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Re: [Discuss-gnuradio] How to get time from GPSDO
From: |
Nowlan, Sean |
Subject: |
Re: [Discuss-gnuradio] How to get time from GPSDO |
Date: |
Fri, 17 Feb 2012 18:54:13 +0000 |
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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