Visible to Intel only — GUID: ldr1656552352624
Ixiasoft
Visible to Intel only — GUID: ldr1656552352624
Ixiasoft
2.6.3.6. Types of SDC Files Used in the Intel® Quartus® Prime Software
The Intel® Quartus® Prime software uses conventional SDC files to target the timing netlist. These SDCs are not applied until the Fitter plan stage completes. However, for Post-Synthesis Static Timing Analysis (STA), you can introduce SDC files to the Intel® Quartus® Prime software in one of the following ways:
- SDC-on-RTL
- Synthesis SDC
The following table attempts to summarize the differences between the various SDC file types:
SDC-on-RTL | Synthesis SDC | SDC (Conventional) | |
---|---|---|---|
Stage where constraints are read | Analysis & Elaboration | Synthesis | Fitter, Signoff |
Stage where constraints are processed |
Synthesis through Fitter | Synthesis only |
Fitter, Signoff |
QSF assignment |
RTL_SDC_FILE (supports entities) | SDC_FILE SDC_ENTITY_FILE -read_during_post_syn_and_post_fit_timing_analysis SDC_FILE SDC_ENTITY_FILE -read_during_post_syn_and_not_post_fit_timing_analysis |
SDC_FILE |
Syntax supported |
Tcl with SDC 2.1 commands | Tcl with Intel® Quartus® Prime SDC commands |
Tcl with Intel® Quartus® Prime SDC commands |
SDC 2.1-compliant |
Yes | No | No |
Target type |
RTL | Intel® Quartus® Prime timing graph |
Intel® Quartus® Prime timing graph |
Hierarchical targets |
Yes | No | No |
Buried timing nodes (used by IP) |
No |
Core fabric only.
Note: Such nodes do not exist for the periphery in post-synthesis STA.
|
Yes |
STA command to load constraints |
Executes the read_sdc or import_sdc command in any snapshot. |
Executes the read_sdc command only during static timing analysis on the synthesized snapshot. |
Executes the read_sdc command during static timing analysis on any fitter snapshot (plan, place, route, retime).
Note: Not loaded during synthesis.
|
As shown in the table, the assignments allow different SDCs to be used during post-synthesis STA and post-fit STA. It is also possible for an SDC to check the current snapshot through is_post_syn_sta to determine the appropriate commands to use, as shown in the following example:
if {[is_post_syn_sta]} { puts "In post syn sta!" }