[USRP-users] Problem Streaming Receive Samples without Deconstructing USRP Object Every Time

Robert Palumbo palumr at gmail.com
Thu Feb 2 12:47:20 EST 2012


I am currently using the USRP N210 (rev. 4) and integrating the UHD
(release 003.003.001) function calls into a GUI interface for ease of
use. I've modified the FPGA code for the transmit path for pulsed
transmission, but the receive path is completely intact and untouched.
Everything is working great, as far as configuring the general
settings (frequency, subdevice specification, data rate, etc.), but
I'm having problems receiving samples with a stream command.

My problem is that when I construct the USRP object, issue a stream
command after configuring the general settings, and subsequently make
a 'recv' call, the call to recv always fails with an error code
ERROR_CODE_TIMEOUT in the receive metadata. However, if I configure
the general settings, deconstruct and reconstruct the USRP object
(i.e. restart the GUI), then issue a stream command, it works fine
with no problem.

Has anyone out there seen this type of behavior before, or has any
suggestions? It seems to happen regardless of what streaming mode I
issue. Within the stream_cmd, I am using the 'stream_now=true' flag,
followed by the 'issue_stream_cmd'.

If it matters, within my program I pass the usrp object as arguments
to lower level functions, which are just wrappers around sequences of
UHD calls.

Any help would be much appreciated.



Robert A Palumbo
palumr at gmail.com

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