Thanks a lot, Josh. I tried to use the time_spec_t class in the GRC
generated python code through the following way:
class TimeFind(grc_wxgui.top_block_gui):
.............................
self.time_spec_t = uhd.time_spec_t(0)
.................................
if __name__ == '__main__':
................................
tb = TimeFind()
var = 1
tb.start()
while var == 1:
sleep(0.1)
print "current fractional time :" ,
tb.time_spec_t.get_frac_secs()
print "System time: " , tb.time_spec_t.get_system_time()
print "full sec: " , tb.time_spec_t.get_full_secs()
print "real second: " , tb.time_spec_t.get_real_secs()
tb.stop()
********************************
Basically, My code produces the following output:
current fractional time : 0.0
System time: <gnuradio.uhd.uhd_swig.time_spec_t; proxy of <Swig Object of
type 'uhd::time_spec_t *' at 0x34fbe10> >
full sec: <Swig Object of type 'time_t *' at 0x34fbe10>swig/python
detected a memory leak of type 'time_t *', no destructor found.
real second: 0.0
Unfortunately, this same output is displayed repeatedly. I am not sure why
the time does not change. Is there any other command that will keep
printing/pulling the recent time after 10 ms (1 ms)?
Thanks,
Nazmul
On Fri, Jul 27, 2012 at 2:07 PM, Josh Blum <j...@ettus.com> wrote:
>
>
> On 07/27/2012 10:24 AM, Nazmul Islam wrote:
> > Sorry for the previous email. I mistakenly hit the sent button before
> > completing the mail. Here is the complete mail:
> >
> > Is it possible to see the time through USRP GPSDO with
> > microsecond/millisecond granularity? I want to synchronize the timing of
> my
> > computers and run gnuradio codes based on the synchronized timing.
> >
>
> When synchronized to a common clock reference and time, a group of USRPs
> can perform actions simultaneously with accuracy down the the jitter of
> GPSDO ref clock + clock synthesizer chain.
>
> > For example, if I have ethernet based internet connection, I can use ntp
> > servers to synchronize the computers and read the time (using
> > "time.time()") with milisecond granularity. I am trying attain the same
> > thing using GPSDO. I am using the following python code.
> >
>
> the "magic" of the GPSDO and time synchronization is that there is a
> shared "pulse" aka PPS. This pulse is used to latch a time value into
> the FPGA at a very specific moment. From that point on, a group of usrps
> share the same concept of time.
>
>
> > ****
> >
> > class TimeFind :
> >
> > .........
> > self.uhd_usrp_source_0 = uhd.usrp_source(
> > device_addr="",
> > stream_args=uhd.stream_args(
> > cpu_format="fc32",
> > args="peak=0.5",
> > channels=range(1),
> > ),
> > )
> >
> > ...........................
> > ..............................
> >
> > if __name__ == '__main__':
> >
> > tb = TimeFind()
> >
> > print "current time :" , tb.uhd_usrp_source_0.get_time_now()
> > print "last pps time :" , tb.uhd_usrp_source_0.get_time_last_pps()
> > print "GPS Time: " ,
> > tb.uhd_usrp_source_0.get_mboard_sensor("gps_time").to_int()
> > tb.Run(True)
> >
> > *************
> >
> > I have the following issues:
> >
> > 1. The current time and last pps time show the following output:
> >
> > current time : <gnuradio.uhd.uhd_swig.time_spec_t; proxy of <Swig Object
> of
> > type 'uhd::time_spec_t *' at 0x331fcf0> >
> > last pps time : <gnuradio.uhd.uhd_swig.time_spec_t; proxy of <Swig Object
> > of type 'uhd::time_spec_t *' at 0x331fcf0> >
> >
> > How can I get the time value?
> see member functions:
> http://files.ettus.com/uhd_docs/doxygen/html/classuhd_1_1time__spec__t.html
> >
> > 2. "GPS Time: " shows the time with 1 second granularity. Can I get
> higher
> > resolution that 1 second? Is there an option that allows to see the exact
> > time instead of the integer time?
> >
>
> GPS time in seconds is actually a blocking call that waits until the
> seconds increments to return you the time. That way you know very
> precisely that the next pulse will be time_read + 1 seconds.
>
> -josh
>
> _______________________________________________
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
--
Muhammad Nazmul Islam
Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.
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