"negative" required longest p2p time

[Altera_Forum]

Hello, everybody. 

I've a small problem with Quartus II message report.  First of all, when I compile my project, time requirements are not met. I read the report and I found a lot of errors related to "Setup Time".  I think there's a problem with required longest p2p time, because it has a negative value. Obviously, "actual longest p2p time" can't be a negative number and so all goes wrong.  Could someone help me about this? If you need more information, please ask and i'll give you. At the moment I don't know what is useful or not.:p  Thanks in advance, Alessio.

[Altera_Forum]

--- Quote Start ---  Hello, everybody. I've a small problem with Quartus II message report.  First of all, when I compile my project, time requirements are not met. I read the report and I found a lot of errors related to "Setup Time".  I think there's a problem with required longest p2p time, because it has a negative value. Obviously, "actual longest p2p time" can't be a negative number and so all goes wrong.  Could someone help me about this? If you need more information, please ask and i'll give you. At the moment I don't know what is useful or not.:p  Thanks in advance, Alessio.  --- Quote End ---    Hi Alessio,  which timing analyzer did you use ? Classic Timing Analyzer ?  I assume you have specified at least your required clock speed and the report shows you that your design is too slow ???  Kind regards  GPK

[Altera_Forum]

--- Quote Start ---  Hi Alessio,  which timing analyzer did you use ? Classic Timing Analyzer ?  I assume you have specified at least your required clock speed and the report shows you that your design is too slow ???  Kind regards  GPK  --- Quote End ---    Hi pletz, thank you for the answer.  I specified "default required fmax" to 96 MHz (the frequency I need) and nothing more.  A colleague suggest me to ignore these messages, at the moment, because it may be I don't specify all the requirements that Quartus needs.  I think it is possible so...I'll try to set all the parameters I can.  Thank you again.  Regards, Alessio.

[Altera_Forum]

--- Quote Start ---  Hi pletz, thank you for the answer.  I specified "default required fmax" to 96 MHz (the frequency I need) and nothing more.  A colleague suggest me to ignore these messages, at the moment, because it may be I don't specify all the requirements that Quartus needs.  I think it is possible so...I'll try to set all the parameters I can.  Thank you again.  Regards, Alessio.  --- Quote End ---    Hi Alessio,  don't forget to set at least:  Settings -> Analyse & Synthesis Settings -> Optimization Technique -> Speed Settings -> Fitter Settings -> Fitter Effort -> Standard Fit

[Altera_Forum]

--- Quote Start ---  Hi Alessio,  don't forget to set at least:  Settings -> Analyse & Synthesis Settings -> Optimization Technique -> Speed Settings -> Fitter Settings -> Fitter Effort -> Standard Fit  --- Quote End ---    Ok,  I do it now.  Thank you, again. :)

[Altera_Forum]

Hi, everybody. 

Finally I found my problem. At the end of compilation I read:  warning: found 1 node(s) in clock paths which may be acting as ripple and/or gated clocks -- node(s) analyzed as buffer(s) resulting in clock skew  info: detected ripple clock "generatore_clock:inst|divisore_clock:inst4|clk_out" as buffer  Quartus Help suggested me to set constraints for the suspect clock. Once I did it, all went right.  Thank you all for your support. See you.  Bye bye,;) Alessio.  ********************Thread Closed********************