Re: [Discuss-gnuradio] XCVR2450: Switch between sending/receiving mode

[Josh Blum]

> So my problem is the switching between sending and receiving modes. How
> do I switch back to "receiving" mode after sending the data? Is it
> possible to do this automatically with the ATR controller? If yes, how
> do I have to setup the ATR registers? The values are handled outside the
> fpga (if I understood that right) and so I don't know the meaning of
> these values.

The ATR registers control the state of all 32 GPIO pins. There are 4 ATR 
states idle, rx, tx, and both. By setting these registers correctly, you 
can get GPIOS and hence, the antennas to switch when the ATR state in 
the FPGA changes.

For inspiration: this is the usrp2-gnuradio xcvr firmware where the atr 
controls the antenna: 
http://gnuradio.org/cgit/gnuradio.git/tree/usrp2/firmware/lib/db_xcvr2450.c#n310

Here is the host-based UHD implementation: 
http://ettus-apps.sourcerepo.com/redmine/ettus/projects/uhd/repository/revisions/master/entry/host/lib/usrp/dboard/db_xcvr2450.cpp#L229

And some app notes if helpful:
http://www.ettus.com/uhd_docs/manual/html/dboards.html#xcvr-2450

Thanks,
-Josh