Synthesis Constraints

The rule is: If your design meet constraints, it is good. Usually the need arises to improve the synthesis results, when the design fails to meet constraints. Then you will need to review may be the synthesis scripts/constraings, RTL or may be the architecture. kr, Avi

Among the optimization constraints, i seen the are "max_area" constraint always setting to 0, what it really mean During synthesis, we used the max_area 0 constraint to minimize the area of each module without violating the timing constraints. Usually, we try to get the smallest/optimize area as possible. Frankly, I've never

Hi Let?s say there enough routing resources available, timing is fine, can you increase clock buffers in clock network? If so will there be any impact on other parameters? How do you optimize skew/insertion delays in CTS? What are differences in clock constraints from pre CTS (Clock Tree synthesis) to post CTS (Clock Tree (...)

Hi In design compiler I found after synthesisi the timing is met but the DRC s (max_transition, max_capacitance) are being violated for some of the nets. Why are there DRC violation. Regards.

Hi all; I need to get the paper named: "ILP-based scheduling with time and resource constraints in highlevel synthesis" 1- How can I get it ? 2- Please, if somone knows how to formulate the cost function of Time Cosnstrained Scheduling TCS using BLP(Binary Integer Programming) that would be more helpful thx in advance

when including the IO PAD module ,the delay for some pad (e.g. reset_pad)is too large in critical setup timing path .Therefore,the violation is too large.can anyone help me? Thanks!

Hi all, Do we have to do 'Clock tree synthesis' separately? or will it be done during the time of RTL synthesis.

DC is used for synthesis and its only for setup. so, if your DC constraints are only for setup; then you will have to define both setup and hold constraints for back-end. if input to DC is full constraints, then SDC from DC will do the job. back-end needs both setup and hold constraints, no matter whether (...)

1. Questions regarding the Synopsys Setup file synthesis. Why link lib and target lib is required and order of search path . 2. clock constraints like uncertainty, clock jitter, skew and etc. 3. explain about timing path. 4. how to specify IO delays. 5. Max dealy significance. 6. Optimization techniques. Best of luck.. Regards,

hi all; in my design I generate local clock using DCM and provide a clock on output of the virtexII. when i try to create timing constraints after synthesis using constraints editor, I don't get the clock signals there. but some other signal which are not clock they are listed as clock. I checked these signals are detected for the (...)

Hi Kalyan, Before you do Post synthesis Simulation you should decide why you need to do that. Post synthesis simulation will not give actual results as you expect on your Actual Hardware Board. So you should do Post Place-Route Simulation. You can do that only if you know I/O constraints, Board constraints (...)

Hi, I think synthesis tool will ignore the delays in RTL..Depends upon ur timing constraints the synthesis tool will pick up appropriate gates from library which accounts for delays. Thanks sri

If you have a post-synthesis SDF you can load the design netlist and SDF in Primetime, give appropriate constraints for Clock,IO and exceptions, Set operating conditions and then you can use report_timing to get the timing information

My design was perfectly working in virtex2 without any error .when I migrate from virtex2 to virtex4 with same RTL I am getting lot of timing violation. Violation especially OFFSET OUT AFTER constraints are not meeting.From my understanding the routing delay in virtex4 is twice that of virtex2. I use DCFPGA for synthesis and Xilinx 9.2

The constraining design comes under synthesis process. The constraints mentioned by you, have their own advantages over each other. Its all depend on you project requirment, which constraint you should put. Go through the constraint manual of your respective tool, so that you will get better idea.

hi Shiv_emf, Regarding the document for Clock tree synthesis constraints : layout Requirement specification, request you to visit this link. This article explains the complete hand-off which needs to be given to the layout designer who performs, the clock tree synthesis. Praise th

Normally you apply timing constraints that specify your required clock frequency, setup times, maximum skew, etc. The synthesis and place-n-route tools will try to achieve those constraints. If the tools were successful (no unhappy timing messages), and if your constraints were thorough, then your design should work (...)

It is actually not related to Verilog HDL language. It is a constraint attribute for logic synthesis especially Xilinx FPGA XST synthesis. You can search the style of entering the constraints from attached doc.

If your synthesis tool didn't put a buffer... either you don't need it or your constraints are wrong. Anyway, you can write a simple script that inserts a buffer in particular net if you want to.

Suppose I have a number processors connected to a shared bus interconnect, as well as a number of slave devices. In a real design, how is something like that clocked/timed/constrained. I can't imagine that they all use the same clock domain. Can anyone provide some insight, what would an actual synthesis script look like?