There are severalXFLOW options that you can use when implementing a design in the System Generator tool. These options are discussed in the System GeneratorUser Guide (UG 640), in the "XFLOW Option Files" section. For example, you can use these option files to add or change switches and their values. You can use the default option files as a template for your design environment, including specifying a user constraints file (.ucf) that includes timing, grouping, and pin constraints. It is recommended that you make a copy of the default options file and specify the new customized file that you want to use.
The next procedure outlines this process.
1. Open the SystemGenerator block.
2. Select Compilation as Bitstream.
3. Click the Settings buttonnext to the Compilation field.
4. In the Compilation Target Settings, click XFLOW Options files.
5. Click the open file Icon next to the Implementation Phase field. This opens in the location where the default options files for your installation are located. For a default Windows installation, the location is C:\Xilinx\13.2\ISE_DS\ISE\sysgen\plugins\compliation\Bitstream.
6. The balanced.opt file contains the default implementation options. Make a copy of this file and place it in the same directory to make it easy to find from the settings dialog; for the remainder of this discussion, assume this file is named "K7_balanced.opt".
7. Open "K7_balanced.opt" and find the ngdbuild options towards the top of the file. Before the line "End Program ngdbuild," put the ngdbuild switch that specifies the UCF file:
-uc [path-to-design]\[ucf file]
-p [partname]; # Partname to use - picked from xflow commandline
-nt timestamp; # NGO File generation. Regenerate only when
# source netlist is newer than existing
#NGO file (default)
-instyle xflow; # Message Reporting Style: ise, xflow, or silent
#-insert_keep_hierarchy; # Retain hierarchy identified by individual source input netlists
[userdesign]; #User design - pick from xflow command line
[design].ngd; #Name of NGD file. Filebase same as design filebase
End Program ngdbuild
8.When specifying XFLOW options files in the Compilation Target Settings dialog, specify the modified file.You must also specify the BitGenoptions file, so select the default "bitgen.opt" file.