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DAC38J84: SYNCB becomes low every other time

JDY
Prodigy 175 points
Part Number: DAC38J84

Hi Jim,

 

I have successfully exported data sourced from JESD block from the DAC since I used the order that you gave me.

But there is still a problem. The signal SYNCB outputted from the DAC38J84 will become low every other time. And then the synchronization will start over again. So is there any possible that some of my registers are not configured correctly?

Attached is my configuration. And the two pictures are 10MHz sine wave signal outputted from DAC captured by the oscilloscope, and the data outputted from the JESD IP core connected to DAC38J84 observed by ILA of VIVADO. 

2308.dacreg.docx

  • 0
    TI__Guru* 91947 points

    1882.DAC3xJ8x Device Initialization and SYSREF Configuration.pdfJDY,

    In register address 0x51, disable bits 0-7 to see if this clears the problem. If so, enable this bits one at a time starting with bit 7.I have also attached some documents to help you with trouble shooting this.

    Regards,

    Jim

  • 0 in reply to jim s
    Prodigy 175 points
    Hi Jim,

    I have try to enable the bits 0-7 of register 0x51 one at time. Now the result is : when I enable the bit 7 only, there is nothing output; when I enable the bit 6 only, the output is right; when I enable the bit 5 only, there is nothing output; when I enable the bit 4 only, there is only messy data (random signal) output; when I enable the bit 3 only, there is only messy data (random signal) output; when enable the bit 2 only, the signal SYNCB outputted from the DAC38J84 will become low every other time just like before; when enable the bit 1 only, the signal SYNCB outputted from the DAC38J84 will become low every other time just like before; when enable the bit 0 only, the signal SYNCB outputted from the DAC38J84 will become low every other time just like before.

    I can not confirm which bit let the SYNCB become low.

    Regards,

    JDY
  • 0 in reply to JDY
    TI__Guru* 91947 points

    JDY,

    The critical errors are bits 0, 1, and 2. These should always be enabled. After setting these and getting a stable SYNC, start adding the other bits one at a time. What setting are you using for RBD? This must be equal to or less than K.

    Regards,

    Jim 

  • 0 in reply to jim s
    Prodigy 175 points

    Jim,

    My value of RBD is 32, and the value of K is also 32.

    Regards,

    JDY