Thanks ! It's still not at all clear to me how the system wall time and the adc sample time could be related, here <https://groups.google.com/forum/#!searchin/beagleboard/timestamp/beagleboard/nbjIofTzgd4/Mi8RFm7VdugJ>another question similar to the one I have, Rick M suggests to:
- use a sw PLL with a frequency related to the needed accuracy, linked to the pps generated by a GPS module, to update a timer. - let the PRU read the timer value at every sample - subtract the reading latencies the problem is that I don't have a PPS signal avaiable, I could modify the ntpd poll interval of the ntpd. It would be perfect if I could enable the PRU IEP timer (ocp_clk 200 Mhz) )soon after the gettimeoftheday() function call and then trigger the ADC. Is this nonsense talk? V. Il giorno giovedì 13 agosto 2015 21:37:21 UTC+2, TJF ha scritto: > > Hi! > > Am Donnerstag, 13. August 2015 17:39:39 UTC+2 schrieb Valeria M.: >> >> The original plan was to use as synchronization source (of the system >> clock) a ptp clock or ntp server and acquire the samples one second >> (200ksamples) a time and attach a timetag to every one of them, and thatìs >> why I was looking for a way to force the fifo counter rollover, I've the >> horrible feeling to have posed the question the wrong way and have >> mistaken the whole clock concept. >> > > You could use libpruio in MM (Measurement Mode) to sample a block of 200 > ksamples at 200 ksample/s. Note: the default size of the external memory is > 128 ksamples, so you have to configure the PRUSS driver (uio_pruss) for > bigger external memory. See this page > <http://users.freebasic-portal.de/tjf/Projekte/libpruio/doc/html/_cha_memory.html>, > > secition *ERam* (at the bottom). > > BR > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
