Yes, actually that makes sense... they would if they're identical. Ok,
then can't you introduce some artificial delays in there somewhere?
Adding registers between stages would allow for buffering.
On 06 Nov 2008, at 18:07, John Ford wrote:
Create more coefficient generators and sprinkle them around inside
the
PFB?
Sorry, I don't have Simulink with me, so can't offer more concrete
advice. But if the problem is with the fanout, why not create
seperate
sources with smaller fanouts?
There are separate coefficient generators for every path in the
library
block, but they seem to get optimized out during the build. That's
the
trick, I guess, that I don't know how to get around...
Thanks
John
Jason
On 06 Nov 2008, at 15:46, John Ford wrote:
Does anyone have any suggestions for fixing this error? It seems
due
entirely to the large fanout (450!) in the coefficient generator.
We're stuck on this for building our 4K channel 800 MHz pulsar
machine.
It is introducing errors into the spectrum.
John
Hi all. Here's a timing error that appears when building a large
(2^^3
parallel paths, 2^^13 points, 4 taps 7 bit coefficients, 7 bit
input, 14
bit output) PFB. The timing wizard's suggestions are below. Note
that
the coeff. generator counter seems to be used for all coeff
generator
counters in the entire PFB's complement of coeff generators.
How can I tell the toolset not to optimize out all the other
counters, or
alternatively, how can I introduce a delay to fix this problem?
I've
attached the twx file, but from the timing wizard:
This path has a net
"b2_gdsp_u1_8k_800_a_nb_xsg_core_config/
b2_gdsp_u1_8k_800_a_nb_xsg_core_config/
top/pfb_fir_real_4k_ch/pol1_in1_first_tap/pfb_coeff_gen/
counter_q(4)"
with a high fanout of 450.
High fanout suggestions.
-Duplicate the net source and direct the synthesis tools not to
remove
duplicate logic.
-Use a specific net fanout control on the problem net if allowed by
the
synthesis tool.
Click Next button if this suggestion does not help.
Thanks for any help!
John
