Re: [Discuss-gnuradio] Passing the payload to the application level

[Eric Blossom]

On Wed, Sep 20, 2006 at 11:49:27PM -0500, Michael Ford wrote:
> I am trying to pass the payload from the layer where it is obtained back to
> the application level. However, I'm having some problems. When examining
> benchmark_gmsk_rx.py, I see that the rx_callback funstion is passed into the
> receive_path class. Going further, I see that the function is passed from
> benchmark_gmsk_rx.py to the receive_path class to the gmsk_demod_pkts class,
> which I understand to be in
> /usr/local/lib/python2.4/site-packages/gnuradio/blksimpl/gmsk2_pkt.py. Here,
> the function is finally called in a class called _queue_watcher_thread.
> However, no matter what I do, I can't get the payload data back to the app
> layer. Just to test things, I commented out the instance of
> _queue_watcher_thread that is instantiated by the gmsk2_demod_pkts() class,
> and the rx_callback function is still running, which leads me to believe
> that I'm not looking in the right place. Also, when I try to make a member
> variable of the _queue_watcher_thread class called self.thepayload and make
> a a return of the payload in the rx_callback function, and then try to print
> self.thepayload from the watcher class, nothing happens. If I make a print
> statement in the rx_callback function, the payload prints.
> 
> -Michael Ford-

First off, I'm assuming that you are running the svn trunk code.  
If not, please start there.

When you run the unmolested benchmark_gmsk_tx.py and
benchmark_gmsk_tx.rx on two machines do they work?  That is, does the
rx code report that it's receiving packets correctly?  I typically get
100% correct packet reception.


If not, what daughterboards are you using?
They need to be RFX-<something>'s.  Basic Tx and Rx won't work.
Long story, it's in the archives somewhere.  Also, keep the boards at
least 3m apart. 


Now, assuming that that's working, what's the question?
Basically, packets are getting from the C++ to the python code by
virtue of a message queues and messages.

You are correct, this is set up in gmsk2_pkt.py.
framer_sink_1 is handed the message queue in its constructor and then at
runtime inserts messages into it.  The _queue_watcher_thread
hangs a blocking read on the queue by doing:

  msg = self.rcvd_pktq.delete_head()

Eric