[Dspforum] More troubles with lab 6

[Wenstrand, Doug S.]

Yes, there are some things that we need to do to setup SDRAM, and they
are in the GEL file, so check to make sure that you are using the gel
file for the c6713dsk.  CCS sets these registers when you connect the
emulator, that why we don't in our software.

The reason I don't see that being an issue is that I thought we saw
beautiful data that you had extracted from SDRAM and put into L2.  Are
you sure that you are waiting for the DMA transfers to happen correctly?
If you can step through all cases, and see the right FFT show up in the
right place in external memory, and only when free-running it goes bad,
I suspect that the waiting process might not be correct.  

Two things :

1) see how long you actually wait in waitfordma.  If it seems too fast,
something is wrong.
2) send me the project at the website... Lab6_merton_test.zip or
something like that. I'll take a look as well

Seeya
Doug





---------------------------------------
D. S. Wenstrand
Johns Hopkins University
Applied Physics Laboratory
(240) 228-4282


-----Original Message-----
From: dspforum-bounces at echelonembedded.com
[mailto:dspforum-bounces at echelonembedded.com] On Behalf Of Ryan Merton
Sent: Thursday, October 16, 2008 3:01 PM
To: dspforum at echelonembedded.com
Subject: [Dspforum] More troubles with lab 6

Doug,

Remember how we figured out that my problem last night was related to
the bit reversal indexing?  It wasn't.  I went home, and I did in fact
call the routine with the correct parameters to begin with.
Breakpointing around the FFT and saving data along the way leads me to
see no problem at all.  Only after I remove the breakpoints and let it
go freerunning do things start to mess up.

Is there some magic we have to configure to get the SDRAM timings right,
or DMA configuration registers aside from the QDMA registers?

I breakpointed after bringing the time domain data in from ext ram,
after the FFT and bit reversal, and after the FFT data is stored off to
RAM.  At each of those steps for the first 7 FFTs I saved the contents
of external RAM.  It all looks fine.  I got tired of it, removed the
breakpoints, and let it run, then dumped it all at the end... and
starting at about the 13th FFT the FFT data is not right.
The time domain data remains intact.  If I do the first 3 FFTs and let
it go free running, it messes up around the 6th or 7th FFT.

Any ideas?  I am using this to wait for the DMA to finish:  while
(!(EDMA_getPriQStatus() & EDMA_OPT_PRI_HIGH)); I stole that line right
from the CSL user's guide.  I am tempted to put something like
for(x=0;x<10000000;x++){blah=sin(x);} and see if it works then.

Thanks,
Ryan

_______________________________________________
Dspforum mailing list
Dspforum at echelonembedded.com
http://echelonembedded.com/mailman/listinfo/dspforum_echelonembedded.com