Achronix ACE Version 5.0 - Manual (Page 283)

Pre-Placing a Design Chapter 4. Tasks
Removing Placement
To un-place objects with key-strokes:
1. In the Floorplanner view or Package view, press and hold the ’r’ key on the keyboard to start a selection
rectangle at the current mouse position to remove placement of objects.
2. Drag the mouse while holding down the key to create a selection rectangle including the objects to be
un-place. Release the key to un-place the objects.
To un-place objects with the Selection Tool:
1. Select the Selection Tool ( ) from the view toolbar.
2. In the Selection ( ) section of the fly-out palette, set the Action control to Remove Placement.
3. Click and drag with the left mouse button in the view to create a selection rectangle. Release the mouse
button to un-place the objects within the rectangle.
Saving Pre-Placement Constraints
To save the current placement to disk as pre-placement constraints in .pdc files:
1. Place objects in the design as described in Placing an Object .
2. In the Floorplanner view or Package view, click on the Save Pre-placement Constraints toolbar button
( ) to bring up the Save Placement dialog.
3. Configure the dialog with appropriate options and click Finish.
After clicking Finish, the pre-placement files are saved to disk. If the option was selected to automatically
add the files to the current project, then the Projects view shows the new files under the active project’s
Constraints folder.
Using Pre-Placement in the Flow
To use pre-placement in the flow, it is recommended to first create the pre-placement constraints:
1. Run the Run Prepare flow step on the active implementation
2. Switch to the Floorplanner perspective and place all the objects for pre-placement (using fixed
placement). See Placing an Object for details.
3. Then, save the pre-placement and automatically add it to the project (see Saving Pre-Placement
Constraints ).
4. Optionally, a pin assignment report can be generated for the current placement with the report pins
Tcl command.
5. Resume running the flow. The pre-placement data is used in the place and route solution.
Then, it is recommended to include the pre-placement constraints in the project for future runs:
1. The next time the flow is run with this implementation, ensure that in the Options view , the new
pre-placement constraints files are enabled.
2. Then, simply run the Run Prepare flow step. The pre-placement constraints are automatically applied.
A pin assignment report is also automatically generated during Run Prepare.
3. Optionally, to see that the objects are pre-placed, switch to the Floorplanner perspective to view the
placement.
271 http://www.achronix.com UG001 Rev. 5.0 - 5th December 2012