All,
First, the good news...
Our 800MHz, 2K-channel version of GUPPi is now running reliably and has
already been
used successfully during several trial observations; yielding excellent
results!
But now, the bad news...
While attempting to implement an 800MHz, 4K-channel version of our GUPPi
instrument,
we've been experiencing lots of timing errors (150+) and horrible timing
scores (100,000+).
Even though these attempts "appear" to build successfully, they, of
course, don't run reliably.
Our basic architecture is comprised of two DSP engines running in USER1
and USER3 which
feed their respective spectral data streams via the IOBs to USER2; where
we calculate Stokes
Parameters, perform scaling and offsets, do Vacc, and packetize and
transmit 10Ge to our big
backend computer.
As a sanity check, we decided to try a 400MHz, 4K-channel version, which
consistently yields
successful builds with NO timing errors and timing scores of 0; feeling
confident that this version
would work right out of the box. No such luck...
Even though the two DSP engines are identical EXCEPT for the directions
of the IOBs used to
carry the spectral data streams to USER2, we've encountered a really
weird problem...
When we load the .bof files for USER1, USER2, and USER3 into the bee2,
all seems well
until we attempt to interact with USER1 via its Tiny Shell; at which
point it hangs up, while
the other two continue to work properly; allowing us to interact through
their Tiny Shells to
read and write software registers, etc.
We've tried interchanging the DSP Engines by swapping the appropriate
.bof files into their
respective FPGAs; but end up with the exact same result... The design
which was originally
intended to run in USER1 won't run in USER3; while the design which was
originally intended
to run in USER3 works just fine in USER1.
As a last ditch effort, we deleted the model file intended for USER1,
cloned the model for
USER3 and re-named it for use in USER1 (changing the IOB directions),
built this version,
and experienced the exact same behavior... i.e., the Tiny Shell in
USER1 simply hangs up
while the other two work just fine.
Remember that these 400MHz versions which exhibit such weird behavior,
built with NO
timing errors!
And, as a final sanity check, we went back and built known working
versions which, of
course, still work perfectly; verifying that our development environment
is still in good
shape...
Any suggestions?
Randy
