Ha, I just read my email in the thread you linked. I guess turning off behavioural hdl isn't (ever? always?) the solution.
On Mon, 25 Jan 2016 5:14 pm Jack Hickish <jackhick...@gmail.com> wrote: > Hi Matt, > > You can resynthesize the "main" simulink netlist, but off the top of my > head I don't know the exact way to go about this. I think you can dig out > the netlist from the sysgen build directory and use the resynth script on > that. Perhaps Dave MacMahon (who I believe wrote that script) could comment > further. > My experience was that adding the lc_off flag helped sometimes, but I > still found luts combined on some occasions - I never got satisfactorily to > the bottom of this. > You can explicitly prevent combining of some blocks (eg. delays) by > turning off any behavioural hdl options they have, but this isn't viable if > it needs doing to so many blocks that resource utilisation ends up being > too horrifically impacted. > > Having just seen the skarab/roach3 presentation in South Africa, I fondly > await the demise of virtex 6 and ISE. > > Jack > > On Sat, 23 Jan 2016 10:48 pm Matt Strader <mstra...@physics.ucsb.edu> > wrote: > >> Hello Casperites (especially Jack), >> >> I've run into the problem that Jack describes in this thread: >> http://www.mail-archive.com/casper%40lists.berkeley.edu/msg05581.html >> The compiler keeps wanting to combine unrelated LUTs on opposite sides of >> the Virtex 6, resulting in timing errors that are 90% routing. >> >> At the end of the thread Jack says the solution is to use the "-lc off" >> option in resynth_netlist and in map. >> I'm using only one black box containing my pfb and fft. The rest of my >> design is not black boxed. I used resynth_netlist on the black box's ngc >> file, but it looks like I can't use it on the netlists generated by >> casper_xps. Is that right? >> I also added "-lc off" to the map options in >> XPS_ROACH2_base/etc/fast_runtime.opt >> >> After doing this, I'm still getting timing errors from LUT combining. Is >> there somewhere else I need to turn this off? Any suggestions? >> >> Thanks, >> Matt Strader >> >> >> >> >>
