Honored ContributorAllo,
I have a problem with Carry or Carry_sum with my Design. I use Stratix III and I would juste use the carry for delay line (for A TDC Time to digital convert). Even if I set ON or OFF the 'Auto Carry Chains logic option' or 'ignore carry' in More Setting (Analysis & synthesis settings) menu, the compiler ignore this carry buffers. See my design bellow. Is there someone who has experience with this? Thank you, Jean
Honored ContributorAt first look, I read that Altera wants you to use the carry_sum going forward, not carry. You go the auto_carry_chains = ON, and you also already have ignore_carry_buffers = OFF. Did you read the rules of use in the QuartusII help for the carry primitive? I don't use them, so the convoluted phasology didn't jump out as something you did wrong there either - but please read that yourself to get more out of it.
The wikipedia page on TDC talks about a counter for the stage after a discriminator. Would a more traditional counter work for this stage of your design?Honored ContributorYour intended structure seems basically to fit the Stratix III ALM structure in arithmetic mode. It's questionable however, if Quartus is able to compile the respective logic from your design example - or any similar construct. It may be simply unable to do it, because the intended function is too far from the ALM's expected purpose.
Did you try with the stratixiii_lcell_comb low-level primitive, as suggested in the "Stratix Cookbook" (advanced synthesis cookbook) and the related design examples? Furthermore, considering the problem of irregular routing delays with larger logic cell delay chain designs. I guess, it's more promising, to use a group of SERDES blocks with phase shifted clocks to design a TDC.Honored ContributorThank you Randall but,
I have already tried all that and the compiler ignored forever. I think I'll have to use the Stratix primitives. See WaveletTDC[1] in google Search. It's really interesting. JeanHonored ContributorThank you FvM,
I will try it. JeanHonored ContributorFvM,
How to use this primitive stratixiii_lcell_comb ? Is there a library?Honored ContributorThere are example files (for Stratix II) supplementing the said Advanced Synthesis Cookbook. Search altera.com for the title.
