discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] UHD default subdevice.


From: Marcus D. Leech
Subject: Re: [Discuss-gnuradio] UHD default subdevice.
Date: Fri, 23 Dec 2011 17:13:43 -0500
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.24) Gecko/20111108 Fedora/3.1.16-1.fc14 Thunderbird/3.1.16

Could you give me a hint? How do you interface with UHD before a C++/python program requests the device?


Well, you complained about having to "type --spec A:0" a lot, which is a natural for a shell script that starts your program--whether that program is written in C++ or Python, and simply pass in a fixed value for "the --spec" option to the program you're trying to run.

For example, any of the setup parameters (well, *most*) of a uhd_usrp_source or uhd_usrp_sink can be taken from a variable or command-line parameter, using the "variables" section in GRC, so you make them come from command-line parameters, and default those parameters, and again, you can make it fancier with a shell script surrounding the invocation of the target program. In fact, I have one startup script that parses the output of "uhd_usrp_probe" to determine what cards I'm dealing with, and set command-line parameters appropriately from parsing the output of "uhd_usrp_probe". I'm also working on an easier-to-use little python program that is intended to set a bunch of shell variables based on probing the hardware and setting a bunch of standard variables--specifically
  to support better autoconfiguration from within shell scripts, etc.

If the target program *doesn't support* the parameter you want as a command-line parameter, then *add it*, and submit it to be folded back in to the mainline. I recently did this for uhd_fft.py and rx_cfile.py to support the "sc8" alternative wire-format, which is
  necessary to support 33.33Msps and 50Msps sample rates out of USRP2/N2XX.

--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org





reply via email to

[Prev in Thread] Current Thread [Next in Thread]