BCK, LRCK and DOUT between Codec and iMX8M processor, is that what you are suggesting.?

    And in that case where the SCKI pin get connected.? Should i keep it connected on board through R3 resistor or simply keep it open.

    As i mentioned earlier i want to use PCM1865 as slave and interface it with iMX8M processor to get the digital audio on board.

    Please brief me with this interface.

  • 0 in reply to Malay Dhrangadhria1
    TI__Mastermind 23050 points

    Hi Malay,

    Correct, since PCM1865 has an internal PLL it can generate its own master clock based on the incoming BCK and LRCK. In that case it is okay to leave the SCKI pin floating.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 230 points

    Hi Zak,

    Thank you for this understanding.

    One thing i noticed here,

    I removed those four resistors from PCM1865evm board.

    Before the removal of these resistors, i was able to write configuration registers through iMX8M board.

    But now i am not able to write any register values, I am able to read its default values but not able right.

    Is it something related to the removal of resistors ?

    I am not getting it why it's happening.

  • 0 in reply to Malay Dhrangadhria1
    Prodigy 230 points

    So, this is what i have observed,

    I removed those four resistors (R3, R20, R21, R22) to use the PCM codec for external I2S interface as per your suggestion. But after removing those resistors i was not able to write any configuration registers through I2C interface. not even through purePath Console.

    I soldered back those resistors and now i am able to configure it through I2C.

    How should i proceed to work PCM1865 codec as slave mode with external iMX8M processor I2S interface.

    Thank you in advance.

  • 0 in reply to Malay Dhrangadhria1
    TI__Mastermind 23050 points

    Hey Malay,

    As mentioned in the discussion here: https://e2e.ti.com/support/audio/f/6/t/924283, I believe you have removed the resistor that connects SCL to the I2X board and SCL test point.

    Best,

    Zak