[USRP-users] Passing arguments to an RFNOC block

Paul Boven p.boven at xs4all.nl
Thu Feb 28 04:30:53 EST 2019


Hi Jonathon,

Thanks for looking at the block, and spotting the mistake.
Unfortunately that doesn't stop the swig part from failing, so I'll keep 
digging further.

Regards, Paul Boven.

On 28/02/2019 04:19, Jonathon Pendlum wrote:
> Hi Paul,
> 
> Your Nocscript has an error on line 47, you are a missing a comma: 
> LE($config 1) should be LE($config, 1). That may not be the source of 
> your issue, but try fixing that first.
> 
> Jonathon
> 
> On Thu, Feb 28, 2019 at 1:14 AM Paul Boven via USRP-users 
> <usrp-users at lists.ettus.com <mailto:usrp-users at lists.ettus.com>> wrote:
> 
>     Hi everyone,
> 
>     As part of the VLBI[1] backend that I'm making in RFNOC, my first step
>     is to make a rational resampler. It takes the 100MS/s signal from a
>     TwinRX, and reduces it to 80MS/s. This can be done with a 5:4
>     resampler.
>     In order to make this work, I'm using the axi_rate_change block.
> 
>     Although the block works in simulation, I keep running into problems
>     with the GRC integration, in particular SWIG throwing run-time errors.
> 
>     The problem seems to be in the way that the arguments (N, M, config)
>     are
>     passed around, but studying other blocks like the DDC block hasn't
>     provided the clues for me to get past this hurdle.
> 
>     The resampler itself does work, which I tested by having it emit zeroes
>     instead of the 'deleted' samples, and using a 'keen 1 in N' in GRC
>     itself.
> 
>     At the moment, the block exits in VLBI_swig.py in set_arg:
>     return _VLBI_swig_resamplerd5x4_sptr_set_arg(self, *args)
>     RuntimeError: SyntaxError: Parsing Stopped at: $N, 5)
> 
>     If you're familiar with RFNOC, can you please have a look at:
> 
>     http://www.jive.nl/~boven/rfnoc-VLBI
> 
>     It contains the source, and also a compiled bitfile for the X310 for
>     your convenience (but use at your own risk, of course).
> 
>     Regards, Paul Boven.
> 
>     [1] Very Long Baseline Interferometry
> 
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