Re: [Discuss-gnuradio] How to get time from GPSDO

[Nowlan, Sean]

Thanks! That setup hadn't been 100% clear to me before. Makes sense now.

Sean

-----Original Message-----
From: Josh Blum [mailto:address@hidden On Behalf Of Josh Blum
Sent: Friday, February 17, 2012 1:23 PM
To: Nowlan, Sean
Cc: address@hidden
Subject: Re: [Discuss-gnuradio] How to get time from GPSDO



On 02/17/2012 09:58 AM, Nowlan, Sean wrote:
> Just to enhance my (and everyone's) knowledge, does that call give you 
> information substantially different from get_time_now()? Other than 
> you get a UHD Time Spec with seconds and fractional seconds?
> 

Well, there is a time in the GPSDO in seconds that increments once a PPS. Then 
there is a time in the FPGA that increments on each clock cycle.

Supposing you make a new uhd device object and a GPSDO is detected, the time 
programmed into the FPGA registers is initialized to march in lock-step with 
the GPSDO. This is done automatically, but its as simple as 
->set_time_next_pps(gpsdo_time + 1);

I wanted Wu to know that all the GPSDO sensors are available for access in 
python. As in "gps_gpgsa", "gps_gprmc", and "gps_gpgga"

-Josh

> Sean
> 
> -----Original Message----- From:
> address@hidden
> [mailto:address@hidden
> On Behalf Of Josh Blum Sent: Friday, February 17, 2012 12:55 PM To:
> address@hidden Subject: Re: [Discuss-gnuradio] How to get 
> time from GPSDO
> 
> 
>> 
>> and thought usrp->get_mboard_sensor is the function that I need.
>> But I don't know how to use this function in GNURadio. It seems that 
>> the code is written in C++. So can I use it directly in GNURadio?
>> 
>> 
> 
> All the functions are brought into python via swig, so: 
> http://gnuradio.org/cgit/gnuradio.git/tree/gr-uhd/include/gr_uhd_usrp_
> sink.h#n279
>
>  you would do this python: secs =
> the_usrp_block.get_mboard_sensor("gps_time").to_int()
> 
> -Josh
> 
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