Re: [Discuss-gnuradio] How can I check usrp.sink_c

[Eric Blossom]

On Thu, Oct 02, 2008 at 09:25:08AM -0700, Dan Halperin wrote:
> On Oct 2, 2008, at 7:34 AM, kaleem ahmad wrote:
> 
> > Hi,
> >
> > I want to transmit some data using usrp.sink_c and immediately after  
> > the
> > data is sent I want to start receiver mode, but my problem is if I  
> > do like
> > this:
> >
> > Send using 'usrp.sink_c'
> > start receive mode
> >
> > My USRP immediately goes into receive mode and the data sent is not
> > successful, so I want to do something like following:
> >
> > Send using 'usrp.sink_c'
> > check 'usrp.sink_c' if the data is sent then
> >                  start receive mode
> 
> There is an automatic switching between transmit and receive modes  
> that does what you want -- whenever there is something being  
> transmitted, it disables the receive chain, and switches back once  
> that buffer is empty. Look through the examples for flow graphs with  
> both transmit and receive chains. It's called something like auto_tr.
> 
> -Dan

This is all good.

Kaleem, I suggest that you take a look at
gnuradio-examples/python/digital/tunnel.py.  The MAC that it implements
is terrible, but it does show how to have both the Tx and Rx running
without having to reconfigure anything.

Basically there are two disjoint pipelines:

  network --> <modulator etc> -> usrp.sink_c
  usrp.source_c --> <demod etc>  --> network

They both run at the same time and use the auto_tr feature.

Eric