Adalm-Pluto Rev D

  • I recently bought an Adalm-Pluto, the GPSDO of Leo Bodnar, studied all notes regarding modification and was surprised that my Pluto is looking totally different from what I have seen so far. To make a long story short, I got revision C and unfortunately, I could not find any documentation in the internet. Difference is that TCXO is on the secondary side of the board and that four small connector sockets (IPX?) are on the primary side. One of them is marked as “CLK_IN 3V3 Max” another as “CLK_OUT”. It seems to me that no further modification is needed to feed in the signal of an external GPSDO but I am not sure.

    - Does anybody already has modified Rev C for QO-100 use?

    - How to feed in the signal of my GPSDO?

    - Anything else I have to consider or take care about?

    Thanks for your help and comments,

    73 Ansgar, dl5zbs

  • Hallo Frank,

    ich habe meinen Pluto bei Digi-Key gekauft.
    Wie gesagt, habe bisher keinerlei Dokumentation finden können. Auf dem TCXO steht 40.0 und S 0F. Mehr kann ich nicht erkennen, bin allerdings auch kein Spezialist ins solchen Dingen, ehr ein "Nachbauer"

    73, Ansgar

  • After DJ5PW mentioned to have Rev. D I checked my Pluto again.
    On the lable at the enclosure back side Rev. C is written but on the board Rev. D which I did't noticed so far.

    Obviously we have hardware Rev. D but with current firmware it is called Rev. C.

    I hope that documentation will be published soon.

    Below are two photos of a little higher resolution which may help those of us who have more experience in this matter.

    73 Ansgar

  • Hello,

    I found some pictures on twitter.

    73, Dolf.

    Interesting to see here my pictures 🤔🙂

    But that´s not the main reason for my posting.

    I tested the external ref and it works like it should. The CLK_Out is activated after CLK_Source is set to external.

    Also the PTT works if you set the "adress" correct.

    not made deep tests while busy with other things but thought it could be interesting for other to hear good news.


    use Putty or what you prefer

    login with 'root' - 'analog'

    fw_setenv refclk_source external // this enables the CLK_IN/OUT

    pluto_reboot reset // reboots pluto and the CLK_IN is active

    If your reference is not perfect you can correct it with:

    fw_setenv xo_correction 39999750 // for example

    Changing the frequency is done with:

    fw_setenv ad936x_ext_refclk '<25000000>' // You must use ' NOT " as describes in the WIKI since 0.32!

    Or you use: fw_setenv ad936x_ext_refclk_override '<25000000>'

    Don´t forget to reboot the Pluto to apply the changes with:

    pluto_reboot reset

    Easy and fast done.

    Hope it helps.



    Edited 6 times, last by DM4DS: Updated the Ref Frequency change Options and the correction. Bold - Italic etc doesn´t work for me so I tryed a few times :) ().

  • Hi,

    Maybe R5 near TCXO that missing is for disabling internal TCXO.

    disabling internal tcxo (now) is done via enable pin and q2 and not via r5!!

    r5 can be installed if you solder in a tuneable tcxo (and want to tune it via auxdac voltage!) ... if you replace tcxo with any other (as example astx13/asvtx13) with no enable pin then switching to external reference does not work anymore ...but i had a clever idea to solve that

    solution is to rewire Q2 to pin 4 of U12 (enable pin of 1p8v_clk regulator) ... so instead of switching enable pin of the tcxo ... you switch enable pin of the power regulator ic that powers the tcxo

    (time for a revision e ?!?)

    why the hell did they not install in minimum the 0.5ppm tcxo from factory?!? grmbl grmbl

    how is rewiring done?? lift pin 4 of u12 ... and rewire that enable pin to R67 (cut connection to enable pin of tcxo)

    r101 ... disconnect from 1p8v_clk and rewire to solder lug pg_1p3v

    now selecting external reference switches power of tcxo instead enable pin of tcxo

    that pin is now free ... so a tuneable tcxo can be mounted (with trimmer or with installing r5 and using ad9363_auxdac)

    happy modding DG9BFC (big fat chicken, beat frequency counter, bastler für charly?)

  • Hallo,

    the above comment sounds strange a bit. If I want to buy a specific revision, I should get one. Otherwise it goes back. Mouser or digikey can sell any revision to customers who don't care.
    Who placed the youngest order? Which version was delivered? Are there older versions in stock? By the way, there are different releases of CN0417 too. Revision C contains a temperature switch. It can be used as a PTT-circuit. 600mA continous current consumption are unacceptable. May be, a chinese version of an amplifier with a SIRENZA-MMIC SZA2044 is doing the same job. Less current, a bit more gain and a standby pin also.
    Happy Easter


  • If your reference is not perfect you can correct it with:

    fw_setenv xo_correction 39999750 // for example

    Hi Sandor,

    Setting a correction for my external reference is not working. I tried it several times and always did a reboot. I want to set it to 40000000 but it stays with 39999716.

    Any idea what I did wrong?

    Thanks for your help