Answers Database
Timing / Flow Engine M1: Using a user-modified PCF file
Record #2315
Product Family: Software
Product Line: M1 Graphical/General
Product Part: Flow Engine
Product Version: 1.5is2
Problem Title:
Timing / Flow Engine M1: Using a user-modified PCF file
Problem Description:
Urgency: Standard
General Description:
PCF files are always regenerated during the Map stage when implementing a
design under Flow Engine. This means that you cannot modify your PCF
file, then create a new revision in Design Manager so that it uses the
new PCF file. Flow Engine also does not offer the ability from the GUI
to specify a user-modified PCF; it always uses the default filename.
Solution 1:
There are two sections to the PCF file, a section for those physical constraints
created by the mapper and a section for physical constraints entered by the
user. Mapper-generated physical constraints appear first in the file, followed
by user physical constraints. The PCF file is layed out as follows:
SCHEMATIC START
...mapper generated physical constraints placed here...
SCHEMATIC END
...user generated physical constraints placed here.....
The mapper generated physical constraints are overwritten every time
the design is remapped. The user constraints section is left intact, but
certain constraints may be invalid because of the new mapping.
Additionally, the user modified PCF file will only be valid on the same
implementation version/revision. If a new version is created, then the
user constraints section of the PCF file will not be maintained. In order
to keep the user constraints section of the PCF file, the user will want
to copy the PCF file from the original location to the new desired
version/revision directory. See Solution 1 for details on this flow.
Solution 2:
The PCF file must be modified (or substituted) after the Map stage but
before the Place&Route stage.
1. In Flow Engine, select Options->Stop After. Set Map as the stop-after
point, and click OK.
2. Run the implementation flow as usual. Implementation will stop after
Map is completed.
3. Modify the PCF file as required. The PCF file is located at:
<work_dir>/<version>/<rev>/<design>.pcf
underneath the design directory. For example:
xproj/ver1/rev1/calc.pcf
4. Run the implementation again to complete the design flow.
End of Record #2315 - Last Modified: 08/12/99 16:12 |
