[USRP-users] USRP1 control GPIOs on SBX boards

Nelson Pina n.pina at tomorrow-options.com
Tue Apr 23 14:06:52 EDT 2013

Hi everyone,

I have been trying to make a gnuradio out-of-the-tree block that is able to
control the four GPIOs, currently attached to LED's, of the SBX
daughter-boards working with an USRP motherboard.

I wonder if anyone can help me on this, making a functional draft code of
such a block:

1 integer input - that will define the state of the GPIOs
1 parameter - to define the motherboard serial number

I believe that for people with knowledge of C++, and Python this is a very
simple module, unfortunately that is not my area since I'm a hardware
engineer and I only work with C.

I tried some approaches, using the gr_modtool to create the module, but it
always fails with GRC running errors like:


Traceback (most recent call last):
  File "/home/to-nelsonpina/Desktop/locus_gnuradio/GRC_files/top_block.py",
line 16, in <module>
    import gpio
  File "/usr/local/lib/python2.7/dist-packages/gpio/__init__.py", line 45,
in <module>
    from gpio_swig import *
  File "/usr/local/lib/python2.7/dist-packages/gpio/gpio_swig.py", line 26,
in <module>
    _gpio_swig = swig_import_helper()
  File "/usr/local/lib/python2.7/dist-packages/gpio/gpio_swig.py", line 22,
in swig_import_helper
    _mod = imp.load_module('_gpio_swig', fp, pathname, description)
ImportError: /usr/local/lib/libgnuradio-gpio.so: undefined symbol:


I will appreciate all the help I can get from you guys.

Best regards,
*Nelson Pina*
Product Developer

*n.pina at tomorrow-options.com*
*T* +351 220 301 596 (PT)
*T* +44 114 213 2712 (UK)

*Porto // Portugal
Sheffield // United Kingdom

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