[Discuss-gnuradio] Assertion Error when running gnuradio examples

[Michael Ford]

Hello everyone,

I'm a first time poster who's generally new to SDR as well as the gnuradio software. I've recently taken a course in communication networks and wireless networks, and this summer I'm working on using a few USRP boards to implement my own CSMA/CA protocol. However, before I get into the meat of that project, I've got to make sure that all my board setups are correct. Forgive me, this is going to be a mouthful.

First things first - after visiting Dawei Shen's tutorials at the GNURadio website, I found that some of the instructions there were inconsistent with the files I got in the package - specifically tutorial number 4. I've installed the gnuradio package, and when reading the usrp tutorial, I'm told to make sure that I have a file called usrp_fpga_rev2.rbf in the /usr/local/share/usrp/rev2/ directory. (Which reminds me, if it helps, I'm running Ubuntu Dapper Drake) However, in the usrp package that I download from the gnuradio download page, I don't find that file, but instead I find two files called std_2rxhb_2tx.rbf and std_4rx_0tx.rbf. My first concern is, why don't I find the files I was told I'd find?

My second concern still involves the 4th tutorial. I'm told to run usrp_oscope.py in the gr-build/gnuradio-examples/python/usrp/ directory, which I'm told will bring up an oscilloscope, which it does, so I'm assuming that's okay. Then I'm told to run wfm_rcv_gui.py [some fm frequency], which will let me hear fm signals. This is where my problem starts. First off, that file doesn't exist. So I try a file with a similar name - usrp_wfm_rcv_nogui.py -f 
101.5. This gives me an assertion error, which looks like this:

Using RX d'board A: Flex 2400 Rx
>>> gr_fir_ccf: using SSE
>>> gr_fir_fff: using SSE
Traceback (most recent call last):
  File "./usrp_wfm_rcv_nogui.py", line 149, in ?
    fg = wfm_rx_graph()
  File "./usrp_wfm_rcv_nogui.py", line 105, in __init__
    if not(self.set_freq(options.freq)):
  File "./usrp_wfm_rcv_nogui.py", line 125, in set_freq
    r = self.u.tune(0, self.subdev, target_freq)
  File "/usr/local/lib/python2.4/site-packages/gnuradio/usrp.py", line 184, in tune
    return tune(self, chan, subdev, target_freq)
  File "/usr/local/lib/python2.4/site-packages/gnuradio/usrp.py", line 122, in tune
    ok, baseband_freq = subdev.set_freq(target_freq)
  File "/usr/local/lib/python2.4/site-packages/gnuradio/db_flexrf.py", line 174, in set_freq
    R, control, N, actual_freq = self._compute_regs(freq)
  File "/usr/local/lib/python2.4/site-packages/gnuradio/db_flexrf.py", line 392, in _compute_regs
    assert self.B_DIV >= self.A_DIV
AssertionError



My second concern is: why does the example file in the 4th tutorial not exist, and what might be causing this assertion error?

-Michael Ford-