Re: [Discuss-gnuradio] Help wanted with building a block

[Bob Cowdery]

 Thanks Eric, that makes sense. I expect to go around the houses a bit
on this but I have working C code so essentially first off I just need
to code the interfaces. I guess therefore I have the equivalent of usrp2
and need to do a somewhat simplified version of gr-usrp2.

Bob
 
On 12/07/2010 20:17, Eric Blossom wrote:
> On Mon, Jul 12, 2010 at 02:18:43PM +0100, Bob Cowdery wrote:
>>  Hi,
>>
>> I've just started investigating the possibility of building a
>> source/sink to a USB device. I've read the 'How to Write a Signal
>> Processing Block', built GNURadio on Ubuntu 10.04 and played around a
>> bit with building the example gr-how -to-write-a -block. I've also had a
>> cursory look at the usrp directories. I'm looking for a little bit of a
>> leg-up to kick me off. I'm assuming that the structure of the usrp2
>> directories would be the best place to start. I have noticed that the
>> document 'How to Write a Signal Processing Block' shows a different
>> directory structure to that in the code example and the usrp directories
>> are different again. There is also a gr-usrp2 and usrp2 and it's not
>> immediately obvious to me how they are split up and why.
> usrp2 provides a non-GNU Radio specific interface to the usrp2.
> gr-usrp2 builds on usrp2 and implements the actual sources and sinks.
>
>> 1. Which would be the best structure to take as a template and do I need
>> both structures as in usrp2.
> Easiest way to get the build framework started is to run
>
>   $ create-gnuradio-out-of-tree-project <my-module-name>
>
> It will create a directory tree starting with <my-module-name>
>
>> 2. Most of the documentation talks about processing blocks,  sources and
>> sinks.  Is there anything that talks about a device which is both a
>> source and a sink or do I need to trawl through the usrp code to see how
>> to handle that.
> The usrp code is a reasonable place to start your study.  It's
> probably more complicated than you need, but then the USRP is really
> flexible.  You should be able to use the fast usb classes as is.
>
> Good luck!
> Eric