Re: [Discuss-gnuradio] Getting to know about USRP FPGA programming

[marcus]

Hi Naceur,
On 2013-10-02 21:57, Naceur wrote:

> What I want to try with the USRP's FPGA is to send it a stream of 
> packets
> (Header + Payload),
> header field's length being known and fixed in advance, I need the 
> FPGA to
> override a part of the Payload's field with its time register's  
> value and
> send the stream after.
> Is that possible first then what steps to do ?
This is possible. However, you have to be aware: The USRPs are 
basically ADCs and DACs on steroids with mixer daughterboards.
So you don't transfer streams of packets from Host to USRP to get them 
onto the ether, you send streams of complex time samples that encode 
such packets. So, the USRP does not see packets, it sees streams (or 
bursts) of samples. You could of course write some HDL to replace 
certain samples in a sample stream with other samples, but then you 
would have to do modulation in hardware -- this is not really the first 
thing I'd try when learnig how to use the FPGA in a USRP.

Hope that helped,
Marcus