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Original question:

PCM1865EVM: PCM1865evk mode coniguration

PCM1865EVM: I2S interface

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

I am working with PCM1865evk module to get FM tuner data to iMX8M board through digital audio interface I2S communication.

Below is the block diagram representation of the setup for the reference.

As per the suggestion received in another thread,  i removed R3, R21, R22, R23 from PCM1865evk to work the module as slave configuration with external iMX8M board interface. 

But this didn't help me. When i removed those registers, i couldn't configure the PCM1865 codec through I2C interface. Is there any limitation for the PCM1865evk to work with external I2S interface?

Please provide some help for this integration.

  • 0
    TI__Mastermind 23050 points

    Hi Malay,

    In the previous thread I recommended you remove R3, R20, R21, and R22. These are only for the I2S bus and have no bearing on the I2C control. You would still have to use the I2X board connected to your PC via USB and control the configuration through the EVM GUI or another app that can issue I2C commands. If you also want the iMX8M to control the I2C bus, then you should remove the I2X board and power up the EVM directly and connect the SCL and SDA lines to you iMX8M board.

    If you removed R23, then this is the resistor that connects the SCL of the I2C bus to the I2X board and the SCL test point on the EVM (refer to the schematic). This is most likely why your communication is not valid. 

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 230 points

    Hi Zak,

    That was my bad, I removed R3, R20, R21 and R22 only to interface the PCM module through external iMX8M I2S protocol.

    I understand these are the I2S bus only and no bearing with I2C control, yet i am facing this issue of I2C when i removed those I2S bus resistors.

    I believe PCM1865 goes to sleep mode if there is no clock on I2S pins and doesn't respond to I2C resistor configuration commands. And that could be the reason that PCM1865 codec isn't responding to I2C configuration commands once the I2S bus resistors removed. This is my understanding, don't know the actual reason behind this.

  • 0 in reply to Malay Dhrangadhria1
    TI__Mastermind 23050 points

    Hi Malay,

    The PCM1865 does enter power down mode when no ASI clocks are applied, but you are still able to issue I2C commands and configure registers. If you are not able to issue I2C commands from your iMX8M board then you may need to verify you have the address set up correctly.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Prodigy 230 points

    Hi Zak,

    I am getting the I2C address correct from iMX8M board as well.

    Even I am not able to configure the I2C registers from the PurePath tool through USB-I2X after removing those I2S lane registers (i.e. R3, R20, R21. R22).

    I don't understand why this is happening. Do this chip require any external pull up to configure it through I2C for this PCM1865evm ?

  • 0 in reply to Malay Dhrangadhria1
    TI__Mastermind 23050 points

    Hi Malay,

    Again if you are not able to issue I2C commands this means you have removed more than just the I2S resistors as it is not necessary to supply I2S clocks to program the device. I2C does require pullup resistors, and these are present on the EVM assuming you are supplying power to the device via the I2X board. If you are not using this board, then your processor needs to have pullup resistors for the I2C lines.

    Best,

    Zak