[USRP-users] RFNoC -- Making FPGA design easy from GNU Radio

Martin Braun martin.braun at ettus.com
Mon Dec 8 14:16:41 EST 2014


Jacob,

I hope you don't mind if I give you some of the answers for now:

On 12/08/2014 04:13 PM, Jacob Gilbert via USRP-users wrote:
> Matt,
> 
> Congratulations on the release of this - this is very exciting! I have a
> few questions:
> 
> 1) This looks targeted at the X3xx series for now; I understand the new
> E310 SDR will have RFNoC support also - is there a timeline for this?

Development is pretty far. It's already possible to do some RFNoC tasks,
we're still ironing out some kinks though.

> 2) If I understand the wiki, the current RFNoC FPGA build has a few
> example signal processing FPGA blocks (FIR, FFT, window, add/sub) and
> several utility blocks (null source/sink, loopback) as well as ‘radio’
> blocks. How does the standard USRP FPGA functionality (DDC/DUC chains,
> timed commands, etc) fit into this? Is all of that packaged in the
> ‘radio’ block or can, for example, a radio block be programmatically
> connected to multiple DDC chains that are independently controlled?

Currently, all the radio stuff is part of the radio block. If you want
full bandwidth, you can simply set the decimation to 1 and process the
sample stream in the next block (which could have its own DDC stage, if
that's what you need).

> 3) What is the FPGA resource utilization of the example X3xx images? Is
> there an idea if the same functionality would fit on the E310 FPGA?

On X300, it's pretty full. We currently distribute the same example
image for X300 and X310, so the latter has free space accordingly.

E310 FPGA space is much smaller, though. We can't fit all the blocks
from the X-Series' image in there. It'll be a while before we know for
sure how much people can get in there (it also depends on one's FPGA
skills, of course).
However, we are using the identical blocks on both devices (X and E), so
it's not like you have to re-write them for E310 or anything. It's just
a subset of what we're currently distributing for X-Series.

Cheers,
Martin





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