Re: [Discuss-gnuradio] Multi USRP on Single Computer

[njm25]

Thanks for the reply.  I'm pretty new to GNU radio so I'm still not sure 
exactly what I need to do (I don't know about the whole "which" constructor 
thing).  All I've been able to do so far is run the examples and modify them as 
needed (minor changes).  I don't need to know which board is which (sending and 
receiving), just as long as 1 is sending and 1 is receiving.  I've looked at 
the multi_usrp_rx_cfile.py example, and I understand that this example is for 
synch-ing 2 boards to both receive, but I don't know if I can use some of the 
same code for my purpose.  The code that looked interesting to me is:

# build the graph
        self.multi=usrp_multi.multi_source_align( fg=self, 
master_serialno=options.master_serialno, decim=options.decim, 
                                                  nchan=options.nchan )
        self.um=self.multi.get_master_usrp()
        self.us=self.multi.get_slave_usrp()

        dst_m=gr.file_sink (gr.sizeof_gr_complex, options.output_file_m)
        dst_s=gr.file_sink (gr.sizeof_gr_complex, options.output_file_s)
        if options.nsamples is None:
            self.connect((self.multi.get_master_source_c(),1),dst_m)
            self.connect((self.multi.get_slave_source_c(),1),dst_s)
        else:
            head_m = gr.head(gr.sizeof_gr_complex, int(options.nsamples))
            head_s = gr.head(gr.sizeof_gr_complex, int(options.nsamples))
            self.connect((self.multi.get_master_source_c(),1),head_m,dst_m)
            self.connect((self.multi.get_slave_source_c(),1),head_s,dst_s)

Can I use this portion of code and just make the small changes to make 1 a 
source instead of a sink?  Also, the first line about the source_align... is 
that for the synchronizing of the 2 boards (which I wouldn't need)?

Thanks for the help,
Nick


----- Original Message -----
From: Eric Blossom <address@hidden>
Date: Friday, March 2, 2007 12:27 pm
Subject: Re: [Discuss-gnuradio] Multi USRP on Single Computer

> On Fri, Mar 02, 2007 at 10:41:06AM -0500, address@hidden wrote:
> 
> > I want to connect 2 USRPs to a single computer (1 to tranmsit 
> and 1
> > to receive).  I saw the examples in the multi-usrp directory, but
> > they allow you to hook up 2 USRPs together so they will both
> > receive.  I'm guessing that I don't even have to hook them up if 1
> > and transmitting and 1 is receiving, but I might still need the
> > whole serial number code of each board to tell which one to transmit
> > and receive.  It doesn't seem like it should be hard, but I'm not
> > sure.  Any help would be greatly appreciated.
> 
> No need to interconnect the two boards.  You can specify which board
> to open using the "which" constructor argument.  The problem with that
> is that you really don't know which board you're getting.  After
> opening it, check the serial_number()
> 
> Note that unless you machine has two ECHI controllers (not two ports),
> your total aggregate bandwidth between the two boards is limited to
> about 32MB/s.
> 
> Eric
>