Hello Franco, As I understand it, PTP wasn't terribly useful in our application (though I wasn't involved with this directly). You can probably sync the little Linux instance that runs on the ROACH2, but getting the time information onto your FPGA may prove somewhat tricky.
Are you using an ADC card in the ROACH2? Or is the data digitised separately? What we've done with ROACH and ROACH2 designs in the past is more or less this: - FPGA's clock comes from a timing & frequency reference (TFR). - ROACH2 gets a 1PPS input from the same TFR. - In the FPGA logic there's a counter which is reset as part of the initialisation, and some logic that starts the counter going after a set number of 1PPS pulses (two to three, I forget exactly now). - The output of this counter is pipelined along with the data and then sent out as part of the SPEAD data on the 10GbE network. The idea here being that you know with a fairly high degree of precision which pulse your ROACH was initialised on. The counter that comes through on the SPEAD packet counts in FPGA clock cycles (or multiples thereof, perhaps you might want to count in spectra), and then you can use the start time to calculate the timestamp of each packet (Unix time, MJD, whichever your preferred reference is). Hope that helps. Regards, James On Wed, Mar 6, 2019 at 7:41 PM Franco <francocuro...@gmail.com> wrote: > Dear Casperiites, > > I was given the task of timestamping ROACH2 spectral data in a telescope > that uses PTP (precision time protocol) as a synchronization protocol. I > understand that ROACH's BORPH come preloaded with NTP (network time > protocol) libraries/daemos, but PTP is preferred because is already in use > in the telescope, and it achieves greater time precision. > > Does somebody know if it is feasible to compile/install PTP libraries in > BORPH? > > Alternatively, we have though of sending the ROACH the current time > through a GPIO pin using IRIG-B timecode standard. Has anybody done > something similar in the past? > > Thanks, > > Franco > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To post to this group, send email to casper@lists.berkeley.edu. > -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To post to this group, send email to casper@lists.berkeley.edu.
