Re: [Discuss-gnuradio] UHD Announcement - July 6th 2010

[Josh Blum]

> 3) set times next pps (synchronously)
> gr_block_executor: source <gr_block uhd mimo source (1)> produced no
> output. We're marking it DONE.

This tells me that the alignment buffer is not finding a common 
timestamp among the 4 channels or one or more channels is not streaming 
(perhaps a timestamp/setup issue). What does your setup look like, is 
there a common pps and common reference split 4X to each usrp2? I forgot 
to add it to the notes but each device should have a common ref and pps 
attached to its front panel. Also, can you try to run with just two 
usrp2 to simplify the problem, does it work with 2 but not 3, 3 but not 
4...?

> Sometimes I also receive these errors that disappear when I power cycle
> the USRP2's:
>
> Error (usrp2 recv pirate loop): bad vrt header or unsupported packet type
> Error (usrp2 recv pirate loop): assertion failed: if_packet_info.has_tsi
> and if_packet_info.has_tsf
> in void
> usrp2_impl::io_impl::recv_pirate_loop(boost::shared_ptr<uhd::transport::zero_copy_if>,
> boost::shared_ptr<usrp2_mboard_impl>, size_t)
> at /home/dave/uhd/host/lib/usrp/usrp2/io_impl.cpp:97

Because the previous run did not exit cleanly and stop streaming, the 
recv loop is catching the middle of a packet from the previous run. This 
is safe to ignore.

-Josh