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CDCE62005: DAC34H84EVM J10/J11 LVDS clock output error (2)

Part Number: CDCE62005
Other Parts Discussed in Thread: DAC34H84

Dear Clock team,

I was advised to contact you again from Data Converters team as the following,

DAC34H84EVM: J10/J11 CDCE62005 LVDS clock output error.

Please review attached configuration files from the customer.
 - DAC_config_CDC.txt  :  Configuration file for CDCE62005 device only
 - DAC_config_full.txt  :  Configuration file including DAC34H84 device

They found a issue. When they set the DAC register "x02", DAC32H84 device settings became default value, although CDCE62005 device settings was kept as the configuration file.
When they read the register value after loading "DAC_config_full.txt", it became different value as the following,
 - DAC_config_full_Read_after_Load.txt

DAC_config_CDC.txt
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x00 x0000
x01 x0000
x02 x0000
x03 x0000
x04 xE5B1
x05 x3A60
x06 x3100
x07 x0000
x08 x0000
x09 x0000
x0A x0000
x0B x0000
x0C x0000
x0D x0000
x0E x0000
x0F x0000
x10 x0000
x11 x0000
x12 x0000
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

DAC_config_full.txt
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x00 x019F
x01 x0402
x02 x7082
x03 xA000
x04 x0000
x05 x0000
x06 x0000
x07 xD8FF
x08 x0000
x09 x8000
x0A x0000
x0B x0000
x0C x0000
x0D x0000
x0E x0000
x0F x0000
x10 x0000
x11 x0000
x12 x0000
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

DAC_config_full_Read_after_Load.txt
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x00 x0000
x01 x0000
x02 x0000
x03 x0000
x04 xFFFF
x05 x267E
x06 x3300
x07 x0000
x08 x0000
x09 x0000
x0A x0000
x0B x0000
x0C x0000
x0D x0000
x0E x0000
x0F x0000
x10 x0000
x11 x0000
x12 x0000
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

I look forward to your reply.
Thank you.

Best Regards,

Koshi Ninomiya

  • Hi Koshi,

    This is a DAC's GUI and I am not familiar of that, how the clocking device is programming. But, I can provide my guidance to some extent.

    As generated frequency (211.29MHz) is different than the programming (207.36MHz), that means CDCM device is not locked and on-board LED is OFF. Please confirm?

    You can try to calibrate the VCO by toggling R6[22] ("1" -> "0" -> "1") while R6[27] = "0", then you should see the PLL locked and can generate correct frequency.

    Regards,

    Ajeet Pal

  • Hi Ajeet-san,

    The customer tried to toggle Register 6 between the followings, but on-board LED was still OFF.

    <Register 6>
    40AF24F6 [1000"0"0010"1"011110010010011110110]
    408F24F6 [1000"0"0010"0"011110010010011110110]

    Best Regards,

    Koshi Ninomiya

  • Hi Koshi-san,

    Oh! so there is a confusion regarding the bit 22. It's for the register 6 and if they considering register address also, then it would be 26th bit.

    It will be ,

    <Register 6> 
    44AF24F6 [01000"1"00101011110010010011110110]
    40AF24F6 [01000"0"00101011110010010011110110]

    44AF24F6 [01000"1"00101011110010010011110110]

    Please try this and see the performance.

    Regards,

    Ajeet Pal

  • Hi Ajeet-san,

    The customer tried the followings, but it was not improved and on-board LED was still OFF.

    #1:
        44AF24F6 [01000"1"00101011110010010011110110]
        40AF24F6 [01000"0"00101011110010010011110110]
        44AF24F6 [01000"1"00101011110010010011110110]

    #2:
       After Manual calibration (Register 6[27-bit]=1), toggle Register 6[22-bit]
       C0AF24F6 ["1"1000"0"00101011110010010011110110]
       C4AF24F6 ["1"1000"1"00101011110010010011110110]

    #3:
       After StartUp calibration (Register 6[27-bit]=0), toggle Register 8[7-bit]
       20001808 ["0"100000000000000001"1"00000001000]
       20001008 ["0"100000000000000001"0"00000001000]

    Only in case of #2, LVDS clock output frequency was changed from 211.29MHz to 216.7MHz, but it was not the target setting of 207.36MHz.
    Are there any other advices?
    Thank you.

    Best Regards,

    Koshi Ninomiya

  • Hi Koshi-san,

    I assume, DAC34H84EVM may have some default setting to program the device. Are the EVM able to program CDCE62005 with default value?

    If it shows PLL lock at their default setting, then I think could help to tweak it for new frequency. Otherwise, we are not sure the device is operating properly or not.

    Regards,

    Ajeet Pal 

  • Hi Ajeet-san,

    When the customer reviewed the frequency settings, they noticed that the frequency settings were incorrect. The output clock frequency and VCO frequency were twice as high as expected. Because the VCO frequency was out of specification, the PLL did not lock, and the output clock was accidentally close to the desired frequency, so it seems that the customer had misidentified it.
    Thank you for your support.

    Best Regards,

    Koshi Ninomiya