AD1939 in selfboot system

Hi!

I have a SW/HW question about programming the AD1939 CODEC in a Selfboot ADAU1446 DSP-System. My board works well with the ADAU1446 in I2C Mode, with selfboot from EEPROM (I2C) and with the AD1939 in Standalone mode. Now I need to program the CODEC to use it with 96- and 192 kHz. The connection to AD1939 over SPI with the ARWB 3.0 Software works, but it doesn't in connection with the ADAU1446 (in I2C or SPI).

1) Is this combination principally possible (ADAU1446 in selfboot-mode with change registers of AD1939)?

2) How do I connect the parts together and how do I have to tell the ADAU1446 to set the CODEC registers?! At the moment, the DSP and EEPROM are connected (SDA and SCL) like on the EVAL-BRD and the DSP with the CODEC (Clatch, Cclk, Cout, Cin) and all to the programming Header of the USBi. Is this the right way to connect them? Or do I have to set the register over some MPIO pins?!

I have seen this posting in the forum (http://ez.analog.com/thread/3631?start=0&tstart=0), but it only seem to work for directly programming with SigmaStudio and not in a selfboot application.

I have also found the part AD1937 with similar properties and Pinouts and with I2C connection. Could it be a solution for directly programming the CODEC easier with SigmaStudio and in Selfboot Mode?

I'm a bit frustrated at the moment, because it would be a very good system, if this issue works. I cannot redesign the whole PCB, because of time and costs!

I would be very grateful for some help!

Best regards,

Fabio Perathoner

  • Hi again,

    I got an assumed correct answer in the following thread: http://ez.analog.com/message/136738#136738

    That means for this thread:

    1) No, it's not possible to combine them and program all together with SigmaStudio and let selfboot the whole system, because the ADAU1446 can only boot in I2C and the AD1939 is only programmed by SPI. AD1939 registers should be changed with an external uC. Am I right with this train of thought?!

    2) see 1)

    I will try out the AD1937 and post the result here...

    Regards,

    Fabio

  • 0
    •  Analog Employees 
    on Mar 19, 2014 11:58 PM

    Hello Fabio,

    The ADAU1446 can only self-boot in I2C mode and can only be an I2C slave with the exception of when it self-boots. The AD1937 does not need an external EEPROM to work in standalone mode but the available modes are limited. The ADAU1446 cannot act as a master and program the AD1937. So with your application you will need an external controller to configure the AD1937 with the proper settings.

    Dave T

  • Hello Dave, thank you for the answer,

    Would it be better to boot the whole system with the controller? Should I be afraid, that there are some pops to hear, if i let the ADAU1446 selfboot from the EEPROM (with a SigmaStudio program in 96kHz or 192kHz) and after that, say to the controller to change the sampling rate of the AD1937/9? Or will this happens fast enough?

    Can someone recommend a cheap controller for the issue mentioned above. That means, after setting a pin low or high by the ADAU1446, the controller should change one register setting (3 bytes in total) of the AD1937/9 in I2C/SPI...

    I have searched very long and tried much for this simple system... It would be very helpful, if there would be a Application Note, to how connect the DSP with the CODEC and how to let them boot, just as a note . Or had I failed to see such a description?

    Best regards,

    Fabio

  • 0
    •  Analog Employees 
    on Mar 20, 2014 10:28 PM

    Hello Fabio,

    The easier thing to do is probably use a small 8-bit controller to boot up the AD193x and let the ADAU1446 boot itself. I will take your suggestion to write an APP-Note about this but that takes a bit of time. I think either writing in a long delay on bootup to keep the DAC muted will prevent clicks or pops. There may be other ways to communicate to the controller to mute and unmute. Using one of the GPIO pins would be a good solution.

    Now, I am attaching a tutorial on how to program a micro-controller to boot up a Sigma processor. I am also attaching a zipped file with an example using a different part but it will all still apply.

    Dave T

    attachments.zip
  • Thank you very much, Dave!

    That should be very useful, I will try this out in the next time.

    Best regards,

    Fabio