Re: [Discuss-gnuradio] 16 digital I/O lines to control external devices like antenna switches

[Matt Ettus]

On 05/18/2010 06:57 PM, Harley Myler wrote:
> Hi all,
>
> Now that I have the USRP2 playing the university NPR station in my
> office, it is now time to get down to serious work.
>
> Could someone please, in a nutshell, explain one of the features of the
> WBX (as one of the transceiver series) daughterboard that states:
>
> /16 digital I/O lines to control external devices like antenna switches/
>
> I would greatly appreciate just a nudge in the right direction, such as,
> where are these (connector?)?
>
> How are they accessed (Python script, FPGA re-write, etc.)?
>
> What I need to do is cycle through a set of receiving antennas, sampling
> signal from each one in a scan operation. If anyone has already done
> this I would dearly love to know your process.


Each daughterboard connector has 16 GPIOs.  Some of them are used by the 
daughterboards, but others are available for your use.  On the WBX, 
io_tx[14:8] are available for you to use, and they come to the connector 
on the grand-daughterboard.

If you need to synchronize the action of these pins precisely, the bets 
way to do this is by modifying the FPGA.  If you just need to turn them 
on and off from software, you can do that with the API.

Matt