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Disable both LO synthesizer and clock synthesizer

Hello,

For a special usage, I need to disable both LO synthesizer and clock synthesizer to provide 18MHz source to them directly, the IF is 15.75MHz. I planned to take the following actions on  AD9864/AD9874 evaluation board: 

1. Install R14, R16, remove R19, R20, R22

2. Install R21, remove R17, R18, C34

3. Remove R28, C34, C35, connect pin 35 to ground directly

4. Set SPI register 0x00 bit[7:4] to 1.

Before I power on the board, I was wondering are the steps correct? Do I miss anything? 

By the way, regarding the ad9874 SPI GUI, can I modify the parameters on GUI? I modified the parameters and click "write", when I read back the registers it seems it doesn't work, all the values are still from the configuration file.

Thank you very much.

The EVAL Board SCH:

https://wiki.analog.com/_media/resources/eval/user-guides/15006c_sch.pdf

The EVAL Board User Guide:

https://wiki.analog.com/_media/resources/eval/user-guides/ad9864_ad9874_users_guide.pdf

The SPI GUI

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  • Hello,

    Hardware changes look good.

    Example script below is used for external CLK (18 MHz) and LO.  Note that the CLK SYN, LO SYN, and CLK Bias are powered down and a more robust LC/RC tank tuning procedure is used.  Please review the AD9864 datasheet  which was recently updated to reflect this more robust tuning procedure (Table 24, page 46).  

    Your screen shot of the GUI panel looks good in that the HEX register values shown on bottom of the display reflect the settings shown for each of the registers above this listing.

    Regards.

    ## Example file loads AD9864 settings with external CLK=18 MHz and External LO.
    ## Wait states (in usec) are also inserted for RESON calibration.
    3F 99
    3A 08
    19 87
    01 F0
    00 75
    3e 43
    38 01
    39 0f
    1c 00
    1c 03
    00 74
    Wait 6000
    38 00
    3e 00
    00 70
    03 00
    04 00
    05 00
    06 00
    07 00
    1A 01
    19 87
    1A 01
    18 00

Reply
  • Hello,

    Hardware changes look good.

    Example script below is used for external CLK (18 MHz) and LO.  Note that the CLK SYN, LO SYN, and CLK Bias are powered down and a more robust LC/RC tank tuning procedure is used.  Please review the AD9864 datasheet  which was recently updated to reflect this more robust tuning procedure (Table 24, page 46).  

    Your screen shot of the GUI panel looks good in that the HEX register values shown on bottom of the display reflect the settings shown for each of the registers above this listing.

    Regards.

    ## Example file loads AD9864 settings with external CLK=18 MHz and External LO.
    ## Wait states (in usec) are also inserted for RESON calibration.
    3F 99
    3A 08
    19 87
    01 F0
    00 75
    3e 43
    38 01
    39 0f
    1c 00
    1c 03
    00 74
    Wait 6000
    38 00
    3e 00
    00 70
    03 00
    04 00
    05 00
    06 00
    07 00
    1A 01
    19 87
    1A 01
    18 00

Children
  • Hi,

    Thanks for the prompt response and sorry for some confusion that I didn't indicate my platform clearly. My platform is AD9874, so as you suggested to reference to AD9864 datasheet, I was wondering that is the script also applies to AD9874? What's the difference between these two chips?

    Regarding the screenshot, the HEX registers match the GUI panel because I customized the configuration TXT file. But if I change parameters on GUI then execute "write" and "read", the readback will be the values of configuration TXT rather than the GUI setting (after reading, the GUI will discard my setting and show configuration TXT values as well). It's not a big problem, but if I could change values on GUI and write them to SPI this will be much easier for debugging. So I was wondering can I change values on GUI?

    Here is one more question:

    Thank you very much.