Thanks for the suggestion Marcus.
I tried adjusting those settings by using the following command:
uhd_usrp_probe --args="serial=123456,
recv_frame_size=4096,num_recv_frames=4096"
The 123456 is replaced with the actual serial number of the usrp1 when I run the command.
When I run that command it shows the USRP1 configuration settings and the daughtercard and then at the bottom it says "Segmentation fault (core dumped)". This happens with other values of recv_frame_size and num_recv_frames. Does anyone know what I'm doing wrong or is this even the right way to change those
settings?
What are the default values in case I need to set them back to what they were? I couldn't find this anywhere in the UHD documentation.
Thank you, - Tom
From: Marcus D. Leech <address@hidden>
To: Tom Hendrick <address@hidden>
Cc: "address@hidden" <address@hidden>
Sent: Wednesday, February 20, 2013 9:53 AM
Subject: Re: [Discuss-gnuradio] USRP1 4 Channel Subdev Issue
I tried the suggestion from Marcus and was
able to get the USRP1 to work with 4 real channels. I have a
simple GRC script which samples the USRP at 1MS/s and then
resamples the signal to 500kS/s and then writes to a file. I am
getting continuous Overruns with this GRC script on my laptop.
I have the same GRC script with the older GNURadio and when I
ran it again on the same laptop (I booted up a prior version of
ubuntu with an older gnuradio version that uses the USRP class
not UHD) it writes to file with no Overruns at all. I saw that
the custom quad channel USRP block has an fusb_block and
fusb_nblocks setting. These are both set to 512*32 but if I
lower them to something like 64*32 I start to see the Overruns.
Are there similar type settings I can adjust on the 3.6.2
version of GRC or GNURadio python scripts to get rid of the
overruns? I'm not sure if this is possible but I would like to
not have to boot into an older ubuntu version when I need 4 real
channels. The only thing that comes to mind is to adjust
noutput_items and I tried this but it didn't eliminate the
overruns.
Thank you, -Tom
http://files.ettus.com/uhd_docs/manual/html/transport.html#usb-transport-libusb
The USB parameters shown there can be passed as device args
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org