Re: [Discuss-gnuradio] Disconnect parts of multiple flowgraphs

[Eric Blossom]

On Fri, Feb 27, 2009 at 10:13:39PM -0800, Paul Mathews wrote:
> I have a nice gnuradio app running using USRP, with 3 FFTsinks going at
> once, with the 1st FFTsink taking data from the USRP and the 2nd and 3rd
> FFTsinks each showing the results of further processing:
> 
> 1) USRP downconverting to 1 MHz ---> FFT display 1
> 2) Channel filter LP to 16 kHz ---> FFT display 2
> 3) AM demod and BP filter 2 to 10 kHz --> FFT display 3
> 
> I've added some code to the worker_thread class to do automatic tuning:
> 
> 1) Coarse tuning based on highest peak location in FFT 1
> 2) Fine AFC based on highest peak location in FFT 2
> 
> Once I've located the carrier peak in FFT 1 and centered USRP tuning on it,
> I have no further need to FFT and display the USRP data, and I'd like to
> shut down that message queue, FFT, and FFT display to free up resources. I'm
> thinking I need to 'disconnect' connected blocks, but I'm having trouble
> figuring out how to do that. Any hints will be appreciated.
> 
> My attempts to naively use the 'disconnect' method consistently yield
> messages like this one:
> 
>   File "/usr/local/lib/python2.5/site-packages/gnuradio/gr/top_block.py",
> line 9
> 5, in disconnect
>     self._tb.disconnect(points[0].basic_block())
>   File
> "/usr/local/lib/python2.5/site-packages/gnuradio/gr/gnuradio_swig_py_runt
> ime.py", line 1477, in disconnect
>     return _gnuradio_swig_py_runtime.gr_top_block_sptr_disconnect(*args)
> ValueError: cannot disconnect block message_sink(15), not found
> 
> 
> Paul Mathews

>From the message, it sounds like the block you are trying to disconnect
has already been disconnected.

Can you post a link to a _small_ test case the demonstrates the problem.

Are you using lock/unlock around your disconnects and connects?

Eric