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Why no timestamping in PlutoSDR?

I was wondering why there is no precision timestamping in the PlutoSDR, something akin to what Ettus does in their USRPs?   Is it simply because it is an educational tool or is it something else, like a limitation in libiio?  I really like the PlutoSDR platform but my application needs the timestamping capability, so I want to add this feature to the FPGA design and the drivers.  Can someone could tell me if is a realistic goal?

  • libiio is a much more generic library than UHD from Ettus and supports drivers running on devices that usually do not have FPGAs where this time stamping is done. It is planned to add this feature in libiio v2 but it’s still in conception stages right now.

    Adding time stamping would likely require adding an additional channel to the DMA configuration which will require HDL and device tree changes. This isn’t really that hard to do assuming you understand how to modify HDL code and the embedded software components.

    -Travis

  • Hello,

    This option seems necessary for some SDR protocols (mobile communications software like openBTS or SRSlte for example can't be implemented with libiio because of this).

    The data DMAs in adalm pluto are 32 bits wide but only 24 bits are used for data. Maybe some rudimentary timestamp could be done with bits not used...but not sure how timestamp should really work.

  • Can you elaborate on that? I am trying to do some kind of timestamping at the moment, but I can not find an example of this implementation.

  • sorry no example for my part. just telling to the analog guys that the timestamp is very important and trying to give my contribution about how could be done but no time to look for in this direction.

    I guess the best way should be look for how Ettus is implementing the timestamp and try to mimic the implementation but not sure if it's possible.