Re: [Discuss-gnuradio] Beginner Question: python script error when doing connect()

[Eric Blossom]

On Wed, Sep 16, 2009 at 03:09:54PM -0400, Chukhman, Ilya A. wrote:
> Hello,
> 
> I am trying to create a python equivalent of tx_samples.cc -- to transmit 
> samples captured with usrp2_rx_cfile.py.  When running my program, I receive 
> the following error:
> 
> Traceback (most recent call last):
>   File "./usrp2_tx_cfile.py", line 151, in <module>
>     tb = tx_cfile_block(options, filename)
>   File "./usrp2_tx_cfile.py", line 80, in __init__
>     self.connect(self._src, self._u);
>   File "/usr/lib/python2.6/dist-packages/gnuradio/gr/top_block.py", line 124, 
> in connect
>     self._connect(points[i-1], points[i])
>   File "/usr/lib/python2.6/dist-packages/gnuradio/gr/top_block.py", line 130, 
> in _connect
>     dst_block.basic_block(), dst_port)
>   File 
> "/usr/lib/python2.6/dist-packages/gnuradio/gr/gnuradio_swig_py_runtime.py", 
> line 1443, in connect
>     return _gnuradio_swig_py_runtime.gr_top_block_sptr_connect(*args)
> ValueError: itemsize mismatch: file_source(2):0 using 2, usrp2_sink_16sc(1):0 
> using 4
> 
> From the error, it appears that the connect() call is failing, but I am not 
> sure why.
> 
> This is what my usrp2_tx_cfile.py looks like.
> 
> Thank you for your help.
> Ilya


You're sending 2-byte wide data into a input that expects 4-byte wide data.

Eric