Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Impact of .sdc-Constrainsfile to Fitter

I have a basic understanding problem of meaning of .sdc-Constainsfile for Quartus Project.

First I understand is, that I can define Timing-Constrains in .sdc-File, that I can check with Timequest if met.

Second what I not now, is how Fitter of Quartus reads statements of .sdc-File as requirement and take more effort to reach this requirement?

Knows anyone how .sdc-File effects Fitter Effort?

Kind regards

Gerhard

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Hi,

    What I know about that is that Fitter uses the informatio provided by sdc file to guide it to place and route the entities in a way to attend the time constraints.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Quartus uses the .SDC file. It will generate a warning if you do not include one.

    In the Quartus GUI, look at the setting: Assignments->Settings, Category: Fitter Settings.

    There is a section called "Timing-driven compilation".

    You can check the "Optimize multi-corner timing" to tell Quartus to use the .SDC file at all process-voltage-temperature (PVT) settings, otherwise it just meets timing at the nominal speed grade setting.

    Cheers,

    Dave