[Discuss-gnuradio] VRT Branch: config_clock / PPS questions

[Tim Pearce]

Hi,

I've finally had a bit of time to have a go with the VRT branch - I noticed with the rx_timed_samples example it's now possible to start rx_streaming at a specific time so I've quickly merged my custom usrp2 timestamp source block (gr-usrp2 - providing a second stream of timestamps - I dont think the vrt_header is available after this block at the moment). 
I think I also need to add the python calls to the start_streaming_at functionality.

As I havent got a scope around at the moment to check, am I correct in thinking that the old config_mimo command to use the 10MHz Ref Input needs to be replaced with something like:

u=usrp2.source_32fc()

clock_settings=usrp2.clock_configt_t()
clock_settings.ref_source=clock_settings.REF_SMA
u.clock_config(clock_settings)

I've also noticed the set_time_at_next_pps() command, I'm assuming I can use this to force the usrp2 to set zero fractional seconds and some integer (or zero) number of seconds - this seems to be similar to what the rx_timed_samples example is doing.

Is the PPS used after this to keep the integer seconds increment aligned with the PPS? 

Thanks in advance,

Tim