Re: [Discuss-gnuradio] Help Req: usrp_sink

[Eric Blossom]

On Thu, Jan 07, 2010 at 06:19:33PM +0000, nadia raj wrote:
> 
> hi,
>
>  If i want to send data to side A of usrp and in it TX/RX side whats the 
> proper syntax for it.
>
> Regards,
> Nadia

Nadia,

Pretty much every transmitter example implements this...
The standard way to specify which transmit daughterboard is the
-T option, like this:

  -T a

Likewise the receive daughterboard can be specified with

  -R a


See for example, gnuradio-examples/python/usrp/fm_tx4.py, in
particular this part:

        # ----------------------------------------------------------------
        # Set up constants and parameters

        self.u = usrp.sink_c ()       # the USRP sink (consumes samples)

        self.dac_rate = self.u.dac_rate()                    # 128 MS/s
        self.usrp_interp = 400
        self.u.set_interp_rate(self.usrp_interp)
        self.usrp_rate = self.dac_rate / self.usrp_interp    # 320 kS/s
        self.sw_interp = 10
        self.audio_rate = self.usrp_rate / self.sw_interp    # 32 kS/s

        # determine the daughterboard subdevice we're using
        if options.tx_subdev_spec is None:
            options.tx_subdev_spec = usrp.pick_tx_subdevice(self.u)

        m = usrp.determine_tx_mux_value(self.u, options.tx_subdev_spec)
        #print "mux = %#04x" % (m,)
        self.u.set_mux(m)
        self.subdev = usrp.selected_subdev(self.u, options.tx_subdev_spec)
        print "Using TX d'board %s" % (self.subdev.side_and_name(),)

        self.subdev.set_gain(self.subdev.gain_range()[1])    # set max Tx gain
        if not self.set_freq(options.freq):
            freq_range = self.subdev.freq_range()
            print "Failed to set frequency to %s.  Daughterboard supports %s to 
%s" % (
                eng_notation.num_to_str(options.freq),
                eng_notation.num_to_str(freq_range[0]),
                eng_notation.num_to_str(freq_range[1]))
            raise SystemExit
        self.subdev.set_enable(True)                         # enable 
transmitter


Also, to see the entire USRP interface, take a look at:

  http://gnuradio.org/doc/doxygen/classusrp__standard__tx.html
  http://gnuradio.org/doc/doxygen/classusrp__basic__tx.html
  
Although they are talking about C++, the mapping to Python is straight forward.


If you haven't already, the USRP FAQ will probably be helpful too:

    http://gnuradio.org/redmine/wiki/gnuradio/UsrpFAQ

and/or the PDF version:

    http://gnuradio.org/redmine/attachments/129/USRP_Documentation.pdf


Eric