[Discuss-gnuradio] need help getting simple exercise to work

[jmdaniel]

Hi,

I've got gnuradio up and running and am now trying to get a better
understanding of how to use it before beginning more involved
projects.  I am trying to write a py script that displays an oscope 
from a PCI-DAS4020/12.  mc4020_fft.py runs and displays the 
excpected results.  Here's the code that I've peiced together.

#!/usr/bin/env python
#
# Copyright 2004 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# GNU Radio is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.
#

from gnuradio import gr
from gnuradio import mc4020
from gnuradio.eng_option import eng_option
from gnuradio.wxgui import stdgui, scopesink
from optparse import OptionParser
import wx

class app_flow_graph (stdgui.gui_flow_graph):
    def __init__(self, frame, panel, vbox, argv):
        stdgui.gui_flow_graph.__init__ (self, frame, panel, vbox, argv)

        input_rate = 20e6
        src = mc4020.source (input_rate, mc4020.MCC_CH3_EN | 
mc4020.MCC_ALL_1V)
        block, scope_win = scopesink.make_scope_sink_f (self, panel, "Rx 
Data", input_rate)

        vbox.Add (scope_win, 1, wx.EXPAND)

        self.connect (src,block)

def main ():
    app = stdgui.stdapp (app_flow_graph, "USRP FFT")
    app.MainLoop ()

if __name__ == '__main__':
    main ()


and here is what I get when I run it...

Traceback (most recent call last):
  File "mc4020_scope.py", line 54, in ?
    main ()
  File "mc4020_scope.py", line 50, in main
    app = stdgui.stdapp (app_flow_graph, "USRP FFT")
  File "/usr/local/lib/python2.3/site-packages/gnuradio/wxgui/stdgui.p y", 
line 35, in __init__
    wx.App.__init__ (self)
  File "/usr/lib/python2.3/site-packages/wx-2.6-gtk2-ansi/wx/_core.py" , line 
6151, in __init__
    self._BootstrapApp()
  File "/usr/lib/python2.3/site-packages/wx-2.6-gtk2-ansi/wx/_core.py" , line 
5803, in _BootstrapApp
    return _core_.PyApp__BootstrapApp(*args, **kwargs)
  File "/usr/local/lib/python2.3/site-packages/gnuradio/wxgui/stdgui.p y", 
line 38, in OnInit
    frame = stdframe (self.flow_graph_maker, self.title)
  File "/usr/local/lib/python2.3/site-packages/gnuradio/wxgui/stdgui.p y", 
line 59, in __init__
    self.panel = stdpanel (self, self, flow_graph_maker)
  File "/usr/local/lib/python2.3/site-packages/gnuradio/wxgui/stdgui.p y", 
line 80, in __init__
    self.fg = flow_graph_maker (frame, self, vbox, sys.argv)
  File "mc4020_scope.py", line 47, in __init__
    self.connect (src,block)
  File "/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_ 
graph.py", line 114, in connect
    self._connect (points[i-1], points[i])
  File "/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_ 
graph.py", line 119, in _connect
    self._connect_prim (s, d)
  File "/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_ 
graph.py", line 127, in _connect_prim
    self._check_type_match (src_endpoint, dst_endpoint)
  File "/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_ 
graph.py", line 238, in _check_type_match
    raise ValueError, 'source and destination data sizes are different '
ValueError: source and destination data sizes are different


I would greatly appreciate any help with understanding what is 
wrong here and how to fix it.

Thanks.

John Daniel
address@hidden
Virginia Tech