Forum: GNU Radio Josh: suggestion for GRC

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558c40b97bd1af8d912424757714bda9?d=identicon&s=25 Marcus D. Leech (Guest)
on 2009-04-05 22:49
(Received via mailing list)
[Like you need suggestions :-) ]

When setting the USRP word-length format, it would be useful to set the
SHIFT and WIDTH parameters separately in the
  USRP objects (both single and dual).

The valid values for WIDTH are {0,1}
The valid values for SHIFT are {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}

I've been naively using width=8, shift=8, because my fuzzy memory left
me with the impression that the only
  valid value for shift was 8.  That no longer appears to be the case,
and at least one of my radio astronomy
  "customers" has a setup where looking at the lower 8 bits instead of
the upper 8 bits would be very useful.

Cheers

--
Marcus Leech
Principal Investigator, Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
558c40b97bd1af8d912424757714bda9?d=identicon&s=25 Marcus D. Leech (Guest)
on 2009-04-05 23:20
(Received via mailing list)
Marcus D. Leech wrote:
> me with the impression that the only
>   valid value for shift was 8.  That no longer appears to be the case,
> and at least one of my radio astronomy
>   "customers" has a setup where looking at the lower 8 bits instead of
> the upper 8 bits would be very useful.
>
> Cheers
>
>
Gark!

Make that WIDTH={8,16}

Forgot to turn on the CPU before enabling the fingers....



--
Marcus Leech
Principal Investigator, Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
4252201ac30d6dd44d8090ce1070e35f?d=identicon&s=25 Josh Blum (Guest)
on 2009-04-06 02:41
(Received via mailing list)
svn up, give it a try
745d8202ef5a58c1058d0e5395a78f9c?d=identicon&s=25 Eric Blossom (Guest)
on 2009-04-06 22:55
(Received via mailing list)
On Sun, Apr 05, 2009 at 04:48:55PM -0400, Marcus D. Leech wrote:
> me with the impression that the only
>   valid value for shift was 8.  That no longer appears to be the case,
> and at least one of my radio astronomy

Marcus, in the code in the trunk, the shift value is currently
ignored.  The the valid combinations of WIDTH and SHIFT are
{16,0} and {8, 8}.

See usrp/fpga/sdr_lib/rx_buffer.v for the FR_RX_FORMAT register.

Eric
558c40b97bd1af8d912424757714bda9?d=identicon&s=25 Marcus D. Leech (Guest)
on 2009-04-06 23:10
(Received via mailing list)
Eric Blossom wrote:
>
> Marcus, in the code in the trunk, the shift value is currently
> ignored.  The the valid combinations of WIDTH and SHIFT are
> {16,0} and {8, 8}.
>
> See usrp/fpga/sdr_lib/rx_buffer.v for the FR_RX_FORMAT register.
>
> Eric
>
>
I thought it was done in the 8051, not the FPGA.   It seemed to make a
difference, so I'll have to re-test.


--
Marcus Leech
Principal Investigator, Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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