Hello Glenn, Marco,
I just want to report that solution that the .m file was
incorporating did indeed fix the problem I was having. :)
Instead of actually running the script I manually went in
and changed the appropriate values from "HIGH" to "LOW"...this was
mostly just because I'm trying to get a deeper understanding of how the
blocks are linked to their configurations.
I do have a couple questions though:
Why is it that I had to go in change these
parameters? Why isn't this available from Simulink, for example?
Is this usually the fix that other people will
incorporate when they need to work with lower sampling rates? Or do most
people just downsample?
Does changing the DCM values from "HIGH" to "LOW"
have any other consequences that could come back and bite me? What are
the ranges of frequencies that "HIGH" & "LOW" refer to?
Would one of the reasons to downsample instead of
changing the clock rate be that the Virtex5 (which is what I'm using)
works better at 200MHz? What is the Virtex5's optimal clock rate?
Answers to any of these questions would be greatly appreciated.
-- Louis Dartez
(956) 372-5812
Arecibo Remote Command Center Researcher
Center for Advanced Radio Astronomy
Department of Physics and Astronomy
University of Texas at Brownsville
On 01/24/2012 10:56 AM, G Jones wrote:
Louis and others,
Note that Marco's script modifies the DCM/MMCM configuration that I
was referring to, so running his script should solve the problem. You
can look at the source to see how it works. It just modifies the word
HIGH in adc_interface.vhd to LOW.
Glenn
On Tue, Jan 24, 2012 at 7:30 AM, Louis Dartez <[email protected]
<mailto:[email protected]>> wrote:
Hello Glenn, Marco,
Thank you for your quick replies. I'll be stopping by the
lab this afternoon to give your suggestions and try.
Glenn: I'll look around for the DCM/MMCM configurations and
I'll let you know where I find them if I do.
Marco: thank you for the m file. I haven't looked at it just
yet but I'll give it a try when I get to the lab.
I appreciate your help.
--Louis P. Dartez
On Jan 24, 2012 8:53 AM, "Marco Bartolini"
<[email protected] <mailto:[email protected]>>
wrote:
Hi Louis,
I had your same problem some time ago. I had written a matlab
function "lower_freq.m" that you can find attached, the code
should be self explanatory ... and i don't remember the details
basically you should compile your design with bee_xps up to
"Copy base package", invoke lower_freq on the target
directory, and terminate the bof file generation with bee_xps.
hope it helps
Marco
Il giorno 23/gen/2012, alle ore 23.57, G Jones ha scritto:
Hi Louis,
The problem is probably that the DCM/MMCM has various
configuration parameters which have default values for the
clock speeds most commonly used for CASPER designs. To run at
lower speeds, you'll need to tweak these values. I thought
they can be found in the XPS_ROACH_base/data/system.ucf file
that is generated for your design, but I'm not seeing it
there right now. Perhaps someone else can guide you to the
location of the parameters if you don't find them first.
Glenn
On Mon, Jan 23, 2012 at 2:46 PM, Louis Dartez
<[email protected] <mailto:[email protected]>> wrote:
Hello fellow CASPERites,
I've been trying to modify the wideband
spectrometer tutorial to have the MSSGE block clock rate
set to 50 MHz and, following the 4 to 1 rule, the ADC
running at 200 MHz. Simulink complains about timing
errors when I try to do this. Is there another parameter
that I'm forgetting about and need to change? Or is there
some lower limit for the ROACH clock rate? I figured that
as long as the adc is clocked at 4x the roach rate then I
should be able to lower both of them as long as I keep
them at the same ratio.
Any thoughts?
--
-- Louis Dartez
(956) 372-5812 <tel:%28956%29%20372-5812>
Arecibo Remote Command Center Scholar
Center for Advanced Radio Astronomy
University of Texas at Brownsville
--
Dr. Marco Bartolini
I.N.A.F. - I.R.A.
National Institute for AstroPhysics - Institute of RadioAstronomy
Medicina Radiotelescopes
Via Fiorentina, 3508/B 40059 - Medicina (BO) - Italy
Phone: +39 051 696 5834 <tel:%2B39%20051%20696%205834> Email:
[email protected] <mailto:[email protected]>
Fax: +39 051 696 5810 <tel:%2B39%20051%20696%205810>
Web: http://www.med.ira.inaf.it
